esp-hal 0.16.1

//! # Serial Peripheral Interface - Master Mode
//!
//! ## Overview
//!
//! There are multiple ways to use SPI, depending on your needs. Regardless of
//! which way you choose, you must first create an SPI instance with
//! [`Spi::new`].
//!
//! ## Example
//! ```rust
//! let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);
//! let sclk = io.pins.gpio12;
//! let miso = io.pins.gpio11;
//! let mosi = io.pins.gpio13;
//! let cs = io.pins.gpio10;
//!
//! let mut spi = hal::spi::Spi::new(
//!     peripherals.SPI2,
//!     100u32.kHz(),
//!     SpiMode::Mode0,
//!     &mut peripheral_clock_control,
//!     &mut clocks,
//! )
//! .with_pins(Some(sclk), Some(mosi), Some(miso), Some(cs));
//! ```
//!
//! ## Exclusive access to the SPI bus
//!
//! If all you want to do is to communicate to a single device, and you initiate
//! transactions yourself, there are a number of ways to achieve this:
//!
//! - Use the [`FullDuplex`](embedded_hal::spi::FullDuplex) trait to read/write
//!   single bytes at a time,
//! - Use the [`SpiBus`](embedded_hal_1::spi::SpiBus) trait (requires the "eh1"
//!   feature) and its associated functions to initiate transactions with
//!   simultaneous reads and writes, or
//! - Use the `ExclusiveDevice` struct from [`embedded-hal-bus`] or `SpiDevice`
//!   from [`embassy-embedded-hal`].
//!
//!
//! ## Shared SPI access
//!
//! If you have multiple devices on the same SPI bus that each have their own CS
//! line, you may want to have a look at the implementations provided by
//! [`embedded-hal-bus`] and [`embassy-embedded-hal`].
//!
//! [`embedded-hal-bus`]: https://docs.rs/embedded-hal-bus/latest/embedded_hal_bus/spi/index.html
//! [`embassy-embedded-hal`]: https://docs.embassy.dev/embassy-embedded-hal/git/default/shared_bus/index.html

use core::marker::PhantomData;

use fugit::HertzU32;
#[cfg(feature = "place-spi-driver-in-ram")]
use procmacros::ram;

use super::{
    DuplexMode,
    Error,
    FullDuplexMode,
    HalfDuplexMode,
    IsFullDuplex,
    IsHalfDuplex,
    SpiDataMode,
    SpiMode,
};
use crate::{
    clock::Clocks,
    dma::{DmaPeripheral, Rx, Tx},
    gpio::{InputPin, InputSignal, OutputPin, OutputSignal},
    peripheral::{Peripheral, PeripheralRef},
    peripherals::spi2::RegisterBlock,
    system::PeripheralClockControl,
};

/// Prelude for the SPI (Master) driver
pub mod prelude {
    #[cfg(spi3)]
    pub use super::dma::WithDmaSpi3 as _esp_hal_spi_master_dma_WithDmaSpi3;
    pub use super::{
        dma::WithDmaSpi2 as _esp_hal_spi_master_dma_WithDmaSpi2,
        Instance as _esp_hal_spi_master_Instance,
        InstanceDma as _esp_hal_spi_master_InstanceDma,
    };
}

/// The size of the FIFO buffer for SPI
#[cfg(not(esp32s2))]
const FIFO_SIZE: usize = 64;
#[cfg(esp32s2)]
const FIFO_SIZE: usize = 72;

/// Padding byte for empty write transfers
const EMPTY_WRITE_PAD: u8 = 0x00u8;

#[allow(unused)]
const MAX_DMA_SIZE: usize = 32736;

/// SPI command, 1 to 16 bits.
///
/// Can be [Command::None] if command phase should be suppressed.
pub enum Command {
    None,
    Command1(u16, SpiDataMode),
    Command2(u16, SpiDataMode),
    Command3(u16, SpiDataMode),
    Command4(u16, SpiDataMode),
    Command5(u16, SpiDataMode),
    Command6(u16, SpiDataMode),
    Command7(u16, SpiDataMode),
    Command8(u16, SpiDataMode),
    Command9(u16, SpiDataMode),
    Command10(u16, SpiDataMode),
    Command11(u16, SpiDataMode),
    Command12(u16, SpiDataMode),
    Command13(u16, SpiDataMode),
    Command14(u16, SpiDataMode),
    Command15(u16, SpiDataMode),
    Command16(u16, SpiDataMode),
}

impl Command {
    fn width(&self) -> usize {
        match self {
            Command::None => 0,
            Command::Command1(_, _) => 1,
            Command::Command2(_, _) => 2,
            Command::Command3(_, _) => 3,
            Command::Command4(_, _) => 4,
            Command::Command5(_, _) => 5,
            Command::Command6(_, _) => 6,
            Command::Command7(_, _) => 7,
            Command::Command8(_, _) => 8,
            Command::Command9(_, _) => 9,
            Command::Command10(_, _) => 10,
            Command::Command11(_, _) => 11,
            Command::Command12(_, _) => 12,
            Command::Command13(_, _) => 13,
            Command::Command14(_, _) => 14,
            Command::Command15(_, _) => 15,
            Command::Command16(_, _) => 16,
        }
    }

    fn value(&self) -> u16 {
        match self {
            Command::None => 0,
            Command::Command1(value, _)
            | Command::Command2(value, _)
            | Command::Command3(value, _)
            | Command::Command4(value, _)
            | Command::Command5(value, _)
            | Command::Command6(value, _)
            | Command::Command7(value, _)
            | Command::Command8(value, _)
            | Command::Command9(value, _)
            | Command::Command10(value, _)
            | Command::Command11(value, _)
            | Command::Command12(value, _)
            | Command::Command13(value, _)
            | Command::Command14(value, _)
            | Command::Command15(value, _)
            | Command::Command16(value, _) => *value,
        }
    }

    fn mode(&self) -> SpiDataMode {
        match self {
            Command::None => SpiDataMode::Single,
            Command::Command1(_, mode)
            | Command::Command2(_, mode)
            | Command::Command3(_, mode)
            | Command::Command4(_, mode)
            | Command::Command5(_, mode)
            | Command::Command6(_, mode)
            | Command::Command7(_, mode)
            | Command::Command8(_, mode)
            | Command::Command9(_, mode)
            | Command::Command10(_, mode)
            | Command::Command11(_, mode)
            | Command::Command12(_, mode)
            | Command::Command13(_, mode)
            | Command::Command14(_, mode)
            | Command::Command15(_, mode)
            | Command::Command16(_, mode) => *mode,
        }
    }

    fn is_none(&self) -> bool {
        matches!(self, Command::None)
    }
}

/// SPI address, 1 to 32 bits.
///
/// Can be [Address::None] if address phase should be suppressed.
pub enum Address {
    None,
    Address1(u32, SpiDataMode),
    Address2(u32, SpiDataMode),
    Address3(u32, SpiDataMode),
    Address4(u32, SpiDataMode),
    Address5(u32, SpiDataMode),
    Address6(u32, SpiDataMode),
    Address7(u32, SpiDataMode),
    Address8(u32, SpiDataMode),
    Address9(u32, SpiDataMode),
    Address10(u32, SpiDataMode),
    Address11(u32, SpiDataMode),
    Address12(u32, SpiDataMode),
    Address13(u32, SpiDataMode),
    Address14(u32, SpiDataMode),
    Address15(u32, SpiDataMode),
    Address16(u32, SpiDataMode),
    Address17(u32, SpiDataMode),
    Address18(u32, SpiDataMode),
    Address19(u32, SpiDataMode),
    Address20(u32, SpiDataMode),
    Address21(u32, SpiDataMode),
    Address22(u32, SpiDataMode),
    Address23(u32, SpiDataMode),
    Address24(u32, SpiDataMode),
    Address25(u32, SpiDataMode),
    Address26(u32, SpiDataMode),
    Address27(u32, SpiDataMode),
    Address28(u32, SpiDataMode),
    Address29(u32, SpiDataMode),
    Address30(u32, SpiDataMode),
    Address31(u32, SpiDataMode),
    Address32(u32, SpiDataMode),
}

impl Address {
    fn width(&self) -> usize {
        match self {
            Address::None => 0,
            Address::Address1(_, _) => 1,
            Address::Address2(_, _) => 2,
            Address::Address3(_, _) => 3,
            Address::Address4(_, _) => 4,
            Address::Address5(_, _) => 5,
            Address::Address6(_, _) => 6,
            Address::Address7(_, _) => 7,
            Address::Address8(_, _) => 8,
            Address::Address9(_, _) => 9,
            Address::Address10(_, _) => 10,
            Address::Address11(_, _) => 11,
            Address::Address12(_, _) => 12,
            Address::Address13(_, _) => 13,
            Address::Address14(_, _) => 14,
            Address::Address15(_, _) => 15,
            Address::Address16(_, _) => 16,
            Address::Address17(_, _) => 17,
            Address::Address18(_, _) => 18,
            Address::Address19(_, _) => 19,
            Address::Address20(_, _) => 20,
            Address::Address21(_, _) => 21,
            Address::Address22(_, _) => 22,
            Address::Address23(_, _) => 23,
            Address::Address24(_, _) => 24,
            Address::Address25(_, _) => 25,
            Address::Address26(_, _) => 26,
            Address::Address27(_, _) => 27,
            Address::Address28(_, _) => 28,
            Address::Address29(_, _) => 29,
            Address::Address30(_, _) => 30,
            Address::Address31(_, _) => 31,
            Address::Address32(_, _) => 32,
        }
    }

    fn value(&self) -> u32 {
        match self {
            Address::None => 0,
            Address::Address1(value, _)
            | Address::Address2(value, _)
            | Address::Address3(value, _)
            | Address::Address4(value, _)
            | Address::Address5(value, _)
            | Address::Address6(value, _)
            | Address::Address7(value, _)
            | Address::Address8(value, _)
            | Address::Address9(value, _)
            | Address::Address10(value, _)
            | Address::Address11(value, _)
            | Address::Address12(value, _)
            | Address::Address13(value, _)
            | Address::Address14(value, _)
            | Address::Address15(value, _)
            | Address::Address16(value, _)
            | Address::Address17(value, _)
            | Address::Address18(value, _)
            | Address::Address19(value, _)
            | Address::Address20(value, _)
            | Address::Address21(value, _)
            | Address::Address22(value, _)
            | Address::Address23(value, _)
            | Address::Address24(value, _)
            | Address::Address25(value, _)
            | Address::Address26(value, _)
            | Address::Address27(value, _)
            | Address::Address28(value, _)
            | Address::Address29(value, _)
            | Address::Address30(value, _)
            | Address::Address31(value, _)
            | Address::Address32(value, _) => *value,
        }
    }

    fn is_none(&self) -> bool {
        matches!(self, Address::None)
    }

    fn mode(&self) -> SpiDataMode {
        match self {
            Address::None => SpiDataMode::Single,
            Address::Address1(_, mode)
            | Address::Address2(_, mode)
            | Address::Address3(_, mode)
            | Address::Address4(_, mode)
            | Address::Address5(_, mode)
            | Address::Address6(_, mode)
            | Address::Address7(_, mode)
            | Address::Address8(_, mode)
            | Address::Address9(_, mode)
            | Address::Address10(_, mode)
            | Address::Address11(_, mode)
            | Address::Address12(_, mode)
            | Address::Address13(_, mode)
            | Address::Address14(_, mode)
            | Address::Address15(_, mode)
            | Address::Address16(_, mode)
            | Address::Address17(_, mode)
            | Address::Address18(_, mode)
            | Address::Address19(_, mode)
            | Address::Address20(_, mode)
            | Address::Address21(_, mode)
            | Address::Address22(_, mode)
            | Address::Address23(_, mode)
            | Address::Address24(_, mode)
            | Address::Address25(_, mode)
            | Address::Address26(_, mode)
            | Address::Address27(_, mode)
            | Address::Address28(_, mode)
            | Address::Address29(_, mode)
            | Address::Address30(_, mode)
            | Address::Address31(_, mode)
            | Address::Address32(_, mode) => *mode,
        }
    }
}

/// Read and Write in half duplex mode.
pub trait HalfDuplexReadWrite {
    type Error;

    /// Half-duplex read.
    fn read(
        &mut self,
        data_mode: SpiDataMode,
        cmd: Command,
        address: Address,
        dummy: u8,
        buffer: &mut [u8],
    ) -> Result<(), Self::Error>;

    /// Half-duplex write.
    fn write(
        &mut self,
        data_mode: SpiDataMode,
        cmd: Command,
        address: Address,
        dummy: u8,
        buffer: &[u8],
    ) -> Result<(), Self::Error>;
}

/// SPI peripheral driver
pub struct Spi<'d, T, M> {
    spi: PeripheralRef<'d, T>,
    _mode: PhantomData<M>,
}

impl<'d, T> Spi<'d, T, FullDuplexMode>
where
    T: Instance,
{
    /// Constructs an SPI instance in 8bit dataframe mode.
    ///
    /// All pins are optional. Setup these pins using
    /// [with_pins](Self::with_pins) or individual methods for each pin.
    pub fn new(
        spi: impl Peripheral<P = T> + 'd,
        frequency: HertzU32,
        mode: SpiMode,
        clocks: &Clocks,
    ) -> Spi<'d, T, FullDuplexMode> {
        crate::into_ref!(spi);
        Self::new_internal(spi, frequency, mode, clocks)
    }

    pub fn with_sck<SCK: OutputPin>(self, sck: impl Peripheral<P = SCK> + 'd) -> Self {
        crate::into_ref!(sck);
        sck.set_to_push_pull_output()
            .connect_peripheral_to_output(self.spi.sclk_signal());

        self
    }

    pub fn with_mosi<MOSI: OutputPin>(self, mosi: impl Peripheral<P = MOSI> + 'd) -> Self {
        crate::into_ref!(mosi);
        mosi.set_to_push_pull_output()
            .connect_peripheral_to_output(self.spi.mosi_signal());

        self
    }

    pub fn with_miso<MISO: InputPin>(self, miso: impl Peripheral<P = MISO> + 'd) -> Self {
        crate::into_ref!(miso);
        miso.set_to_input()
            .connect_input_to_peripheral(self.spi.miso_signal());

        self
    }

    pub fn with_cs<CS: OutputPin>(self, cs: impl Peripheral<P = CS> + 'd) -> Self {
        crate::into_ref!(cs);
        cs.set_to_push_pull_output()
            .connect_peripheral_to_output(self.spi.cs_signal());

        self
    }

    /// Setup pins for this SPI instance.
    ///
    /// All pins are optional. Pass [crate::gpio::NO_PIN] if you don't need the
    /// given pin.
    pub fn with_pins<SCK: OutputPin, MOSI: OutputPin, MISO: InputPin, CS: OutputPin>(
        self,
        sck: Option<impl Peripheral<P = SCK> + 'd>,
        mosi: Option<impl Peripheral<P = MOSI> + 'd>,
        miso: Option<impl Peripheral<P = MISO> + 'd>,
        cs: Option<impl Peripheral<P = CS> + 'd>,
    ) -> Self {
        if let Some(sck) = sck {
            crate::into_ref!(sck);
            sck.set_to_push_pull_output()
                .connect_peripheral_to_output(self.spi.sclk_signal());
        }

        if let Some(mosi) = mosi {
            crate::into_ref!(mosi);
            mosi.set_to_push_pull_output()
                .connect_peripheral_to_output(self.spi.mosi_signal());
        }

        if let Some(miso) = miso {
            crate::into_ref!(miso);
            miso.set_to_input()
                .connect_input_to_peripheral(self.spi.miso_signal());
        }

        if let Some(cs) = cs {
            crate::into_ref!(cs);
            cs.set_to_push_pull_output()
                .connect_peripheral_to_output(self.spi.cs_signal());
        }

        self
    }

    pub(crate) fn new_internal(
        spi: PeripheralRef<'d, T>,
        frequency: HertzU32,
        mode: SpiMode,
        clocks: &Clocks,
    ) -> Spi<'d, T, FullDuplexMode> {
        spi.enable_peripheral();

        let mut spi = Spi {
            spi,
            _mode: PhantomData,
        };
        spi.spi.setup(frequency, clocks);
        spi.spi.init();
        spi.spi.set_data_mode(mode);

        spi
    }

    pub fn change_bus_frequency(&mut self, frequency: HertzU32, clocks: &Clocks) {
        self.spi.ch_bus_freq(frequency, clocks);
    }
}

impl<'d, T> Spi<'d, T, HalfDuplexMode>
where
    T: ExtendedInstance,
{
    /// Constructs an SPI instance in half-duplex mode.
    ///
    /// All pins are optional. Setup these pins using
    /// [with_pins](Self::with_pins) or individual methods for each pin.
    pub fn new_half_duplex(
        spi: impl Peripheral<P = T> + 'd,
        frequency: HertzU32,
        mode: SpiMode,
        clocks: &Clocks,
    ) -> Spi<'d, T, HalfDuplexMode> {
        crate::into_ref!(spi);
        Self::new_internal(spi, frequency, mode, clocks)
    }

    pub fn with_sck<SCK: OutputPin>(self, sck: impl Peripheral<P = SCK> + 'd) -> Self {
        crate::into_ref!(sck);
        sck.set_to_push_pull_output()
            .connect_peripheral_to_output(self.spi.sclk_signal());

        self
    }

    pub fn with_mosi<MOSI: OutputPin + InputPin>(
        self,
        mosi: impl Peripheral<P = MOSI> + 'd,
    ) -> Self {
        crate::into_ref!(mosi);
        mosi.enable_output(true);
        mosi.connect_peripheral_to_output(self.spi.mosi_signal());
        mosi.enable_input(true);
        mosi.connect_input_to_peripheral(self.spi.sio0_input_signal());

        self
    }

    pub fn with_miso<MISO: OutputPin + InputPin>(
        self,
        miso: impl Peripheral<P = MISO> + 'd,
    ) -> Self {
        crate::into_ref!(miso);
        miso.enable_output(true);
        miso.connect_peripheral_to_output(self.spi.sio1_output_signal());
        miso.enable_input(true);
        miso.connect_input_to_peripheral(self.spi.miso_signal());

        self
    }

    pub fn with_sio2<SIO2: OutputPin + InputPin>(
        self,
        sio2: impl Peripheral<P = SIO2> + 'd,
    ) -> Self {
        crate::into_ref!(sio2);
        sio2.enable_output(true);
        sio2.connect_peripheral_to_output(self.spi.sio2_output_signal());
        sio2.enable_input(true);
        sio2.connect_input_to_peripheral(self.spi.sio2_input_signal());

        self
    }

    pub fn with_sio3<SIO3: OutputPin + InputPin>(
        self,
        sio3: impl Peripheral<P = SIO3> + 'd,
    ) -> Self {
        crate::into_ref!(sio3);
        sio3.enable_output(true);
        sio3.connect_peripheral_to_output(self.spi.sio3_output_signal());
        sio3.enable_input(true);
        sio3.connect_input_to_peripheral(self.spi.sio3_input_signal());

        self
    }

    pub fn with_cs<CS: OutputPin>(self, cs: impl Peripheral<P = CS> + 'd) -> Self {
        crate::into_ref!(cs);
        cs.set_to_push_pull_output()
            .connect_peripheral_to_output(self.spi.cs_signal());

        self
    }

    /// Setup pins for this SPI instance.
    ///
    /// All pins are optional. Pass [crate::gpio::NO_PIN] if you don't need the
    /// given pin.
    pub fn with_pins<
        SCK: OutputPin,
        MOSI: OutputPin + InputPin,
        MISO: OutputPin + InputPin,
        SIO2: OutputPin + InputPin,
        SIO3: OutputPin + InputPin,
        CS: OutputPin,
    >(
        self,
        sck: Option<impl Peripheral<P = SCK> + 'd>,
        mosi: Option<impl Peripheral<P = MOSI> + 'd>,
        miso: Option<impl Peripheral<P = MISO> + 'd>,
        sio2: Option<impl Peripheral<P = SIO2> + 'd>,
        sio3: Option<impl Peripheral<P = SIO3> + 'd>,
        cs: Option<impl Peripheral<P = CS> + 'd>,
    ) -> Self {
        if let Some(sck) = sck {
            crate::into_ref!(sck);
            sck.set_to_push_pull_output()
                .connect_peripheral_to_output(self.spi.sclk_signal());
        }

        if let Some(mosi) = mosi {
            crate::into_ref!(mosi);
            mosi.enable_output(true);
            mosi.connect_peripheral_to_output(self.spi.mosi_signal());
            mosi.enable_input(true);
            mosi.connect_input_to_peripheral(self.spi.sio0_input_signal());
        }

        if let Some(miso) = miso {
            crate::into_ref!(miso);
            miso.enable_output(true);
            miso.connect_peripheral_to_output(self.spi.sio1_output_signal());
            miso.enable_input(true);
            miso.connect_input_to_peripheral(self.spi.miso_signal());
        }

        if let Some(sio2) = sio2 {
            crate::into_ref!(sio2);
            sio2.enable_output(true);
            sio2.connect_peripheral_to_output(self.spi.sio2_output_signal());
            sio2.enable_input(true);
            sio2.connect_input_to_peripheral(self.spi.sio2_input_signal());
        }

        if let Some(sio3) = sio3 {
            crate::into_ref!(sio3);
            sio3.enable_output(true);
            sio3.connect_peripheral_to_output(self.spi.sio3_output_signal());
            sio3.enable_input(true);
            sio3.connect_input_to_peripheral(self.spi.sio3_input_signal());
        }

        if let Some(cs) = cs {
            crate::into_ref!(cs);
            cs.set_to_push_pull_output()
                .connect_peripheral_to_output(self.spi.cs_signal());
        }

        self
    }

    pub(crate) fn new_internal(
        spi: PeripheralRef<'d, T>,
        frequency: HertzU32,
        mode: SpiMode,
        clocks: &Clocks,
    ) -> Spi<'d, T, HalfDuplexMode> {
        spi.enable_peripheral();

        let mut spi = Spi {
            spi,
            _mode: PhantomData,
        };
        spi.spi.setup(frequency, clocks);
        spi.spi.init();
        spi.spi.set_data_mode(mode);

        spi
    }

    pub fn change_bus_frequency(&mut self, frequency: HertzU32, clocks: &Clocks) {
        self.spi.ch_bus_freq(frequency, clocks);
    }
}

impl<T, M> HalfDuplexReadWrite for Spi<'_, T, M>
where
    T: Instance,
    M: IsHalfDuplex,
{
    type Error = Error;

    fn read(
        &mut self,
        data_mode: SpiDataMode,
        cmd: Command,
        address: Address,
        dummy: u8,
        buffer: &mut [u8],
    ) -> Result<(), Self::Error> {
        if buffer.len() > FIFO_SIZE {
            return Err(Error::FifoSizeExeeded);
        }

        if buffer.is_empty() {
            return Err(Error::Unsupported);
        }

        self.spi
            .init_spi_data_mode(cmd.mode(), address.mode(), data_mode);
        self.spi.read_bytes_half_duplex(cmd, address, dummy, buffer)
    }

    fn write(
        &mut self,
        data_mode: SpiDataMode,
        cmd: Command,
        address: Address,
        dummy: u8,
        buffer: &[u8],
    ) -> Result<(), Self::Error> {
        if buffer.len() > FIFO_SIZE {
            return Err(Error::FifoSizeExeeded);
        }

        self.spi
            .init_spi_data_mode(cmd.mode(), address.mode(), data_mode);
        self.spi
            .write_bytes_half_duplex(cmd, address, dummy, buffer)
    }
}

impl<T, M> embedded_hal::spi::FullDuplex<u8> for Spi<'_, T, M>
where
    T: Instance,
    M: IsFullDuplex,
{
    type Error = Error;

    fn read(&mut self) -> nb::Result<u8, Self::Error> {
        self.spi.read_byte()
    }

    fn send(&mut self, word: u8) -> nb::Result<(), Self::Error> {
        self.spi.write_byte(word)
    }
}

impl<T, M> embedded_hal::blocking::spi::Transfer<u8> for Spi<'_, T, M>
where
    T: Instance,
    M: IsFullDuplex,
{
    type Error = Error;

    fn transfer<'w>(&mut self, words: &'w mut [u8]) -> Result<&'w [u8], Self::Error> {
        self.spi.transfer(words)
    }
}

impl<T, M> embedded_hal::blocking::spi::Write<u8> for Spi<'_, T, M>
where
    T: Instance,
    M: IsFullDuplex,
{
    type Error = Error;

    fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
        self.spi.write_bytes(words)?;
        self.spi.flush()?;
        Ok(())
    }
}

pub mod dma {
    use core::mem;

    use embedded_dma::{ReadBuffer, WriteBuffer};

    use super::*;
    #[cfg(spi3)]
    use crate::dma::Spi3Peripheral;
    use crate::{
        dma::{
            Channel,
            ChannelTypes,
            DmaError,
            DmaTransfer,
            DmaTransferRxTx,
            RxPrivate,
            Spi2Peripheral,
            SpiPeripheral,
            TxPrivate,
        },
        FlashSafeDma,
    };

    pub trait WithDmaSpi2<'d, C, M>
    where
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        fn with_dma(self, channel: Channel<'d, C>) -> SpiDma<'d, crate::peripherals::SPI2, C, M>;
    }

    #[cfg(spi3)]
    pub trait WithDmaSpi3<'d, C, M>
    where
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        fn with_dma(self, channel: Channel<'d, C>) -> SpiDma<'d, crate::peripherals::SPI3, C, M>;
    }

    impl<'d, C, M> WithDmaSpi2<'d, C, M> for Spi<'d, crate::peripherals::SPI2, M>
    where
        C: ChannelTypes,
        C::P: SpiPeripheral + Spi2Peripheral,
        M: DuplexMode,
    {
        fn with_dma(
            self,
            mut channel: Channel<'d, C>,
        ) -> SpiDma<'d, crate::peripherals::SPI2, C, M> {
            channel.tx.init_channel(); // no need to call this for both, TX and RX

            SpiDma {
                spi: self.spi,
                channel,
                _mode: PhantomData,
            }
        }
    }

    #[cfg(spi3)]
    impl<'d, C, M> WithDmaSpi3<'d, C, M> for Spi<'d, crate::peripherals::SPI3, M>
    where
        C: ChannelTypes,
        C::P: SpiPeripheral + Spi3Peripheral,
        M: DuplexMode,
    {
        fn with_dma(
            self,
            mut channel: Channel<'d, C>,
        ) -> SpiDma<'d, crate::peripherals::SPI3, C, M> {
            channel.tx.init_channel(); // no need to call this for both, TX and RX

            SpiDma {
                spi: self.spi,
                channel,
                _mode: PhantomData,
            }
        }
    }
    /// An in-progress DMA transfer
    pub struct SpiDmaTransferRxTx<'d, T, C, RBUFFER, TBUFFER, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        spi_dma: SpiDma<'d, T, C, M>,
        rbuffer: RBUFFER,
        tbuffer: TBUFFER,
    }

    impl<'d, T, C, RXBUF, TXBUF, M> DmaTransferRxTx<RXBUF, TXBUF, SpiDma<'d, T, C, M>>
        for SpiDmaTransferRxTx<'d, T, C, RXBUF, TXBUF, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        /// Wait for the DMA transfer to complete and return the buffers and the
        /// SPI instance.
        fn wait(
            mut self,
        ) -> Result<
            (RXBUF, TXBUF, SpiDma<'d, T, C, M>),
            (DmaError, RXBUF, TXBUF, SpiDma<'d, T, C, M>),
        > {
            // Waiting for the DMA transfer is not enough. We need to wait for the
            // peripheral to finish flushing its buffers, too.
            self.spi_dma.spi.flush().ok();
            let err = self.spi_dma.channel.rx.has_error() || self.spi_dma.channel.tx.has_error();

            // `DmaTransfer` needs to have a `Drop` implementation, because we accept
            // managed buffers that can free their memory on drop. Because of that
            // we can't move out of the `DmaTransfer`'s fields, so we use `ptr::read`
            // and `mem::forget`.
            //
            // NOTE(unsafe) There is no panic branch between getting the resources
            // and forgetting `self`.
            unsafe {
                let rbuffer = core::ptr::read(&self.rbuffer);
                let tbuffer = core::ptr::read(&self.tbuffer);
                let payload = core::ptr::read(&self.spi_dma);
                mem::forget(self);
                if err {
                    Err((DmaError::DescriptorError, rbuffer, tbuffer, payload))
                } else {
                    Ok((rbuffer, tbuffer, payload))
                }
            }
        }

        /// Check if the DMA transfer is complete
        fn is_done(&self) -> bool {
            let ch = &self.spi_dma.channel;
            ch.tx.is_done() && ch.rx.is_done()
        }
    }

    impl<'d, T, C, RXBUF, TXBUF, M> Drop for SpiDmaTransferRxTx<'d, T, C, RXBUF, TXBUF, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        fn drop(&mut self) {
            self.spi_dma.spi.flush().ok();
        }
    }

    /// An in-progress DMA transfer.
    pub struct SpiDmaTransfer<'d, T, C, BUFFER, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        spi_dma: SpiDma<'d, T, C, M>,
        buffer: BUFFER,
    }

    impl<'d, T, C, BUFFER, M> DmaTransfer<BUFFER, SpiDma<'d, T, C, M>>
        for SpiDmaTransfer<'d, T, C, BUFFER, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        /// Wait for the DMA transfer to complete and return the buffers and the
        /// SPI instance.
        fn wait(
            mut self,
        ) -> Result<(BUFFER, SpiDma<'d, T, C, M>), (DmaError, BUFFER, SpiDma<'d, T, C, M>)>
        {
            // Waiting for the DMA transfer is not enough. We need to wait for the
            // peripheral to finish flushing its buffers, too.
            self.spi_dma.spi.flush().ok();
            let err = self.spi_dma.channel.rx.has_error() || self.spi_dma.channel.tx.has_error();

            // `DmaTransfer` needs to have a `Drop` implementation, because we accept
            // managed buffers that can free their memory on drop. Because of that
            // we can't move out of the `DmaTransfer`'s fields, so we use `ptr::read`
            // and `mem::forget`.
            //
            // NOTE(unsafe) There is no panic branch between getting the resources
            // and forgetting `self`.
            unsafe {
                let buffer = core::ptr::read(&self.buffer);
                let payload = core::ptr::read(&self.spi_dma);
                mem::forget(self);
                if err {
                    Err((DmaError::DescriptorError, buffer, payload))
                } else {
                    Ok((buffer, payload))
                }
            }
        }

        /// Check if the DMA transfer is complete
        fn is_done(&self) -> bool {
            let ch = &self.spi_dma.channel;
            ch.tx.is_done() && ch.rx.is_done()
        }
    }

    impl<'d, T, C, BUFFER, M> Drop for SpiDmaTransfer<'d, T, C, BUFFER, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        fn drop(&mut self) {
            self.spi_dma.spi.flush().ok();
        }
    }

    /// A DMA capable SPI instance.
    pub struct SpiDma<'d, T, C, M>
    where
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        pub(crate) spi: PeripheralRef<'d, T>,
        pub(crate) channel: Channel<'d, C>,
        _mode: PhantomData<M>,
    }

    impl<'d, T, C, M> core::fmt::Debug for SpiDma<'d, T, C, M>
    where
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
            f.debug_struct("SpiDma").finish()
        }
    }

    impl<'d, T, C, M> SpiDma<'d, T, C, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: DuplexMode,
    {
        pub fn change_bus_frequency(&mut self, frequency: HertzU32, clocks: &Clocks) {
            self.spi.ch_bus_freq(frequency, clocks);
        }
    }

    impl<'d, T, C, M> SpiDma<'d, T, C, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: IsFullDuplex,
    {
        /// Perform a DMA write.
        ///
        /// This will return a [SpiDmaTransfer] owning the buffer(s) and the SPI
        /// instance. The maximum amount of data to be sent is 32736
        /// bytes.
        #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
        pub fn dma_write<TXBUF>(
            mut self,
            words: TXBUF,
        ) -> Result<SpiDmaTransfer<'d, T, C, TXBUF, M>, super::Error>
        where
            TXBUF: ReadBuffer<Word = u8>,
        {
            let (ptr, len) = unsafe { words.read_buffer() };

            if len > MAX_DMA_SIZE {
                return Err(super::Error::MaxDmaTransferSizeExceeded);
            }

            self.spi
                .start_write_bytes_dma(ptr, len, &mut self.channel.tx, false)?;
            Ok(SpiDmaTransfer {
                spi_dma: self,
                buffer: words,
            })
        }

        /// Perform a DMA read.
        ///
        /// This will return a [SpiDmaTransfer] owning the buffer(s) and the SPI
        /// instance. The maximum amount of data to be received is 32736
        /// bytes.
        #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
        pub fn dma_read<RXBUF>(
            mut self,
            mut words: RXBUF,
        ) -> Result<SpiDmaTransfer<'d, T, C, RXBUF, M>, super::Error>
        where
            RXBUF: WriteBuffer<Word = u8>,
        {
            let (ptr, len) = unsafe { words.write_buffer() };

            if len > MAX_DMA_SIZE {
                return Err(super::Error::MaxDmaTransferSizeExceeded);
            }

            self.spi
                .start_read_bytes_dma(ptr, len, &mut self.channel.rx, false)?;
            Ok(SpiDmaTransfer {
                spi_dma: self,
                buffer: words,
            })
        }

        /// Perform a DMA transfer.
        ///
        /// This will return a [SpiDmaTransfer] owning the buffer(s) and the SPI
        /// instance. The maximum amount of data to be sent/received is
        /// 32736 bytes.
        pub fn dma_transfer<TXBUF, RXBUF>(
            mut self,
            words: TXBUF,
            mut read_buffer: RXBUF,
        ) -> Result<SpiDmaTransferRxTx<'d, T, C, RXBUF, TXBUF, M>, super::Error>
        where
            TXBUF: ReadBuffer<Word = u8>,
            RXBUF: WriteBuffer<Word = u8>,
        {
            let (write_ptr, write_len) = unsafe { words.read_buffer() };
            let (read_ptr, read_len) = unsafe { read_buffer.write_buffer() };

            if write_len > MAX_DMA_SIZE || read_len > MAX_DMA_SIZE {
                return Err(super::Error::MaxDmaTransferSizeExceeded);
            }

            self.spi.start_transfer_dma(
                write_ptr,
                write_len,
                read_ptr,
                read_len,
                &mut self.channel.tx,
                &mut self.channel.rx,
                false,
            )?;
            Ok(SpiDmaTransferRxTx {
                spi_dma: self,
                rbuffer: read_buffer,
                tbuffer: words,
            })
        }
    }

    impl<'d, T, C, M> SpiDma<'d, T, C, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: IsHalfDuplex,
    {
        #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
        pub fn read<RXBUF>(
            mut self,
            data_mode: SpiDataMode,
            cmd: Command,
            address: Address,
            dummy: u8,
            mut buffer: RXBUF,
        ) -> Result<SpiDmaTransfer<'d, T, C, RXBUF, M>, super::Error>
        where
            RXBUF: WriteBuffer<Word = u8>,
        {
            let (ptr, len) = unsafe { buffer.write_buffer() };

            if len > MAX_DMA_SIZE {
                return Err(super::Error::MaxDmaTransferSizeExceeded);
            }

            self.spi.init_half_duplex(
                false,
                !cmd.is_none(),
                !address.is_none(),
                false,
                dummy != 0,
                len == 0,
            );
            self.spi
                .init_spi_data_mode(cmd.mode(), address.mode(), data_mode);

            // set cmd, address, dummy cycles
            let reg_block = self.spi.register_block();
            if !cmd.is_none() {
                reg_block.user2().modify(|_, w| {
                    w.usr_command_bitlen()
                        .variant((cmd.width() - 1) as u8)
                        .usr_command_value()
                        .variant(cmd.value())
                });
            }

            #[cfg(not(esp32))]
            if !address.is_none() {
                reg_block
                    .user1()
                    .modify(|_, w| w.usr_addr_bitlen().variant((address.width() - 1) as u8));

                let addr = address.value() << (32 - address.width());
                reg_block.addr().write(|w| w.usr_addr_value().variant(addr));
            }

            #[cfg(esp32)]
            if !address.is_none() {
                reg_block.user1().modify(|r, w| unsafe {
                    w.bits(r.bits() & !(0x3f << 26) | (((address.width() - 1) as u32) & 0x3f) << 26)
                });

                let addr = address.value() << (32 - address.width());
                reg_block.addr().write(|w| unsafe { w.bits(addr) });
            }

            if dummy > 0 {
                reg_block
                    .user1()
                    .modify(|_, w| w.usr_dummy_cyclelen().variant(dummy - 1));
            }

            self.spi
                .start_read_bytes_dma(ptr, len, &mut self.channel.rx, false)?;
            Ok(SpiDmaTransfer {
                spi_dma: self,
                buffer,
            })
        }

        #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
        pub fn write<TXBUF>(
            mut self,
            data_mode: SpiDataMode,
            cmd: Command,
            address: Address,
            dummy: u8,
            buffer: TXBUF,
        ) -> Result<SpiDmaTransfer<'d, T, C, TXBUF, M>, super::Error>
        where
            TXBUF: ReadBuffer<Word = u8>,
        {
            let (ptr, len) = unsafe { buffer.read_buffer() };

            if len > MAX_DMA_SIZE {
                return Err(super::Error::MaxDmaTransferSizeExceeded);
            }

            self.spi.init_half_duplex(
                true,
                !cmd.is_none(),
                !address.is_none(),
                false,
                dummy != 0,
                len == 0,
            );
            self.spi
                .init_spi_data_mode(cmd.mode(), address.mode(), data_mode);

            // set cmd, address, dummy cycles
            let reg_block = self.spi.register_block();
            if !cmd.is_none() {
                reg_block.user2().modify(|_, w| {
                    w.usr_command_bitlen()
                        .variant((cmd.width() - 1) as u8)
                        .usr_command_value()
                        .variant(cmd.value())
                });
            }

            #[cfg(not(esp32))]
            if !address.is_none() {
                reg_block
                    .user1()
                    .modify(|_, w| w.usr_addr_bitlen().variant((address.width() - 1) as u8));

                let addr = address.value() << (32 - address.width());
                reg_block.addr().write(|w| w.usr_addr_value().variant(addr));
            }

            #[cfg(esp32)]
            if !address.is_none() {
                reg_block.user1().modify(|r, w| unsafe {
                    w.bits(r.bits() & !(0x3f << 26) | (((address.width() - 1) as u32) & 0x3f) << 26)
                });

                let addr = address.value() << (32 - address.width());
                reg_block.addr().write(|w| unsafe { w.bits(addr) });
            }

            if dummy > 0 {
                reg_block
                    .user1()
                    .modify(|_, w| w.usr_dummy_cyclelen().variant(dummy - 1));
            }

            self.spi
                .start_write_bytes_dma(ptr, len, &mut self.channel.tx, false)?;
            Ok(SpiDmaTransfer {
                spi_dma: self,
                buffer,
            })
        }
    }

    impl<'d, T, C, M> embedded_hal::blocking::spi::Transfer<u8> for SpiDma<'d, T, C, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: IsFullDuplex,
    {
        type Error = super::Error;

        fn transfer<'w>(&mut self, words: &'w mut [u8]) -> Result<&'w [u8], Self::Error> {
            self.spi
                .transfer_in_place_dma(words, &mut self.channel.tx, &mut self.channel.rx)
        }
    }

    impl<'d, T, C, M> embedded_hal::blocking::spi::Write<u8> for SpiDma<'d, T, C, M>
    where
        T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
        C: ChannelTypes,
        C::P: SpiPeripheral,
        M: IsFullDuplex,
    {
        type Error = super::Error;

        fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
            self.spi.write_bytes_dma(words, &mut self.channel.tx)?;
            self.spi.flush()?;
            Ok(())
        }
    }

    impl<T: embedded_hal::blocking::spi::Transfer<u8>, const SIZE: usize>
        embedded_hal::blocking::spi::Transfer<u8> for FlashSafeDma<T, SIZE>
    {
        type Error = T::Error;

        fn transfer<'w>(&mut self, words: &'w mut [u8]) -> Result<&'w [u8], Self::Error> {
            self.inner.transfer(words)
        }
    }

    impl<T: embedded_hal::blocking::spi::Write<u8>, const SIZE: usize>
        embedded_hal::blocking::spi::Write<u8> for FlashSafeDma<T, SIZE>
    {
        type Error = T::Error;

        fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
            if !crate::soc::is_valid_ram_address(&words[0] as *const _ as u32) {
                for chunk in words.chunks(SIZE) {
                    self.buffer[..chunk.len()].copy_from_slice(chunk);
                    self.inner.write(&self.buffer[..chunk.len()])?;
                }
            } else {
                self.inner.write(words)?;
            };

            Ok(())
        }
    }

    impl<T: embedded_hal::spi::FullDuplex<u8>, const SIZE: usize> embedded_hal::spi::FullDuplex<u8>
        for FlashSafeDma<T, SIZE>
    where
        Self: embedded_hal::blocking::spi::Transfer<u8, Error = T::Error>,
        Self: embedded_hal::blocking::spi::Write<u8, Error = T::Error>,
    {
        type Error = T::Error;

        fn read(&mut self) -> nb::Result<u8, Self::Error> {
            use embedded_hal::blocking::spi::Transfer;
            let mut buf = [0; 1];
            self.transfer(&mut buf)?;
            Ok(buf[0])
        }

        fn send(&mut self, word: u8) -> nb::Result<(), Self::Error> {
            use embedded_hal::blocking::spi::Write;
            self.write(&[word])?;
            Ok(())
        }
    }

    #[cfg(feature = "async")]
    mod asynch {
        use super::*;

        impl<'d, T, C, M> embedded_hal_async::spi::SpiBus for SpiDma<'d, T, C, M>
        where
            T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
            C: ChannelTypes,
            C::P: SpiPeripheral,
            M: IsFullDuplex,
        {
            async fn read(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.spi.start_read_bytes_dma(
                    words.as_mut_ptr(),
                    words.len(),
                    &mut self.channel.rx,
                    true,
                )?;

                crate::dma::asynch::DmaRxFuture::new(&mut self.channel.rx).await;

                Ok(())
            }

            async fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
                for chunk in words.chunks(MAX_DMA_SIZE) {
                    self.spi.start_write_bytes_dma(
                        chunk.as_ptr(),
                        chunk.len(),
                        &mut self.channel.tx,
                        true,
                    )?;

                    crate::dma::asynch::DmaTxFuture::new(&mut self.channel.tx).await;

                    // FIXME: in the future we should use the peripheral DMA status registers to
                    // await on both the dma transfer _and_ the peripherals status
                    self.spi.flush()?;
                }

                Ok(())
            }

            async fn transfer(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Self::Error> {
                let mut idx = 0;
                loop {
                    let write_idx = isize::min(idx, write.len() as isize);
                    let write_len = usize::min(write.len() - idx as usize, MAX_DMA_SIZE);

                    let read_idx = isize::min(idx, read.len() as isize);
                    let read_len = usize::min(read.len() - idx as usize, MAX_DMA_SIZE);

                    self.spi.start_transfer_dma(
                        unsafe { write.as_ptr().offset(write_idx) },
                        write_len,
                        unsafe { read.as_mut_ptr().offset(read_idx) },
                        read_len,
                        &mut self.channel.tx,
                        &mut self.channel.rx,
                        true,
                    )?;

                    embassy_futures::join::join(
                        crate::dma::asynch::DmaTxFuture::new(&mut self.channel.tx),
                        crate::dma::asynch::DmaRxFuture::new(&mut self.channel.rx),
                    )
                    .await;

                    // FIXME: in the future we should use the peripheral DMA status registers to
                    // await on both the dma transfer _and_ the peripherals status
                    self.spi.flush()?;

                    idx += MAX_DMA_SIZE as isize;
                    if idx >= write.len() as isize && idx >= read.len() as isize {
                        break;
                    }
                }

                Ok(())
            }

            async fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                for chunk in words.chunks_mut(MAX_DMA_SIZE) {
                    self.spi.start_transfer_dma(
                        chunk.as_ptr(),
                        chunk.len(),
                        chunk.as_mut_ptr(),
                        chunk.len(),
                        &mut self.channel.tx,
                        &mut self.channel.rx,
                        true,
                    )?;

                    embassy_futures::join::join(
                        crate::dma::asynch::DmaTxFuture::new(&mut self.channel.tx),
                        crate::dma::asynch::DmaRxFuture::new(&mut self.channel.rx),
                    )
                    .await;

                    // FIXME: in the future we should use the peripheral DMA status registers to
                    // await on both the dma transfer _and_ the peripherals status
                    self.spi.flush()?;
                }

                Ok(())
            }

            async fn flush(&mut self) -> Result<(), Self::Error> {
                // TODO use async flush in the future
                self.spi.flush()
            }
        }

        impl<T: embedded_hal_async::spi::SpiBus, const SIZE: usize> embedded_hal_async::spi::SpiBus
            for FlashSafeDma<T, SIZE>
        {
            async fn read(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.inner.read(words).await
            }

            async fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
                Ok(
                    if !crate::soc::is_valid_ram_address(&words[0] as *const _ as u32) {
                        for chunk in words.chunks(SIZE) {
                            self.buffer[..chunk.len()].copy_from_slice(chunk);
                            self.inner.write(&self.buffer[..chunk.len()]).await?;
                        }
                    } else {
                        self.inner.write(words).await?;
                    },
                )
            }

            async fn flush(&mut self) -> Result<(), Self::Error> {
                self.inner.flush().await
            }

            async fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.inner.transfer_in_place(words).await
            }

            async fn transfer(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Self::Error> {
                Ok(
                    if !crate::soc::is_valid_ram_address(&write[0] as *const _ as u32) {
                        for (read, write) in read.chunks_mut(SIZE).zip(write.chunks(SIZE)) {
                            self.buffer[..write.len()].copy_from_slice(write);
                            self.inner
                                .transfer(read, &self.buffer[..write.len()])
                                .await?;
                        }
                    } else {
                        self.inner.transfer(read, write).await?;
                    },
                )
            }
        }
    }

    #[cfg(feature = "eh1")]
    mod ehal1 {
        use embedded_hal_1::spi::{ErrorType, SpiBus};

        use super::{super::InstanceDma, *};
        use crate::{dma::ChannelTypes, FlashSafeDma};

        impl<'d, T, C, M> ErrorType for SpiDma<'d, T, C, M>
        where
            T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
            C: ChannelTypes,
            C::P: SpiPeripheral,
            M: IsFullDuplex,
        {
            type Error = Error;
        }

        impl<'d, T, C, M> SpiBus for SpiDma<'d, T, C, M>
        where
            T: InstanceDma<C::Tx<'d>, C::Rx<'d>>,
            C: ChannelTypes,
            C::P: SpiPeripheral,
            M: IsFullDuplex,
        {
            fn read(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.spi
                    .transfer_dma(&[], words, &mut self.channel.tx, &mut self.channel.rx)?;
                self.flush()
            }

            fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
                self.spi.write_bytes_dma(words, &mut self.channel.tx)?;
                self.flush()
            }

            fn transfer(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Self::Error> {
                self.spi
                    .transfer_dma(write, read, &mut self.channel.tx, &mut self.channel.rx)?;
                self.flush()
            }

            /// Transfer data in place.
            ///
            /// Writes data from `words` out on the bus and stores the reply
            /// into `words`. A convenient wrapper around
            /// [`write`](SpiBus::write), [`flush`](SpiBus::flush) and
            /// [`read`](SpiBus::read).
            fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.spi.transfer_in_place_dma(
                    words,
                    &mut self.channel.tx,
                    &mut self.channel.rx,
                )?;
                self.flush()
            }

            fn flush(&mut self) -> Result<(), Self::Error> {
                self.spi.flush()
            }
        }

        impl<T: ErrorType, const SIZE: usize> ErrorType for FlashSafeDma<T, SIZE> {
            type Error = T::Error;
        }

        impl<T: SpiBus, const SIZE: usize> SpiBus for FlashSafeDma<T, SIZE> {
            fn read(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.inner.read(words)
            }

            fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
                Ok(
                    if !crate::soc::is_valid_ram_address(&words[0] as *const _ as u32) {
                        for chunk in words.chunks(SIZE) {
                            self.buffer[..chunk.len()].copy_from_slice(chunk);
                            self.inner.write(&self.buffer[..chunk.len()])?;
                        }
                    } else {
                        self.inner.write(words)?;
                    },
                )
            }

            fn transfer(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Self::Error> {
                Ok(
                    if !crate::soc::is_valid_ram_address(&write[0] as *const _ as u32) {
                        for (read, write) in read.chunks_mut(SIZE).zip(write.chunks(SIZE)) {
                            self.buffer[..write.len()].copy_from_slice(write);
                            self.inner.transfer(read, &self.buffer[..write.len()])?;
                        }
                    } else {
                        self.inner.transfer(read, write)?;
                    },
                )
            }

            fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
                self.inner.transfer_in_place(words)
            }

            fn flush(&mut self) -> Result<(), Self::Error> {
                self.inner.flush()
            }
        }
    }
}

#[cfg(feature = "eh1")]
mod ehal1 {
    use embedded_hal_1::spi::SpiBus;
    use embedded_hal_nb::spi::FullDuplex;

    use super::*;

    impl<T, M> embedded_hal_1::spi::ErrorType for Spi<'_, T, M> {
        type Error = super::Error;
    }

    impl<T, M> FullDuplex for Spi<'_, T, M>
    where
        T: Instance,
        M: IsFullDuplex,
    {
        fn read(&mut self) -> nb::Result<u8, Self::Error> {
            self.spi.read_byte()
        }

        fn write(&mut self, word: u8) -> nb::Result<(), Self::Error> {
            self.spi.write_byte(word)
        }
    }

    impl<T, M> SpiBus for Spi<'_, T, M>
    where
        T: Instance,
        M: IsFullDuplex,
    {
        fn read(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
            self.spi.read_bytes(words)
        }

        fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
            self.spi.write_bytes(words)
        }

        fn transfer(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Self::Error> {
            // Optimizations
            if read.len() == 0 {
                SpiBus::write(self, write)?;
            } else if write.len() == 0 {
                SpiBus::read(self, read)?;
            }

            let mut write_from = 0;
            let mut read_from = 0;

            loop {
                // How many bytes we write in this chunk
                let write_inc = core::cmp::min(FIFO_SIZE, write.len() - write_from);
                let write_to = write_from + write_inc;
                // How many bytes we read in this chunk
                let read_inc = core::cmp::min(FIFO_SIZE, read.len() - read_from);
                let read_to = read_from + read_inc;

                if (write_inc == 0) && (read_inc == 0) {
                    break;
                }

                if write_to < read_to {
                    // Read more than we write, must pad writing part with zeros
                    let mut empty = [EMPTY_WRITE_PAD; FIFO_SIZE];
                    empty[0..write_inc].copy_from_slice(&write[write_from..write_to]);
                    SpiBus::write(self, &empty)?;
                } else {
                    SpiBus::write(self, &write[write_from..write_to])?;
                }

                SpiBus::flush(self)?;

                if read_inc > 0 {
                    self.spi
                        .read_bytes_from_fifo(&mut read[read_from..read_to])?;
                }

                write_from = write_to;
                read_from = read_to;
            }
            Ok(())
        }

        fn transfer_in_place(&mut self, words: &mut [u8]) -> Result<(), Self::Error> {
            // Since we have the traits so neatly implemented above, use them!
            for chunk in words.chunks_mut(FIFO_SIZE) {
                SpiBus::write(self, chunk)?;
                SpiBus::flush(self)?;
                self.spi.read_bytes_from_fifo(chunk)?;
            }
            Ok(())
        }

        fn flush(&mut self) -> Result<(), Self::Error> {
            self.spi.flush()
        }
    }
}

pub trait InstanceDma<TX, RX>: Instance
where
    TX: Tx,
    RX: Rx,
{
    fn transfer_in_place_dma<'w>(
        &mut self,
        words: &'w mut [u8],
        tx: &mut TX,
        rx: &mut RX,
    ) -> Result<&'w [u8], Error> {
        for chunk in words.chunks_mut(MAX_DMA_SIZE) {
            self.start_transfer_dma(
                chunk.as_ptr(),
                chunk.len(),
                chunk.as_mut_ptr(),
                chunk.len(),
                tx,
                rx,
                false,
            )?;

            while !tx.is_done() && !rx.is_done() {}
            self.flush().unwrap();
        }

        Ok(words)
    }

    fn transfer_dma<'w>(
        &mut self,
        write_buffer: &'w [u8],
        read_buffer: &'w mut [u8],
        tx: &mut TX,
        rx: &mut RX,
    ) -> Result<&'w [u8], Error> {
        let mut idx = 0;
        loop {
            let write_idx = isize::min(idx, write_buffer.len() as isize);
            let write_len = usize::min(write_buffer.len() - idx as usize, MAX_DMA_SIZE);

            let read_idx = isize::min(idx, read_buffer.len() as isize);
            let read_len = usize::min(read_buffer.len() - idx as usize, MAX_DMA_SIZE);

            self.start_transfer_dma(
                unsafe { write_buffer.as_ptr().offset(write_idx) },
                write_len,
                unsafe { read_buffer.as_mut_ptr().offset(read_idx) },
                read_len,
                tx,
                rx,
                false,
            )?;

            while !tx.is_done() && !rx.is_done() {}
            self.flush().unwrap();

            idx += MAX_DMA_SIZE as isize;
            if idx >= write_buffer.len() as isize && idx >= read_buffer.len() as isize {
                break;
            }
        }

        Ok(read_buffer)
    }

    #[allow(clippy::too_many_arguments)]
    fn start_transfer_dma(
        &mut self,
        write_buffer_ptr: *const u8,
        write_buffer_len: usize,
        read_buffer_ptr: *mut u8,
        read_buffer_len: usize,
        tx: &mut TX,
        rx: &mut RX,
        listen: bool,
    ) -> Result<(), Error> {
        let reg_block = self.register_block();
        self.configure_datalen(usize::max(read_buffer_len, write_buffer_len) as u32 * 8);

        tx.is_done();
        rx.is_done();

        self.enable_dma();
        self.update();

        reset_dma_before_load_dma_dscr(reg_block);
        tx.prepare_transfer_without_start(
            self.dma_peripheral(),
            false,
            write_buffer_ptr,
            write_buffer_len,
        )
        .and_then(|_| tx.start_transfer())?;
        rx.prepare_transfer_without_start(
            false,
            self.dma_peripheral(),
            read_buffer_ptr,
            read_buffer_len,
        )
        .and_then(|_| rx.start_transfer())?;

        self.clear_dma_interrupts();
        reset_dma_before_usr_cmd(reg_block);

        if listen {
            tx.listen_eof();
            rx.listen_eof();
        }
        reg_block.cmd().modify(|_, w| w.usr().set_bit());

        Ok(())
    }

    fn write_bytes_dma<'w>(&mut self, words: &'w [u8], tx: &mut TX) -> Result<&'w [u8], Error> {
        for chunk in words.chunks(MAX_DMA_SIZE) {
            self.start_write_bytes_dma(chunk.as_ptr(), chunk.len(), tx, false)?;

            while !tx.is_done() {}
            self.flush().unwrap(); // seems "is_done" doesn't work as intended?
        }

        Ok(words)
    }

    #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
    fn start_write_bytes_dma(
        &mut self,
        ptr: *const u8,
        len: usize,
        tx: &mut TX,
        listen: bool,
    ) -> Result<(), Error> {
        let reg_block = self.register_block();
        self.configure_datalen(len as u32 * 8);

        tx.is_done();

        self.enable_dma();
        self.update();

        reset_dma_before_load_dma_dscr(reg_block);
        tx.prepare_transfer_without_start(self.dma_peripheral(), false, ptr, len)
            .and_then(|_| tx.start_transfer())?;

        self.clear_dma_interrupts();
        reset_dma_before_usr_cmd(reg_block);

        if listen {
            tx.listen_eof();
        }
        reg_block.cmd().modify(|_, w| w.usr().set_bit());

        Ok(())
    }

    #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
    fn start_read_bytes_dma(
        &mut self,
        ptr: *mut u8,
        len: usize,
        rx: &mut RX,
        listen: bool,
    ) -> Result<(), Error> {
        let reg_block = self.register_block();
        self.configure_datalen(len as u32 * 8);

        rx.is_done();

        self.enable_dma();
        self.update();

        reset_dma_before_load_dma_dscr(reg_block);
        rx.prepare_transfer_without_start(false, self.dma_peripheral(), ptr, len)
            .and_then(|_| rx.start_transfer())?;

        self.clear_dma_interrupts();
        reset_dma_before_usr_cmd(reg_block);

        if listen {
            rx.listen_eof();
        }
        reg_block.cmd().modify(|_, w| w.usr().set_bit());

        Ok(())
    }

    fn dma_peripheral(&self) -> DmaPeripheral {
        match self.spi_num() {
            2 => DmaPeripheral::Spi2,
            #[cfg(spi3)]
            3 => DmaPeripheral::Spi3,
            _ => panic!("Illegal SPI instance"),
        }
    }

    #[cfg(any(esp32c2, esp32c3, esp32c6, esp32h2, esp32s3))]
    fn enable_dma(&self) {
        let reg_block = self.register_block();
        reg_block.dma_conf().modify(|_, w| w.dma_tx_ena().set_bit());
        reg_block.dma_conf().modify(|_, w| w.dma_rx_ena().set_bit());
    }

    #[cfg(any(esp32, esp32s2))]
    fn enable_dma(&self) {
        // for non GDMA this is done in `assign_tx_device` / `assign_rx_device`
    }

    #[cfg(any(esp32c2, esp32c3, esp32c6, esp32h2, esp32s3))]
    fn clear_dma_interrupts(&self) {
        let reg_block = self.register_block();
        reg_block.dma_int_clr().write(|w| {
            w.dma_infifo_full_err_int_clr()
                .set_bit()
                .dma_outfifo_empty_err_int_clr()
                .set_bit()
                .trans_done_int_clr()
                .set_bit()
                .mst_rx_afifo_wfull_err_int_clr()
                .set_bit()
                .mst_tx_afifo_rempty_err_int_clr()
                .set_bit()
        });
    }

    #[cfg(any(esp32, esp32s2))]
    fn clear_dma_interrupts(&self) {
        let reg_block = self.register_block();
        reg_block.dma_int_clr().write(|w| {
            w.inlink_dscr_empty_int_clr()
                .set_bit()
                .outlink_dscr_error_int_clr()
                .set_bit()
                .inlink_dscr_error_int_clr()
                .set_bit()
                .in_done_int_clr()
                .set_bit()
                .in_err_eof_int_clr()
                .set_bit()
                .in_suc_eof_int_clr()
                .set_bit()
                .out_done_int_clr()
                .set_bit()
                .out_eof_int_clr()
                .set_bit()
                .out_total_eof_int_clr()
                .set_bit()
        });
    }
}

#[cfg(not(any(esp32, esp32s2)))]
fn reset_dma_before_usr_cmd(reg_block: &RegisterBlock) {
    reg_block.dma_conf().modify(|_, w| {
        w.rx_afifo_rst()
            .set_bit()
            .buf_afifo_rst()
            .set_bit()
            .dma_afifo_rst()
            .set_bit()
    });
}

#[cfg(any(esp32, esp32s2))]
fn reset_dma_before_usr_cmd(_reg_block: &RegisterBlock) {}

#[cfg(not(any(esp32, esp32s2)))]
fn reset_dma_before_load_dma_dscr(_reg_block: &RegisterBlock) {}

#[cfg(any(esp32, esp32s2))]
fn reset_dma_before_load_dma_dscr(reg_block: &RegisterBlock) {
    reg_block.dma_conf().modify(|_, w| {
        w.out_rst()
            .set_bit()
            .in_rst()
            .set_bit()
            .ahbm_fifo_rst()
            .set_bit()
            .ahbm_rst()
            .set_bit()
    });

    reg_block.dma_conf().modify(|_, w| {
        w.out_rst()
            .clear_bit()
            .in_rst()
            .clear_bit()
            .ahbm_fifo_rst()
            .clear_bit()
            .ahbm_rst()
            .clear_bit()
    });
}

impl<TX, RX> InstanceDma<TX, RX> for crate::peripherals::SPI2
where
    TX: Tx,
    RX: Rx,
{
}

#[cfg(spi3)]
impl<TX, RX> InstanceDma<TX, RX> for crate::peripherals::SPI3
where
    TX: Tx,
    RX: Rx,
{
}

pub trait ExtendedInstance: Instance {
    fn sio0_input_signal(&self) -> InputSignal;

    fn sio1_output_signal(&self) -> OutputSignal;

    fn sio2_output_signal(&self) -> OutputSignal;

    fn sio2_input_signal(&self) -> InputSignal;

    fn sio3_output_signal(&self) -> OutputSignal;

    fn sio3_input_signal(&self) -> InputSignal;
}

pub trait Instance {
    fn register_block(&self) -> &RegisterBlock;

    fn sclk_signal(&self) -> OutputSignal;

    fn mosi_signal(&self) -> OutputSignal;

    fn miso_signal(&self) -> InputSignal;

    fn cs_signal(&self) -> OutputSignal;

    fn enable_peripheral(&self);

    fn spi_num(&self) -> u8;

    /// Initialize for full-duplex 1 bit mode
    fn init(&mut self) {
        let reg_block = self.register_block();
        reg_block.user().modify(|_, w| {
            w.usr_miso_highpart()
                .clear_bit()
                .usr_miso_highpart()
                .clear_bit()
                .doutdin()
                .set_bit()
                .usr_miso()
                .set_bit()
                .usr_mosi()
                .set_bit()
                .cs_hold()
                .set_bit()
                .usr_dummy_idle()
                .set_bit()
                .usr_addr()
                .clear_bit()
                .usr_command()
                .clear_bit()
        });

        #[cfg(not(any(esp32, esp32s2)))]
        reg_block.clk_gate().modify(|_, w| {
            w.clk_en()
                .set_bit()
                .mst_clk_active()
                .set_bit()
                .mst_clk_sel()
                .set_bit()
        });

        #[cfg(any(esp32c6, esp32h2))]
        unsafe {
            // use default clock source PLL_F80M_CLK (ESP32-C6) and
            // PLL_F48M_CLK (ESP32-H2)
            (*crate::peripherals::PCR::PTR)
                .spi2_clkm_conf()
                .modify(|_, w| w.spi2_clkm_sel().bits(1));
        }

        #[cfg(not(any(esp32, esp32s2)))]
        reg_block.ctrl().modify(|_, w| {
            w.q_pol()
                .clear_bit()
                .d_pol()
                .clear_bit()
                .hold_pol()
                .clear_bit()
        });

        #[cfg(esp32s2)]
        reg_block
            .ctrl()
            .modify(|_, w| w.q_pol().clear_bit().d_pol().clear_bit().wp().clear_bit());

        #[cfg(esp32)]
        reg_block.ctrl().modify(|_, w| w.wp().clear_bit());

        #[cfg(not(esp32))]
        reg_block.misc().write(|w| unsafe { w.bits(0) });

        reg_block.slave().write(|w| unsafe { w.bits(0) });
    }

    #[cfg(not(esp32))]
    fn init_spi_data_mode(
        &mut self,
        cmd_mode: SpiDataMode,
        address_mode: SpiDataMode,
        data_mode: SpiDataMode,
    ) {
        let reg_block = self.register_block();
        match cmd_mode {
            SpiDataMode::Single => reg_block
                .ctrl()
                .modify(|_, w| w.fcmd_dual().clear_bit().fcmd_quad().clear_bit()),
            SpiDataMode::Dual => reg_block
                .ctrl()
                .modify(|_, w| w.fcmd_dual().set_bit().fcmd_quad().clear_bit()),
            SpiDataMode::Quad => reg_block
                .ctrl()
                .modify(|_, w| w.fcmd_dual().clear_bit().fcmd_quad().set_bit()),
        }

        match address_mode {
            SpiDataMode::Single => reg_block
                .ctrl()
                .modify(|_, w| w.faddr_dual().clear_bit().faddr_quad().clear_bit()),
            SpiDataMode::Dual => reg_block
                .ctrl()
                .modify(|_, w| w.faddr_dual().set_bit().faddr_quad().clear_bit()),
            SpiDataMode::Quad => reg_block
                .ctrl()
                .modify(|_, w| w.faddr_dual().clear_bit().faddr_quad().set_bit()),
        }

        match data_mode {
            SpiDataMode::Single => {
                reg_block
                    .ctrl()
                    .modify(|_, w| w.fread_dual().clear_bit().fread_quad().clear_bit());
                reg_block
                    .user()
                    .modify(|_, w| w.fwrite_dual().clear_bit().fwrite_quad().clear_bit());
            }
            SpiDataMode::Dual => {
                reg_block
                    .ctrl()
                    .modify(|_, w| w.fread_dual().set_bit().fread_quad().clear_bit());
                reg_block
                    .user()
                    .modify(|_, w| w.fwrite_dual().set_bit().fwrite_quad().clear_bit());
            }
            SpiDataMode::Quad => {
                reg_block
                    .ctrl()
                    .modify(|_, w| w.fread_quad().set_bit().fread_dual().clear_bit());
                reg_block
                    .user()
                    .modify(|_, w| w.fwrite_quad().set_bit().fwrite_dual().clear_bit());
            }
        }
    }

    #[cfg(esp32)]
    fn init_spi_data_mode(
        &mut self,
        cmd_mode: SpiDataMode,
        address_mode: SpiDataMode,
        data_mode: SpiDataMode,
    ) {
        let reg_block = self.register_block();
        match cmd_mode {
            SpiDataMode::Single => (),
            _ => panic!("Only 1-bit command supported"),
        }

        match (address_mode, data_mode) {
            (SpiDataMode::Single, SpiDataMode::Single) => {
                reg_block.ctrl().modify(|_, w| {
                    w.fread_dio()
                        .clear_bit()
                        .fread_qio()
                        .clear_bit()
                        .fread_dual()
                        .clear_bit()
                        .fread_quad()
                        .clear_bit()
                });

                reg_block.user().modify(|_, w| {
                    w.fwrite_dio()
                        .clear_bit()
                        .fwrite_qio()
                        .clear_bit()
                        .fwrite_dual()
                        .clear_bit()
                        .fwrite_quad()
                        .clear_bit()
                });
            }
            (SpiDataMode::Single, SpiDataMode::Dual) => {
                reg_block.ctrl().modify(|_, w| {
                    w.fread_dio()
                        .clear_bit()
                        .fread_qio()
                        .clear_bit()
                        .fread_dual()
                        .set_bit()
                        .fread_quad()
                        .clear_bit()
                });

                reg_block.user().modify(|_, w| {
                    w.fwrite_dio()
                        .clear_bit()
                        .fwrite_qio()
                        .clear_bit()
                        .fwrite_dual()
                        .set_bit()
                        .fwrite_quad()
                        .clear_bit()
                });
            }
            (SpiDataMode::Single, SpiDataMode::Quad) => {
                reg_block.ctrl().modify(|_, w| {
                    w.fread_dio()
                        .clear_bit()
                        .fread_qio()
                        .clear_bit()
                        .fread_dual()
                        .clear_bit()
                        .fread_quad()
                        .set_bit()
                });

                reg_block.user().modify(|_, w| {
                    w.fwrite_dio()
                        .clear_bit()
                        .fwrite_qio()
                        .clear_bit()
                        .fwrite_dual()
                        .clear_bit()
                        .fwrite_quad()
                        .set_bit()
                });
            }
            (SpiDataMode::Dual, SpiDataMode::Single) => {
                panic!("Unsupported combination of data-modes")
            }
            (SpiDataMode::Dual, SpiDataMode::Dual) => {
                reg_block.ctrl().modify(|_, w| {
                    w.fread_dio()
                        .set_bit()
                        .fread_qio()
                        .clear_bit()
                        .fread_dual()
                        .clear_bit()
                        .fread_quad()
                        .clear_bit()
                });

                reg_block.user().modify(|_, w| {
                    w.fwrite_dio()
                        .set_bit()
                        .fwrite_qio()
                        .clear_bit()
                        .fwrite_dual()
                        .clear_bit()
                        .fwrite_quad()
                        .clear_bit()
                });
            }
            (SpiDataMode::Dual, SpiDataMode::Quad) => {
                panic!("Unsupported combination of data-modes")
            }
            (SpiDataMode::Quad, SpiDataMode::Single) => {
                panic!("Unsupported combination of data-modes")
            }
            (SpiDataMode::Quad, SpiDataMode::Dual) => {
                panic!("Unsupported combination of data-modes")
            }
            (SpiDataMode::Quad, SpiDataMode::Quad) => {
                reg_block.ctrl().modify(|_, w| {
                    w.fread_dio()
                        .clear_bit()
                        .fread_qio()
                        .set_bit()
                        .fread_dual()
                        .clear_bit()
                        .fread_quad()
                        .clear_bit()
                });

                reg_block.user().modify(|_, w| {
                    w.fwrite_dio()
                        .clear_bit()
                        .fwrite_qio()
                        .set_bit()
                        .fwrite_dual()
                        .clear_bit()
                        .fwrite_quad()
                        .clear_bit()
                });
            }
        }
    }

    // taken from https://github.com/apache/incubator-nuttx/blob/8267a7618629838231256edfa666e44b5313348e/arch/risc-v/src/esp32c3/esp32c3_spi.c#L496
    fn setup(&mut self, frequency: HertzU32, clocks: &Clocks) {
        // FIXME: this might not be always true
        #[cfg(not(esp32h2))]
        let apb_clk_freq: HertzU32 = HertzU32::Hz(clocks.apb_clock.to_Hz());
        // ESP32-H2 is using PLL_48M_CLK source instead of APB_CLK
        #[cfg(esp32h2)]
        let apb_clk_freq: HertzU32 = HertzU32::Hz(clocks.pll_48m_clock.to_Hz());

        let reg_val: u32;
        let duty_cycle = 128;

        // In HW, n, h and l fields range from 1 to 64, pre ranges from 1 to 8K.
        // The value written to register is one lower than the used value.

        if frequency > ((apb_clk_freq / 4) * 3) {
            // Using APB frequency directly will give us the best result here.
            reg_val = 1 << 31;
        } else {
            /* For best duty cycle resolution, we want n to be as close to 32 as
             * possible, but we also need a pre/n combo that gets us as close as
             * possible to the intended frequency. To do this, we bruteforce n and
             * calculate the best pre to go along with that. If there's a choice
             * between pre/n combos that give the same result, use the one with the
             * higher n.
             */

            let mut pre: i32;
            let mut bestn: i32 = -1;
            let mut bestpre: i32 = -1;
            let mut besterr: i32 = 0;
            let mut errval: i32;

            /* Start at n = 2. We need to be able to set h/l so we have at least
             * one high and one low pulse.
             */

            for n in 2..64 {
                /* Effectively, this does:
                 *   pre = round((APB_CLK_FREQ / n) / frequency)
                 */

                pre = ((apb_clk_freq.raw() as i32 / n) + (frequency.raw() as i32 / 2))
                    / frequency.raw() as i32;

                if pre <= 0 {
                    pre = 1;
                }

                if pre > 16 {
                    pre = 16;
                }

                errval = (apb_clk_freq.raw() as i32 / (pre * n)
                    - frequency.raw() as i32)
                    .abs();
                if bestn == -1 || errval <= besterr {
                    besterr = errval;
                    bestn = n;
                    bestpre = pre;
                }
            }

            let n: i32 = bestn;
            pre = bestpre;
            let l: i32 = n;

            /* Effectively, this does:
             *   h = round((duty_cycle * n) / 256)
             */

            let mut h: i32 = (duty_cycle * n + 127) / 256;
            if h <= 0 {
                h = 1;
            }

            reg_val = (l as u32 - 1)
                | ((h as u32 - 1) << 6)
                | ((n as u32 - 1) << 12)
                | ((pre as u32 - 1) << 18);
        }

        self.register_block()
            .clock()
            .write(|w| unsafe { w.bits(reg_val) });
    }

    #[cfg(not(esp32))]
    fn set_data_mode(&mut self, data_mode: SpiMode) -> &mut Self {
        let reg_block = self.register_block();

        match data_mode {
            SpiMode::Mode0 => {
                reg_block.misc().modify(|_, w| w.ck_idle_edge().clear_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().clear_bit());
            }
            SpiMode::Mode1 => {
                reg_block.misc().modify(|_, w| w.ck_idle_edge().clear_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().set_bit());
            }
            SpiMode::Mode2 => {
                reg_block.misc().modify(|_, w| w.ck_idle_edge().set_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().set_bit());
            }
            SpiMode::Mode3 => {
                reg_block.misc().modify(|_, w| w.ck_idle_edge().set_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().clear_bit());
            }
        }
        self
    }

    #[cfg(esp32)]
    fn set_data_mode(&mut self, data_mode: SpiMode) -> &mut Self {
        let reg_block = self.register_block();

        match data_mode {
            SpiMode::Mode0 => {
                reg_block.pin().modify(|_, w| w.ck_idle_edge().clear_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().clear_bit());
            }
            SpiMode::Mode1 => {
                reg_block.pin().modify(|_, w| w.ck_idle_edge().clear_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().set_bit());
            }
            SpiMode::Mode2 => {
                reg_block.pin().modify(|_, w| w.ck_idle_edge().set_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().set_bit());
            }
            SpiMode::Mode3 => {
                reg_block.pin().modify(|_, w| w.ck_idle_edge().set_bit());
                reg_block.user().modify(|_, w| w.ck_out_edge().clear_bit());
            }
        }
        self
    }

    fn ch_bus_freq(&mut self, frequency: HertzU32, clocks: &Clocks) {
        // Disable clock source
        #[cfg(not(any(feature = "esp32", feature = "esp32s2")))]
        self.register_block().clk_gate().modify(|_, w| {
            w.clk_en()
                .clear_bit()
                .mst_clk_active()
                .clear_bit()
                .mst_clk_sel()
                .clear_bit()
        });

        // Change clock frequency
        self.setup(frequency, clocks);

        // Enable clock source
        #[cfg(not(any(feature = "esp32", feature = "esp32s2")))]
        self.register_block().clk_gate().modify(|_, w| {
            w.clk_en()
                .set_bit()
                .mst_clk_active()
                .set_bit()
                .mst_clk_sel()
                .set_bit()
        });
    }

    fn read_byte(&mut self) -> nb::Result<u8, Error> {
        if self.busy() {
            return Err(nb::Error::WouldBlock);
        }

        let reg_block = self.register_block();
        Ok(u32::try_into(reg_block.w0().read().bits()).unwrap_or_default())
    }

    fn write_byte(&mut self, word: u8) -> nb::Result<(), Error> {
        if self.busy() {
            return Err(nb::Error::WouldBlock);
        }

        self.configure_datalen(8);

        let reg_block = self.register_block();
        reg_block.w0().write(|w| unsafe { w.bits(word.into()) });

        self.update();

        reg_block.cmd().modify(|_, w| w.usr().set_bit());

        Ok(())
    }

    /// Write bytes to SPI.
    ///
    /// Copies the content of `words` in chunks of 64 bytes into the SPI
    /// transmission FIFO. If `words` is longer than 64 bytes, multiple
    /// sequential transfers are performed. This function will return before
    /// all bytes of the last chunk to transmit have been sent to the wire. If
    /// you must ensure that the whole messages was written correctly, use
    /// [`Self::flush`].
    // FIXME: See below.
    #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
    fn write_bytes(&mut self, words: &[u8]) -> Result<(), Error> {
        let num_chunks = words.len() / FIFO_SIZE;

        // The fifo has a limited fixed size, so the data must be chunked and then
        // transmitted
        for (i, chunk) in words.chunks(FIFO_SIZE).enumerate() {
            self.configure_datalen(chunk.len() as u32 * 8);

            let fifo_ptr = self.register_block().w0().as_ptr();
            for i in (0..chunk.len()).step_by(4) {
                let state = if chunk.len() - i < 4 {
                    chunk.len() % 4
                } else {
                    0
                };
                let word = match state {
                    0 => {
                        (chunk[i] as u32)
                            | (chunk[i + 1] as u32) << 8
                            | (chunk[i + 2] as u32) << 16
                            | (chunk[i + 3] as u32) << 24
                    }

                    3 => {
                        (chunk[i] as u32) | (chunk[i + 1] as u32) << 8 | (chunk[i + 2] as u32) << 16
                    }

                    2 => (chunk[i] as u32) | (chunk[i + 1] as u32) << 8,

                    1 => chunk[i] as u32,

                    _ => panic!(),
                };
                unsafe {
                    fifo_ptr.add(i / 4).write_volatile(word);
                }
            }

            self.update();

            self.register_block().cmd().modify(|_, w| w.usr().set_bit());

            // Wait for all chunks to complete except the last one.
            // The function is allowed to return before the bus is idle.
            // see [embedded-hal flushing](https://docs.rs/embedded-hal/1.0.0-alpha.8/embedded_hal/spi/blocking/index.html#flushing)
            //
            // THIS IS NOT TRUE FOR EH 0.2.X! MAKE SURE TO FLUSH IN EH 0.2.X TRAIT
            // IMPLEMENTATIONS!
            if i < num_chunks {
                self.flush()?;
            }
        }
        Ok(())
    }

    /// Read bytes from SPI.
    ///
    /// Sends out a stuffing byte for every byte to read. This function doesn't
    /// perform flushing. If you want to read the response to something you
    /// have written before, consider using [`Self::transfer`] instead.
    #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
    fn read_bytes(&mut self, words: &mut [u8]) -> Result<(), Error> {
        let empty_array = [EMPTY_WRITE_PAD; FIFO_SIZE];

        for chunk in words.chunks_mut(FIFO_SIZE) {
            self.write_bytes(&empty_array[0..chunk.len()])?;
            self.flush()?;
            self.read_bytes_from_fifo(chunk)?;
        }
        Ok(())
    }

    /// Read received bytes from SPI FIFO.
    ///
    /// Copies the contents of the SPI receive FIFO into `words`. This function
    /// doesn't perform flushing. If you want to read the response to
    /// something you have written before, consider using [`Self::transfer`]
    /// instead.
    // FIXME: Using something like `core::slice::from_raw_parts` and
    // `copy_from_slice` on the receive registers works only for the esp32 and
    // esp32c3 varaints. The reason for this is unknown.
    #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
    fn read_bytes_from_fifo(&mut self, words: &mut [u8]) -> Result<(), Error> {
        let reg_block = self.register_block();

        for chunk in words.chunks_mut(FIFO_SIZE) {
            self.configure_datalen(chunk.len() as u32 * 8);

            let mut fifo_ptr = reg_block.w0().as_ptr();
            for index in (0..chunk.len()).step_by(4) {
                let reg_val = unsafe { *fifo_ptr };
                let bytes = reg_val.to_le_bytes();

                let len = usize::min(chunk.len(), index + 4) - index;
                chunk[index..(index + len)].clone_from_slice(&bytes[0..len]);

                unsafe {
                    fifo_ptr = fifo_ptr.offset(1);
                };
            }
        }

        Ok(())
    }

    fn busy(&self) -> bool {
        let reg_block = self.register_block();
        reg_block.cmd().read().usr().bit_is_set()
    }

    // Check if the bus is busy and if it is wait for it to be idle
    fn flush(&mut self) -> Result<(), Error> {
        while self.busy() {
            // wait for bus to be clear
        }
        Ok(())
    }

    #[cfg_attr(feature = "place-spi-driver-in-ram", ram)]
    fn transfer<'w>(&mut self, words: &'w mut [u8]) -> Result<&'w [u8], Error> {
        for chunk in words.chunks_mut(FIFO_SIZE) {
            self.write_bytes(chunk)?;
            self.flush()?;
            self.read_bytes_from_fifo(chunk)?;
        }

        Ok(words)
    }

    fn start_operation(&self) {
        let reg_block = self.register_block();
        self.update();
        reg_block.cmd().modify(|_, w| w.usr().set_bit());
    }

    fn init_half_duplex(
        &mut self,
        is_write: bool,
        command_state: bool,
        address_state: bool,
        dummy_idle: bool,
        dummy_state: bool,
        no_mosi_miso: bool,
    ) {
        let reg_block = self.register_block();
        reg_block.user().modify(|_, w| {
            w.usr_miso_highpart()
                .clear_bit()
                .usr_miso_highpart()
                .clear_bit()
                .doutdin()
                .clear_bit()
                .usr_miso()
                .bit(!is_write && !no_mosi_miso)
                .usr_mosi()
                .bit(is_write && !no_mosi_miso)
                .cs_hold()
                .set_bit()
                .usr_dummy_idle()
                .bit(dummy_idle)
                .usr_dummy()
                .bit(dummy_state)
                .usr_addr()
                .bit(address_state)
                .usr_command()
                .bit(command_state)
        });

        #[cfg(not(any(esp32, esp32s2)))]
        reg_block.clk_gate().modify(|_, w| {
            w.clk_en()
                .set_bit()
                .mst_clk_active()
                .set_bit()
                .mst_clk_sel()
                .set_bit()
        });

        #[cfg(any(esp32c6, esp32h2))]
        unsafe {
            let pcr = &*crate::peripherals::PCR::PTR;

            // use default clock source PLL_F80M_CLK
            pcr.spi2_clkm_conf()
                .modify(|_, w| w.spi2_clkm_sel().bits(1));
        }

        #[cfg(not(esp32))]
        reg_block.misc().write(|w| unsafe { w.bits(0) });

        reg_block.slave().write(|w| unsafe { w.bits(0) });

        self.update();
    }

    fn write_bytes_half_duplex(
        &mut self,
        cmd: Command,
        address: Address,
        dummy: u8,
        buffer: &[u8],
    ) -> Result<(), Error> {
        self.init_half_duplex(
            true,
            !cmd.is_none(),
            !address.is_none(),
            false,
            dummy != 0,
            buffer.is_empty(),
        );

        // set cmd, address, dummy cycles
        let reg_block = self.register_block();
        if !cmd.is_none() {
            reg_block.user2().modify(|_, w| {
                w.usr_command_bitlen()
                    .variant((cmd.width() - 1) as u8)
                    .usr_command_value()
                    .variant(cmd.value())
            });
        }

        #[cfg(not(esp32))]
        if !address.is_none() {
            reg_block
                .user1()
                .modify(|_, w| w.usr_addr_bitlen().variant((address.width() - 1) as u8));

            let addr = address.value() << (32 - address.width());
            reg_block.addr().write(|w| w.usr_addr_value().variant(addr));
        }

        #[cfg(esp32)]
        if !address.is_none() {
            reg_block.user1().modify(|r, w| unsafe {
                w.bits(r.bits() & !(0x3f << 26) | (((address.width() - 1) as u32) & 0x3f) << 26)
            });

            let addr = address.value() << (32 - address.width());
            reg_block.addr().write(|w| unsafe { w.bits(addr) });
        }

        if dummy > 0 {
            reg_block
                .user1()
                .modify(|_, w| w.usr_dummy_cyclelen().variant(dummy - 1));
        }

        if !buffer.is_empty() {
            // re-using the full-duplex write here
            self.write_bytes(buffer)?;
        } else {
            self.start_operation();
        }

        self.flush()
    }

    fn read_bytes_half_duplex(
        &mut self,
        cmd: Command,
        address: Address,
        dummy: u8,
        buffer: &mut [u8],
    ) -> Result<(), Error> {
        self.init_half_duplex(
            false,
            !cmd.is_none(),
            !address.is_none(),
            false,
            dummy != 0,
            buffer.is_empty(),
        );

        // set cmd, address, dummy cycles
        let reg_block = self.register_block();
        if !cmd.is_none() {
            reg_block.user2().modify(|_, w| {
                w.usr_command_bitlen()
                    .variant((cmd.width() - 1) as u8)
                    .usr_command_value()
                    .variant(cmd.value())
            });
        }

        #[cfg(not(esp32))]
        if !address.is_none() {
            reg_block
                .user1()
                .modify(|_, w| w.usr_addr_bitlen().variant((address.width() - 1) as u8));

            let addr = address.value() << (32 - address.width());
            reg_block.addr().write(|w| w.usr_addr_value().variant(addr));
        }

        #[cfg(esp32)]
        if !address.is_none() {
            reg_block.user1().modify(|r, w| unsafe {
                w.bits(r.bits() & !(0x3f << 26) | (((address.width() - 1) as u32) & 0x3f) << 26)
            });

            let addr = address.value() << (32 - address.width());
            reg_block.addr().write(|w| unsafe { w.bits(addr) });
        }

        if dummy > 0 {
            reg_block
                .user1()
                .modify(|_, w| w.usr_dummy_cyclelen().variant(dummy - 1));
        }

        self.configure_datalen(buffer.len() as u32 * 8);
        self.update();
        reg_block.cmd().modify(|_, w| w.usr().set_bit());
        self.flush()?;
        self.read_bytes_from_fifo(buffer)
    }

    #[cfg(not(any(esp32, esp32s2)))]
    fn update(&self) {
        let reg_block = self.register_block();

        reg_block.cmd().modify(|_, w| w.update().set_bit());

        while reg_block.cmd().read().update().bit_is_set() {
            // wait
        }
    }

    #[cfg(any(esp32, esp32s2))]
    fn update(&self) {
        // not need/available on ESP32/ESP32S2
    }

    fn configure_datalen(&self, len: u32) {
        let reg_block = self.register_block();
        let len = if len > 0 { len - 1 } else { 0 };

        #[cfg(any(esp32c2, esp32c3, esp32c6, esp32h2, esp32s3))]
        reg_block
            .ms_dlen()
            .write(|w| unsafe { w.ms_data_bitlen().bits(len) });

        #[cfg(not(any(esp32c2, esp32c3, esp32c6, esp32h2, esp32s3)))]
        {
            reg_block
                .mosi_dlen()
                .write(|w| unsafe { w.usr_mosi_dbitlen().bits(len) });

            reg_block
                .miso_dlen()
                .write(|w| unsafe { w.usr_miso_dbitlen().bits(len) });
        }
    }
}

#[cfg(any(esp32c2, esp32c3, esp32c6, esp32h2))]
impl Instance for crate::peripherals::SPI2 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    #[inline(always)]
    fn sclk_signal(&self) -> OutputSignal {
        OutputSignal::FSPICLK_MUX
    }

    #[inline(always)]
    fn mosi_signal(&self) -> OutputSignal {
        OutputSignal::FSPID
    }

    #[inline(always)]
    fn miso_signal(&self) -> InputSignal {
        InputSignal::FSPIQ
    }

    #[inline(always)]
    fn cs_signal(&self) -> OutputSignal {
        OutputSignal::FSPICS0
    }

    #[inline(always)]
    fn enable_peripheral(&self) {
        PeripheralClockControl::enable(crate::system::Peripheral::Spi2);
    }

    #[inline(always)]
    fn spi_num(&self) -> u8 {
        2
    }
}

#[cfg(any(esp32c2, esp32c3, esp32c6, esp32h2))]
impl ExtendedInstance for crate::peripherals::SPI2 {
    #[inline(always)]
    fn sio0_input_signal(&self) -> InputSignal {
        InputSignal::FSPID
    }

    #[inline(always)]
    fn sio1_output_signal(&self) -> OutputSignal {
        OutputSignal::FSPIQ
    }

    #[inline(always)]
    fn sio2_output_signal(&self) -> OutputSignal {
        OutputSignal::FSPIWP
    }

    #[inline(always)]
    fn sio2_input_signal(&self) -> InputSignal {
        InputSignal::FSPIWP
    }

    #[inline(always)]
    fn sio3_output_signal(&self) -> OutputSignal {
        OutputSignal::FSPIHD
    }

    #[inline(always)]
    fn sio3_input_signal(&self) -> InputSignal {
        InputSignal::FSPIHD
    }
}

#[cfg(esp32)]
impl Instance for crate::peripherals::SPI2 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    #[inline(always)]
    fn sclk_signal(&self) -> OutputSignal {
        OutputSignal::HSPICLK
    }

    #[inline(always)]
    fn mosi_signal(&self) -> OutputSignal {
        OutputSignal::HSPID
    }

    #[inline(always)]
    fn miso_signal(&self) -> InputSignal {
        InputSignal::HSPIQ
    }

    #[inline(always)]
    fn cs_signal(&self) -> OutputSignal {
        OutputSignal::HSPICS0
    }

    #[inline(always)]
    fn enable_peripheral(&self) {
        PeripheralClockControl::enable(crate::system::Peripheral::Spi2);
    }

    #[inline(always)]
    fn spi_num(&self) -> u8 {
        2
    }
}

#[cfg(esp32)]
impl ExtendedInstance for crate::peripherals::SPI2 {
    fn sio0_input_signal(&self) -> InputSignal {
        InputSignal::HSPID
    }

    fn sio1_output_signal(&self) -> OutputSignal {
        OutputSignal::HSPIQ
    }

    fn sio2_output_signal(&self) -> OutputSignal {
        OutputSignal::HSPIWP
    }

    fn sio2_input_signal(&self) -> InputSignal {
        InputSignal::HSPIWP
    }

    fn sio3_output_signal(&self) -> OutputSignal {
        OutputSignal::HSPIHD
    }

    fn sio3_input_signal(&self) -> InputSignal {
        InputSignal::HSPIHD
    }
}

#[cfg(esp32)]
impl Instance for crate::peripherals::SPI3 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    #[inline(always)]
    fn sclk_signal(&self) -> OutputSignal {
        OutputSignal::VSPICLK
    }

    #[inline(always)]
    fn mosi_signal(&self) -> OutputSignal {
        OutputSignal::VSPID
    }

    #[inline(always)]
    fn miso_signal(&self) -> InputSignal {
        InputSignal::VSPIQ
    }

    #[inline(always)]
    fn cs_signal(&self) -> OutputSignal {
        OutputSignal::VSPICS0
    }

    #[inline(always)]
    fn enable_peripheral(&self) {
        PeripheralClockControl::enable(crate::system::Peripheral::Spi3)
    }

    #[inline(always)]
    fn spi_num(&self) -> u8 {
        3
    }
}

#[cfg(any(esp32s2, esp32s3))]
impl Instance for crate::peripherals::SPI2 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    #[inline(always)]
    fn sclk_signal(&self) -> OutputSignal {
        OutputSignal::FSPICLK
    }

    #[inline(always)]
    fn mosi_signal(&self) -> OutputSignal {
        OutputSignal::FSPID
    }

    #[inline(always)]
    fn miso_signal(&self) -> InputSignal {
        InputSignal::FSPIQ
    }

    #[inline(always)]
    fn cs_signal(&self) -> OutputSignal {
        OutputSignal::FSPICS0
    }

    #[inline(always)]
    fn enable_peripheral(&self) {
        PeripheralClockControl::enable(crate::system::Peripheral::Spi2)
    }

    #[inline(always)]
    fn spi_num(&self) -> u8 {
        2
    }
}

#[cfg(any(esp32s2, esp32s3))]
impl ExtendedInstance for crate::peripherals::SPI2 {
    #[inline(always)]
    fn sio0_input_signal(&self) -> InputSignal {
        InputSignal::FSPID
    }

    #[inline(always)]
    fn sio1_output_signal(&self) -> OutputSignal {
        OutputSignal::FSPIQ
    }

    #[inline(always)]
    fn sio2_output_signal(&self) -> OutputSignal {
        OutputSignal::FSPIWP
    }

    #[inline(always)]
    fn sio2_input_signal(&self) -> InputSignal {
        InputSignal::FSPIWP
    }

    #[inline(always)]
    fn sio3_output_signal(&self) -> OutputSignal {
        OutputSignal::FSPIHD
    }

    #[inline(always)]
    fn sio3_input_signal(&self) -> InputSignal {
        InputSignal::FSPIHD
    }
}

#[cfg(any(esp32s2, esp32s3))]
impl Instance for crate::peripherals::SPI3 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    #[inline(always)]
    fn sclk_signal(&self) -> OutputSignal {
        OutputSignal::SPI3_CLK
    }

    #[inline(always)]
    fn mosi_signal(&self) -> OutputSignal {
        OutputSignal::SPI3_D
    }

    #[inline(always)]
    fn miso_signal(&self) -> InputSignal {
        InputSignal::SPI3_Q
    }

    #[inline(always)]
    fn cs_signal(&self) -> OutputSignal {
        OutputSignal::SPI3_CS0
    }

    #[inline(always)]
    fn enable_peripheral(&self) {
        PeripheralClockControl::enable(crate::system::Peripheral::Spi3)
    }

    #[inline(always)]
    fn spi_num(&self) -> u8 {
        3
    }
}

#[cfg(esp32s3)]
impl ExtendedInstance for crate::peripherals::SPI3 {
    #[inline(always)]
    fn sio0_input_signal(&self) -> InputSignal {
        InputSignal::SPI3_D
    }

    #[inline(always)]
    fn sio1_output_signal(&self) -> OutputSignal {
        OutputSignal::SPI3_Q
    }

    #[inline(always)]
    fn sio2_output_signal(&self) -> OutputSignal {
        OutputSignal::SPI3_WP
    }

    #[inline(always)]
    fn sio2_input_signal(&self) -> InputSignal {
        InputSignal::SPI3_WP
    }

    #[inline(always)]
    fn sio3_output_signal(&self) -> OutputSignal {
        OutputSignal::SPI3_HD
    }

    #[inline(always)]
    fn sio3_input_signal(&self) -> InputSignal {
        InputSignal::SPI3_HD
    }
}