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//! A collection of utility functions for interfacing with registers across an I2C bus
//!
//! This module provides both blocking and async variants of register read/write operations
//! and command invocation for I2C devices. All operations handle device addressing and
//! proper byte serialization/deserialization of register values.
use crate::{
byte_array::ByteArray as _,
errors::CommandError,
errors::{ReadRegisterError, WriteRegisterError},
Command, FromByteArray, ReadableRegister, ToByteArray, WritableRegister,
};
pub mod r#async {
use super::*;
/// Read a register value from an I2C device.
///
/// This function performs a write-read I2C transaction, first sending the register ID
/// then reading the register value. The received bytes are deserialized into the
/// specified register type.
///
/// # Parameters
/// * `device` - The I2C device to communicate with
/// * `device_addr` - The I2C address of the target device
///
/// # Errors
/// * `ReadRegisterError::BusError` - Communication with the device failed
/// * `ReadRegisterError::DeserializationError` - Failed to convert received bytes into register value
///
/// # Example
/// ```no_run
/// # use embedded_hal_async::i2c::I2c;
/// # use regiface::{register, i2c, ReadableRegister, FromByteArray};
/// # #[register(42u8)]
/// # #[derive(ReadableRegister)]
/// # struct TemperatureRegister;
/// # impl FromByteArray for TemperatureRegister {
/// # type Array = [u8; 2];
/// # type Error = ();
/// # fn from_bytes(_: Self::Array) -> Result<Self, Self::Error> { todo!() }
/// # }
/// async fn read_temp<D: I2c<u8>>(device: &mut D) {
/// let temp: TemperatureRegister = i2c::r#async::read_register(device, 0x48).await.unwrap();
/// }
/// ```
pub async fn read_register<D, A, R>(
device: &mut D,
device_addr: A,
) -> Result<R, ReadRegisterError<D::Error, R::Error>>
where
A: embedded_hal_async::i2c::AddressMode,
D: embedded_hal_async::i2c::I2c<A>,
R: ReadableRegister,
{
let mut buf = <R as FromByteArray>::Array::new();
// Register ID types have compiler enforced infallible byte conversions, thus this unwrap is safe
let reg_id = R::readable_id().to_bytes().unwrap();
device
.write_read(device_addr, reg_id.as_ref(), buf.as_mut())
.await
.map_err(ReadRegisterError::BusError)?;
R::from_bytes(buf).map_err(ReadRegisterError::DeserializationError)
}
/// Write a register value to an I2C device.
///
/// This function performs a write I2C transaction, sending both the register ID
/// and the serialized register value. The operation is atomic, using the device's
/// transaction capability to ensure both writes occur without interruption.
///
/// # Parameters
/// * `device` - The I2C device to communicate with
/// * `device_addr` - The I2C address of the target device
/// * `register` - The register value to write
///
/// # Errors
/// * `WriteRegisterError::BusError` - Communication with the device failed
/// * `WriteRegisterError::SerializationError` - Failed to convert register value to bytes
///
/// # Example
/// ```no_run
/// # use embedded_hal_async::i2c::I2c;
/// # use regiface::{register, i2c, WritableRegister, ToByteArray};
/// #[register(42u8)]
/// #[derive(WritableRegister)]
/// # struct ConfigRegister{};
/// # impl ToByteArray for ConfigRegister {
/// # type Array = [u8; 1];
/// # type Error = ();
/// # fn to_bytes(self) -> Result<Self::Array, Self::Error> { Ok([0]) }
/// # }
/// async fn configure<D: I2c<u8>>(device: &mut D) {
/// i2c::r#async::write_register(device, 0x48, ConfigRegister{ /* ... */}).await.unwrap();
/// }
/// ```
pub async fn write_register<D, A, R>(
device: &mut D,
device_addr: A,
register: R,
) -> Result<(), WriteRegisterError<D::Error, R::Error>>
where
A: embedded_hal_async::i2c::AddressMode,
D: embedded_hal_async::i2c::I2c<A>,
R: WritableRegister,
{
let buf = register
.to_bytes()
.map_err(WriteRegisterError::SerializationError)?;
// Register ID types have compiler enforced infallible byte conversions, thus this unwrap is safe
let reg_id = R::writeable_id().to_bytes().unwrap();
device
.transaction(
device_addr,
&mut [
embedded_hal_async::i2c::Operation::Write(reg_id.as_ref()),
embedded_hal_async::i2c::Operation::Write(buf.as_ref()),
],
)
.await
.map_err(WriteRegisterError::BusError)
}
/// Invoke a command on an I2C device and receive its response.
///
/// This function performs a complete command transaction:
/// 1. Sends the command ID
/// 2. Sends the serialized command parameters
/// 3. Reads the command response
///
/// The entire operation is atomic, using the device's transaction capability to
/// ensure all steps occur without interruption.
///
/// # Parameters
/// * `device` - The I2C device to communicate with
/// * `device_addr` - The I2C address of the target device
/// * `cmd` - The command to invoke
///
/// # Errors
/// * `CommandError::BusError` - Communication with the device failed
/// * `CommandError::SerializationError` - Failed to convert command parameters to bytes
/// * `CommandError::DeserializationError` - Failed to convert received bytes into response parameters
///
/// # Example
/// ```no_run
/// # use embedded_hal_async::i2c::I2c;
/// # use regiface::{NoParameters, i2c, Command, FromByteArray, ToByteArray};
/// # struct SelfTestCommand{};
/// # struct SelfTestResponse;
/// # impl Command for SelfTestCommand {
/// # type IdType = u8;
/// # type CommandParameters = NoParameters;
/// # type ResponseParameters = SelfTestResponse;
/// # fn id() -> Self::IdType { 0xF0 }
/// # fn invoking_parameters(self) -> Self::CommandParameters { todo!() }
/// # }
/// # impl FromByteArray for SelfTestResponse {
/// # type Array = [u8; 1];
/// # type Error = ();
/// # fn from_bytes(_: Self::Array) -> Result<Self, Self::Error> { Ok(Self) }
/// # }
/// async fn perform_self_test<D: I2c<u8>>(device: &mut D) {
/// let result: SelfTestResponse = i2c::r#async::invoke_command(device, 0x48, SelfTestCommand{ /* ... */}).await.unwrap();
/// }
/// ```
#[allow(clippy::type_complexity)]
pub async fn invoke_command<D, A, C>(
device: &mut D,
device_addr: A,
cmd: C,
) -> Result<
C::ResponseParameters,
CommandError<
D::Error,
<C::CommandParameters as ToByteArray>::Error,
<C::ResponseParameters as FromByteArray>::Error,
>,
>
where
A: embedded_hal_async::i2c::AddressMode,
D: embedded_hal_async::i2c::I2c<A>,
C: Command,
{
let cmd_buf = cmd
.invoking_parameters()
.to_bytes()
.map_err(CommandError::SerializationError)?;
let mut resp_buf = <C::ResponseParameters as FromByteArray>::Array::new();
// Register ID types have compiler enforced infallible byte conversions, thus this unwrap is safe
let reg_id = unsafe { C::id().to_bytes().unwrap_unchecked() };
device
.transaction(
device_addr,
&mut [
embedded_hal::i2c::Operation::Write(reg_id.as_ref()),
embedded_hal::i2c::Operation::Write(cmd_buf.as_ref()),
embedded_hal::i2c::Operation::Read(resp_buf.as_mut()),
],
)
.await
.map_err(CommandError::BusError)?;
C::ResponseParameters::from_bytes(resp_buf).map_err(CommandError::DeserializationError)
}
}
pub mod blocking {
use super::*;
/// Read a register value from an I2C device.
///
/// Blocking variant of [`read_register`](crate::i2c::async::read_register).
/// See the async function documentation for detailed behavior description.
///
/// # Example
/// ```no_run
/// # use embedded_hal::i2c::I2c;
/// # use regiface::{register, i2c, ReadableRegister, FromByteArray};
/// # #[register(42u8)]
/// # #[derive(ReadableRegister)]
/// # struct TemperatureRegister;
/// # impl FromByteArray for TemperatureRegister {
/// # type Array = [u8; 2];
/// # type Error = ();
/// # fn from_bytes(_: Self::Array) -> Result<Self, Self::Error> {todo!()}
/// # }
/// fn read_temp<D: I2c<u8>>(device: &mut D) {
/// let temp: TemperatureRegister = i2c::blocking::read_register(device, 0x48).unwrap();
/// }
/// ```
pub fn read_register<D, A, R>(
device: &mut D,
device_addr: A,
) -> Result<R, ReadRegisterError<D::Error, R::Error>>
where
A: embedded_hal::i2c::AddressMode,
D: embedded_hal::i2c::I2c<A>,
R: ReadableRegister,
{
let mut buf = <R as FromByteArray>::Array::new();
// Register ID types have compiler enforced infallible byte conversions, thus this unwrap is safe
let reg_id = R::readable_id().to_bytes().unwrap();
device
.write_read(device_addr, reg_id.as_ref(), buf.as_mut())
.map_err(ReadRegisterError::BusError)?;
R::from_bytes(buf).map_err(ReadRegisterError::DeserializationError)
}
/// Write a register value to an I2C device.
///
/// Blocking variant of [`write_register`](crate::i2c::async::write_register).
/// See the async function documentation for detailed behavior description.
///
/// # Example
/// ```no_run
/// # use embedded_hal::i2c::I2c;
/// # use regiface::{register, i2c, WritableRegister, ToByteArray};
/// #[register(42u8)]
/// #[derive(WritableRegister)]
/// # struct ConfigRegister;
/// # impl ToByteArray for ConfigRegister {
/// # type Array = [u8; 1];
/// # type Error = ();
/// # fn to_bytes(self) -> Result<Self::Array, Self::Error> { Ok([0]) }
/// # }
/// fn configure<D: I2c<u8>>(device: &mut D) {
/// i2c::blocking::write_register(device, 0x48, ConfigRegister{ /* ... */}).unwrap();
/// }
/// ```
pub fn write_register<D, A, R>(
device: &mut D,
device_addr: A,
register: R,
) -> Result<(), WriteRegisterError<D::Error, R::Error>>
where
A: embedded_hal::i2c::AddressMode,
D: embedded_hal::i2c::I2c<A>,
R: WritableRegister,
{
let buf = register
.to_bytes()
.map_err(WriteRegisterError::SerializationError)?;
// Register ID types have compiler enforced infallible byte conversions, thus this unwrap is safe
let reg_id = R::writeable_id().to_bytes().unwrap();
device
.transaction(
device_addr,
&mut [
embedded_hal_async::i2c::Operation::Write(reg_id.as_ref()),
embedded_hal_async::i2c::Operation::Write(buf.as_ref()),
],
)
.map_err(WriteRegisterError::BusError)
}
/// Invoke a command on an I2C device and receive its response.
///
/// Blocking variant of [`invoke_command`](crate::i2c::async::invoke_command).
/// See the async function documentation for detailed behavior description.
///
/// # Example
/// ```no_run
/// # use embedded_hal::i2c::I2c;
/// # use regiface::{NoParameters, i2c, Command, FromByteArray, ToByteArray};
/// # struct SelfTestCommand;
/// # struct SelfTestResponse;
/// # impl Command for SelfTestCommand {
/// # type IdType = u8;
/// # type CommandParameters = NoParameters;
/// # type ResponseParameters = SelfTestResponse;
/// # fn id() -> Self::IdType { 0xF0 }
/// # fn invoking_parameters(self) -> Self::CommandParameters { todo!() }
/// # }
/// # impl FromByteArray for SelfTestResponse {
/// # type Array = [u8; 1];
/// # type Error = ();
/// # fn from_bytes(_: Self::Array) -> Result<Self, Self::Error> { Ok(Self) }
/// # }
/// fn perform_self_test<D: I2c<u8>>(device: &mut D) {
/// let result: SelfTestResponse = i2c::blocking::invoke_command(device, 0x48, SelfTestCommand).unwrap();
/// }
/// ```
#[allow(clippy::type_complexity)]
pub fn invoke_command<D, A, C>(
device: &mut D,
device_addr: A,
cmd: C,
) -> Result<
C::ResponseParameters,
CommandError<
D::Error,
<C::CommandParameters as ToByteArray>::Error,
<C::ResponseParameters as FromByteArray>::Error,
>,
>
where
A: embedded_hal::i2c::AddressMode,
D: embedded_hal::i2c::I2c<A>,
C: Command,
{
let cmd_buf = cmd
.invoking_parameters()
.to_bytes()
.map_err(CommandError::SerializationError)?;
let mut resp_buf = <C::ResponseParameters as FromByteArray>::Array::new();
// Register ID types have compiler enforced infallible byte conversions, thus this unwrap is safe
let reg_id = unsafe { C::id().to_bytes().unwrap_unchecked() };
device
.transaction(
device_addr,
&mut [
embedded_hal::i2c::Operation::Write(reg_id.as_ref()),
embedded_hal::i2c::Operation::Write(cmd_buf.as_ref()),
embedded_hal::i2c::Operation::Read(resp_buf.as_mut()),
],
)
.map_err(CommandError::BusError)?;
C::ResponseParameters::from_bytes(resp_buf).map_err(CommandError::DeserializationError)
}
}