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// Copyright 2015, Paul Osborne <osbpau@gmail.com> // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/license/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. use byteorder::{ByteOrder, LittleEndian}; use std::error::Error; /// Interface to an I2C Slave Device from an I2C Master /// /// Typical implementations will store state with references to the bus /// in use and the address of the slave device. The trait is based on the /// Linux i2cdev interface. pub trait I2CDevice { type Error: Error; /// Read data from the device to fill the provided slice fn read(&mut self, data: &mut [u8]) -> Result<(), Self::Error>; /// Write the provided buffer to the device fn write(&mut self, data: &[u8]) -> Result<(), Self::Error>; /// This sends a single bit to the device, at the place of the Rd/Wr bit fn smbus_write_quick(&mut self, bit: bool) -> Result<(), Self::Error>; /// Read a single byte from a device, without specifying a device register /// /// Some devices are so simple that this interface is enough; for /// others, it is a shorthand if you want to read the same register as in /// the previous SMBus command. fn smbus_read_byte(&mut self) -> Result<u8, Self::Error> { let mut buf = [0_u8]; self.read(&mut buf)?; Ok(buf[0]) } /// Write a single byte to a device, without specifying a device register /// /// This is the opposite operation as smbus_read_byte. As with read_byte, /// no register is specified. fn smbus_write_byte(&mut self, value: u8) -> Result<(), Self::Error> { self.write(&mut [value]) } /// Read a single byte from a device, from a designated register /// /// The register is specified through the Comm byte. fn smbus_read_byte_data(&mut self, register: u8) -> Result<u8, Self::Error> { self.smbus_write_byte(register)?; self.smbus_read_byte() } /// Write a single byte to a specific register on a device /// /// The register is specified through the Comm byte. fn smbus_write_byte_data(&mut self, register: u8, value: u8) -> Result<(), Self::Error> { self.write(&mut [register, value]) } /// Read 2 bytes from a given register on a device (lsb first) fn smbus_read_word_data(&mut self, register: u8) -> Result<u16, Self::Error> { let mut buf: [u8; 2] = [0x00; 2]; self.smbus_write_byte(register)?; self.read(&mut buf)?; Ok(LittleEndian::read_u16(&buf)) } /// Write 2 bytes to a given register on a device (lsb first) fn smbus_write_word_data(&mut self, register: u8, value: u16) -> Result<(), Self::Error> { let mut buf: [u8; 3] = [register, 0, 0]; LittleEndian::write_u16(&mut buf[1..], value); self.write(&buf) } /// Select a register, send 16 bits of data to it, and read 16 bits of data fn smbus_process_word(&mut self, register: u8, value: u16) -> Result<u16, Self::Error> { let mut buf: [u8; 2] = [0x00; 2]; self.smbus_write_word_data(register, value)?; self.read(&mut buf)?; Ok(LittleEndian::read_u16(&buf)) } /// Read a block of up to 32 bytes from a device /// /// The actual number of bytes available to read is returned in the count /// byte. This code returns a correctly sized vector containing the /// count bytes read from the device. fn smbus_read_block_data(&mut self, register: u8) -> Result<Vec<u8>, Self::Error>; /// Read a block of up to 32 bytes from a device /// /// Uses read_i2c_block_data instead read_block_data. fn smbus_read_i2c_block_data(&mut self, register: u8, len: u8) -> Result<Vec<u8>, Self::Error>; /// Write a block of up to 32 bytes to a device /// /// The opposite of the Block Read command, this writes up to 32 bytes to /// a device, to a designated register that is specified through the /// Comm byte. The amount of data is specified in the Count byte. fn smbus_write_block_data(&mut self, register: u8, values: &[u8]) -> Result<(), Self::Error>; /// Write a block of up to 32 bytes from a device /// /// Uses write_i2c_block_data instead write_block_data. fn smbus_write_i2c_block_data(&mut self, register: u8, values: &[u8]) -> Result<(), Self::Error>; /// Select a register, send 1 to 31 bytes of data to it, and reads /// 1 to 31 bytes of data from it. fn smbus_process_block(&mut self, register: u8, values: &[u8]) -> Result<Vec<u8>, Self::Error>; } /// Interface to an I2C Bus from an I2C Master /// /// This is used when the client wants to interact directly with the bus /// without specifying an I2C slave address up-front, either because it needs /// to communicate with multiple addresses without creatings separate /// I2CDevice objects, or because it wants to make used of the I2C_RDWR ioctl /// which allows the client to send and transmit multiple sets I2C data in a /// single operation, potentially to different I2C slave addresses. /// /// Typical implementations will store state with references to the bus /// in use. The trait is based on the Linux i2cdev interface. pub trait I2CBus { type Error: Error; // Performs multiple serially chained I2C read/write transactions. On // success the return code is the number of successfully executed // transactions fn rdwr<'a>(&mut self, msgs: &mut Vec<I2CMsg<'a>>) -> Result<i32, Self::Error>; } bitflags! { pub struct I2CMsgFlags: u16 { /// this is a ten bit chip address const I2C_M_TEN = 0x0010; /// read data, from slave to master const I2C_M_RD = 0x0001; /// if I2C_FUNC_PROTOCOL_MANGLING const I2C_M_STOP = 0x8000; /// if I2C_FUNC_NOSTART const I2C_M_NOSTART = 0x4000; /// if I2C_FUNC_PROTOCOL_MANGLING const I2C_M_REV_DIR_ADDR = 0x2000; /// if I2C_FUNC_PROTOCOL_MANGLING const I2C_M_IGNORE_NAK = 0x1000; /// if I2C_FUNC_PROTOCOL_MANGLING const I2C_M_NO_RD_ACK = 0x0800; /// length will be first received byte const I2C_M_RECV_LEN = 0x0400; } } /// Rust version of i2c_msg pub struct I2CMsg<'a> { /// slave address pub(crate) addr: u16, /// serialized I2CMsgFlags pub(crate) flags: u16, /// msg length comes from msg Vector length /// msg data to be sent/received pub(crate) data: &'a mut Vec<u8>, } impl<'a> I2CMsg<'a> { /// Create I2CMsg from address and data buffer pub fn new(addr: u16, data: &'a mut Vec<u8>) -> Self { I2CMsg { addr, flags: 0, data } } /// Set flags pub fn set_flags(&mut self, flags: u16) { self.flags = flags; } /// Get flags pub fn flags(&mut self) -> u16 { self.flags } /// Set addr pub fn set_addr(&mut self, addr: u16) { self.addr = addr; } /// Get addr pub fn addr(&mut self) -> u16 { self.addr } /// Set data pub fn set_data(&mut self, data: &'a mut Vec<u8>) { self.data = data; } /// Get addr pub fn data(&mut self) -> Vec<u8> { self.data.clone() } /// Sets the read flag pub fn set_read(&mut self) { self.flags |= I2CMsgFlags::I2C_M_RD.bits; } }