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RIOT/drivers/periph_common/i2c.c

104 lines
2.8 KiB
C

/*
* Copyright (C) 2018 Mesotic SAS <dylan.laduranty@mesotic.com>
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @ingroup drivers_periph_i2c
* @{
*
* @file
* @brief common I2C function fallback implementations
*
* @author Dylan Laduranty <dylan.laduranty@mesotic.com>
*
* @}
*/
#include <errno.h>
#include "board.h"
#include "cpu.h"
#include "periph/i2c.h"
#include "byteorder.h"
#ifdef PERIPH_I2C_NEED_READ_REG
int i2c_read_reg(i2c_t dev, uint16_t addr, uint16_t reg,
void *data, uint8_t flags)
{
return i2c_read_regs(dev, addr, reg, data, 1, flags);
}
#endif /* PERIPH_I2C_NEED_READ_REG */
#ifdef PERIPH_I2C_NEED_READ_REGS
int i2c_read_regs(i2c_t dev, uint16_t addr, uint16_t reg,
void *data, size_t len, uint8_t flags)
{
uint16_t reg_end = reg;
if (flags & (I2C_NOSTOP | I2C_NOSTART)) {
return -EOPNOTSUPP;
}
/* Handle endianness of register if 16 bit */
if (flags & I2C_REG16) {
reg_end = htons(reg); /* Make sure register is in big-endian on I2C bus */
}
/* First set ADDR and register with no stop */
int ret = i2c_write_bytes(dev, addr, &reg_end, (flags & I2C_REG16) ? 2 : 1,
flags | I2C_NOSTOP);
if (ret < 0) {
return ret;
}
/* Then get the data from device */
return i2c_read_bytes(dev, addr, data, len, flags);
}
#endif /* PERIPH_I2C_NEED_READ_REGS */
int i2c_read_byte(i2c_t dev, uint16_t addr, void *data, uint8_t flags)
{
return i2c_read_bytes(dev, addr, data, 1, flags);
}
int i2c_write_byte(i2c_t dev, uint16_t addr, uint8_t data, uint8_t flags)
{
return i2c_write_bytes(dev, addr, &data, 1, flags);
}
#ifdef PERIPH_I2C_NEED_WRITE_REG
int i2c_write_reg(i2c_t dev, uint16_t addr, uint16_t reg,
uint8_t data, uint8_t flags)
{
return i2c_write_regs(dev, addr, reg, &data, 1, flags);
}
#endif /* PERIPH_I2C_NEED_WRITE_REG */
#ifdef PERIPH_I2C_NEED_WRITE_REGS
int i2c_write_regs(i2c_t dev, uint16_t addr, uint16_t reg,
const void *data, size_t len, uint8_t flags)
{
uint16_t reg_end = reg;
if (flags & (I2C_NOSTOP | I2C_NOSTART)) {
return -EOPNOTSUPP;
}
/* Handle endianness of register if 16 bit */
if (flags & I2C_REG16) {
reg_end = htons(reg); /* Make sure register is in big-endian on I2C bus */
}
/* First set ADDR and register with no stop */
int ret = i2c_write_bytes(dev, addr, &reg_end, (flags & I2C_REG16) ? 2 : 1,
flags | I2C_NOSTOP);
if (ret < 0) {
return ret;
}
/* Then write data to the device */
return i2c_write_bytes(dev, addr, data, len, flags | I2C_NOSTART);
}
#endif /* PERIPH_I2C_NEED_WRITE_REGS */