tsl/common/i2c.cc

93 lines
1.9 KiB
C++

#include "common/i2c.h"
#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <cassert>
#include <cstdio>
#include <stdexcept>
#include "common/swaglog.h"
#include "common/util.h"
#define UNUSED(x) (void)(x)
#ifdef QCOM2
// TODO: decide if we want to install libi2c-dev everywhere
extern "C" {
#include <linux/i2c-dev.h>
#include <i2c/smbus.h>
}
I2CBus::I2CBus(uint8_t bus_id) {
char bus_name[20];
snprintf(bus_name, 20, "/dev/i2c-%d", bus_id);
i2c_fd = HANDLE_EINTR(open(bus_name, O_RDWR));
if (i2c_fd < 0) {
throw std::runtime_error("Failed to open I2C bus");
}
}
I2CBus::~I2CBus() {
if (i2c_fd >= 0) {
close(i2c_fd);
}
}
int I2CBus::read_register(uint8_t device_address, uint register_address, uint8_t *buffer, uint8_t len) {
std::lock_guard lk(m);
int ret = 0;
ret = HANDLE_EINTR(ioctl(i2c_fd, I2C_SLAVE, device_address));
if (ret < 0) { goto fail; }
ret = i2c_smbus_read_i2c_block_data(i2c_fd, register_address, len, buffer);
if ((ret < 0) || (ret != len)) { goto fail; }
fail:
return ret;
}
int I2CBus::set_register(uint8_t device_address, uint register_address, uint8_t data) {
std::lock_guard lk(m);
int ret = 0;
ret = HANDLE_EINTR(ioctl(i2c_fd, I2C_SLAVE, device_address));
if (ret < 0) { goto fail; }
ret = i2c_smbus_write_byte_data(i2c_fd, register_address, data);
if (ret < 0) { goto fail; }
fail:
return ret;
}
#else
I2CBus::I2CBus(uint8_t bus_id) {
UNUSED(bus_id);
i2c_fd = -1;
}
I2CBus::~I2CBus() {}
int I2CBus::read_register(uint8_t device_address, uint register_address, uint8_t *buffer, uint8_t len) {
UNUSED(device_address);
UNUSED(register_address);
UNUSED(buffer);
UNUSED(len);
return -1;
}
int I2CBus::set_register(uint8_t device_address, uint register_address, uint8_t data) {
UNUSED(device_address);
UNUSED(register_address);
UNUSED(data);
return -1;
}
#endif