ardupilot/libraries/AP_HAL_Linux/I2CDriver.cpp

299 lines
6.6 KiB
C++

#include <AP_HAL/AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_LINUX
#include "I2CDriver.h"
#include "Util.h"
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/ioctl.h>
#include <linux/i2c-dev.h>
#ifndef I2C_SMBUS_BLOCK_MAX
#include <linux/i2c.h>
#endif
extern const AP_HAL::HAL& hal;
using namespace Linux;
/*
constructor
*/
I2CDriver::I2CDriver(AP_HAL::Semaphore* semaphore, const char *device) :
_semaphore(semaphore)
{
_device = strdup(device);
#if CONFIG_HAL_BOARD_SUBTYPE != HAL_BOARD_SUBTYPE_LINUX_NONE
if (!((Util*)hal.util)->is_chardev_node(_device))
hal.scheduler->panic("I2C device is not a chardev node");
#endif
}
/* Match a given device by the prefix its devpath, i.e. the path returned by
* udevadm info -q path /dev/<i2c-device>'. This constructor can be used when
* the number of the I2C bus is not stable across reboots. It matches the
* first device with a prefix in @devpaths */
I2CDriver::I2CDriver(AP_HAL::Semaphore* semaphore,
const char * const devpaths[]) :
_semaphore(semaphore)
{
const char *dirname = "/sys/class/i2c-dev";
struct dirent *de;
DIR *d;
d = opendir(dirname);
if (!d)
hal.scheduler->panic("Could not get list of I2C buses");
for (de = readdir(d); de; de = readdir(d)) {
const char *p, * const *t;
char buf[PATH_MAX], buf2[PATH_MAX];
if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
continue;
if (snprintf(buf, sizeof(buf), "%s/%s", dirname, de->d_name) >= PATH_MAX)
continue;
p = realpath(buf, buf2);
if (!p || strncmp(p, "/sys", sizeof("/sys") - 1))
continue;
p += sizeof("/sys") - 1;
for (t = devpaths; t && *t; t++) {
if (strncmp(p, *t, strlen(*t)) == 0)
break;
}
if (!*t)
continue;
/* Found the device name, use the new path */
asprintf(&_device, "/dev/%s", de->d_name);
break;
}
closedir(d);
if (!((Util*)hal.util)->is_chardev_node(_device))
hal.scheduler->panic("I2C device is not a chardev node");
}
I2CDriver::~I2CDriver()
{
free(_device);
}
/*
called from HAL class init()
*/
void I2CDriver::begin()
{
if (_fd != -1) {
close(_fd);
}
_fd = open(_device, O_RDWR);
}
void I2CDriver::end()
{
if (_fd != -1) {
::close(_fd);
_fd = -1;
}
}
/*
tell the I2C library what device we want to talk to
*/
bool I2CDriver::set_address(uint8_t addr)
{
if (_fd == -1) {
return false;
}
if (_addr != addr) {
ioctl(_fd, I2C_SLAVE, addr);
_addr = addr;
}
return true;
}
void I2CDriver::setTimeout(uint16_t ms)
{
// unimplemented
}
void I2CDriver::setHighSpeed(bool active)
{
// unimplemented
}
uint8_t I2CDriver::write(uint8_t addr, uint8_t len, uint8_t* data)
{
if (!set_address(addr)) {
return 1;
}
if (::write(_fd, data, len) != len) {
return 1;
}
return 0; // success
}
uint8_t I2CDriver::writeRegisters(uint8_t addr, uint8_t reg,
uint8_t len, uint8_t* data)
{
uint8_t buf[len+1];
buf[0] = reg;
if (len != 0) {
memcpy(&buf[1], data, len);
}
return write(addr, len+1, buf);
}
/*
this is a copy of i2c_smbus_access() from i2c-dev.h. We need it for
platforms with older headers
*/
static inline __s32 _i2c_smbus_access(int file, char read_write, __u8 command,
int size, union i2c_smbus_data *data)
{
struct i2c_smbus_ioctl_data args;
args.read_write = read_write;
args.command = command;
args.size = size;
args.data = data;
return ioctl(file,I2C_SMBUS,&args);
}
uint8_t I2CDriver::writeRegister(uint8_t addr, uint8_t reg, uint8_t val)
{
if (!set_address(addr)) {
return 1;
}
union i2c_smbus_data data;
data.byte = val;
if (_i2c_smbus_access(_fd,I2C_SMBUS_WRITE, reg,
I2C_SMBUS_BYTE_DATA, &data) == -1) {
return 1;
}
return 0;
}
uint8_t I2CDriver::read(uint8_t addr, uint8_t len, uint8_t* data)
{
if (!set_address(addr)) {
return 1;
}
if (::read(_fd, data, len) != len) {
return 1;
}
return 0;
}
uint8_t I2CDriver::readRegisters(uint8_t addr, uint8_t reg,
uint8_t len, uint8_t* data)
{
if (_fd == -1) {
return 1;
}
struct i2c_msg msgs[] = {
{
addr : addr,
flags : 0,
len : 1,
buf : (typeof(msgs->buf))&reg
},
{
addr : addr,
flags : I2C_M_RD,
len : len,
buf : (typeof(msgs->buf))data,
}
};
struct i2c_rdwr_ioctl_data i2c_data = {
msgs : msgs,
nmsgs : 2
};
// prevent valgrind error
memset(data, 0, len);
if (ioctl(_fd, I2C_RDWR, &i2c_data) == -1) {
return 1;
}
return 0;
}
uint8_t I2CDriver::readRegistersMultiple(uint8_t addr, uint8_t reg,
uint8_t len,
uint8_t count, uint8_t* data)
{
#ifdef I2C_RDRW_IOCTL_MAX_MSGS
const uint8_t max_count = I2C_RDRW_IOCTL_MAX_MSGS / 2;
#else
const uint8_t max_count = 8;
#endif
if (_fd == -1) {
return 1;
}
while (count > 0) {
uint8_t n = count > max_count ? max_count : count;
struct i2c_msg msgs[2*n];
struct i2c_rdwr_ioctl_data i2c_data = {
msgs : msgs,
nmsgs : (typeof(i2c_data.nmsgs))(2*n)
};
for (uint8_t i=0; i<n; i++) {
msgs[i*2].addr = addr;
msgs[i*2].flags = 0;
msgs[i*2].len = 1;
msgs[i*2].buf = (typeof(msgs->buf))&reg;
msgs[i*2+1].addr = addr;
msgs[i*2+1].flags = I2C_M_RD;
msgs[i*2+1].len = len;
msgs[i*2+1].buf = (typeof(msgs->buf))data;
data += len;
};
if (ioctl(_fd, I2C_RDWR, &i2c_data) == -1) {
return 1;
}
count -= n;
}
return 0;
}
uint8_t I2CDriver::readRegister(uint8_t addr, uint8_t reg, uint8_t* data)
{
if (!set_address(addr)) {
return 1;
}
union i2c_smbus_data v;
memset(&v, 0, sizeof(v));
if (_i2c_smbus_access(_fd,I2C_SMBUS_READ, reg,
I2C_SMBUS_BYTE_DATA, &v)) {
return 1;
}
*data = v.byte;
return 0;
}
uint8_t I2CDriver::lockup_count()
{
return 0;
}
#endif // CONFIG_HAL_BOARD