ardupilot/libraries/AP_HAL_Linux/GPIO_Sysfs.cpp

254 lines
5.8 KiB
C++
Raw Normal View History

#include "GPIO_Sysfs.h"
#include <AP_HAL/AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_LINUX
#include <fcntl.h>
#include <linux/limits.h>
#include <stdio.h>
#include <sys/stat.h>
#include <unistd.h>
#define LOW 0
#define HIGH 1
#define GPIO_PATH_FORMAT "/sys/class/gpio/gpio%u"
#define assert_vpin(v_, max_, ...) do { \
if (v_ >= max_) { \
hal.console->printf("warning (%s): vpin %u out of range [0, %u)\n",\
__PRETTY_FUNCTION__, v_, max_); \
return __VA_ARGS__; \
} \
} while (0)
using namespace Linux;
static const AP_HAL::HAL& hal = AP_HAL::get_HAL();
DigitalSource_Sysfs::DigitalSource_Sysfs(unsigned pin, int value_fd)
: _pin(pin)
, _value_fd(value_fd)
{
}
DigitalSource_Sysfs::~DigitalSource_Sysfs()
{
if (_value_fd >= 0) {
::close(_value_fd);
}
}
uint8_t DigitalSource_Sysfs::read()
{
char char_value;
int r = ::pread(_value_fd, &char_value, 1, 0);
if (r < 0) {
hal.console->printf("warning: unable to read GPIO value for pin %u\n",
_pin);
return LOW;
}
return char_value == '1' ? HIGH : LOW;
}
void DigitalSource_Sysfs::write(uint8_t value)
{
int r = ::pwrite(_value_fd, value == HIGH ? "1" : "0", 1, 0);
if (r < 0) {
hal.console->printf("warning: unable to write GPIO value for pin %u\n",
_pin);
}
}
void DigitalSource_Sysfs::mode(uint8_t output)
{
auto gpio_sysfs = GPIO_Sysfs::from(hal.gpio);
gpio_sysfs->_pinMode(_pin, output);
}
void DigitalSource_Sysfs::toggle()
{
write(!read());
}
void GPIO_Sysfs::init()
{
}
void GPIO_Sysfs::pinMode(uint8_t vpin, uint8_t output)
{
assert_vpin(vpin, n_pins);
unsigned pin = pin_table[vpin];
_pinMode(pin, output);
}
void GPIO_Sysfs::_pinMode(unsigned int pin, uint8_t output)
{
char direction_path[PATH_MAX];
snprintf(direction_path, PATH_MAX, GPIO_PATH_FORMAT "/direction", pin);
int fd = open(direction_path, O_WRONLY | O_CLOEXEC);
if (fd < 0) {
hal.console->printf("unable to open %s\n", direction_path);
return;
}
int r = dprintf(fd, output == HAL_GPIO_INPUT ? "in\n" : "out\n");
if (r < 0) {
hal.console->printf("unable to write to %s\n", direction_path);
}
close(fd);
}
int GPIO_Sysfs::_open_pin_value(unsigned int pin, int flags)
{
char path[PATH_MAX];
int fd;
snprintf(path, PATH_MAX, GPIO_PATH_FORMAT "/value", pin);
fd = open(path, flags | O_CLOEXEC);
if (fd < 0) {
hal.console->printf("warning: unable to open %s\n", path);
return -1;
}
return fd;
}
uint8_t GPIO_Sysfs::read(uint8_t vpin)
{
assert_vpin(vpin, n_pins, LOW);
unsigned pin = pin_table[vpin];
int fd = _open_pin_value(pin, O_RDONLY);
if (fd < 0)
return LOW;
char char_value;
uint8_t value;
int r = ::pread(fd, &char_value, 1, 0);
if (r < 0) {
hal.console->printf("warning: unable to read pin %u\n", pin);
value = LOW;
} else {
value = char_value == '1' ? HIGH : LOW;
}
close(fd);
return value;
}
void GPIO_Sysfs::write(uint8_t vpin, uint8_t value)
{
assert_vpin(vpin, n_pins);
unsigned pin = pin_table[vpin];
int fd = _open_pin_value(pin, O_WRONLY);
if (fd < 0)
return;
int r = ::pwrite(fd, value == HIGH ? "1" : "0", 1, 0);
if (r < 0) {
hal.console->printf("warning: unable to write pin %u\n", pin);
}
close(fd);
}
void GPIO_Sysfs::toggle(uint8_t vpin)
{
write(vpin, !read(vpin));
}
int8_t GPIO_Sysfs::analogPinToDigitalPin(uint8_t vpin)
{
return -1;
}
AP_HAL::DigitalSource* GPIO_Sysfs::channel(uint16_t vpin)
{
assert_vpin(vpin, n_pins, nullptr);
unsigned pin = pin_table[vpin];
int value_fd = -1;
if (export_pin(vpin)) {
char value_path[PATH_MAX];
snprintf(value_path, PATH_MAX, GPIO_PATH_FORMAT "/value", pin);
value_fd = open(value_path, O_RDWR | O_CLOEXEC);
if (value_fd < 0) {
hal.console->printf("unable to open %s\n", value_path);
}
}
/* Even if we couldn't open the fd, return a new DigitalSource and let
* reads and writes fail later due to invalid. Otherwise we
* could crash in undesired places */
return new DigitalSource_Sysfs(pin, value_fd);
}
bool GPIO_Sysfs::attach_interrupt(uint8_t interrupt_num, AP_HAL::Proc p,
uint8_t mode)
{
return false;
}
bool GPIO_Sysfs::usb_connected(void)
{
return false;
}
bool GPIO_Sysfs::export_pin(uint8_t vpin)
{
uint8_t vpins[] = { vpin };
return export_pins(vpins, 1);
}
bool GPIO_Sysfs::export_pins(uint8_t vpins[], size_t len)
{
int fd = open("/sys/class/gpio/export", O_WRONLY | O_CLOEXEC);
if (fd < 0) {
hal.console->printf("unable to open /sys/class/gpio/export");
return false;
}
bool success = true;
for (unsigned int i = 0; i < len; i++) {
if (vpins[i] >= n_pins) {
hal.console->printf("GPIO_Sysfs: can't open pin %u\n",
vpins[i]);
success = false;
break;
}
unsigned int pin = pin_table[vpins[i]];
char gpio_path[PATH_MAX];
snprintf(gpio_path, PATH_MAX, GPIO_PATH_FORMAT, pin);
// Verify if the pin is not already exported
if (access(gpio_path, F_OK) == 0)
continue;
int r = dprintf(fd, "%u\n", pin);
if (r < 0) {
hal.console->printf("error on exporting gpio pin number %u\n", pin);
success = false;
break;
}
}
close(fd);
return success;
}
#endif