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linux_gpio: open fd once, and reuse it

Browse Source 
Signed-off-by: Nicolae Rosia <nicolae.rosia@gmail.com>
This commit is contained in:
Nicolae Rosia
2017-06-06 09:59:49 +02:00
committed by Beat Küng
parent 92ac6f0c89
commit 6ddc0b3fef
2 changed files with 80 additions and 107 deletions
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src/drivers/linux_gpio/linux_gpio.cpp
+78 -100
View File
@@ -43,100 +43,111 @@
LinuxGPIO::LinuxGPIO(unsigned int pin)
: _pin(pin)
, _fd(-1)
{
}
LinuxGPIO::~LinuxGPIO()
{
if (_fd != -1) {
close(_fd);
}
}
int LinuxGPIO::exportPin()
{
return LinuxGPIO::_exportPin(_pin);
}
int LinuxGPIO::unexportPin()
{
return LinuxGPIO::_unexportPin(_pin);
}
int LinuxGPIO::setDirection(LinuxGPIO::Direction dir)
{
return LinuxGPIO::_setDirection(_pin, (int)dir);
}
int LinuxGPIO::readValue()
{
return LinuxGPIO::_readValue(_pin);
}
int LinuxGPIO::writeValue(LinuxGPIO::Value value)
{
return LinuxGPIO::_writeValue(_pin, (unsigned int)value);
}
int LinuxGPIO::_exportPin(unsigned int pin)
{
char pinIndex[PIN_INDEX_BUFFER_MAX];
int fd;
int ret;
char pinIndex[PIN_INDEX_BUFFER_MAX];
char valuePath[PIN_VALUE_BUFFER_MAX];
int fd = -1;
int bytes_to_write;
if (_readValue(pin) != -1) {
/* GPIO is already exported */
return 0;
struct stat statbuf;
/* If GPIO was already opened, close it */
if (_fd != -1) {
close(_fd);
_fd = -1;
}
fd = open("/sys/class/gpio/export", O_WRONLY);
if (fd == -1) {
int err = errno;
PX4_ERR("export failed: open: %s (%d)", strerror(err), err);
return -1;
}
bytes_to_write = snprintf(pinIndex, PIN_INDEX_BUFFER_MAX, "%u", pin);
ret = write(fd, pinIndex, bytes_to_write);
/* Check if GPIO is already exported */
snprintf(valuePath, PIN_VALUE_BUFFER_MAX, "/sys/class/gpio/gpio%d/value", _pin);
ret = stat(valuePath, &statbuf);
if (ret == -1) {
int err = errno;
PX4_ERR("export failed: write: %s (%d)", strerror(err), err);
goto cleanup;
/* GPIO is not exported */
fd = open("/sys/class/gpio/export", O_WRONLY);
} else if (ret != bytes_to_write) {
PX4_ERR("failed to write: incomplete %d != %d", ret, bytes_to_write);
if (fd == -1) {
int err = errno;
PX4_ERR("export %u: open: %s (%d)", _pin, strerror(err), err);
return -1;
}
bytes_to_write = snprintf(pinIndex, PIN_INDEX_BUFFER_MAX, "%u", _pin);
ret = write(fd, pinIndex, bytes_to_write);
if (ret == -1) {
int err = errno;
PX4_ERR("export %u: write: %s (%d)", _pin, strerror(err), err);
goto cleanup;
} else if (ret != bytes_to_write) {
PX4_ERR("export %u: write incomplete %d != %d", _pin, ret, bytes_to_write);
goto cleanup;
}
}
_fd = open(valuePath, O_RDWR);
if (_fd == -1) {
int err = errno;
ret = -1;
PX4_ERR("export %u: open: %s (%d)", _pin, strerror(err), err);
goto cleanup;
}
ret = 0;
cleanup:
close(fd);
if (fd != -1) {
close(fd);
}
return ret;
}
int LinuxGPIO::_unexportPin(unsigned int pin)
int LinuxGPIO::unexportPin()
{
char pinIndex[PIN_INDEX_BUFFER_MAX];
int fd;
int ret;
int bytes_to_write;
if (_fd != -1) {
close(_fd);
_fd = -1;
}
fd = open("/sys/class/gpio/unexport", O_WRONLY);
if (fd == -1) {
int err = errno;
PX4_ERR("unexport %u: open: %s (%d)", pin, strerror(err), err);
PX4_ERR("unexport %u: open: %s (%d)", _pin, strerror(err), err);
return -1;
}
bytes_to_write = snprintf(pinIndex, PIN_INDEX_BUFFER_MAX, "%u", pin);
bytes_to_write = snprintf(pinIndex, PIN_INDEX_BUFFER_MAX, "%u", _pin);
ret = write(fd, pinIndex, bytes_to_write);
if (ret == -1) {
int err = errno;
PX4_ERR("unexport %u: write: %s (%d)", pin, strerror(err), err);
PX4_ERR("unexport %u: write: %s (%d)", _pin, strerror(err), err);
goto cleanup;
} else if (ret != bytes_to_write) {
PX4_ERR("unexport %u: write incomplete %d != %d", pin, ret, bytes_to_write);
PX4_ERR("unexport %u: write incomplete %d != %d", _pin, ret, bytes_to_write);
goto cleanup;
}
@@ -148,22 +159,22 @@ cleanup:
return ret;
}
int LinuxGPIO::_setDirection(unsigned int pin, int dir)
int LinuxGPIO::setDirection(LinuxGPIO::Direction dir)
{
char path[PIN_DIRECTION_BUFFER_MAX];
int fd;
int ret;
snprintf(path, PIN_DIRECTION_BUFFER_MAX, "/sys/class/gpio/gpio%d/direction", pin);
snprintf(path, PIN_DIRECTION_BUFFER_MAX, "/sys/class/gpio/gpio%d/direction", _pin);
fd = open(path, O_WRONLY);
if (fd == -1) {
int err = errno;
PX4_ERR("dir %u: open: %s (%d)", pin, strerror(err), err);
PX4_ERR("dir %u: open: %s (%d)", _pin, strerror(err), err);
return -1;
}
if (dir == 0) {
if (dir == Direction::IN) {
ret = write(fd, "in", 2);
} else {
@@ -172,7 +183,7 @@ int LinuxGPIO::_setDirection(unsigned int pin, int dir)
if (ret == -1) {
int err = errno;
PX4_ERR("dir %u: write: %s (%d)", pin, strerror(err), err);
PX4_ERR("dir %u: write: %s (%d)", _pin, strerror(err), err);
goto cleanup;
}
@@ -184,75 +195,42 @@ cleanup:
return ret;
}
int LinuxGPIO::_readValue(unsigned int pin)
int LinuxGPIO::readValue()
{
char path[PIN_VALUE_BUFFER_MAX];
char buf[2];
int fd;
int ret;
snprintf(path, PIN_VALUE_BUFFER_MAX, "/sys/class/gpio/gpio%d/value", pin);
fd = open(path, O_RDONLY);
if (fd == -1) {
int err = errno;
PX4_ERR("read %u: open: %s (%d)", pin, strerror(err), err);
return -1;
}
ret = read(fd, buf, sizeof(buf));
ret = ::read(_fd, buf, sizeof(buf));
if (ret == -1) {
int err = errno;
PX4_ERR("read %u: write: %s (%d)", pin, strerror(err), err);
goto cleanup;
PX4_ERR("readValue %u: read: %s (%d)", _pin, strerror(err), err);
return ret;
}
ret = 0;
ret = strtol(buf, nullptr, 10);
cleanup:
close(fd);
return ret;
}
int LinuxGPIO::_writeValue(unsigned int pin, unsigned int value)
int LinuxGPIO::writeValue(LinuxGPIO::Value value)
{
char path[PIN_VALUE_BUFFER_MAX];
char buf[2];
int fd;
int ret;
if (value != (unsigned int)Value::LOW && value != (unsigned int)Value::HIGH) {
if (value != Value::LOW && value != Value::HIGH) {
return -EINVAL;
}
snprintf(path, PIN_VALUE_BUFFER_MAX, "/sys/class/gpio/gpio%d/value", pin);
fd = open(path, O_WRONLY);
int buflen = snprintf(buf, sizeof(buf), "%u", (unsigned int)value);
if (fd == -1) {
int err = errno;
PX4_ERR("set %u: open: %s (%d)", pin, strerror(err), err);
return -1;
}
int buflen = snprintf(buf, sizeof(buf), "%u", value);
ret = write(fd, buf, buflen);
ret = ::write(_fd, buf, buflen);
if (ret == -1) {
int err = errno;
PX4_ERR("set %u: write: %s (%d)", pin, strerror(err), err);
goto cleanup;
PX4_ERR("writeValue %u: write: %s (%d)", _pin, strerror(err), err);
return ret;
}
ret = 0;
cleanup:
close(fd);
return ret;
return 0;
}
src/drivers/linux_gpio/linux_gpio.h
+2 -7
View File
@@ -46,7 +46,7 @@ class LinuxGPIO
{
public:
LinuxGPIO(unsigned int pin);
~LinuxGPIO() = default;
~LinuxGPIO();
enum class Direction {
IN = 0,
@@ -65,11 +65,6 @@ public:
int writeValue(LinuxGPIO::Value value);
private:
static int _exportPin(unsigned int pin);
static int _unexportPin(unsigned int pin);
static int _setDirection(unsigned int pin, int dir);
static int _readValue(unsigned int pin);
static int _writeValue(unsigned int pin, unsigned int value);
int _pin;
int _fd;
};