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gpio: add mraa_gpio_read_dir

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Add support for reading the direction of a GPIO
and expose it through mraa_gpio_read_dir.

Signed-off-by: Constantin Musca <constantin.musca@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Constantin Musca
2016-02-05 13:36:56 +02:00
committed by Brendan Le Foll
parent 084883c210
commit cc4fe26c09
2 changed files with 41 additions and 0 deletions
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9
api/mraa/gpio.h
View File

@@ -154,6 +154,15 @@ mraa_result_t mraa_gpio_mode(mraa_gpio_context dev, mraa_gpio_mode_t mode);
*/
mraa_result_t mraa_gpio_dir(mraa_gpio_context dev, mraa_gpio_dir_t dir);
/**
* Read Gpio direction
*
* @param dev The Gpio context
* @param dir The address where to store the Gpio direction
* @return Result of operation
*/
mraa_result_t mraa_gpio_read_dir(mraa_gpio_context dev, mraa_gpio_dir_t *dir);
/**
* Close the Gpio context
* - Will free the memory for the context and unexport the Gpio

32
src/gpio/gpio.c
View File

@@ -654,6 +654,38 @@ mraa_gpio_dir(mraa_gpio_context dev, mraa_gpio_dir_t dir)
return MRAA_SUCCESS;
}
mraa_result_t
mraa_gpio_read_dir(mraa_gpio_context dev, mraa_gpio_dir_t *dir)
{
char value[5];
char filepath[MAX_SIZE];
int fd, rc;
mraa_result_t result = MRAA_SUCCESS;
snprintf(filepath, MAX_SIZE, SYSFS_CLASS_GPIO "/gpio%d/direction", dev->pin);
fd = open(filepath, O_RDONLY);
if (fd == -1) {
return MRAA_ERROR_INVALID_RESOURCE;
}
memset(value, '\0', sizeof(value));
rc = read(fd, value, sizeof(value));
close(fd);
if (rc <= 0) {
return MRAA_ERROR_INVALID_RESOURCE;
}
if (strcmp(value, "out\n") == 0) {
*dir = MRAA_GPIO_OUT;
} else if (strcmp(value, "in\n") == 0) {
*dir = MRAA_GPIO_IN;
} else {
result = MRAA_ERROR_INVALID_RESOURCE;
}
return result;
}
int
mraa_gpio_read(mraa_gpio_context dev)
{