Raspberries/mraa
Private
Public Access
2
0
Fork 0
Code Activity

gpio : Add support for input pull up/down modes

Browse Source 
Make use of 'active_low' interface in sysfs for configuring input pin
in pull up / pull down mode. C++ binding also has been added.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Manivannan Sadhasivam
2017-06-21 18:56:23 +05:30
committed by Brendan Le Foll
parent 3f932ac952
commit bd3d9d8cab
3 changed files with 81 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
src/gpio/gpio.c
View File

@@ -839,3 +839,45 @@ mraa_gpio_get_pin_raw(mraa_gpio_context dev)
}
return dev->pin;
}
mraa_result_t
mraa_gpio_input_mode(mraa_gpio_context dev, mraa_gpio_input_mode_t mode)
{
if (dev == NULL) {
syslog(LOG_ERR, "gpio: in_mode: context is invalid");
return MRAA_ERROR_INVALID_HANDLE;
}
char filepath[MAX_SIZE];
snprintf(filepath, MAX_SIZE, SYSFS_CLASS_GPIO "/gpio%d/active_low", dev->pin);
int active_low = open(filepath, O_WRONLY);
if (active_low == -1) {
syslog(LOG_ERR, "gpio%i: mode: Failed to open 'active_low' for writing: %s", dev->pin, strerror(errno));
return MRAA_ERROR_INVALID_RESOURCE;
}
char bu[MAX_SIZE];
int length;
switch (mode) {
case MRAA_GPIO_ACTIVE_HIGH:
length = snprintf(bu, sizeof(bu), "%d", 0);
break;
case MRAA_GPIO_ACTIVE_LOW:
length = snprintf(bu, sizeof(bu), "%d", 1);
break;
default:
close(active_low);
return MRAA_ERROR_FEATURE_NOT_IMPLEMENTED;
}
if (write(active_low, bu, length * sizeof(char)) == -1) {
syslog(LOG_ERR, "gpio%i: mode: Failed to write to 'active_low': %s", dev->pin, strerror(errno));
close(active_low);
return MRAA_ERROR_INVALID_RESOURCE;
}
close(active_low);
return MRAA_SUCCESS;
}