100 lines
2.9 KiB
Markdown
100 lines
2.9 KiB
Markdown
|
# GPIO_SYS
|
||
|
|
|
||
|
|
Gpio driver using sys file systeme.g.:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
echo "4" > /sys/class/gpio/export
|
||
|
|
echo "out" > /sys/class/gpio/gpio4/direction
|
||
|
|
echo "1"> /sys/class/gpio/gpio4/value
|
||
|
|
echo "4" > /sys/class/gpio/unexport
|
||
|
|
```
|
||
|
|
|
||
|
|
## Installation
|
||
|
|
|
||
|
|
```shell
|
||
|
|
make install
|
||
|
|
```
|
||
|
|
|
||
|
|
Installs `libgpio_sys.a` and `libgpio_sys.so` in the directory `$(PREFIX)/lib/`. It also installs the include header file `gpio.h` in the directory `$(PREFIX)/include/gpio_sys/`. The default value for `PREFIX` is: `PREFIX=usr`. To use another location for installation changing the value of the `PREFIX` variable is needed. E.g.:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
PREFIX=/usr/local/ make install
|
||
|
|
```
|
||
|
|
|
||
|
|
## Uninstallation
|
||
|
|
|
||
|
|
```shell
|
||
|
|
make install
|
||
|
|
```
|
||
|
|
|
||
|
|
Removes the files installed with the `install` make target.
|
||
|
|
> **NOTE:** If `PREFIX` variable was changed during installation process the same value needs to be set for uninstallation. E.g.:
|
||
|
|
|
||
|
|
```shell
|
||
|
|
PREFIX=/usr/local/ make install
|
||
|
|
```
|
||
|
|
|
||
|
|
## Example
|
||
|
|
|
||
|
|
```C
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <syslog.h>
|
||
|
|
#include <stdbool.h>
|
||
|
|
#include <gpio_sys/gpio.h>
|
||
|
|
|
||
|
|
|
||
|
|
static const struct gpio_sys gpio_4 = {
|
||
|
|
.pin = 4,
|
||
|
|
.direction = 0, // out
|
||
|
|
};
|
||
|
|
|
||
|
|
int main(void)
|
||
|
|
{
|
||
|
|
int res, cnt;
|
||
|
|
int value;
|
||
|
|
|
||
|
|
openlog("gpio_sys", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
|
||
|
|
|
||
|
|
res = gpio_open(&gpio_4);
|
||
|
|
if(res != EXIT_SUCCESS) {
|
||
|
|
syslog(LOG_ERR, "Unable to open gpio %d\n", gpio_4.pin);
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
|
||
|
|
gpio_write(&gpio_4, 1);
|
||
|
|
for(cnt = 0; cnt < 10; cnt++) {
|
||
|
|
if(cnt % 2) {
|
||
|
|
gpio_write(&gpio_4, 1);
|
||
|
|
} else {
|
||
|
|
gpio_write(&gpio_4, 0);
|
||
|
|
}
|
||
|
|
value = gpio_read(&gpio_4);
|
||
|
|
if(value < 0) {
|
||
|
|
syslog(LOG_ERR, "Unable to read from gpio %d\n", gpio_4.pin);
|
||
|
|
return EXIT_FAILURE;
|
||
|
|
} else {
|
||
|
|
printf("Gpio 4: %d\n", value);
|
||
|
|
}
|
||
|
|
sleep(1);
|
||
|
|
}
|
||
|
|
gpio_close(&gpio_4);
|
||
|
|
|
||
|
|
return EXIT_SUCCESS;
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
## Additional make targets
|
||
|
|
|
||
|
|
| Target | Meaning |
|
||
|
|
| --------------- | ----------------------------------------------------------- |
|
||
|
|
| all | Build the code, assemble the static and shared library. |
|
||
|
|
| install | Install the libraries and necessary include header files. |
|
||
|
|
| uninstall | Uninstall the libraries and necessary include header files. |
|
||
|
|
| clean | Clean up build artifacts. |
|
||
|
|
| build_unit_test | Build the unit tests. |
|
||
|
|
| exec_unit_test | Execute the unit tests. |
|
||
|
|
| coverage | Determine code coverage of the unit tests. |
|
||
|
|
| check | Static code analysis (cppcheck). |
|