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