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Add working gpio_pin_rpi3

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This commit is contained in:
Florian RICHER 2025-02-24 20:09:04 +01:00
parent 7723b2e823
commit b920979d5b
Signed by: florian.richer
GPG key ID: C73D37CBED7BFC77
3 changed files with 67 additions and 71 deletions
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67
08_gpio_pin_rpi3/test_module.c Normal file
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#include <linux/init.h>
#include <linux/module.h>
#include <linux/gpio/consumer.h>
// gpiochip0: GPIOs 512-565, parent: platform/3f200000.gpio, pinctrl-bcm2835
// From /sys/kernel/debug/gpio
#define RPI3_BCM2835_GPIO_OFFSET 512
#define BCM_TO_LINUX_GPIO(bcm) (RPI3_BCM2835_GPIO_OFFSET + (bcm))
static int gpio_pin = -1;
module_param(gpio_pin, int, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
MODULE_PARM_DESC(gpio_pin, "BCM GPIO pin number (e.g., 17)");
struct gpio_pin_rpi3 {
int linux_gpio;
int bcm_gpio;
struct gpio_desc *desc;
};
static struct gpio_pin_rpi3 pin;
static int __init gpio_pin_rpi3_init(void)
{
if (gpio_pin < 0) {
pr_err("gpio_pin_rpi3: You must specify 'gpio_pin' (e.g., gpio_pin=17)\n");
return -EINVAL;
}
pin.bcm_gpio = gpio_pin;
pin.linux_gpio = BCM_TO_LINUX_GPIO(pin.bcm_gpio);
// Récupération du descripteur GPIO à partir du numéro Globale Linux
pin.desc = gpio_to_desc(pin.linux_gpio);
if (!pin.desc) {
pr_err("gpio_pin_rpi3: Le GPIO %d (BCM %d) non trouvé\n", pin.linux_gpio, pin.bcm_gpio);
return -ENODEV;
}
// Réclame le PIN GPIO
if (gpiod_direction_output(pin.desc, 0)) {
pr_err("gpio_pin_rpi3: Impossible de configurer le GPIO %d\n", pin.linux_gpio);
gpiod_put(pin.desc);
return -EINVAL;
}
// Allume la LED
gpiod_set_value(pin.desc, 1);
pr_info("gpio_pin_rpi3: GPIO %d (BCM %d) activé (LED ON)\n", pin.linux_gpio, pin.bcm_gpio);
return 0;
}
static void __exit gpio_pin_rpi3_exit(void)
{
// Turn LED off and release GPIO
gpiod_set_value(pin.desc, 0);
gpiod_put(pin.desc);
pr_info("gpio_pin_rpi3: GPIO %d (BCM %d) libéré (LED OFF)\n", pin.linux_gpio, pin.bcm_gpio);
}
module_init(gpio_pin_rpi3_init);
module_exit(gpio_pin_rpi3_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Florian RICHER <florian.richer@protonmail.com>");
MODULE_DESCRIPTION("Un module noyau pour utiliser un PIN GPIO d'une RPI");
MODULE_VERSION("1.0");