Ajout d'un driver pour la gestion d'une led via un PIN GPIO

09_gpio_led_rpi3/Makefile

@@ -0,0 +1,7 @@
+obj-m += test_module.o
+
+all:
+	make -C $(LINUX_MODULES_FOLDER)/build M=$(PWD) modules
+
+clean:
+	make -C $(LINUX_MODULES_FOLDER)/build M=$(PWD) clean

09_gpio_led_rpi3/test_module.c

@@ -0,0 +1,141 @@
+#include <linux/init.h>
+#include <linux/leds.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_led_rpi3 {
+	int linux_gpio;
+	int bcm_gpio;
+	struct gpio_desc *desc;
+    struct led_classdev *led;
+};
+
+static struct gpio_led_rpi3 pin;
+
+static void gpio_led_rpi3_brightness_set(struct led_classdev *led_cdev, enum led_brightness brightness) {
+	pr_info("gpio_led_rpi3: Luminosité défini sur la LED %s à %d\n", led_cdev->name, brightness);
+
+    if (brightness < 0 || brightness > 1) {
+        pr_err("gpio_led_rpi3: Valeur incorrecte");
+        return;
+    }
+
+    // Applique la nouvelle valeur à la LED
+    gpiod_set_value(pin.desc, brightness);
+    pr_info("gpio_pin_rpi3: GPIO %d (BCM %d) défini à %d\n", pin.linux_gpio, pin.bcm_gpio, brightness);
+}
+
+static enum led_brightness gpio_led_rpi3_brightness_get(struct led_classdev *led_cdev) {
+	pr_info("Luminosité lu sur la LED %s, valeur actuelle: %d\n", led_cdev->name, led_cdev->brightness);
+	return led_cdev->brightness;
+}
+
+static int register_rpi3_gpio_pin(void)
+{
+    if (gpio_pin < 0) {
+        pr_err("gpio_led_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_led_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_led_rpi3: Impossible de configurer le GPIO %d\n", pin.linux_gpio);
+		gpiod_put(pin.desc);
+        return -EINVAL;
+    }
+
+    // Réinitialise la LED
+    gpiod_set_value(pin.desc, 0);
+
+    return 0;
+}
+
+static void unregister_rpi3_gpio_pin(void)
+{
+    // Turn LED off and release GPIO
+    gpiod_set_value(pin.desc, 0);
+    gpiod_put(pin.desc);
+    pr_info("gpio_led_rpi3: GPIO %d (BCM %d) libéré (LED OFF)\n", pin.linux_gpio, pin.bcm_gpio);
+}
+
+static int register_rpi3_led(void)
+{
+    pin.led = kzalloc(sizeof(struct led_classdev), GFP_KERNEL);
+    if (!pin.led) {
+        pr_err("Échec de l'allocation de mémoire pour la LED virtuelle\n");
+		return -ENOMEM;
+    }
+
+    pin.led->name = kasprintf(GFP_KERNEL, "rpi3-led:white:gpio-%d", pin.bcm_gpio);
+    pin.led->color = LED_COLOR_ID_WHITE;
+    pin.led->brightness = 0;
+    pin.led->max_brightness = 1;
+    pin.led->brightness_set = gpio_led_rpi3_brightness_set;
+    pin.led->brightness_get = gpio_led_rpi3_brightness_get;
+
+    int ret = led_classdev_register(NULL, pin.led);
+	if (ret < 0) {
+        kfree(pin.led->name);
+        kfree(pin.led);
+		pr_err("Impossible d'ajouter la LED virtuelle\n");
+		return ret;
+	}
+
+    return 0;
+}
+
+static void unregister_rpi3_led(void)
+{
+    led_classdev_unregister(pin.led);
+    kfree(pin.led->name);
+    kfree(pin.led);
+}
+
+static int __init gpio_led_rpi3_init(void)
+{
+	int ret = register_rpi3_gpio_pin();
+    if (ret != 0) {
+        return ret;
+    }
+
+    ret = register_rpi3_led();
+    if (ret != 0) {
+        unregister_rpi3_gpio_pin();
+        return ret;
+    }
+
+    return 0;
+}
+
+static void __exit gpio_led_rpi3_exit(void)
+{
+    unregister_rpi3_led();
+    unregister_rpi3_gpio_pin();
+}
+
+module_init(gpio_led_rpi3_init);
+module_exit(gpio_led_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 en tant que LED");
+MODULE_VERSION("1.0");