67 lines
No EOL
1.9 KiB
C
67 lines
No EOL
1.9 KiB
C
#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/gpio/consumer.h>
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// gpiochip0: GPIOs 512-565, parent: platform/3f200000.gpio, pinctrl-bcm2835
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// From /sys/kernel/debug/gpio
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#define RPI3_BCM2835_GPIO_OFFSET 512
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#define BCM_TO_LINUX_GPIO(bcm) (RPI3_BCM2835_GPIO_OFFSET + (bcm))
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static int gpio_pin = -1;
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module_param(gpio_pin, int, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
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MODULE_PARM_DESC(gpio_pin, "BCM GPIO pin number (e.g., 17)");
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struct gpio_pin_rpi3 {
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int linux_gpio;
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int bcm_gpio;
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struct gpio_desc *desc;
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};
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static struct gpio_pin_rpi3 pin;
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static int __init gpio_pin_rpi3_init(void)
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{
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if (gpio_pin < 0) {
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pr_err("gpio_pin_rpi3: You must specify 'gpio_pin' (e.g., gpio_pin=17)\n");
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return -EINVAL;
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}
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pin.bcm_gpio = gpio_pin;
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pin.linux_gpio = BCM_TO_LINUX_GPIO(pin.bcm_gpio);
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// Récupération du descripteur GPIO à partir du numéro Globale Linux
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pin.desc = gpio_to_desc(pin.linux_gpio);
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if (!pin.desc) {
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pr_err("gpio_pin_rpi3: Le GPIO %d (BCM %d) non trouvé\n", pin.linux_gpio, pin.bcm_gpio);
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return -ENODEV;
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}
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// Réclame le PIN GPIO
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if (gpiod_direction_output(pin.desc, 0)) {
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pr_err("gpio_pin_rpi3: Impossible de configurer le GPIO %d\n", pin.linux_gpio);
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gpiod_put(pin.desc);
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return -EINVAL;
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}
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// Allume la LED
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gpiod_set_value(pin.desc, 1);
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pr_info("gpio_pin_rpi3: GPIO %d (BCM %d) activé (LED ON)\n", pin.linux_gpio, pin.bcm_gpio);
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return 0;
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}
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static void __exit gpio_pin_rpi3_exit(void)
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{
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// Turn LED off and release GPIO
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gpiod_set_value(pin.desc, 0);
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gpiod_put(pin.desc);
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pr_info("gpio_pin_rpi3: GPIO %d (BCM %d) libéré (LED OFF)\n", pin.linux_gpio, pin.bcm_gpio);
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}
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module_init(gpio_pin_rpi3_init);
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module_exit(gpio_pin_rpi3_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Florian RICHER <florian.richer@protonmail.com>");
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MODULE_DESCRIPTION("Un module noyau pour utiliser un PIN GPIO d'une RPI");
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MODULE_VERSION("1.0"); |