Linux 驱动开发基础知识——LED 模板驱动程序的改造：设备树

#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/leds.h>

/* 假设在设备树中定义了LED相关属性 */
static struct of_device_id my_led_of_match[] = {
    { .compatible = "my,led", },
    { /* Sentinel */ }
};
MODULE_DEVICE_TABLE(of, my_led_of_match);

/* 平台设备注册函数 */
static int my_led_probe(struct platform_device *pdev)
{
    struct device *dev = &pdev->dev;
    struct device_node *np = dev->of_node;
    struct led_classdev *led_cdev;
    int led_gpio;
    int ret;

    /* 获取GPIO编号 */
    led_gpio = of_get_named_gpio(np, "led-gpio", 0);
    if (led_gpio < 0) {
        dev_err(dev, "Failed to get LED GPIO: %d\n", led_gpio);
        return led_gpio;
    }

    /* 分配和初始化led_classdev结构体 */
    led_cdev = kzalloc(sizeof(*led_cdev), GFP_KERNEL);
    if (!led_cdev) {
        dev_err(dev, "Failed to allocate memory for LED\n");
        return -ENOMEM;
    }

    /* 设置 led_classdev 的属性和回调函数 */
    led_cdev->brightness_set = my_led_set;
    led_cdev->brightness_get = my_led_get;
    led_cdev->default_trigger = "none";
    led_cdev->flags |= LED_CORE_SUSPENDRESUME;

    /* 注册到LED子系统 */
    ret = led_classdev_register(dev, led_cdev);
    if (ret < 0) {
        dev_err(dev, "LED register failed with error %d\n", ret);
        goto err_led_register;
    }

    platform_set_drvdata(pdev, led_cdev);
    return 0;

err_led_register:
    kfree(led_cdev);
    return ret;
}

/* 平台设备移除函数 */
static int my_led_remove(struct platform_device *pdev)
{
    struct led_classdev *led_cdev = platform_get_drvdata(pdev);

    led_classdev_unregister(led_cdev);
    kfree(led_cdev);

    return 0;
}

/* 平台驱动结构体 */
static struct platform_driver my_led_driver = {
    .probe  = my_led_probe,
    .remove = my_led_remove,
    .driver = {
        .name = "my-led",
        .of_match_table = my_led_of_match,
    },
};

module_platform_driver(my_led_driver);