写个linux LED驱动

好的，这里提供一个Linux LED驱动的示例代码，通过sysfs接口控制LED的亮灭。

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/gpio.h>

#define LED_NAME "my_led"
#define LED_GPIO 20

struct my_led_data {
    struct led_classdev cdev;
    int gpio;
};

static int my_led_brightness_set(struct led_classdev *led_cdev, enum led_brightness brightness)
{
    struct my_led_data *data = container_of(led_cdev, struct my_led_data, cdev);
    gpio_set_value(data->gpio, brightness);
    return 0;
}

static int __init my_led_probe(struct platform_device *pdev)
{
    struct my_led_data *data;
    struct led_classdev *cdev;
    int ret;

    data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    cdev = &data->cdev;
    cdev->name = LED_NAME;
    cdev->brightness_set = my_led_brightness_set;
    cdev->flags = LED_CORE_SUSPENDRESUME;

    data->gpio = LED_GPIO;
    ret = gpio_request(data->gpio, "my_led");
    if (ret) {
        dev_err(&pdev->dev, "Failed to request gpio %d\n", data->gpio);
        return ret;
    }
    gpio_direction_output(data->gpio, 0);

    ret = devm_led_classdev_register(&pdev->dev, cdev);
    if (ret) {
        dev_err(&pdev->dev, "Failed to register LED class device\n");
        gpio_free(data->gpio);
    }

    platform_set_drvdata(pdev, data);
    return ret;
}

static int __exit my_led_remove(struct platform_device *pdev)
{
    struct my_led_data *data = platform_get_drvdata(pdev);
    devm_led_classdev_unregister(&pdev->dev, &data->cdev);
    gpio_free(data->gpio);
    return 0;
}

static struct platform_driver my_led_driver = {
    .probe = my_led_probe,
    .remove = my_led_remove,
    .driver = {
        .name = "my_led",
        .owner = THIS_MODULE,
    },
};

module_platform_driver(my_led_driver);

MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("LED driver for my device");
MODULE_LICENSE("GPL v2"); 

这段代码实现的功能是：注册一个名为“my_led”的LED驱动，通过sysfs接口控制GPIO20的电平，从而控制LED的亮灭。用户可以通过“/sys/class/leds/my_led/brightness”文件来控制LED的亮度，文件内容为0或1，分别表示LED灭和LED亮。

需要注意的是，在使用该驱动时，需要将GPIO20配置为输出模式。此外，该驱动还支持系统挂起和恢复功能。