为什么linux驱动里面的leds/s3c24xx.c里面没有实现字符设备的操作比如open，以及注册

dsj889

版本linux-2.6.28
/* drivers/leds/leds-s3c24xx.c
*
* (c) 2006 Simtec Electronics
*        http://armlinux.simtec.co.uk/
*        Ben Dooks <ben@simtec.co.uk>
*
* S3C24XX - LEDs GPIO driver
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/

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

#include <mach/hardware.h>
#include <mach/regs-gpio.h>
#include <mach/leds-gpio.h>

/* our context */

struct s3c24xx_gpio_led {
        struct led_classdev                 cdev;
        struct s3c24xx_led_platdata        *pdata;
};

static inline struct s3c24xx_gpio_led *pdev_to_gpio(struct platform_device *dev)
{
        return platform_get_drvdata(dev);
}

static inline struct s3c24xx_gpio_led *to_gpio(struct led_classdev *led_cdev)
{
        return container_of(led_cdev, struct s3c24xx_gpio_led, cdev);
}

static void s3c24xx_led_set(struct led_classdev *led_cdev,
                            enum led_brightness value)
{
        struct s3c24xx_gpio_led *led = to_gpio(led_cdev);
        struct s3c24xx_led_platdata *pd = led->pdata;

        /* there will be a short delay between setting the output and
         * going from output to input when using tristate. */

        s3c2410_gpio_setpin(pd->gpio, (value ? 1 : 0) ^
                            (pd->flags & S3C24XX_LEDF_ACTLOW));

        if (pd->flags & S3C24XX_LEDF_TRISTATE)
                s3c2410_gpio_cfgpin(pd->gpio,
                        value ? S3C2410_GPIO_OUTPUT : S3C2410_GPIO_INPUT);

}

static int s3c24xx_led_remove(struct platform_device *dev)
{
        struct s3c24xx_gpio_led *led = pdev_to_gpio(dev);

        led_classdev_unregister(&led->cdev);
        kfree(led);

        return 0;
}

static int s3c24xx_led_probe(struct platform_device *dev)
{
        struct s3c24xx_led_platdata *pdata = dev->dev.platform_data;
        struct s3c24xx_gpio_led *led;
        int ret;

        led = kzalloc(sizeof(struct s3c24xx_gpio_led), GFP_KERNEL);
        if (led == NULL) {
                dev_err(&dev->dev, "No memory for device\n");
                return -ENOMEM;
        }

        platform_set_drvdata(dev, led);

        led->cdev.brightness_set = s3c24xx_led_set;
        led->cdev.default_trigger = pdata->def_trigger;
        led->cdev.name = pdata->name;

        led->pdata = pdata;

        /* no point in having a pull-up if we are always driving */

        if (pdata->flags & S3C24XX_LEDF_TRISTATE) {
                s3c2410_gpio_setpin(pdata->gpio, 0);
                s3c2410_gpio_cfgpin(pdata->gpio, S3C2410_GPIO_INPUT);
        } else {
                s3c2410_gpio_pullup(pdata->gpio, 0);
                s3c2410_gpio_setpin(pdata->gpio, 0);
                s3c2410_gpio_cfgpin(pdata->gpio, S3C2410_GPIO_OUTPUT);
        }

        /* register our new led device */

        ret = led_classdev_register(&dev->dev, &led->cdev);
        if (ret < 0) {
                dev_err(&dev->dev, "led_classdev_register failed\n");
                goto exit_err1;
        }

        return 0;

exit_err1:
        kfree(led);
        return ret;
}


#ifdef CONFIG_PM
static int s3c24xx_led_suspend(struct platform_device *dev, pm_message_t state)
{
        struct s3c24xx_gpio_led *led = pdev_to_gpio(dev);

        led_classdev_suspend(&led->cdev);
        return 0;
}

static int s3c24xx_led_resume(struct platform_device *dev)
{
        struct s3c24xx_gpio_led *led = pdev_to_gpio(dev);

        led_classdev_resume(&led->cdev);
        return 0;
}
#else
#define s3c24xx_led_suspend NULL
#define s3c24xx_led_resume NULL
#endif

static struct platform_driver s3c24xx_led_driver = {
        .probe                = s3c24xx_led_probe,
        .remove                = s3c24xx_led_remove,
        .suspend        = s3c24xx_led_suspend,
        .resume                = s3c24xx_led_resume,
        .driver                = {
                .name                = "s3c24xx_led",
                .owner                = THIS_MODULE,
        },
};

static int __init s3c24xx_led_init(void)
{
        return platform_driver_register(&s3c24xx_led_driver);
}

static void __exit s3c24xx_led_exit(void)
{
        platform_driver_unregister(&s3c24xx_led_driver);
}

module_init(s3c24xx_led_init);
module_exit(s3c24xx_led_exit);

MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_DESCRIPTION("S3C24XX LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:s3c24xx_led");

dsj889

自己对设备模型不怎么理解

youjujun

你看到的只是一部分代码
led_classdev_register（）这个函数。你跟踪一下，里面应该有。