platform_driver与file_operations两种方法开发led驱动

下面是两个LED灯的驱动程序 一个用platform_driver 另一个用file_operations

 #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 <[email protected]>");
 MODULE_DESCRIPTION("S3C24XX LED driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:s3c24xx_led");




 另一个如下：

   #include <asm/uaccess.h>
   #include <asm/atomic.h>
   #include <asm/unistd.h>

   #define DEVICE_NAME "leds"

   static unsigned long led_table [] = {
   S3C2410_GPB5,

   S3C2410_GPB6,
   S3C2410_GPB7,
   S3C2410_GPB8,
 };

 static unsigned int led_cfg_table [] = {
   S3C2410_GPB5_OUTP,

   S3C2410_GPB6_OUTP,
   S3C2410_GPB7_OUTP,
   S3C2410_GPB8_OUTP,
 };

 static int sbc2440_leds_ioctl(
   struct inode *inode,
   struct file *file,
   unsigned int cmd,
   unsigned long arg)
 {
   switch(cmd) {
   case 0:
   case 1:
   if (arg > 4) {
   return -EINVAL;
   }
   s3c2410_gpio_setpin(led_table[arg], !cmd);
   return 0;
   default:
   return -EINVAL;
   }
 }

 static struct file_operations dev_fops = {
   .owner = THIS_MODULE,
   .ioctl = sbc2440_leds_ioctl,
 };

 static struct miscdevice misc = {
   .minor = MISC_DYNAMIC_MINOR,
   .name = DEVICE_NAME,
   .fops = &dev_fops,
 };

 static int __init dev_init(void)
   {
   int ret;

   int i;

   for (i = 0; i < 4; i++) {
   s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
   s3c2410_gpio_setpin(led_table[i], 0);
   }

   ret = misc_register(&misc);

   printk (DEVICE_NAME"\tinitialized\n");

   return ret;
 }

 static void __exit dev_exit(void)
 {
   misc_deregister(&misc);
 }

 module_init(dev_init);
 module_exit(dev_exit);
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("FriendlyARM Inc.");