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.");