linux2.6.20下AT91的LED驱动

/*
 * AT91 GPIO based LED driver
 *
 * Copyright (C) 2006 David Brownell
 *
 * 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
#include
#include
#include

#include
#include

static LIST_HEAD(at91_led_list); /* list of AT91 LEDs */

struct at91_led {
 struct led_classdev cdev;
 struct list_head list;
 struct at91_gpio_led *led_data;
};

/*
 * Change the state of the LED.
 */
static void at91_led_set(struct led_classdev *cdev, enum led_brightness value)
{
 struct at91_led *led = container_of(cdev, struct at91_led, cdev);
 short  active = (value == LED_OFF);

 if (led->led_data->flags & 1) /* active high/low? */
  active = !active;
 at91_set_gpio_value(led->led_data->gpio, value == LED_OFF);
}

static int __devexit at91_led_remove(struct platform_device *pdev)
{
 struct at91_led  *led;

 list_for_each_entry (led, &at91_led_list, list)
  led_classdev_unregister(&led->cdev);

#warning "Free allocated memory"
 // TODO: Free memory. kfree(led);

 return 0;
}

static int __init at91_led_probe(struct platform_device *pdev)
{
 int   status = 0;
 struct at91_gpio_led *pdata = pdev->dev.platform_data;
 unsigned  nr_leds;
 struct at91_led  *led;

 if (!pdata)
  return -ENODEV;

 nr_leds = pdata->index;  /* first index stores number of LEDs */

 while (nr_leds--) {
  led = kzalloc(sizeof(struct at91_led), GFP_KERNEL);
  if (!led) {
   dev_err(&pdev->dev, "No memory for device\n");
   status = -ENOMEM;
   goto cleanup;
  }
  led->led_data = pdata;
  led->cdev.name = pdata->name;
  led->cdev.brightness_set = at91_led_set,
  led->cdev.default_trigger = pdata->trigger;

  status = led_classdev_register(&pdev->dev, &led->cdev);
  if (status < 0) {
   dev_err(&pdev->dev, "led_classdev_register failed - %d\n", status);
cleanup:
   at91_led_remove(pdev);
   break;
  }
  list_add(&led->list, &at91_led_list);
  pdata++;
 }
 return status;
}

#ifdef CONFIG_PM
static int at91_led_suspend(struct platform_device *dev, pm_message_t state)
{
 struct at91_led *led;

 list_for_each_entry (led, &at91_led_list, list)
  led_classdev_suspend(&led->cdev);

 return 0;
}

static int at91_led_resume(struct platform_device *dev)
{
 struct at91_led *led;

 list_for_each_entry (led, &at91_led_list, list)
  led_classdev_resume(&led->cdev);

 return 0;
}
#else
#define at91_led_suspend NULL
#define at91_led_resume  NULL
#endif

static struct platform_driver at91_led_driver = {
 .probe  = at91_led_probe,
 .remove  = __devexit_p(at91_led_remove),
 .suspend = at91_led_suspend,
 .resume  = at91_led_resume,
 .driver  = {
  .name = "at91_leds",
  .owner = THIS_MODULE,
 },
};

static int __init at91_led_init(void)
{
 return platform_driver_register(&at91_led_driver);
}
module_init(at91_led_init);

static void __exit at91_led_exit(void)
{
 platform_driver_unregister(&at91_led_driver);
}
module_exit(at91_led_exit);

MODULE_DESCRIPTION("AT91 GPIO LED driver");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");