Logo Search packages:      
Sourcecode: linux version File versions  Download package

leds-gpio.c

/*
 * LEDs driver for GPIOs
 *
 * Copyright (C) 2007 8D Technologies inc.
 * Raphael Assenat <raph@8d.com>
 *
 * 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 <linux/workqueue.h>

#include <asm/gpio.h>

struct gpio_led_data {
      struct led_classdev cdev;
      unsigned gpio;
      struct work_struct work;
      u8 new_level;
      u8 can_sleep;
      u8 active_low;
};

static void gpio_led_work(struct work_struct *work)
{
      struct gpio_led_data    *led_dat =
            container_of(work, struct gpio_led_data, work);

      gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
}

static void gpio_led_set(struct led_classdev *led_cdev,
      enum led_brightness value)
{
      struct gpio_led_data *led_dat =
            container_of(led_cdev, struct gpio_led_data, cdev);
      int level;

      if (value == LED_OFF)
            level = 0;
      else
            level = 1;

      if (led_dat->active_low)
            level = !level;

      /* setting GPIOs with I2C/etc requires a preemptible task context */
      if (led_dat->can_sleep) {
            if (preempt_count()) {
                  led_dat->new_level = level;
                  schedule_work(&led_dat->work);
            } else
                  gpio_set_value_cansleep(led_dat->gpio, level);
      } else
            gpio_set_value(led_dat->gpio, level);
}

static int gpio_led_probe(struct platform_device *pdev)
{
      struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
      struct gpio_led *cur_led;
      struct gpio_led_data *leds_data, *led_dat;
      int i, ret = 0;

      if (!pdata)
            return -EBUSY;

      leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
                        GFP_KERNEL);
      if (!leds_data)
            return -ENOMEM;

      for (i = 0; i < pdata->num_leds; i++) {
            cur_led = &pdata->leds[i];
            led_dat = &leds_data[i];

            led_dat->cdev.name = cur_led->name;
            led_dat->cdev.default_trigger = cur_led->default_trigger;
            led_dat->gpio = cur_led->gpio;
            led_dat->can_sleep = gpio_cansleep(cur_led->gpio);
            led_dat->active_low = cur_led->active_low;
            led_dat->cdev.brightness_set = gpio_led_set;
            led_dat->cdev.brightness = cur_led->active_low ? LED_FULL : LED_OFF;

            ret = gpio_request(led_dat->gpio, led_dat->cdev.name);
            if (ret < 0)
                  goto err;

            gpio_direction_output(led_dat->gpio, led_dat->active_low);

            INIT_WORK(&led_dat->work, gpio_led_work);

            ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
            if (ret < 0) {
                  gpio_free(led_dat->gpio);
                  goto err;
            }
      }

      platform_set_drvdata(pdev, leds_data);

      return 0;

err:
      if (i > 0) {
            for (i = i - 1; i >= 0; i--) {
                  led_classdev_unregister(&leds_data[i].cdev);
                  cancel_work_sync(&leds_data[i].work);
                  gpio_free(leds_data[i].gpio);
            }
      }

      kfree(leds_data);

      return ret;
}

static int __devexit gpio_led_remove(struct platform_device *pdev)
{
      int i;
      struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
      struct gpio_led_data *leds_data;

      leds_data = platform_get_drvdata(pdev);

      for (i = 0; i < pdata->num_leds; i++) {
            led_classdev_unregister(&leds_data[i].cdev);
            cancel_work_sync(&leds_data[i].work);
            gpio_free(leds_data[i].gpio);
      }

      kfree(leds_data);

      return 0;
}

#ifdef CONFIG_PM
static int gpio_led_suspend(struct platform_device *pdev, pm_message_t state)
{
      struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
      struct gpio_led_data *leds_data;
      int i;

      leds_data = platform_get_drvdata(pdev);

      for (i = 0; i < pdata->num_leds; i++)
            led_classdev_suspend(&leds_data[i].cdev);

      return 0;
}

static int gpio_led_resume(struct platform_device *pdev)
{
      struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
      struct gpio_led_data *leds_data;
      int i;

      leds_data = platform_get_drvdata(pdev);

      for (i = 0; i < pdata->num_leds; i++)
            led_classdev_resume(&leds_data[i].cdev);

      return 0;
}
#else
#define gpio_led_suspend NULL
#define gpio_led_resume NULL
#endif

static struct platform_driver gpio_led_driver = {
      .probe            = gpio_led_probe,
      .remove           = __devexit_p(gpio_led_remove),
      .suspend    = gpio_led_suspend,
      .resume           = gpio_led_resume,
      .driver           = {
            .name = "leds-gpio",
            .owner      = THIS_MODULE,
      },
};

static int __init gpio_led_init(void)
{
      return platform_driver_register(&gpio_led_driver);
}

static void __exit gpio_led_exit(void)
{
      platform_driver_unregister(&gpio_led_driver);
}

module_init(gpio_led_init);
module_exit(gpio_led_exit);

MODULE_AUTHOR("Raphael Assenat <raph@8d.com>");
MODULE_DESCRIPTION("GPIO LED driver");
MODULE_LICENSE("GPL");

Generated by  Doxygen 1.6.0   Back to index