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

   * Copyright (C) 2008 Freescale Semiconductor, Inc.

   *
   * 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/of_platform.h>
  #include <linux/of_gpio.h>

  #include <linux/slab.h>

  #include <linux/workqueue.h>

  #include <linux/module.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;

  	u8 blinking;
  	int (*platform_gpio_blink_set)(unsigned gpio, int state,

  			unsigned long *delay_on, unsigned long *delay_off);

  };

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

  	if (led_dat->blinking) {
  		led_dat->platform_gpio_blink_set(led_dat->gpio,
  						 led_dat->new_level,
  						 NULL, NULL);
  		led_dat->blinking = 0;
  	} else
  		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 task context, and we don't
  	 * seem to have a reliable way to know if we're already in one; so
  	 * let's just assume the worst.
  	 */

  	if (led_dat->can_sleep) {

  		led_dat->new_level = level;
  		schedule_work(&led_dat->work);

  	} else {
  		if (led_dat->blinking) {
  			led_dat->platform_gpio_blink_set(led_dat->gpio, level,
  							 NULL, NULL);
  			led_dat->blinking = 0;
  		} else
  			gpio_set_value(led_dat->gpio, level);
  	}

  }

  static int gpio_blink_set(struct led_classdev *led_cdev,
  	unsigned long *delay_on, unsigned long *delay_off)
  {
  	struct gpio_led_data *led_dat =
  		container_of(led_cdev, struct gpio_led_data, cdev);

  	led_dat->blinking = 1;
  	return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK,
  						delay_on, delay_off);

  }

  static int __devinit create_gpio_led(const struct gpio_led *template,
  	struct gpio_led_data *led_dat, struct device *parent,

  	int (*blink_set)(unsigned, int, unsigned long *, unsigned long *))

  {

  	int ret, state;

  	led_dat->gpio = -1;

  	/* skip leds that aren't available */
  	if (!gpio_is_valid(template->gpio)) {

  		printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)
  ",

  				template->gpio, template->name);

  		return 0;

  	}

  	ret = gpio_request(template->gpio, template->name);
  	if (ret < 0)
  		return ret;
  
  	led_dat->cdev.name = template->name;
  	led_dat->cdev.default_trigger = template->default_trigger;
  	led_dat->gpio = template->gpio;
  	led_dat->can_sleep = gpio_cansleep(template->gpio);
  	led_dat->active_low = template->active_low;

  	led_dat->blinking = 0;

  	if (blink_set) {
  		led_dat->platform_gpio_blink_set = blink_set;
  		led_dat->cdev.blink_set = gpio_blink_set;
  	}
  	led_dat->cdev.brightness_set = gpio_led_set;

  	if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)

  		state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low;

  	else
  		state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
  	led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;

  	if (!template->retain_state_suspended)
  		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;

  	ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);

  	if (ret < 0)
  		goto err;

  	INIT_WORK(&led_dat->work, gpio_led_work);
  
  	ret = led_classdev_register(parent, &led_dat->cdev);
  	if (ret < 0)
  		goto err;
  
  	return 0;
  err:
  	gpio_free(led_dat->gpio);
  	return ret;
  }
  
  static void delete_gpio_led(struct gpio_led_data *led)
  {

  	if (!gpio_is_valid(led->gpio))
  		return;

  	led_classdev_unregister(&led->cdev);
  	cancel_work_sync(&led->work);
  	gpio_free(led->gpio);
  }

  struct gpio_leds_priv {
  	int num_leds;
  	struct gpio_led_data leds[];
  };

  static inline int sizeof_gpio_leds_priv(int num_leds)

  {

  	return sizeof(struct gpio_leds_priv) +
  		(sizeof(struct gpio_led_data) * num_leds);

  }

  /* Code to create from OpenFirmware platform devices */

  #ifdef CONFIG_OF_GPIO

  static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)

  {

  	struct device_node *np = pdev->dev.of_node, *child;
  	struct gpio_leds_priv *priv;

  	int count = 0, ret;

  	/* count LEDs in this device, so we know how much to allocate */

  	for_each_child_of_node(np, child)
  		count++;
  	if (!count)

  		return NULL;

  	priv = kzalloc(sizeof_gpio_leds_priv(count), GFP_KERNEL);
  	if (!priv)
  		return NULL;

  	for_each_child_of_node(np, child) {

  		struct gpio_led led = {};

  		enum of_gpio_flags flags;

  		const char *state;

  
  		led.gpio = of_get_gpio_flags(child, 0, &flags);
  		led.active_low = flags & OF_GPIO_ACTIVE_LOW;
  		led.name = of_get_property(child, "label", NULL) ? : child->name;
  		led.default_trigger =
  			of_get_property(child, "linux,default-trigger", NULL);

  		state = of_get_property(child, "default-state", NULL);
  		if (state) {
  			if (!strcmp(state, "keep"))
  				led.default_state = LEDS_GPIO_DEFSTATE_KEEP;

  			else if (!strcmp(state, "on"))

  				led.default_state = LEDS_GPIO_DEFSTATE_ON;
  			else
  				led.default_state = LEDS_GPIO_DEFSTATE_OFF;
  		}

  		ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],
  				      &pdev->dev, NULL);

  		if (ret < 0) {
  			of_node_put(child);
  			goto err;
  		}
  	}

  	return priv;

  
  err:

  	for (count = priv->num_leds - 2; count >= 0; count--)
  		delete_gpio_led(&priv->leds[count]);
  	kfree(priv);
  	return NULL;
  }

  static const struct of_device_id of_gpio_leds_match[] = {
  	{ .compatible = "gpio-leds", },
  	{},
  };

  #else /* CONFIG_OF_GPIO */

  static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
  {
  	return NULL;
  }
  #define of_gpio_leds_match NULL

  #endif /* CONFIG_OF_GPIO */

  
  static int __devinit gpio_led_probe(struct platform_device *pdev)
  {
  	struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
  	struct gpio_leds_priv *priv;
  	int i, ret = 0;
  
  	if (pdata && pdata->num_leds) {
  		priv = kzalloc(sizeof_gpio_leds_priv(pdata->num_leds),
  				GFP_KERNEL);
  		if (!priv)
  			return -ENOMEM;
  
  		priv->num_leds = pdata->num_leds;
  		for (i = 0; i < priv->num_leds; i++) {
  			ret = create_gpio_led(&pdata->leds[i],
  					      &priv->leds[i],
  					      &pdev->dev, pdata->gpio_blink_set);
  			if (ret < 0) {
  				/* On failure: unwind the led creations */
  				for (i = i - 1; i >= 0; i--)
  					delete_gpio_led(&priv->leds[i]);
  				kfree(priv);
  				return ret;
  			}
  		}
  	} else {
  		priv = gpio_leds_create_of(pdev);
  		if (!priv)
  			return -ENODEV;
  	}
  
  	platform_set_drvdata(pdev, priv);
  
  	return 0;

  }

  static int __devexit gpio_led_remove(struct platform_device *pdev)

  {

  	struct gpio_leds_priv *priv = dev_get_drvdata(&pdev->dev);

  	int i;

  	for (i = 0; i < priv->num_leds; i++)
  		delete_gpio_led(&priv->leds[i]);

  	dev_set_drvdata(&pdev->dev, NULL);
  	kfree(priv);

  
  	return 0;
  }

  static struct platform_driver gpio_led_driver = {
  	.probe		= gpio_led_probe,
  	.remove		= __devexit_p(gpio_led_remove),
  	.driver		= {
  		.name	= "leds-gpio",
  		.owner	= THIS_MODULE,

  		.of_match_table = of_gpio_leds_match,

  	},

  };

  module_platform_driver(gpio_led_driver);

  
  MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");

  MODULE_DESCRIPTION("GPIO LED driver");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:leds-gpio");