/*
   * 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/err.h>

  #include <linux/gpio.h>

  #include <linux/gpio/consumer.h>

  #include <linux/kernel.h>

  #include <linux/leds.h>

  #include <linux/module.h>

  #include <linux/platform_device.h>

  #include <linux/property.h>

  #include <linux/slab.h>

  #include <linux/workqueue.h>

  struct gpio_led_data {
  	struct led_classdev cdev;

  	struct gpio_desc *gpiod;

  	struct work_struct work;
  	u8 new_level;
  	u8 can_sleep;

  	u8 blinking;

  	int (*platform_gpio_blink_set)(struct gpio_desc *desc, 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->gpiod,
  					led_dat->new_level, NULL, NULL);

  		led_dat->blinking = 0;
  	} else

  		gpiod_set_value_cansleep(led_dat->gpiod, 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;

  	/* 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->gpiod, level,
  							 NULL, NULL);

  			led_dat->blinking = 0;
  		} else

  			gpiod_set_value(led_dat->gpiod, 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->gpiod, GPIO_LED_BLINK,

  						delay_on, delay_off);

  }

  static int create_gpio_led(const struct gpio_led *template,

  	struct gpio_led_data *led_dat, struct device *parent,

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

  {

  	int ret, state;

  	led_dat->gpiod = template->gpiod;
  	if (!led_dat->gpiod) {

  		/*
  		 * This is the legacy code path for platform code that
  		 * still uses GPIO numbers. Ultimately we would like to get
  		 * rid of this block completely.
  		 */

  		unsigned long flags = 0;

  		/* skip leds that aren't available */
  		if (!gpio_is_valid(template->gpio)) {
  			dev_info(parent, "Skipping unavailable LED gpio %d (%s)
  ",
  					template->gpio, template->name);
  			return 0;
  		}

  		if (template->active_low)
  			flags |= GPIOF_ACTIVE_LOW;
  
  		ret = devm_gpio_request_one(parent, template->gpio, flags,
  					    template->name);
  		if (ret < 0)
  			return ret;
  
  		led_dat->gpiod = gpio_to_desc(template->gpio);
  		if (IS_ERR(led_dat->gpiod))
  			return PTR_ERR(led_dat->gpiod);
  	}

  	led_dat->cdev.name = template->name;
  	led_dat->cdev.default_trigger = template->default_trigger;

  	led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod);

  	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 = !!gpiod_get_value_cansleep(led_dat->gpiod);

  	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 = gpiod_direction_output(led_dat->gpiod, state);

  	if (ret < 0)

  		return ret;

  	INIT_WORK(&led_dat->work, gpio_led_work);

  	return led_classdev_register(parent, &led_dat->cdev);

  }
  
  static void delete_gpio_led(struct gpio_led_data *led)
  {
  	led_classdev_unregister(&led->cdev);
  	cancel_work_sync(&led->work);

  }

  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);

  }

  static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)

  {

  	struct device *dev = &pdev->dev;
  	struct fwnode_handle *child;

  	struct gpio_leds_priv *priv;

  	int count, ret;

  	struct device_node *np;

  	count = device_get_child_node_count(dev);

  	if (!count)

  		return ERR_PTR(-ENODEV);

  	priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL);

  	if (!priv)

  		return ERR_PTR(-ENOMEM);

  	device_for_each_child_node(dev, child) {

  		struct gpio_led led = {};

  		const char *state = NULL;

  		led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);

  		if (IS_ERR(led.gpiod)) {
  			fwnode_handle_put(child);

  			ret = PTR_ERR(led.gpiod);

  			goto err;
  		}

  		np = of_node(child);
  
  		if (fwnode_property_present(child, "label")) {
  			fwnode_property_read_string(child, "label", &led.name);
  		} else {
  			if (IS_ENABLED(CONFIG_OF) && !led.name && np)
  				led.name = np->name;
  			if (!led.name)
  				return ERR_PTR(-EINVAL);
  		}

  		fwnode_property_read_string(child, "linux,default-trigger",
  					    &led.default_trigger);

  		if (!fwnode_property_read_string(child, "default-state",

  						 &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;
  		}

  		if (fwnode_property_present(child, "retain-state-suspended"))

  			led.retain_state_suspended = 1;

  		ret = create_gpio_led(&led, &priv->leds[priv->num_leds++],

  				      dev, NULL);

  		if (ret < 0) {

  			fwnode_handle_put(child);

  			goto err;
  		}
  	}

  	return priv;

  
  err:

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

  	return ERR_PTR(ret);

  }

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

  
  MODULE_DEVICE_TABLE(of, of_gpio_leds_match);

  static int gpio_led_probe(struct platform_device *pdev)

  {

  	struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);

  	struct gpio_leds_priv *priv;
  	int i, ret = 0;
  
  	if (pdata && pdata->num_leds) {

  		priv = devm_kzalloc(&pdev->dev,
  				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]);

  				return ret;
  			}
  		}
  	} else {

  		priv = gpio_leds_create(pdev);

  		if (IS_ERR(priv))
  			return PTR_ERR(priv);

  	}
  
  	platform_set_drvdata(pdev, priv);
  
  	return 0;

  }

  static int gpio_led_remove(struct platform_device *pdev)

  {

  	struct gpio_leds_priv *priv = platform_get_drvdata(pdev);

  	int i;

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

  	return 0;
  }

  static struct platform_driver gpio_led_driver = {
  	.probe		= gpio_led_probe,

  	.remove		= gpio_led_remove,

  	.driver		= {
  		.name	= "leds-gpio",

  		.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");