/*
 * Copyright (C) 2018 John Crispin <john@phrozen.org>
 *
 * 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/reset.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset.h>

struct reset_led_data {
	struct led_classdev cdev;
	struct reset_control *rst;
};

static inline struct reset_led_data *
			cdev_to_reset_led_data(struct led_classdev *led_cdev)
{
	return container_of(led_cdev, struct reset_led_data, cdev);
}

static void reset_led_set(struct led_classdev *led_cdev,
	enum led_brightness value)
{
	struct reset_led_data *led_dat = cdev_to_reset_led_data(led_cdev);

	if (value == LED_OFF)
		reset_control_assert(led_dat->rst);
	else
		reset_control_deassert(led_dat->rst);
}

struct reset_leds_priv {
	int num_leds;
	struct reset_led_data leds[];
};

static inline int sizeof_reset_leds_priv(int num_leds)
{
	return sizeof(struct reset_leds_priv) +
		(sizeof(struct reset_led_data) * num_leds);
}

static struct reset_leds_priv *reset_leds_create(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct fwnode_handle *child;
	struct reset_leds_priv *priv;
	int count, ret;

	count = device_get_child_node_count(dev);
	if (!count)
		return ERR_PTR(-ENODEV);

	priv = devm_kzalloc(dev, sizeof_reset_leds_priv(count), GFP_KERNEL);
	if (!priv)
		return ERR_PTR(-ENOMEM);

	device_for_each_child_node(dev, child) {
		struct reset_led_data *led = &priv->leds[priv->num_leds];
		struct device_node *np = to_of_node(child);

		ret = fwnode_property_read_string(child, "label", &led->cdev.name);
		if (!led->cdev.name) {
			fwnode_handle_put(child);
			return ERR_PTR(-EINVAL);
		}
		led->rst = __of_reset_control_get(np, NULL, 0, 0, 0);
		if (IS_ERR(led->rst))
			return ERR_PTR(-EINVAL);

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

		led->cdev.brightness_set = reset_led_set;
		ret = devm_of_led_classdev_register(&pdev->dev, np, &led->cdev);
		if (ret < 0)
			return ERR_PTR(ret);
		led->cdev.dev->of_node = np;
		priv->num_leds++;
	}

	return priv;
}

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

MODULE_DEVICE_TABLE(of, of_reset_leds_match);

static int reset_led_probe(struct platform_device *pdev)
{
	struct reset_leds_priv *priv;

	priv = reset_leds_create(pdev);
	if (IS_ERR(priv))
		return PTR_ERR(priv);

	platform_set_drvdata(pdev, priv);

	return 0;
}

static void reset_led_shutdown(struct platform_device *pdev)
{
	struct reset_leds_priv *priv = platform_get_drvdata(pdev);
	int i;

	for (i = 0; i < priv->num_leds; i++) {
		struct reset_led_data *led = &priv->leds[i];

		if (!(led->cdev.flags & LED_RETAIN_AT_SHUTDOWN))
			reset_led_set(&led->cdev, LED_OFF);
	}
}

static struct platform_driver reset_led_driver = {
	.probe		= reset_led_probe,
	.shutdown	= reset_led_shutdown,
	.driver		= {
		.name	= "leds-reset",
		.of_match_table = of_reset_leds_match,
	},
};

module_platform_driver(reset_led_driver);

MODULE_AUTHOR("John Crispin <john@phrozen.org>");
MODULE_DESCRIPTION("reset controller LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:leds-reset");