// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * Generic Syscon LEDs Driver
   *
   * Copyright (c) 2014, Linaro Limited
   * Author: Linus Walleij <linus.walleij@linaro.org>

   */
  #include <linux/io.h>

  #include <linux/init.h>

  #include <linux/of_device.h>
  #include <linux/of_address.h>
  #include <linux/platform_device.h>
  #include <linux/stat.h>
  #include <linux/slab.h>
  #include <linux/mfd/syscon.h>
  #include <linux/regmap.h>
  #include <linux/leds.h>
  
  /**
   * struct syscon_led - state container for syscon based LEDs
   * @cdev: LED class device for this LED
   * @map: regmap to access the syscon device backing this LED
   * @offset: the offset into the syscon regmap for the LED register
   * @mask: the bit in the register corresponding to the LED
   * @state: current state of the LED
   */
  struct syscon_led {
  	struct led_classdev cdev;
  	struct regmap *map;
  	u32 offset;
  	u32 mask;
  	bool state;
  };
  
  static void syscon_led_set(struct led_classdev *led_cdev,
  	enum led_brightness value)
  {
  	struct syscon_led *sled =
  		container_of(led_cdev, struct syscon_led, cdev);
  	u32 val;
  	int ret;
  
  	if (value == LED_OFF) {
  		val = 0;
  		sled->state = false;
  	} else {
  		val = sled->mask;
  		sled->state = true;
  	}
  
  	ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);
  	if (ret < 0)
  		dev_err(sled->cdev.dev, "error updating LED status
  ");
  }

  static int syscon_led_probe(struct platform_device *pdev)

  {

  	struct led_init_data init_data = {};

  	struct device *dev = &pdev->dev;

  	struct device_node *np = dev_of_node(dev);

  	struct device *parent;
  	struct regmap *map;
  	struct syscon_led *sled;
  	const char *state;

  	int ret;

  	parent = dev->parent;
  	if (!parent) {
  		dev_err(dev, "no parent for syscon LED
  ");
  		return -ENODEV;
  	}

  	map = syscon_node_to_regmap(dev_of_node(parent));

  	if (IS_ERR(map)) {

  		dev_err(dev, "no regmap for syscon LED parent
  ");

  		return PTR_ERR(map);

  	}
  
  	sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
  	if (!sled)
  		return -ENOMEM;
  
  	sled->map = map;
  
  	if (of_property_read_u32(np, "offset", &sled->offset))
  		return -EINVAL;
  	if (of_property_read_u32(np, "mask", &sled->mask))
  		return -EINVAL;

  
  	state = of_get_property(np, "default-state", NULL);
  	if (state) {
  		if (!strcmp(state, "keep")) {
  			u32 val;
  
  			ret = regmap_read(map, sled->offset, &val);
  			if (ret < 0)
  				return ret;
  			sled->state = !!(val & sled->mask);
  		} else if (!strcmp(state, "on")) {
  			sled->state = true;
  			ret = regmap_update_bits(map, sled->offset,
  						 sled->mask,
  						 sled->mask);
  			if (ret < 0)
  				return ret;
  		} else {
  			sled->state = false;
  			ret = regmap_update_bits(map, sled->offset,
  						 sled->mask, 0);
  			if (ret < 0)
  				return ret;

  		}

  	}
  	sled->cdev.brightness_set = syscon_led_set;

  	init_data.fwnode = of_fwnode_handle(np);
  
  	ret = devm_led_classdev_register_ext(dev, &sled->cdev, &init_data);

  	if (ret < 0)
  		return ret;
  
  	platform_set_drvdata(pdev, sled);
  	dev_info(dev, "registered LED %s
  ", sled->cdev.name);

  	return 0;
  }

  static const struct of_device_id of_syscon_leds_match[] = {
  	{ .compatible = "register-bit-led", },
  	{},
  };

  static struct platform_driver syscon_led_driver = {
  	.probe		= syscon_led_probe,

  	.driver		= {
  		.name	= "leds-syscon",
  		.of_match_table = of_syscon_leds_match,

  		.suppress_bind_attrs = true,

  	},
  };

  builtin_platform_driver(syscon_led_driver);