// 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.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\n");
}

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;
        enum led_default_state state;
        u32 value;
        int ret;

        parent = dev->parent;
        if (!parent) {
                dev_err(dev, "no parent for syscon LED\n");
                return -ENODEV;
        }
        map = syscon_node_to_regmap(dev_of_node(parent));
        if (IS_ERR(map)) {
                dev_err(dev, "no regmap for syscon LED parent\n");
                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, "reg", &sled->offset) &&
            of_property_read_u32(np, "offset", &sled->offset))
                return -EINVAL;
        if (of_property_read_u32(np, "mask", &sled->mask))
                return -EINVAL;

        init_data.fwnode = of_fwnode_handle(np);

        state = led_init_default_state_get(init_data.fwnode);
        switch (state) {
        case LEDS_DEFSTATE_ON:
                ret = regmap_update_bits(map, sled->offset, sled->mask, sled->mask);
                if (ret < 0)
                        return ret;
                sled->state = true;
                break;
        case LEDS_DEFSTATE_KEEP:
                ret = regmap_read(map, sled->offset, &value);
                if (ret < 0)
                        return ret;
                sled->state = !!(value & sled->mask);
                break;
        default:
                ret = regmap_update_bits(map, sled->offset, sled->mask, 0);
                if (ret < 0)
                        return ret;
                sled->state = false;
        }
        sled->cdev.brightness_set = syscon_led_set;

        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\n", 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);