// SPDX-License-Identifier: GPL-2.0-only
/*
 * Backlight driver for Maxim MAX8925
 *
 * Copyright (C) 2009 Marvell International Ltd.
 *      Haojian Zhuang <haojian.zhuang@marvell.com>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/backlight.h>
#include <linux/mfd/max8925.h>
#include <linux/slab.h>
#include <linux/module.h>

#define MAX_BRIGHTNESS          (0xff)
#define MIN_BRIGHTNESS          (0)

#define LWX_FREQ(x)             (((x - 601) / 100) & 0x7)

struct max8925_backlight_data {
        struct max8925_chip     *chip;

        int     current_brightness;
        int     reg_mode_cntl;
        int     reg_cntl;
};

static int max8925_backlight_set(struct backlight_device *bl, int brightness)
{
        struct max8925_backlight_data *data = bl_get_data(bl);
        struct max8925_chip *chip = data->chip;
        unsigned char value;
        int ret;

        if (brightness > MAX_BRIGHTNESS)
                value = MAX_BRIGHTNESS;
        else
                value = brightness;

        ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);
        if (ret < 0)
                goto out;

        if (!data->current_brightness && brightness)
                /* enable WLED output */
                ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);
        else if (!brightness)
                /* disable WLED output */
                ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);
        if (ret < 0)
                goto out;
        dev_dbg(chip->dev, "set brightness %d\n", value);
        data->current_brightness = value;
        return 0;
out:
        dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
                value, ret);
        return ret;
}

static int max8925_backlight_update_status(struct backlight_device *bl)
{
        return max8925_backlight_set(bl, backlight_get_brightness(bl));
}

static int max8925_backlight_get_brightness(struct backlight_device *bl)
{
        struct max8925_backlight_data *data = bl_get_data(bl);
        struct max8925_chip *chip = data->chip;
        int ret;

        ret = max8925_reg_read(chip->i2c, data->reg_cntl);
        if (ret < 0)
                return -EINVAL;
        data->current_brightness = ret;
        dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
        return ret;
}

static const struct backlight_ops max8925_backlight_ops = {
        .options        = BL_CORE_SUSPENDRESUME,
        .update_status  = max8925_backlight_update_status,
        .get_brightness = max8925_backlight_get_brightness,
};

static void max8925_backlight_dt_init(struct platform_device *pdev)
{
        struct device_node *nproot = pdev->dev.parent->of_node, *np;
        struct max8925_backlight_pdata *pdata;
        u32 val;

        if (!nproot || !IS_ENABLED(CONFIG_OF))
                return;

        pdata = devm_kzalloc(&pdev->dev,
                             sizeof(struct max8925_backlight_pdata),
                             GFP_KERNEL);
        if (!pdata)
                return;

        np = of_get_child_by_name(nproot, "backlight");
        if (!np) {
                dev_err(&pdev->dev, "failed to find backlight node\n");
                return;
        }

        if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
                pdata->dual_string = val;

        of_node_put(np);

        pdev->dev.platform_data = pdata;
}

static int max8925_backlight_probe(struct platform_device *pdev)
{
        struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
        struct max8925_backlight_pdata *pdata;
        struct max8925_backlight_data *data;
        struct backlight_device *bl;
        struct backlight_properties props;
        struct resource *res;
        unsigned char value;
        int ret = 0;

        data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
                            GFP_KERNEL);
        if (data == NULL)
                return -ENOMEM;

        res = platform_get_resource(pdev, IORESOURCE_REG, 0);
        if (!res) {
                dev_err(&pdev->dev, "No REG resource for mode control!\n");
                return -ENXIO;
        }
        data->reg_mode_cntl = res->start;
        res = platform_get_resource(pdev, IORESOURCE_REG, 1);
        if (!res) {
                dev_err(&pdev->dev, "No REG resource for control!\n");
                return -ENXIO;
        }
        data->reg_cntl = res->start;

        data->chip = chip;
        data->current_brightness = 0;

        memset(&props, 0, sizeof(struct backlight_properties));
        props.type = BACKLIGHT_RAW;
        props.max_brightness = MAX_BRIGHTNESS;
        bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight",
                                        &pdev->dev, data,
                                        &max8925_backlight_ops, &props);
        if (IS_ERR(bl)) {
                dev_err(&pdev->dev, "failed to register backlight\n");
                return PTR_ERR(bl);
        }
        bl->props.brightness = MAX_BRIGHTNESS;

        platform_set_drvdata(pdev, bl);

        value = 0;
        if (!pdev->dev.platform_data)
                max8925_backlight_dt_init(pdev);

        pdata = pdev->dev.platform_data;
        if (pdata) {
                if (pdata->lxw_scl)
                        value |= (1 << 7);
                if (pdata->lxw_freq)
                        value |= (LWX_FREQ(pdata->lxw_freq) << 4);
                if (pdata->dual_string)
                        value |= (1 << 1);
        }
        ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
        if (ret < 0)
                return ret;
        backlight_update_status(bl);
        return 0;
}

static struct platform_driver max8925_backlight_driver = {
        .driver         = {
                .name   = "max8925-backlight",
        },
        .probe          = max8925_backlight_probe,
};

module_platform_driver(max8925_backlight_driver);

MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:max8925-backlight");