// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Backlight driver for HP Jornada 700 series (710/720/728)
 * Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com>
 */

#include <linux/backlight.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <mach/jornada720.h>
#include <mach/hardware.h>

#include <video/s1d13xxxfb.h>

#define BL_MAX_BRIGHT   255
#define BL_DEF_BRIGHT   25

static int jornada_bl_get_brightness(struct backlight_device *bd)
{
        int ret;

        /* check if backlight is on */
        if (!(PPSR & PPC_LDD1))
                return 0;

        jornada_ssp_start();

        /* cmd should return txdummy */
        ret = jornada_ssp_byte(GETBRIGHTNESS);

        if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) {
                dev_err(&bd->dev, "get brightness timeout\n");
                jornada_ssp_end();
                return -ETIMEDOUT;
        }

        /* exchange txdummy for value */
        ret = jornada_ssp_byte(TXDUMMY);

        jornada_ssp_end();

        return BL_MAX_BRIGHT - ret;
}

static int jornada_bl_update_status(struct backlight_device *bd)
{
        int ret = 0;

        jornada_ssp_start();

        /* If backlight is off then really turn it off */
        if (backlight_is_blank(bd)) {
                ret = jornada_ssp_byte(BRIGHTNESSOFF);
                if (ret != TXDUMMY) {
                        dev_info(&bd->dev, "brightness off timeout\n");
                        /* turn off backlight */
                        PPSR &= ~PPC_LDD1;
                        PPDR |= PPC_LDD1;
                        ret = -ETIMEDOUT;
                }
        } else  /* turn on backlight */
                PPSR |= PPC_LDD1;

        /* send command to our mcu */
        if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) {
                dev_info(&bd->dev, "failed to set brightness\n");
                ret = -ETIMEDOUT;
                goto out;
        }

        /*
         * at this point we expect that the mcu has accepted
         * our command and is waiting for our new value
         * please note that maximum brightness is 255,
         * but due to physical layout it is equal to 0, so we simply
         * invert the value (MAX VALUE - NEW VALUE).
         */
        if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness)
                != TXDUMMY) {
                dev_err(&bd->dev, "set brightness failed\n");
                ret = -ETIMEDOUT;
        }

        /*
         * If infact we get an TXDUMMY as output we are happy and dont
         * make any further comments about it
         */
out:
        jornada_ssp_end();

        return ret;
}

static const struct backlight_ops jornada_bl_ops = {
        .get_brightness = jornada_bl_get_brightness,
        .update_status = jornada_bl_update_status,
        .options = BL_CORE_SUSPENDRESUME,
};

static int jornada_bl_probe(struct platform_device *pdev)
{
        struct backlight_properties props;
        int ret;
        struct backlight_device *bd;

        memset(&props, 0, sizeof(struct backlight_properties));
        props.type = BACKLIGHT_RAW;
        props.max_brightness = BL_MAX_BRIGHT;

        bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME,
                                        &pdev->dev, NULL, &jornada_bl_ops,
                                        &props);
        if (IS_ERR(bd)) {
                ret = PTR_ERR(bd);
                dev_err(&pdev->dev, "failed to register device, err=%x\n", ret);
                return ret;
        }

        bd->props.power = BACKLIGHT_POWER_ON;
        bd->props.brightness = BL_DEF_BRIGHT;
        /*
         * note. make sure max brightness is set otherwise
         * you will get seemingly non-related errors when
         * trying to change brightness
         */
        jornada_bl_update_status(bd);

        platform_set_drvdata(pdev, bd);
        dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n");

        return 0;
}

static struct platform_driver jornada_bl_driver = {
        .probe          = jornada_bl_probe,
        .driver = {
                .name   = "jornada_bl",
        },
};

module_platform_driver(jornada_bl_driver);

MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>");
MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver");
MODULE_LICENSE("GPL");