// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * iPAQ microcontroller backlight support
 * Author : Linus Walleij <linus.walleij@linaro.org>
 */

#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/mfd/ipaq-micro.h>
#include <linux/module.h>
#include <linux/platform_device.h>

static int micro_bl_update_status(struct backlight_device *bd)
{
        struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
        int intensity = backlight_get_brightness(bd);
        struct ipaq_micro_msg msg = {
                .id = MSG_BACKLIGHT,
                .tx_len = 3,
        };

        /*
         * Message format:
         * Byte 0: backlight instance (usually 1)
         * Byte 1: on/off
         * Byte 2: intensity, 0-255
         */
        msg.tx_data[0] = 0x01;
        msg.tx_data[1] = intensity > 0 ? 1 : 0;
        msg.tx_data[2] = intensity;
        return ipaq_micro_tx_msg_sync(micro, &msg);
}

static const struct backlight_ops micro_bl_ops = {
        .options = BL_CORE_SUSPENDRESUME,
        .update_status  = micro_bl_update_status,
};

static const struct backlight_properties micro_bl_props = {
        .type = BACKLIGHT_RAW,
        .max_brightness = 255,
        .power = BACKLIGHT_POWER_ON,
        .brightness = 64,
};

static int micro_backlight_probe(struct platform_device *pdev)
{
        struct backlight_device *bd;
        struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);

        bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
                                            &pdev->dev, micro, &micro_bl_ops,
                                            &micro_bl_props);
        if (IS_ERR(bd))
                return PTR_ERR(bd);

        platform_set_drvdata(pdev, bd);
        backlight_update_status(bd);

        return 0;
}

static struct platform_driver micro_backlight_device_driver = {
        .driver = {
                .name    = "ipaq-micro-backlight",
        },
        .probe   = micro_backlight_probe,
};
module_platform_driver(micro_backlight_device_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
MODULE_ALIAS("platform:ipaq-micro-backlight");