da9052_bl.c

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/*
 * Backlight Driver for Dialog DA9052 PMICs
 *
 * Copyright(c) 2012 Dialog Semiconductor Ltd.
 *
 * Author: David Dajun Chen <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 */

#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <linux/mfd/da9052/da9052.h>
#include <linux/mfd/da9052/reg.h>

#define DA9052_MAX_BRIGHTNESS       0xFF

enum {
    DA9052_WLEDS_OFF,
    DA9052_WLEDS_ON,
};

enum {
    DA9052_TYPE_WLED1,
    DA9052_TYPE_WLED2,
    DA9052_TYPE_WLED3,
};

static unsigned char wled_bank[] = {
    DA9052_LED1_CONF_REG,
    DA9052_LED2_CONF_REG,
    DA9052_LED3_CONF_REG,
};

struct da9052_bl {
    struct da9052 *da9052;
    uint brightness;
    uint state;
    uint led_reg;
};

static int da9052_adjust_wled_brightness(struct da9052_bl *wleds)
{
    unsigned char boost_en;
    unsigned char i_sink;
    int ret;

    boost_en = 0x3F;
    i_sink = 0xFF;
    if (wleds->state == DA9052_WLEDS_OFF) {
        boost_en = 0x00;
        i_sink = 0x00;
    }

    ret = da9052_reg_write(wleds->da9052, DA9052_BOOST_REG, boost_en);
    if (ret < 0)
        return ret;

    ret = da9052_reg_write(wleds->da9052, DA9052_LED_CONT_REG, i_sink);
    if (ret < 0)
        return ret;

    ret = da9052_reg_write(wleds->da9052, wled_bank[wleds->led_reg], 0x0);
    if (ret < 0)
        return ret;

    usleep_range(10000, 11000);

    if (wleds->brightness) {
        ret = da9052_reg_write(wleds->da9052, wled_bank[wleds->led_reg],
                       wleds->brightness);
        if (ret < 0)
            return ret;
    }

    return 0;
}

static int da9052_backlight_update_status(struct backlight_device *bl)
{
    int brightness = bl->props.brightness;
    struct da9052_bl *wleds = bl_get_data(bl);

    wleds->brightness = brightness;
    wleds->state = DA9052_WLEDS_ON;

    return da9052_adjust_wled_brightness(wleds);
}

static int da9052_backlight_get_brightness(struct backlight_device *bl)
{
    struct da9052_bl *wleds = bl_get_data(bl);

    return wleds->brightness;
}

static const struct backlight_ops da9052_backlight_ops = {
    .update_status = da9052_backlight_update_status,
    .get_brightness = da9052_backlight_get_brightness,
};

static int da9052_backlight_probe(struct platform_device *pdev)
{
    struct backlight_device *bl;
    struct backlight_properties props;
    struct da9052_bl *wleds;

    wleds = devm_kzalloc(&pdev->dev, sizeof(struct da9052_bl), GFP_KERNEL);
    if (!wleds)
        return -ENOMEM;

    wleds->da9052 = dev_get_drvdata(pdev->dev.parent);
    wleds->brightness = 0;
    wleds->led_reg = platform_get_device_id(pdev)->driver_data;
    wleds->state = DA9052_WLEDS_OFF;

    props.type = BACKLIGHT_RAW;
    props.max_brightness = DA9052_MAX_BRIGHTNESS;

    bl = backlight_device_register(pdev->name, wleds->da9052->dev, wleds,
                       &da9052_backlight_ops, &props);
    if (IS_ERR(bl)) {
        dev_err(&pdev->dev, "Failed to register backlight\n");
        return PTR_ERR(bl);
    }

    bl->props.max_brightness = DA9052_MAX_BRIGHTNESS;
    bl->props.brightness = 0;
    platform_set_drvdata(pdev, bl);

    return da9052_adjust_wled_brightness(wleds);
}

static int da9052_backlight_remove(struct platform_device *pdev)
{
    struct backlight_device *bl = platform_get_drvdata(pdev);
    struct da9052_bl *wleds = bl_get_data(bl);

    wleds->brightness = 0;
    wleds->state = DA9052_WLEDS_OFF;
    da9052_adjust_wled_brightness(wleds);
    backlight_device_unregister(bl);

    return 0;
}

static struct platform_device_id da9052_wled_ids[] = {
    {
        .name       = "da9052-wled1",
        .driver_data    = DA9052_TYPE_WLED1,
    },
    {
        .name       = "da9052-wled2",
        .driver_data    = DA9052_TYPE_WLED2,
    },
    {
        .name       = "da9052-wled3",
        .driver_data    = DA9052_TYPE_WLED3,
    },
};

static struct platform_driver da9052_wled_driver = {
    .probe      = da9052_backlight_probe,
    .remove     = da9052_backlight_remove,
    .id_table   = da9052_wled_ids,
    .driver = {
        .name   = "da9052-wled",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(da9052_wled_driver);

MODULE_AUTHOR("David Dajun Chen <[email protected]>");
MODULE_DESCRIPTION("Backlight driver for DA9052 PMIC");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9052-backlight");