da903x_bl.c

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/*
 * Backlight driver for Dialog Semiconductor DA9030/DA9034
 *
 * Copyright (C) 2008 Compulab, Ltd.
 *  Mike Rapoport <[email protected]>
 *
 * Copyright (C) 2006-2008 Marvell International Ltd.
 *  Eric Miao <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/mfd/da903x.h>
#include <linux/slab.h>
#include <linux/module.h>

#define DA9030_WLED_CONTROL 0x25
#define DA9030_WLED_CP_EN   (1 << 6)
#define DA9030_WLED_TRIM(x) ((x) & 0x7)

#define DA9034_WLED_CONTROL1    0x3C
#define DA9034_WLED_CONTROL2    0x3D
#define DA9034_WLED_ISET(x) ((x) & 0x1f)

#define DA9034_WLED_BOOST_EN    (1 << 5)

#define DA9030_MAX_BRIGHTNESS   7
#define DA9034_MAX_BRIGHTNESS   0x7f

struct da903x_backlight_data {
    struct device *da903x_dev;
    int id;
    int current_brightness;
};

static int da903x_backlight_set(struct backlight_device *bl, int brightness)
{
    struct da903x_backlight_data *data = bl_get_data(bl);
    struct device *dev = data->da903x_dev;
    uint8_t val;
    int ret = 0;

    switch (data->id) {
    case DA9034_ID_WLED:
        ret = da903x_update(dev, DA9034_WLED_CONTROL1,
                brightness, 0x7f);
        if (ret)
            return ret;

        if (data->current_brightness && brightness == 0)
            ret = da903x_clr_bits(dev,
                    DA9034_WLED_CONTROL2,
                    DA9034_WLED_BOOST_EN);

        if (data->current_brightness == 0 && brightness)
            ret = da903x_set_bits(dev,
                    DA9034_WLED_CONTROL2,
                    DA9034_WLED_BOOST_EN);
        break;
    case DA9030_ID_WLED:
        val = DA9030_WLED_TRIM(brightness);
        val |= brightness ? DA9030_WLED_CP_EN : 0;
        ret = da903x_write(dev, DA9030_WLED_CONTROL, val);
        break;
    }

    if (ret)
        return ret;

    data->current_brightness = brightness;
    return 0;
}

static int da903x_backlight_update_status(struct backlight_device *bl)
{
    int brightness = bl->props.brightness;

    if (bl->props.power != FB_BLANK_UNBLANK)
        brightness = 0;

    if (bl->props.fb_blank != FB_BLANK_UNBLANK)
        brightness = 0;

    return da903x_backlight_set(bl, brightness);
}

static int da903x_backlight_get_brightness(struct backlight_device *bl)
{
    struct da903x_backlight_data *data = bl_get_data(bl);
    return data->current_brightness;
}

static const struct backlight_ops da903x_backlight_ops = {
    .update_status  = da903x_backlight_update_status,
    .get_brightness = da903x_backlight_get_brightness,
};

static int da903x_backlight_probe(struct platform_device *pdev)
{
    struct da9034_backlight_pdata *pdata = pdev->dev.platform_data;
    struct da903x_backlight_data *data;
    struct backlight_device *bl;
    struct backlight_properties props;
    int max_brightness;

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

    switch (pdev->id) {
    case DA9030_ID_WLED:
        max_brightness = DA9030_MAX_BRIGHTNESS;
        break;
    case DA9034_ID_WLED:
        max_brightness = DA9034_MAX_BRIGHTNESS;
        break;
    default:
        dev_err(&pdev->dev, "invalid backlight device ID(%d)\n",
                pdev->id);
        return -EINVAL;
    }

    data->id = pdev->id;
    data->da903x_dev = pdev->dev.parent;
    data->current_brightness = 0;

    /* adjust the WLED output current */
    if (pdata)
        da903x_write(data->da903x_dev, DA9034_WLED_CONTROL2,
                DA9034_WLED_ISET(pdata->output_current));

    memset(&props, 0, sizeof(props));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = max_brightness;
    bl = backlight_device_register(pdev->name, data->da903x_dev, data,
                       &da903x_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);
    backlight_update_status(bl);
    return 0;
}

static int da903x_backlight_remove(struct platform_device *pdev)
{
    struct backlight_device *bl = platform_get_drvdata(pdev);

    backlight_device_unregister(bl);
    return 0;
}

#ifdef CONFIG_PM
static int da903x_backlight_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct backlight_device *bl = platform_get_drvdata(pdev);
    return da903x_backlight_set(bl, 0);
}

static int da903x_backlight_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct backlight_device *bl = platform_get_drvdata(pdev);

    backlight_update_status(bl);
    return 0;
}

static const struct dev_pm_ops da903x_backlight_pm_ops = {
    .suspend    = da903x_backlight_suspend,
    .resume     = da903x_backlight_resume,
};
#endif

static struct platform_driver da903x_backlight_driver = {
    .driver     = {
        .name   = "da903x-backlight",
        .owner  = THIS_MODULE,
#ifdef CONFIG_PM
        .pm = &da903x_backlight_pm_ops,
#endif
    },
    .probe      = da903x_backlight_probe,
    .remove     = da903x_backlight_remove,
};

module_platform_driver(da903x_backlight_driver);

MODULE_DESCRIPTION("Backlight Driver for Dialog Semiconductor DA9030/DA9034");
MODULE_AUTHOR("Eric Miao <[email protected]>"
          "Mike Rapoport <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da903x-backlight");