omap1_bl.c

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/*
 * Backlight driver for OMAP based boards.
 *
 * Copyright (c) 2006 Andrzej Zaborowski  <[email protected]>
 *
 * This package 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.
 *
 * This package is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this package; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/slab.h>
#include <linux/platform_data/omap1_bl.h>

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

#define OMAPBL_MAX_INTENSITY        0xff

struct omap_backlight {
    int powermode;
    int current_intensity;

    struct device *dev;
    struct omap_backlight_config *pdata;
};

static void inline omapbl_send_intensity(int intensity)
{
    omap_writeb(intensity, OMAP_PWL_ENABLE);
}

static void inline omapbl_send_enable(int enable)
{
    omap_writeb(enable, OMAP_PWL_CLK_ENABLE);
}

static void omapbl_blank(struct omap_backlight *bl, int mode)
{
    if (bl->pdata->set_power)
        bl->pdata->set_power(bl->dev, mode);

    switch (mode) {
    case FB_BLANK_NORMAL:
    case FB_BLANK_VSYNC_SUSPEND:
    case FB_BLANK_HSYNC_SUSPEND:
    case FB_BLANK_POWERDOWN:
        omapbl_send_intensity(0);
        omapbl_send_enable(0);
        break;

    case FB_BLANK_UNBLANK:
        omapbl_send_intensity(bl->current_intensity);
        omapbl_send_enable(1);
        break;
    }
}

#ifdef CONFIG_PM
static int omapbl_suspend(struct platform_device *pdev, pm_message_t state)
{
    struct backlight_device *dev = platform_get_drvdata(pdev);
    struct omap_backlight *bl = dev_get_drvdata(&dev->dev);

    omapbl_blank(bl, FB_BLANK_POWERDOWN);
    return 0;
}

static int omapbl_resume(struct platform_device *pdev)
{
    struct backlight_device *dev = platform_get_drvdata(pdev);
    struct omap_backlight *bl = dev_get_drvdata(&dev->dev);

    omapbl_blank(bl, bl->powermode);
    return 0;
}
#else
#define omapbl_suspend  NULL
#define omapbl_resume   NULL
#endif

static int omapbl_set_power(struct backlight_device *dev, int state)
{
    struct omap_backlight *bl = dev_get_drvdata(&dev->dev);

    omapbl_blank(bl, state);
    bl->powermode = state;

    return 0;
}

static int omapbl_update_status(struct backlight_device *dev)
{
    struct omap_backlight *bl = dev_get_drvdata(&dev->dev);

    if (bl->current_intensity != dev->props.brightness) {
        if (bl->powermode == FB_BLANK_UNBLANK)
            omapbl_send_intensity(dev->props.brightness);
        bl->current_intensity = dev->props.brightness;
    }

    if (dev->props.fb_blank != bl->powermode)
        omapbl_set_power(dev, dev->props.fb_blank);

    return 0;
}

static int omapbl_get_intensity(struct backlight_device *dev)
{
    struct omap_backlight *bl = dev_get_drvdata(&dev->dev);
    return bl->current_intensity;
}

static const struct backlight_ops omapbl_ops = {
    .get_brightness = omapbl_get_intensity,
    .update_status  = omapbl_update_status,
};

static int omapbl_probe(struct platform_device *pdev)
{
    struct backlight_properties props;
    struct backlight_device *dev;
    struct omap_backlight *bl;
    struct omap_backlight_config *pdata = pdev->dev.platform_data;

    if (!pdata)
        return -ENXIO;

    bl = devm_kzalloc(&pdev->dev, sizeof(struct omap_backlight),
              GFP_KERNEL);
    if (unlikely(!bl))
        return -ENOMEM;

    memset(&props, 0, sizeof(struct backlight_properties));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = OMAPBL_MAX_INTENSITY;
    dev = backlight_device_register("omap-bl", &pdev->dev, bl, &omapbl_ops,
                    &props);
    if (IS_ERR(dev))
        return PTR_ERR(dev);

    bl->powermode = FB_BLANK_POWERDOWN;
    bl->current_intensity = 0;

    bl->pdata = pdata;
    bl->dev = &pdev->dev;

    platform_set_drvdata(pdev, dev);

    omap_cfg_reg(PWL);  /* Conflicts with UART3 */

    dev->props.fb_blank = FB_BLANK_UNBLANK;
    dev->props.brightness = pdata->default_intensity;
    omapbl_update_status(dev);

    pr_info("OMAP LCD backlight initialised\n");

    return 0;
}

static int omapbl_remove(struct platform_device *pdev)
{
    struct backlight_device *dev = platform_get_drvdata(pdev);

    backlight_device_unregister(dev);

    return 0;
}

static struct platform_driver omapbl_driver = {
    .probe      = omapbl_probe,
    .remove     = omapbl_remove,
    .suspend    = omapbl_suspend,
    .resume     = omapbl_resume,
    .driver     = {
        .name   = "omap-bl",
    },
};

module_platform_driver(omapbl_driver);

MODULE_AUTHOR("Andrzej Zaborowski <[email protected]>");
MODULE_DESCRIPTION("OMAP LCD Backlight driver");
MODULE_LICENSE("GPL");