/*
 * Backlight driver for OMAP based boards.
 *
 * Copyright (c) 2006 Andrzej Zaborowski  <balrog@zabor.org>
 *
 * 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
 */

#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 <mach/hardware.h>
#include <plat/board.h>
#include <plat/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 = kzalloc(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)) {
                kfree(bl);
                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);

        printk(KERN_INFO "OMAP LCD backlight initialised\n");

        return 0;
}

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

        backlight_device_unregister(dev);
        kfree(bl);

        return 0;
}

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

static int __init omapbl_init(void)
{
        return platform_driver_register(&omapbl_driver);
}

static void __exit omapbl_exit(void)
{
        platform_driver_unregister(&omapbl_driver);
}

module_init(omapbl_init);
module_exit(omapbl_exit);

MODULE_AUTHOR("Andrzej Zaborowski <balrog@zabor.org>");
MODULE_DESCRIPTION("OMAP LCD Backlight driver");
MODULE_LICENSE("GPL");