drivers/video/backlight/hp680_bl.c

/*
 *  Backlight Driver for HP Jornada 680
 *
 *  Copyright (c) 2005 Andriy Skulysh
 *
 *  Based on Sharp's Corgi Backlight Driver
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/spinlock.h>
#include <linux/fb.h>
#include <linux/backlight.h>

#include <asm/cpu/dac.h>
#include <asm/hp6xx/hp6xx.h>
#include <asm/hd64461/hd64461.h>

#define HP680_MAX_INTENSITY 255
#define HP680_DEFAULT_INTENSITY 10

static int hp680bl_powermode = FB_BLANK_UNBLANK;
static int current_intensity = 0;
static spinlock_t bl_lock = SPIN_LOCK_UNLOCKED;

static void hp680bl_send_intensity(int intensity)
{
	unsigned long flags;

	if (hp680bl_powermode != FB_BLANK_UNBLANK)
		intensity = 0;

	spin_lock_irqsave(&bl_lock, flags);
	sh_dac_output(255-(u8)intensity, DAC_LCD_BRIGHTNESS);
	spin_unlock_irqrestore(&bl_lock, flags);
}

static void hp680bl_blank(int blank)
{
	u16 v;

	switch(blank) {

	case FB_BLANK_NORMAL:
	case FB_BLANK_VSYNC_SUSPEND:
	case FB_BLANK_HSYNC_SUSPEND:
	case FB_BLANK_POWERDOWN:
		if (hp680bl_powermode == FB_BLANK_UNBLANK) {
			hp680bl_send_intensity(0);
			hp680bl_powermode = blank;
			sh_dac_disable(DAC_LCD_BRIGHTNESS);
			v = inw(HD64461_GPBDR);
			v |= HD64461_GPBDR_LCDOFF;
			outw(v, HD64461_GPBDR);
		}
		break;
	case FB_BLANK_UNBLANK:
		if (hp680bl_powermode != FB_BLANK_UNBLANK) {
			sh_dac_enable(DAC_LCD_BRIGHTNESS);
			v = inw(HD64461_GPBDR);
			v &= ~HD64461_GPBDR_LCDOFF;
			outw(v, HD64461_GPBDR);
			hp680bl_powermode = blank;
			hp680bl_send_intensity(current_intensity);
		}
		break;
	}
}

#ifdef CONFIG_PM
static int hp680bl_suspend(struct device *dev, pm_message_t state, u32 level)
{
	if (level == SUSPEND_POWER_DOWN)
		hp680bl_blank(FB_BLANK_POWERDOWN);
	return 0;
}

static int hp680bl_resume(struct device *dev, u32 level)
{
	if (level == RESUME_POWER_ON)
		hp680bl_blank(FB_BLANK_UNBLANK);
	return 0;
}
#else
#define hp680bl_suspend	NULL
#define hp680bl_resume	NULL
#endif


static int hp680bl_set_power(struct backlight_device *bd, int state)
{
	hp680bl_blank(state);
	return 0;
}

static int hp680bl_get_power(struct backlight_device *bd)
{
	return hp680bl_powermode;
}

static int hp680bl_set_intensity(struct backlight_device *bd, int intensity)
{
	if (intensity > HP680_MAX_INTENSITY)
		intensity = HP680_MAX_INTENSITY;
	hp680bl_send_intensity(intensity);
	current_intensity = intensity;
	return 0;
}

static int hp680bl_get_intensity(struct backlight_device *bd)
{
	return current_intensity;
}

static struct backlight_properties hp680bl_data = {
	.owner		= THIS_MODULE,
	.get_power      = hp680bl_get_power,
	.set_power      = hp680bl_set_power,
	.max_brightness = HP680_MAX_INTENSITY,
	.get_brightness = hp680bl_get_intensity,
	.set_brightness = hp680bl_set_intensity,
};

static struct backlight_device *hp680_backlight_device;

static int __init hp680bl_probe(struct device *dev)
{
	hp680_backlight_device = backlight_device_register ("hp680-bl",
		NULL, &hp680bl_data);
	if (IS_ERR (hp680_backlight_device))
		return PTR_ERR (hp680_backlight_device);

	hp680bl_set_intensity(NULL, HP680_DEFAULT_INTENSITY);

	return 0;
}

static int hp680bl_remove(struct device *dev)
{
	backlight_device_unregister(hp680_backlight_device);

	return 0;
}

static struct device_driver hp680bl_driver = {
	.name		= "hp680-bl",
	.bus		= &platform_bus_type,
	.probe		= hp680bl_probe,
	.remove		= hp680bl_remove,
	.suspend	= hp680bl_suspend,
	.resume		= hp680bl_resume,
};

static struct platform_device hp680bl_device = {
	.name	= "hp680-bl",
	.id	= -1,
};

static int __init hp680bl_init(void)
{
	int ret;

	ret=driver_register(&hp680bl_driver);
	if (!ret) {
		ret = platform_device_register(&hp680bl_device);
		if (ret)
			driver_unregister(&hp680bl_driver);
	}
	return ret;
}

static void __exit hp680bl_exit(void)
{
	platform_device_unregister(&hp680bl_device);
 	driver_unregister(&hp680bl_driver);
}

module_init(hp680bl_init);
module_exit(hp680bl_exit);

MODULE_AUTHOR("Andriy Skulysh <askulysh@image.kiev.ua>");
MODULE_DESCRIPTION("HP Jornada 680 Backlight Driver");
MODULE_LICENSE("GPL");