linux/drivers/video/backlight/corgi_bl.c
Henrique de Moraes Holschuh 4437cd1e98 [PATCH] backlight: do not power off backlight when unregistering
ACPI drivers like ibm-acpi are moving to the backlight sysfs
infrastructure.  During ibm-acpi testing, I have noticed that
backlight_device_unregister() sets the display brightness and power to
zero.

This causes the display to be dimmed on ibm-acpi module removal.  It will
affect all other ACPI drivers that are being converted to use the backlight
class, as well.  It also affects a number of framebuffer devices that are
used on desktops and laptops which might also not want such behaviour.

Since working around this behaviour requires undesireable hacks, Richard
Purdie decided that we would be better off reverting the changes in the
sysfs class, and adding the code to dim and power off the backlight device
to the drivers that want it.  This patch is my attempt to do so.

Patch against latest linux-2.6.git.  Changes untested, as I lack the
required hardware.  Still, they are trivial enough that, apart from typos,
there is little chance of getting them wrong.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:29:07 -08:00

174 lines
4.2 KiB
C

/*
* Backlight Driver for Sharp Zaurus Handhelds (various models)
*
* Copyright (c) 2004-2006 Richard Purdie
*
* Based on Sharp's 2.4 Backlight Driver
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <asm/arch/sharpsl.h>
#include <asm/hardware/sharpsl_pm.h>
static int corgibl_intensity;
static DEFINE_MUTEX(bl_mutex);
static struct backlight_properties corgibl_data;
static struct backlight_device *corgi_backlight_device;
static struct corgibl_machinfo *bl_machinfo;
static unsigned long corgibl_flags;
#define CORGIBL_SUSPENDED 0x01
#define CORGIBL_BATTLOW 0x02
static int corgibl_send_intensity(struct backlight_device *bd)
{
void (*corgi_kick_batt)(void);
int intensity = bd->props->brightness;
if (bd->props->power != FB_BLANK_UNBLANK)
intensity = 0;
if (bd->props->fb_blank != FB_BLANK_UNBLANK)
intensity = 0;
if (corgibl_flags & CORGIBL_SUSPENDED)
intensity = 0;
if (corgibl_flags & CORGIBL_BATTLOW)
intensity &= bl_machinfo->limit_mask;
mutex_lock(&bl_mutex);
bl_machinfo->set_bl_intensity(intensity);
mutex_unlock(&bl_mutex);
corgibl_intensity = intensity;
corgi_kick_batt = symbol_get(sharpsl_battery_kick);
if (corgi_kick_batt) {
corgi_kick_batt();
symbol_put(sharpsl_battery_kick);
}
return 0;
}
#ifdef CONFIG_PM
static int corgibl_suspend(struct platform_device *dev, pm_message_t state)
{
corgibl_flags |= CORGIBL_SUSPENDED;
corgibl_send_intensity(corgi_backlight_device);
return 0;
}
static int corgibl_resume(struct platform_device *dev)
{
corgibl_flags &= ~CORGIBL_SUSPENDED;
corgibl_send_intensity(corgi_backlight_device);
return 0;
}
#else
#define corgibl_suspend NULL
#define corgibl_resume NULL
#endif
static int corgibl_get_intensity(struct backlight_device *bd)
{
return corgibl_intensity;
}
static int corgibl_set_intensity(struct backlight_device *bd)
{
corgibl_send_intensity(corgi_backlight_device);
return 0;
}
/*
* Called when the battery is low to limit the backlight intensity.
* If limit==0 clear any limit, otherwise limit the intensity
*/
void corgibl_limit_intensity(int limit)
{
if (limit)
corgibl_flags |= CORGIBL_BATTLOW;
else
corgibl_flags &= ~CORGIBL_BATTLOW;
corgibl_send_intensity(corgi_backlight_device);
}
EXPORT_SYMBOL(corgibl_limit_intensity);
static struct backlight_properties corgibl_data = {
.owner = THIS_MODULE,
.get_brightness = corgibl_get_intensity,
.update_status = corgibl_set_intensity,
};
static int corgibl_probe(struct platform_device *pdev)
{
struct corgibl_machinfo *machinfo = pdev->dev.platform_data;
bl_machinfo = machinfo;
corgibl_data.max_brightness = machinfo->max_intensity;
if (!machinfo->limit_mask)
machinfo->limit_mask = -1;
corgi_backlight_device = backlight_device_register ("corgi-bl",
NULL, &corgibl_data);
if (IS_ERR (corgi_backlight_device))
return PTR_ERR (corgi_backlight_device);
corgibl_data.power = FB_BLANK_UNBLANK;
corgibl_data.brightness = machinfo->default_intensity;
corgibl_send_intensity(corgi_backlight_device);
printk("Corgi Backlight Driver Initialized.\n");
return 0;
}
static int corgibl_remove(struct platform_device *dev)
{
corgibl_data.power = 0;
corgibl_data.brightness = 0;
corgibl_send_intensity(corgi_backlight_device);
backlight_device_unregister(corgi_backlight_device);
printk("Corgi Backlight Driver Unloaded\n");
return 0;
}
static struct platform_driver corgibl_driver = {
.probe = corgibl_probe,
.remove = corgibl_remove,
.suspend = corgibl_suspend,
.resume = corgibl_resume,
.driver = {
.name = "corgi-bl",
},
};
static int __init corgibl_init(void)
{
return platform_driver_register(&corgibl_driver);
}
static void __exit corgibl_exit(void)
{
platform_driver_unregister(&corgibl_driver);
}
module_init(corgibl_init);
module_exit(corgibl_exit);
MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
MODULE_DESCRIPTION("Corgi Backlight Driver");
MODULE_LICENSE("GPL");