linux/drivers/video/backlight/mbp_nvidia_bl.c
Matthew Garrett 7be35c72e6 backlight: Add Nvidia-based Apple Macbook Pro backlight driver
Nvidia-based Apple Macbook Pros don't appear to handle backlight control
through the graphics card registers or ACPI, but instead trigger changes
via SMI calls. This driver registers a generic backlight device that
lets existing userspace deal with it. Code derived from Julien Blache's
Pommed application.

Signed-off-by: Julien Blache <jb@jblache.org>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-07-23 09:50:18 +01:00

117 lines
2.9 KiB
C

/*
* Backlight Driver for Nvidia 8600 in Macbook Pro
*
* Copyright (c) Red Hat <mjg@redhat.com>
* Based on code from Pommed:
* Copyright (C) 2006 Nicolas Boichat <nicolas @boichat.ch>
* Copyright (C) 2006 Felipe Alfaro Solana <felipe_alfaro @linuxmail.org>
* Copyright (C) 2007 Julien BLACHE <jb@jblache.org>
*
* 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.
*
* This driver triggers SMIs which cause the firmware to change the
* backlight brightness. This is icky in many ways, but it's impractical to
* get at the firmware code in order to figure out what it's actually doing.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/dmi.h>
#include <linux/io.h>
static struct backlight_device *mbp_backlight_device;
static struct dmi_system_id __initdata mbp_device_table[] = {
{
.ident = "3,1",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro3,1"),
},
},
{
.ident = "3,2",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro3,2"),
},
},
{
.ident = "4,1",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro4,1"),
},
},
{ }
};
static int mbp_send_intensity(struct backlight_device *bd)
{
int intensity = bd->props.brightness;
outb(0x04 | (intensity << 4), 0xb3);
outb(0xbf, 0xb2);
return 0;
}
static int mbp_get_intensity(struct backlight_device *bd)
{
outb(0x03, 0xb3);
outb(0xbf, 0xb2);
return inb(0xb3) >> 4;
}
static struct backlight_ops mbp_ops = {
.get_brightness = mbp_get_intensity,
.update_status = mbp_send_intensity,
};
static int __init mbp_init(void)
{
if (!dmi_check_system(mbp_device_table))
return -ENODEV;
if (!request_region(0xb2, 2, "Macbook Pro backlight"))
return -ENXIO;
mbp_backlight_device = backlight_device_register("mbp_backlight",
NULL, NULL,
&mbp_ops);
if (IS_ERR(mbp_backlight_device)) {
release_region(0xb2, 2);
return PTR_ERR(mbp_backlight_device);
}
mbp_backlight_device->props.max_brightness = 15;
mbp_backlight_device->props.brightness =
mbp_get_intensity(mbp_backlight_device);
backlight_update_status(mbp_backlight_device);
return 0;
}
static void __exit mbp_exit(void)
{
backlight_device_unregister(mbp_backlight_device);
release_region(0xb2, 2);
}
module_init(mbp_init);
module_exit(mbp_exit);
MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
MODULE_DESCRIPTION("Nvidia-based Macbook Pro Backlight Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("svnAppleInc.:pnMacBookPro3,1");
MODULE_ALIAS("svnAppleInc.:pnMacBookPro3,2");
MODULE_ALIAS("svnAppleInc.:pnMacBookPro4,1");