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/*
* Gmux driver for Apple laptops
*
* Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/backlight.h>
#include <linux/acpi.h>
#include <linux/pnp.h>
#include <linux/apple_bl.h>
#include <linux/slab.h>
#include <acpi/video.h>
#include <asm/io.h>
struct apple_gmux_data {
unsigned long iostart;
unsigned long iolen;
struct backlight_device *bdev;
};
/*
* gmux port offsets. Many of these are not yet used, but may be in the
* future, and it's useful to have them documented here anyhow.
*/
#define GMUX_PORT_VERSION_MAJOR 0x04
#define GMUX_PORT_VERSION_MINOR 0x05
#define GMUX_PORT_VERSION_RELEASE 0x06
#define GMUX_PORT_SWITCH_DISPLAY 0x10
#define GMUX_PORT_SWITCH_GET_DISPLAY 0x11
#define GMUX_PORT_INTERRUPT_ENABLE 0x14
#define GMUX_PORT_INTERRUPT_STATUS 0x16
#define GMUX_PORT_SWITCH_DDC 0x28
#define GMUX_PORT_SWITCH_EXTERNAL 0x40
#define GMUX_PORT_SWITCH_GET_EXTERNAL 0x41
#define GMUX_PORT_DISCRETE_POWER 0x50
#define GMUX_PORT_MAX_BRIGHTNESS 0x70
#define GMUX_PORT_BRIGHTNESS 0x74
#define GMUX_MIN_IO_LEN (GMUX_PORT_BRIGHTNESS + 4)
#define GMUX_INTERRUPT_ENABLE 0xff
#define GMUX_INTERRUPT_DISABLE 0x00
#define GMUX_INTERRUPT_STATUS_ACTIVE 0
#define GMUX_INTERRUPT_STATUS_DISPLAY (1 << 0)
#define GMUX_INTERRUPT_STATUS_POWER (1 << 2)
#define GMUX_INTERRUPT_STATUS_HOTPLUG (1 << 3)
#define GMUX_BRIGHTNESS_MASK 0x00ffffff
#define GMUX_MAX_BRIGHTNESS GMUX_BRIGHTNESS_MASK
static inline u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
{
return inb(gmux_data->iostart + port);
}
static inline void gmux_write8(struct apple_gmux_data *gmux_data, int port,
u8 val)
{
outb(val, gmux_data->iostart + port);
}
static inline u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
{
return inl(gmux_data->iostart + port);
}
static int gmux_get_brightness(struct backlight_device *bd)
{
struct apple_gmux_data *gmux_data = bl_get_data(bd);
return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
GMUX_BRIGHTNESS_MASK;
}
static int gmux_update_status(struct backlight_device *bd)
{
struct apple_gmux_data *gmux_data = bl_get_data(bd);
u32 brightness = bd->props.brightness;
/*
* Older gmux versions require writing out lower bytes first then
* setting the upper byte to 0 to flush the values. Newer versions
* accept a single u32 write, but the old method also works, so we
* just use the old method for all gmux versions.
*/
gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 1, brightness >> 8);
gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 2, brightness >> 16);
gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 3, 0);
return 0;
}
static const struct backlight_ops gmux_bl_ops = {
.get_brightness = gmux_get_brightness,
.update_status = gmux_update_status,
};
static int __devinit gmux_probe(struct pnp_dev *pnp,
const struct pnp_device_id *id)
{
struct apple_gmux_data *gmux_data;
struct resource *res;
struct backlight_properties props;
struct backlight_device *bdev;
u8 ver_major, ver_minor, ver_release;
int ret = -ENXIO;
gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
if (!gmux_data)
return -ENOMEM;
pnp_set_drvdata(pnp, gmux_data);
res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
if (!res) {
pr_err("Failed to find gmux I/O resource\n");
goto err_free;
}
gmux_data->iostart = res->start;
gmux_data->iolen = res->end - res->start;
if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
pr_err("gmux I/O region too small (%lu < %u)\n",
gmux_data->iolen, GMUX_MIN_IO_LEN);
goto err_free;
}
if (!request_region(gmux_data->iostart, gmux_data->iolen,
"Apple gmux")) {
pr_err("gmux I/O already in use\n");
goto err_free;
}
/*
* On some machines the gmux is in ACPI even thought the machine
* doesn't really have a gmux. Check for invalid version information
* to detect this.
*/
ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
pr_info("gmux device not present\n");
ret = -ENODEV;
goto err_release;
}
pr_info("Found gmux version %d.%d.%d\n", ver_major, ver_minor,
ver_release);
memset(&props, 0, sizeof(props));
props.type = BACKLIGHT_PLATFORM;
props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
/*
* Currently it's assumed that the maximum brightness is less than
* 2^24 for compatibility with old gmux versions. Cap the max
* brightness at this value, but print a warning if the hardware
* reports something higher so that it can be fixed.
*/
if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
props.max_brightness = GMUX_MAX_BRIGHTNESS;
bdev = backlight_device_register("gmux_backlight", &pnp->dev,
gmux_data, &gmux_bl_ops, &props);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
goto err_release;
}
gmux_data->bdev = bdev;
bdev->props.brightness = gmux_get_brightness(bdev);
backlight_update_status(bdev);
/*
* The backlight situation on Macs is complicated. If the gmux is
* present it's the best choice, because it always works for
* backlight control and supports more levels than other options.
* Disable the other backlight choices.
*/
acpi_video_unregister();
apple_bl_unregister();
return 0;
err_release:
release_region(gmux_data->iostart, gmux_data->iolen);
err_free:
kfree(gmux_data);
return ret;
}
static void __devexit gmux_remove(struct pnp_dev *pnp)
{
struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
backlight_device_unregister(gmux_data->bdev);
release_region(gmux_data->iostart, gmux_data->iolen);
kfree(gmux_data);
acpi_video_register();
apple_bl_register();
}
static const struct pnp_device_id gmux_device_ids[] = {
{"APP000B", 0},
{"", 0}
};
static struct pnp_driver gmux_pnp_driver = {
.name = "apple-gmux",
.probe = gmux_probe,
.remove = __devexit_p(gmux_remove),
.id_table = gmux_device_ids,
};
static int __init apple_gmux_init(void)
{
return pnp_register_driver(&gmux_pnp_driver);
}
static void __exit apple_gmux_exit(void)
{
pnp_unregister_driver(&gmux_pnp_driver);
}
module_init(apple_gmux_init);
module_exit(apple_gmux_exit);
MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>");
MODULE_DESCRIPTION("Apple Gmux Driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pnp, gmux_device_ids);
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