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