Attachment 2095 Details for Bug 5570 – apple_gmux.c

apple_gmux.c

apple_gmux.c (text/x-csrc), 6.45 KB, created by Andy Liebman on 2012-04-24 15:58:19 CEST

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Creator: Andy Liebman

Created: 2012-04-24 15:58:19 CEST

Size: 6.45 KB

patch

obsolete

>/*
> *  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.
> *
> *  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.
> */
>
>#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
>#include <linux/module.h>
>#include <linux/kernel.h>
>#include <linux/init.h>
>#include <linux/slab.h>
>#include <linux/pnp.h>
>#include <linux/backlight.h>
>
>struct apple_gmux_data {
>	unsigned long iostart;
>	unsigned long iolen;
>
>	int max_brightness;
>	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 work, 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);
>
>	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);
>}
>
>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);

/*
 *  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.
 *
 *  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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pnp.h>
#include <linux/backlight.h>

struct apple_gmux_data {
	unsigned long iostart;
	unsigned long iolen;

	int max_brightness;
	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 work, 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);

	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);
}

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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