drivers/hwmon/hdaps.c - kernel/msm - Gitiles

 /*
  * drivers/hwmon/hdaps.c - driver for IBM's Hard Drive Active Protection System
  *
  * Copyright (C) 2005 Robert Love <rml@novell.com>
  * Copyright (C) 2005 Jesper Juhl <jesper.juhl@gmail.com>
  *
  * The HardDisk Active Protection System (hdaps) is present in IBM ThinkPads
  * starting with the R40, T41, and X40.  It provides a basic two-axis
  * accelerometer and other data, such as the device's temperature.
  *
  * This driver is based on the document by Mark A. Smith available at
  * http://www.almaden.ibm.com/cs/people/marksmith/tpaps.html and a lot of trial
  * and error.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License v2 as published by the
  * Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */

 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/input.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/timer.h>
 #include <linux/dmi.h>
 #include <linux/jiffies.h>
 #include <asm/io.h>

 #define HDAPS_LOW_PORT		0x1600	/* first port used by hdaps */
 #define HDAPS_NR_PORTS		0x30	/* number of ports: 0x1600 - 0x162f */

 #define HDAPS_PORT_STATE	0x1611	/* device state */
 #define HDAPS_PORT_YPOS		0x1612	/* y-axis position */
 #define	HDAPS_PORT_XPOS		0x1614	/* x-axis position */
 #define HDAPS_PORT_TEMP1	0x1616	/* device temperature, in Celsius */
 #define HDAPS_PORT_YVAR		0x1617	/* y-axis variance (what is this?) */
 #define HDAPS_PORT_XVAR		0x1619	/* x-axis variance (what is this?) */
 #define HDAPS_PORT_TEMP2	0x161b	/* device temperature (again?) */
 #define HDAPS_PORT_UNKNOWN	0x161c	/* what is this? */
 #define HDAPS_PORT_KMACT	0x161d	/* keyboard or mouse activity */

 #define STATE_FRESH		0x50	/* accelerometer data is fresh */

 #define KEYBD_MASK		0x20	/* set if keyboard activity */
 #define MOUSE_MASK		0x40	/* set if mouse activity */
 #define KEYBD_ISSET(n)		(!! (n & KEYBD_MASK))	/* keyboard used? */
 #define MOUSE_ISSET(n)		(!! (n & MOUSE_MASK))	/* mouse used? */

 #define INIT_TIMEOUT_MSECS	4000	/* wait up to 4s for device init ... */
 #define INIT_WAIT_MSECS		200	/* ... in 200ms increments */

 #define HDAPS_POLL_PERIOD	(HZ/20)	/* poll for input every 1/20s */
 #define HDAPS_INPUT_FUZZ	4	/* input event threshold */
 #define HDAPS_INPUT_FLAT	4

 static struct timer_list hdaps_timer;
 static struct platform_device *pdev;
 static struct input_dev *hdaps_idev;
 static unsigned int hdaps_invert;
 static u8 km_activity;
 static int rest_x;
 static int rest_y;

 static DECLARE_MUTEX(hdaps_sem);

 /*
  * __get_latch - Get the value from a given port.  Callers must hold hdaps_sem.
  */
 static inline u8 __get_latch(u16 port)
 {
 	return inb(port) & 0xff;
 }

 /*
  * __check_latch - Check a port latch for a given value.  Returns zero if the
  * port contains the given value.  Callers must hold hdaps_sem.
  */
 static inline int __check_latch(u16 port, u8 val)
 {
 	if (__get_latch(port) == val)
 		return 0;
 	return -EINVAL;
 }

 /*
  * __wait_latch - Wait up to 100us for a port latch to get a certain value,
  * returning zero if the value is obtained.  Callers must hold hdaps_sem.
  */
 static int __wait_latch(u16 port, u8 val)
 {
 	unsigned int i;

 	for (i = 0; i < 20; i++) {
 		if (!__check_latch(port, val))
 			return 0;
 		udelay(5);
 	}

 	return -EIO;
 }

 /*
  * __device_refresh - request a refresh from the accelerometer.  Does not wait
  * for refresh to complete.  Callers must hold hdaps_sem.
  */
 static void __device_refresh(void)
 {
 	udelay(200);
 	if (inb(0x1604) != STATE_FRESH) {
 		outb(0x11, 0x1610);
 		outb(0x01, 0x161f);
 	}
 }

 /*
  * __device_refresh_sync - request a synchronous refresh from the
  * accelerometer.  We wait for the refresh to complete.  Returns zero if
  * successful and nonzero on error.  Callers must hold hdaps_sem.
  */
 static int __device_refresh_sync(void)
 {
 	__device_refresh();
 	return __wait_latch(0x1604, STATE_FRESH);
 }

 /*
  * __device_complete - indicate to the accelerometer that we are done reading
  * data, and then initiate an async refresh.  Callers must hold hdaps_sem.
  */
 static inline void __device_complete(void)
 {
 	inb(0x161f);
 	inb(0x1604);
 	__device_refresh();
 }

 /*
  * hdaps_readb_one - reads a byte from a single I/O port, placing the value in
  * the given pointer.  Returns zero on success or a negative error on failure.
  * Can sleep.
  */
 static int hdaps_readb_one(unsigned int port, u8 *val)
 {
 	int ret;

 	down(&hdaps_sem);

 	/* do a sync refresh -- we need to be sure that we read fresh data */
 	ret = __device_refresh_sync();
 	if (ret)
 		goto out;

 	*val = inb(port);
 	__device_complete();

 out:
 	up(&hdaps_sem);
 	return ret;
 }

 /* __hdaps_read_pair - internal lockless helper for hdaps_read_pair(). */
 static int __hdaps_read_pair(unsigned int port1, unsigned int port2,
 			     int *x, int *y)
 {
 	/* do a sync refresh -- we need to be sure that we read fresh data */
 	if (__device_refresh_sync())
 		return -EIO;

 	*y = inw(port2);
 	*x = inw(port1);
 	km_activity = inb(HDAPS_PORT_KMACT);
 	__device_complete();

 	/* if hdaps_invert is set, negate the two values */
 	if (hdaps_invert) {
 		*x = -*x;
 		*y = -*y;
 	}

 	return 0;
 }

 /*
  * hdaps_read_pair - reads the values from a pair of ports, placing the values
  * in the given pointers.  Returns zero on success.  Can sleep.
  */
 static int hdaps_read_pair(unsigned int port1, unsigned int port2,
 			   int *val1, int *val2)
 {
 	int ret;

 	down(&hdaps_sem);
 	ret = __hdaps_read_pair(port1, port2, val1, val2);
 	up(&hdaps_sem);

 	return ret;
 }

 /*
  * hdaps_device_init - initialize the accelerometer.  Returns zero on success
  * and negative error code on failure.  Can sleep.
  */
 static int hdaps_device_init(void)
 {
 	int total, ret = -ENXIO;

 	down(&hdaps_sem);

 	outb(0x13, 0x1610);
 	outb(0x01, 0x161f);
 	if (__wait_latch(0x161f, 0x00))
 		goto out;

 	/*
 	 * Most ThinkPads return 0x01.
 	 *
 	 * Others--namely the R50p, T41p, and T42p--return 0x03.  These laptops
 	 * have "inverted" axises.
 	 *
 	 * The 0x02 value occurs when the chip has been previously initialized.
 	 */
 	if (__check_latch(0x1611, 0x03) &&
 		     __check_latch(0x1611, 0x02) &&
 		     __check_latch(0x1611, 0x01))
 		goto out;

 	printk(KERN_DEBUG "hdaps: initial latch check good (0x%02x).\n",
 	       __get_latch(0x1611));

 	outb(0x17, 0x1610);
 	outb(0x81, 0x1611);
 	outb(0x01, 0x161f);
 	if (__wait_latch(0x161f, 0x00))
 		goto out;
 	if (__wait_latch(0x1611, 0x00))
 		goto out;
 	if (__wait_latch(0x1612, 0x60))
 		goto out;
 	if (__wait_latch(0x1613, 0x00))
 		goto out;
 	outb(0x14, 0x1610);
 	outb(0x01, 0x1611);
 	outb(0x01, 0x161f);
 	if (__wait_latch(0x161f, 0x00))
 		goto out;
 	outb(0x10, 0x1610);
 	outb(0xc8, 0x1611);
 	outb(0x00, 0x1612);
 	outb(0x02, 0x1613);
 	outb(0x01, 0x161f);
 	if (__wait_latch(0x161f, 0x00))
 		goto out;
 	if (__device_refresh_sync())
 		goto out;
 	if (__wait_latch(0x1611, 0x00))
 		goto out;

 	/* we have done our dance, now let's wait for the applause */
 	for (total = INIT_TIMEOUT_MSECS; total > 0; total -= INIT_WAIT_MSECS) {
 		int x, y;

 		/* a read of the device helps push it into action */
 		__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
 		if (!__wait_latch(0x1611, 0x02)) {
 			ret = 0;
 			break;
 		}

 		msleep(INIT_WAIT_MSECS);
 	}

 out:
 	up(&hdaps_sem);
 	return ret;
 }


 /* Device model stuff */

 static int hdaps_probe(struct platform_device *dev)
 {
 	int ret;

 	ret = hdaps_device_init();
 	if (ret)
 		return ret;

 	printk(KERN_INFO "hdaps: device successfully initialized.\n");
 	return 0;
 }

 static int hdaps_resume(struct platform_device *dev)
 {
 	return hdaps_device_init();
 }

 static struct platform_driver hdaps_driver = {
 	.probe = hdaps_probe,
 	.resume = hdaps_resume,
 	.driver	= {
 		.name = "hdaps",
 		.owner = THIS_MODULE,
 	},
 };

 /*
  * hdaps_calibrate - Set our "resting" values.  Callers must hold hdaps_sem.
  */
 static void hdaps_calibrate(void)
 {
 	__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y);
 }

 static void hdaps_mousedev_poll(unsigned long unused)
 {
 	int x, y;

 	/* Cannot sleep.  Try nonblockingly.  If we fail, try again later. */
 	if (down_trylock(&hdaps_sem)) {
 		mod_timer(&hdaps_timer,jiffies + HDAPS_POLL_PERIOD);
 		return;
 	}

 	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
 		goto out;

 	input_report_abs(hdaps_idev, ABS_X, x - rest_x);
 	input_report_abs(hdaps_idev, ABS_Y, y - rest_y);
 	input_sync(hdaps_idev);

 	mod_timer(&hdaps_timer, jiffies + HDAPS_POLL_PERIOD);

 out:
 	up(&hdaps_sem);
 }


 /* Sysfs Files */

 static ssize_t hdaps_position_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
 	int ret, x, y;

 	ret = hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
 	if (ret)
 		return ret;

 	return sprintf(buf, "(%d,%d)\n", x, y);
 }

 static ssize_t hdaps_variance_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
 	int ret, x, y;

 	ret = hdaps_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y);
 	if (ret)
 		return ret;

 	return sprintf(buf, "(%d,%d)\n", x, y);
 }

 static ssize_t hdaps_temp1_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	u8 temp;
 	int ret;

 	ret = hdaps_readb_one(HDAPS_PORT_TEMP1, &temp);
 	if (ret < 0)
 		return ret;

 	return sprintf(buf, "%u\n", temp);
 }

 static ssize_t hdaps_temp2_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	u8 temp;
 	int ret;

 	ret = hdaps_readb_one(HDAPS_PORT_TEMP2, &temp);
 	if (ret < 0)
 		return ret;

 	return sprintf(buf, "%u\n", temp);
 }

 static ssize_t hdaps_keyboard_activity_show(struct device *dev,
 					    struct device_attribute *attr,
 					    char *buf)
 {
 	return sprintf(buf, "%u\n", KEYBD_ISSET(km_activity));
 }

 static ssize_t hdaps_mouse_activity_show(struct device *dev,
 					 struct device_attribute *attr,
 					 char *buf)
 {
 	return sprintf(buf, "%u\n", MOUSE_ISSET(km_activity));
 }

 static ssize_t hdaps_calibrate_show(struct device *dev,
 				    struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "(%d,%d)\n", rest_x, rest_y);
 }

 static ssize_t hdaps_calibrate_store(struct device *dev,
 				     struct device_attribute *attr,
 				     const char *buf, size_t count)
 {
 	down(&hdaps_sem);
 	hdaps_calibrate();
 	up(&hdaps_sem);

 	return count;
 }

 static ssize_t hdaps_invert_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%u\n", hdaps_invert);
 }

 static ssize_t hdaps_invert_store(struct device *dev,
 				  struct device_attribute *attr,
 				  const char *buf, size_t count)
 {
 	int invert;

 	if (sscanf(buf, "%d", &invert) != 1 || (invert != 1 && invert != 0))
 		return -EINVAL;

 	hdaps_invert = invert;
 	hdaps_calibrate();

 	return count;
 }

 static DEVICE_ATTR(position, 0444, hdaps_position_show, NULL);
 static DEVICE_ATTR(variance, 0444, hdaps_variance_show, NULL);
 static DEVICE_ATTR(temp1, 0444, hdaps_temp1_show, NULL);
 static DEVICE_ATTR(temp2, 0444, hdaps_temp2_show, NULL);
 static DEVICE_ATTR(keyboard_activity, 0444, hdaps_keyboard_activity_show, NULL);
 static DEVICE_ATTR(mouse_activity, 0444, hdaps_mouse_activity_show, NULL);
 static DEVICE_ATTR(calibrate, 0644, hdaps_calibrate_show,hdaps_calibrate_store);
 static DEVICE_ATTR(invert, 0644, hdaps_invert_show, hdaps_invert_store);

 static struct attribute *hdaps_attributes[] = {
 	&dev_attr_position.attr,
 	&dev_attr_variance.attr,
 	&dev_attr_temp1.attr,
 	&dev_attr_temp2.attr,
 	&dev_attr_keyboard_activity.attr,
 	&dev_attr_mouse_activity.attr,
 	&dev_attr_calibrate.attr,
 	&dev_attr_invert.attr,
 	NULL,
 };

 static struct attribute_group hdaps_attribute_group = {
 	.attrs = hdaps_attributes,
 };


 /* Module stuff */

 /* hdaps_dmi_match - found a match.  return one, short-circuiting the hunt. */
 static int hdaps_dmi_match(struct dmi_system_id *id)
 {
 	printk(KERN_INFO "hdaps: %s detected.\n", id->ident);
 	return 1;
 }

 /* hdaps_dmi_match_invert - found an inverted match. */
 static int hdaps_dmi_match_invert(struct dmi_system_id *id)
 {
 	hdaps_invert = 1;
 	printk(KERN_INFO "hdaps: inverting axis readings.\n");
 	return hdaps_dmi_match(id);
 }

 #define HDAPS_DMI_MATCH_NORMAL(model)	{		\
 	.ident = "IBM " model,				\
 	.callback = hdaps_dmi_match,			\
 	.matches = {					\
 		DMI_MATCH(DMI_BOARD_VENDOR, "IBM"),	\
 		DMI_MATCH(DMI_PRODUCT_VERSION, model)	\
 	}						\
 }

 #define HDAPS_DMI_MATCH_INVERT(model)	{		\
 	.ident = "IBM " model,				\
 	.callback = hdaps_dmi_match_invert,		\
 	.matches = {					\
 		DMI_MATCH(DMI_BOARD_VENDOR, "IBM"),	\
 		DMI_MATCH(DMI_PRODUCT_VERSION, model)	\
 	}						\
 }

 #define HDAPS_DMI_MATCH_LENOVO(model)   {               \
         .ident = "Lenovo " model,                       \
         .callback = hdaps_dmi_match_invert,             \
         .matches = {                                    \
                 DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"),  \
                 DMI_MATCH(DMI_PRODUCT_VERSION, model)   \
         }                                               \
 }

 static int __init hdaps_init(void)
 {
 	int ret;

 	/* Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match
 	  "ThinkPad T42p", so the order of the entries matters */
 	struct dmi_system_id hdaps_whitelist[] = {
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad H"),
 		HDAPS_DMI_MATCH_INVERT("ThinkPad R50p"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad R50"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad R51"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad R52"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad H"),	 /* R52 (1846AQG) */
 		HDAPS_DMI_MATCH_INVERT("ThinkPad T41p"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad T41"),
 		HDAPS_DMI_MATCH_INVERT("ThinkPad T42p"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad T42"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad T43"),
 		HDAPS_DMI_MATCH_LENOVO("ThinkPad T60p"),
 		HDAPS_DMI_MATCH_LENOVO("ThinkPad T60"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad X40"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad X41"),
 		HDAPS_DMI_MATCH_LENOVO("ThinkPad X60"),
 		HDAPS_DMI_MATCH_NORMAL("ThinkPad Z60m"),
 		{ .ident = NULL }
 	};

 	if (!dmi_check_system(hdaps_whitelist)) {
 		printk(KERN_WARNING "hdaps: supported laptop not found!\n");
 		ret = -ENODEV;
 		goto out;
 	}

 	if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) {
 		ret = -ENXIO;
 		goto out;
 	}

 	ret = platform_driver_register(&hdaps_driver);
 	if (ret)
 		goto out_region;

 	pdev = platform_device_register_simple("hdaps", -1, NULL, 0);
 	if (IS_ERR(pdev)) {
 		ret = PTR_ERR(pdev);
 		goto out_driver;
 	}

 	ret = sysfs_create_group(&pdev->dev.kobj, &hdaps_attribute_group);
 	if (ret)
 		goto out_device;

 	hdaps_idev = input_allocate_device();
 	if (!hdaps_idev) {
 		ret = -ENOMEM;
 		goto out_group;
 	}

 	/* initial calibrate for the input device */
 	hdaps_calibrate();

 	/* initialize the input class */
 	hdaps_idev->name = "hdaps";
 	hdaps_idev->cdev.dev = &pdev->dev;
 	hdaps_idev->evbit[0] = BIT(EV_ABS);
 	input_set_abs_params(hdaps_idev, ABS_X,
 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
 	input_set_abs_params(hdaps_idev, ABS_Y,
 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);

 	ret = input_register_device(hdaps_idev);
 	if (ret)
 		goto out_idev;

 	/* start up our timer for the input device */
 	init_timer(&hdaps_timer);
 	hdaps_timer.function = hdaps_mousedev_poll;
 	hdaps_timer.expires = jiffies + HDAPS_POLL_PERIOD;
 	add_timer(&hdaps_timer);

 	printk(KERN_INFO "hdaps: driver successfully loaded.\n");
 	return 0;

 out_idev:
 	input_free_device(hdaps_idev);
 out_group:
 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
 out_device:
 	platform_device_unregister(pdev);
 out_driver:
 	platform_driver_unregister(&hdaps_driver);
 out_region:
 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
 out:
 	printk(KERN_WARNING "hdaps: driver init failed (ret=%d)!\n", ret);
 	return ret;
 }

 static void __exit hdaps_exit(void)
 {
 	del_timer_sync(&hdaps_timer);
 	input_unregister_device(hdaps_idev);
 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
 	platform_device_unregister(pdev);
 	platform_driver_unregister(&hdaps_driver);
 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);

 	printk(KERN_INFO "hdaps: driver unloaded.\n");
 }

 module_init(hdaps_init);
 module_exit(hdaps_exit);

 module_param_named(invert, hdaps_invert, bool, 0);
 MODULE_PARM_DESC(invert, "invert data along each axis");

 MODULE_AUTHOR("Robert Love");
 MODULE_DESCRIPTION("IBM Hard Drive Active Protection System (HDAPS) driver");
 MODULE_LICENSE("GPL v2");
	/*
	* drivers/hwmon/hdaps.c - driver for IBM's Hard Drive Active Protection System
	*
	* Copyright (C) 2005 Robert Love <rml@novell.com>
	* Copyright (C) 2005 Jesper Juhl <jesper.juhl@gmail.com>
	*
	* The HardDisk Active Protection System (hdaps) is present in IBM ThinkPads
	* starting with the R40, T41, and X40. It provides a basic two-axis
	* accelerometer and other data, such as the device's temperature.
	*
	* This driver is based on the document by Mark A. Smith available at
	* http://www.almaden.ibm.com/cs/people/marksmith/tpaps.html and a lot of trial
	* and error.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License v2 as published by the
	* Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
	*/

	#include <linux/delay.h>
	#include <linux/platform_device.h>
	#include <linux/input.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/timer.h>
	#include <linux/dmi.h>
	#include <linux/jiffies.h>
	#include <asm/io.h>

	#define HDAPS_LOW_PORT 0x1600 /* first port used by hdaps */
	#define HDAPS_NR_PORTS 0x30 /* number of ports: 0x1600 - 0x162f */

	#define HDAPS_PORT_STATE 0x1611 /* device state */
	#define HDAPS_PORT_YPOS 0x1612 /* y-axis position */
	#define HDAPS_PORT_XPOS 0x1614 /* x-axis position */
	#define HDAPS_PORT_TEMP1 0x1616 /* device temperature, in Celsius */
	#define HDAPS_PORT_YVAR 0x1617 /* y-axis variance (what is this?) */
	#define HDAPS_PORT_XVAR 0x1619 /* x-axis variance (what is this?) */
	#define HDAPS_PORT_TEMP2 0x161b /* device temperature (again?) */
	#define HDAPS_PORT_UNKNOWN 0x161c /* what is this? */
	#define HDAPS_PORT_KMACT 0x161d /* keyboard or mouse activity */

	#define STATE_FRESH 0x50 /* accelerometer data is fresh */

	#define KEYBD_MASK 0x20 /* set if keyboard activity */
	#define MOUSE_MASK 0x40 /* set if mouse activity */
	#define KEYBD_ISSET(n) (!! (n & KEYBD_MASK)) /* keyboard used? */
	#define MOUSE_ISSET(n) (!! (n & MOUSE_MASK)) /* mouse used? */

	#define INIT_TIMEOUT_MSECS 4000 /* wait up to 4s for device init ... */
	#define INIT_WAIT_MSECS 200 /* ... in 200ms increments */

	#define HDAPS_POLL_PERIOD (HZ/20) /* poll for input every 1/20s */
	#define HDAPS_INPUT_FUZZ 4 /* input event threshold */
	#define HDAPS_INPUT_FLAT 4

	static struct timer_list hdaps_timer;
	static struct platform_device *pdev;
	static struct input_dev *hdaps_idev;
	static unsigned int hdaps_invert;
	static u8 km_activity;
	static int rest_x;
	static int rest_y;

	static DECLARE_MUTEX(hdaps_sem);

	/*
	* __get_latch - Get the value from a given port. Callers must hold hdaps_sem.
	*/
	static inline u8 __get_latch(u16 port)
	{
	return inb(port) & 0xff;
	}

	/*
	* __check_latch - Check a port latch for a given value. Returns zero if the
	* port contains the given value. Callers must hold hdaps_sem.
	*/
	static inline int __check_latch(u16 port, u8 val)
	{
	if (__get_latch(port) == val)
	return 0;
	return -EINVAL;
	}

	/*
	* __wait_latch - Wait up to 100us for a port latch to get a certain value,
	* returning zero if the value is obtained. Callers must hold hdaps_sem.
	*/
	static int __wait_latch(u16 port, u8 val)
	{
	unsigned int i;

	for (i = 0; i < 20; i++) {
	if (!__check_latch(port, val))
	return 0;
	udelay(5);
	}

	return -EIO;
	}

	/*
	* __device_refresh - request a refresh from the accelerometer. Does not wait
	* for refresh to complete. Callers must hold hdaps_sem.
	*/
	static void __device_refresh(void)
	{
	udelay(200);
	if (inb(0x1604) != STATE_FRESH) {
	outb(0x11, 0x1610);
	outb(0x01, 0x161f);
	}
	}

	/*
	* __device_refresh_sync - request a synchronous refresh from the
	* accelerometer. We wait for the refresh to complete. Returns zero if
	* successful and nonzero on error. Callers must hold hdaps_sem.
	*/
	static int __device_refresh_sync(void)
	{
	__device_refresh();
	return __wait_latch(0x1604, STATE_FRESH);
	}

	/*
	* __device_complete - indicate to the accelerometer that we are done reading
	* data, and then initiate an async refresh. Callers must hold hdaps_sem.
	*/
	static inline void __device_complete(void)
	{
	inb(0x161f);
	inb(0x1604);
	__device_refresh();
	}

	/*
	* hdaps_readb_one - reads a byte from a single I/O port, placing the value in
	* the given pointer. Returns zero on success or a negative error on failure.
	* Can sleep.
	*/
	static int hdaps_readb_one(unsigned int port, u8 *val)
	{
	int ret;

	down(&hdaps_sem);

	/* do a sync refresh -- we need to be sure that we read fresh data */
	ret = __device_refresh_sync();
	if (ret)
	goto out;

	*val = inb(port);
	__device_complete();

	out:
	up(&hdaps_sem);
	return ret;
	}

	/* __hdaps_read_pair - internal lockless helper for hdaps_read_pair(). */
	static int __hdaps_read_pair(unsigned int port1, unsigned int port2,
	int x, int y)
	{
	/* do a sync refresh -- we need to be sure that we read fresh data */
	if (__device_refresh_sync())
	return -EIO;

	*y = inw(port2);
	*x = inw(port1);
	km_activity = inb(HDAPS_PORT_KMACT);
	__device_complete();

	/* if hdaps_invert is set, negate the two values */
	if (hdaps_invert) {
	x = -x;
	y = -y;
	}

	return 0;
	}

	/*
	* hdaps_read_pair - reads the values from a pair of ports, placing the values
	* in the given pointers. Returns zero on success. Can sleep.
	*/
	static int hdaps_read_pair(unsigned int port1, unsigned int port2,
	int val1, int val2)
	{
	int ret;

	down(&hdaps_sem);
	ret = __hdaps_read_pair(port1, port2, val1, val2);
	up(&hdaps_sem);

	return ret;
	}

	/*
	* hdaps_device_init - initialize the accelerometer. Returns zero on success
	* and negative error code on failure. Can sleep.
	*/
	static int hdaps_device_init(void)
	{
	int total, ret = -ENXIO;

	down(&hdaps_sem);

	outb(0x13, 0x1610);
	outb(0x01, 0x161f);
	if (__wait_latch(0x161f, 0x00))
	goto out;

	/*
	* Most ThinkPads return 0x01.
	*
	* Others--namely the R50p, T41p, and T42p--return 0x03. These laptops
	* have "inverted" axises.
	*
	* The 0x02 value occurs when the chip has been previously initialized.
	*/
	if (__check_latch(0x1611, 0x03) &&
	__check_latch(0x1611, 0x02) &&
	__check_latch(0x1611, 0x01))
	goto out;

	printk(KERN_DEBUG "hdaps: initial latch check good (0x%02x).\n",
	__get_latch(0x1611));

	outb(0x17, 0x1610);
	outb(0x81, 0x1611);
	outb(0x01, 0x161f);
	if (__wait_latch(0x161f, 0x00))
	goto out;
	if (__wait_latch(0x1611, 0x00))
	goto out;
	if (__wait_latch(0x1612, 0x60))
	goto out;
	if (__wait_latch(0x1613, 0x00))
	goto out;
	outb(0x14, 0x1610);
	outb(0x01, 0x1611);
	outb(0x01, 0x161f);
	if (__wait_latch(0x161f, 0x00))
	goto out;
	outb(0x10, 0x1610);
	outb(0xc8, 0x1611);
	outb(0x00, 0x1612);
	outb(0x02, 0x1613);
	outb(0x01, 0x161f);
	if (__wait_latch(0x161f, 0x00))
	goto out;
	if (__device_refresh_sync())
	goto out;
	if (__wait_latch(0x1611, 0x00))
	goto out;

	/* we have done our dance, now let's wait for the applause */
	for (total = INIT_TIMEOUT_MSECS; total > 0; total -= INIT_WAIT_MSECS) {
	int x, y;

	/* a read of the device helps push it into action */
	__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
	if (!__wait_latch(0x1611, 0x02)) {
	ret = 0;
	break;
	}

	msleep(INIT_WAIT_MSECS);
	}

	out:
	up(&hdaps_sem);
	return ret;
	}


	/* Device model stuff */

	static int hdaps_probe(struct platform_device *dev)
	{
	int ret;

	ret = hdaps_device_init();
	if (ret)
	return ret;

	printk(KERN_INFO "hdaps: device successfully initialized.\n");
	return 0;
	}

	static int hdaps_resume(struct platform_device *dev)
	{
	return hdaps_device_init();
	}

	static struct platform_driver hdaps_driver = {
	.probe = hdaps_probe,
	.resume = hdaps_resume,
	.driver = {
	.name = "hdaps",
	.owner = THIS_MODULE,
	},
	};

	/*
	* hdaps_calibrate - Set our "resting" values. Callers must hold hdaps_sem.
	*/
	static void hdaps_calibrate(void)
	{
	__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y);
	}

	static void hdaps_mousedev_poll(unsigned long unused)
	{
	int x, y;

	/* Cannot sleep. Try nonblockingly. If we fail, try again later. */
	if (down_trylock(&hdaps_sem)) {
	mod_timer(&hdaps_timer,jiffies + HDAPS_POLL_PERIOD);
	return;
	}

	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
	goto out;

	input_report_abs(hdaps_idev, ABS_X, x - rest_x);
	input_report_abs(hdaps_idev, ABS_Y, y - rest_y);
	input_sync(hdaps_idev);

	mod_timer(&hdaps_timer, jiffies + HDAPS_POLL_PERIOD);

	out:
	up(&hdaps_sem);
	}


	/* Sysfs Files */

	static ssize_t hdaps_position_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	int ret, x, y;

	ret = hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
	if (ret)
	return ret;

	return sprintf(buf, "(%d,%d)\n", x, y);
	}

	static ssize_t hdaps_variance_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	int ret, x, y;

	ret = hdaps_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y);
	if (ret)
	return ret;

	return sprintf(buf, "(%d,%d)\n", x, y);
	}

	static ssize_t hdaps_temp1_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	u8 temp;
	int ret;

	ret = hdaps_readb_one(HDAPS_PORT_TEMP1, &temp);
	if (ret < 0)
	return ret;

	return sprintf(buf, "%u\n", temp);
	}

	static ssize_t hdaps_temp2_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	u8 temp;
	int ret;

	ret = hdaps_readb_one(HDAPS_PORT_TEMP2, &temp);
	if (ret < 0)
	return ret;

	return sprintf(buf, "%u\n", temp);
	}

	static ssize_t hdaps_keyboard_activity_show(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "%u\n", KEYBD_ISSET(km_activity));
	}

	static ssize_t hdaps_mouse_activity_show(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	return sprintf(buf, "%u\n", MOUSE_ISSET(km_activity));
	}

	static ssize_t hdaps_calibrate_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return sprintf(buf, "(%d,%d)\n", rest_x, rest_y);
	}

	static ssize_t hdaps_calibrate_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	down(&hdaps_sem);
	hdaps_calibrate();
	up(&hdaps_sem);

	return count;
	}

	static ssize_t hdaps_invert_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return sprintf(buf, "%u\n", hdaps_invert);
	}

	static ssize_t hdaps_invert_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	int invert;

	if (sscanf(buf, "%d", &invert) != 1 \|\| (invert != 1 && invert != 0))
	return -EINVAL;

	hdaps_invert = invert;
	hdaps_calibrate();

	return count;
	}

	static DEVICE_ATTR(position, 0444, hdaps_position_show, NULL);
	static DEVICE_ATTR(variance, 0444, hdaps_variance_show, NULL);
	static DEVICE_ATTR(temp1, 0444, hdaps_temp1_show, NULL);
	static DEVICE_ATTR(temp2, 0444, hdaps_temp2_show, NULL);
	static DEVICE_ATTR(keyboard_activity, 0444, hdaps_keyboard_activity_show, NULL);
	static DEVICE_ATTR(mouse_activity, 0444, hdaps_mouse_activity_show, NULL);
	static DEVICE_ATTR(calibrate, 0644, hdaps_calibrate_show,hdaps_calibrate_store);
	static DEVICE_ATTR(invert, 0644, hdaps_invert_show, hdaps_invert_store);

	static struct attribute *hdaps_attributes[] = {
	&dev_attr_position.attr,
	&dev_attr_variance.attr,
	&dev_attr_temp1.attr,
	&dev_attr_temp2.attr,
	&dev_attr_keyboard_activity.attr,
	&dev_attr_mouse_activity.attr,
	&dev_attr_calibrate.attr,
	&dev_attr_invert.attr,
	NULL,
	};

	static struct attribute_group hdaps_attribute_group = {
	.attrs = hdaps_attributes,
	};


	/* Module stuff */

	/* hdaps_dmi_match - found a match. return one, short-circuiting the hunt. */
	static int hdaps_dmi_match(struct dmi_system_id *id)
	{
	printk(KERN_INFO "hdaps: %s detected.\n", id->ident);
	return 1;
	}

	/* hdaps_dmi_match_invert - found an inverted match. */
	static int hdaps_dmi_match_invert(struct dmi_system_id *id)
	{
	hdaps_invert = 1;
	printk(KERN_INFO "hdaps: inverting axis readings.\n");
	return hdaps_dmi_match(id);
	}

	#define HDAPS_DMI_MATCH_NORMAL(model) { \
	.ident = "IBM " model, \
	.callback = hdaps_dmi_match, \
	.matches = { \
	DMI_MATCH(DMI_BOARD_VENDOR, "IBM"), \
	DMI_MATCH(DMI_PRODUCT_VERSION, model) \
	} \
	}

	#define HDAPS_DMI_MATCH_INVERT(model) { \
	.ident = "IBM " model, \
	.callback = hdaps_dmi_match_invert, \
	.matches = { \
	DMI_MATCH(DMI_BOARD_VENDOR, "IBM"), \
	DMI_MATCH(DMI_PRODUCT_VERSION, model) \
	} \
	}

	#define HDAPS_DMI_MATCH_LENOVO(model) { \
	.ident = "Lenovo " model, \
	.callback = hdaps_dmi_match_invert, \
	.matches = { \
	DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"), \
	DMI_MATCH(DMI_PRODUCT_VERSION, model) \
	} \
	}

	static int __init hdaps_init(void)
	{
	int ret;

	/* Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match
	"ThinkPad T42p", so the order of the entries matters */
	struct dmi_system_id hdaps_whitelist[] = {
	HDAPS_DMI_MATCH_NORMAL("ThinkPad H"),
	HDAPS_DMI_MATCH_INVERT("ThinkPad R50p"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad R50"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad R51"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad R52"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad H"), /* R52 (1846AQG) */
	HDAPS_DMI_MATCH_INVERT("ThinkPad T41p"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad T41"),
	HDAPS_DMI_MATCH_INVERT("ThinkPad T42p"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad T42"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad T43"),
	HDAPS_DMI_MATCH_LENOVO("ThinkPad T60p"),
	HDAPS_DMI_MATCH_LENOVO("ThinkPad T60"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad X40"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad X41"),
	HDAPS_DMI_MATCH_LENOVO("ThinkPad X60"),
	HDAPS_DMI_MATCH_NORMAL("ThinkPad Z60m"),
	{ .ident = NULL }
	};

	if (!dmi_check_system(hdaps_whitelist)) {
	printk(KERN_WARNING "hdaps: supported laptop not found!\n");
	ret = -ENODEV;
	goto out;
	}

	if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) {
	ret = -ENXIO;
	goto out;
	}

	ret = platform_driver_register(&hdaps_driver);
	if (ret)
	goto out_region;

	pdev = platform_device_register_simple("hdaps", -1, NULL, 0);
	if (IS_ERR(pdev)) {
	ret = PTR_ERR(pdev);
	goto out_driver;
	}

	ret = sysfs_create_group(&pdev->dev.kobj, &hdaps_attribute_group);
	if (ret)
	goto out_device;

	hdaps_idev = input_allocate_device();
	if (!hdaps_idev) {
	ret = -ENOMEM;
	goto out_group;
	}

	/* initial calibrate for the input device */
	hdaps_calibrate();

	/* initialize the input class */
	hdaps_idev->name = "hdaps";
	hdaps_idev->cdev.dev = &pdev->dev;
	hdaps_idev->evbit[0] = BIT(EV_ABS);
	input_set_abs_params(hdaps_idev, ABS_X,
	-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
	input_set_abs_params(hdaps_idev, ABS_Y,
	-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);

	ret = input_register_device(hdaps_idev);
	if (ret)
	goto out_idev;

	/* start up our timer for the input device */
	init_timer(&hdaps_timer);
	hdaps_timer.function = hdaps_mousedev_poll;
	hdaps_timer.expires = jiffies + HDAPS_POLL_PERIOD;
	add_timer(&hdaps_timer);

	printk(KERN_INFO "hdaps: driver successfully loaded.\n");
	return 0;

	out_idev:
	input_free_device(hdaps_idev);
	out_group:
	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
	out_device:
	platform_device_unregister(pdev);
	out_driver:
	platform_driver_unregister(&hdaps_driver);
	out_region:
	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
	out:
	printk(KERN_WARNING "hdaps: driver init failed (ret=%d)!\n", ret);
	return ret;
	}

	static void __exit hdaps_exit(void)
	{
	del_timer_sync(&hdaps_timer);
	input_unregister_device(hdaps_idev);
	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
	platform_device_unregister(pdev);
	platform_driver_unregister(&hdaps_driver);
	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);

	printk(KERN_INFO "hdaps: driver unloaded.\n");
	}

	module_init(hdaps_init);
	module_exit(hdaps_exit);

	module_param_named(invert, hdaps_invert, bool, 0);
	MODULE_PARM_DESC(invert, "invert data along each axis");

	MODULE_AUTHOR("Robert Love");
	MODULE_DESCRIPTION("IBM Hard Drive Active Protection System (HDAPS) driver");
	MODULE_LICENSE("GPL v2");