[PATCH] updated hdaps driver.

Driver for the IBM Hard Drive Active Protection System (HDAPS), an
accelerometer found in most modern ThinkPads.

Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 764 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index eaa46594f0211a..1dc2a6b0f642f0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -951,6 +951,13 @@ L:	lm-sensors@lm-sensors.org
 W:	http://www.lm-sensors.nu/
 S:	Maintained
 
+HARD DRIVE ACTIVE PROTECTION SYSTEM (HDAPS) DRIVER
+P:	Robert Love
+M:	rlove@rlove.org
+M:	linux-kernel@vger.kernel.org
+W:	http://www.kernel.org/pub/linux/kernel/people/rml/hdaps/
+S:	Maintained
+
 HARMONY SOUND DRIVER
 P:	Kyle McMartin
 M:	kyle@parisc-linux.org
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 138dc50270e3e5..7e72e922b41c2c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -411,6 +411,23 @@ config SENSORS_W83627EHF
 	  This driver can also be built as a module.  If so, the module
 	  will be called w83627ehf.
 
+config SENSORS_HDAPS
+	tristate "IBM Hard Drive Active Protection System (hdaps)"
+	depends on HWMON && INPUT && X86
+	default n
+	help
+	  This driver provides support for the IBM Hard Drive Active Protection
+	  System (hdaps), which provides an accelerometer and other misc. data.
+	  Supported laptops include the IBM ThinkPad T41, T42, T43, and R51.
+	  The accelerometer data is readable via sysfs.
+
+	  This driver also provides an input class device, allowing the
+	  laptop to act as a pinball machine-esque mouse.  This is off by
+	  default but enabled via sysfs or the module parameter "mousedev".
+
+	  Say Y here if you have an applicable laptop and want to experience
+	  the awesome power of hdaps.
+
 config HWMON_DEBUG_CHIP
 	bool "Hardware Monitoring Chip debugging messages"
 	depends on HWMON
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 381f1bf04cc553..f7d6a2f61ee74b 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_SENSORS_FSCHER)	+= fscher.o
 obj-$(CONFIG_SENSORS_FSCPOS)	+= fscpos.o
 obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o
 obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o
+obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_SENSORS_IT87)	+= it87.o
 obj-$(CONFIG_SENSORS_LM63)	+= lm63.o
 obj-$(CONFIG_SENSORS_LM75)	+= lm75.o
diff --git a/drivers/hwmon/hdaps.c b/drivers/hwmon/hdaps.c
new file mode 100644
index 00000000000000..eaebfc14c933c1
--- /dev/null
+++ b/drivers/hwmon/hdaps.c
@@ -0,0 +1,739 @@
+/*
+ * 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 the IBM ThinkPad
+ * T41, T42, T43, R51, and X40, at least.  It provides a basic two-axis
+ * accelerometer and other data, such as the device's temperature.
+ *
+ * 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/device.h>
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/dmi.h>
+#include <asm/io.h>
+
+#define HDAPS_LOW_PORT		0x1600	/* first port used by hdaps */
+#define HDAPS_NR_PORTS		0x30	/* 0x1600 - 0x162f */
+
+#define STATE_FRESH		0x50	/* accelerometer data is fresh */
+
+#define REFRESH_ASYNC		0x00	/* do asynchronous refresh */
+#define REFRESH_SYNC		0x01	/* do synchronous refresh */
+
+#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 celcius */
+#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 HDAPS_READ_MASK		0xff	/* some reads have the low 8 bits set */
+
+#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 */
+
+static struct platform_device *pdev;
+static struct input_dev hdaps_idev;
+static struct timer_list hdaps_timer;
+static unsigned int hdaps_mousedev_threshold = 4;
+static unsigned long hdaps_poll_ms = 50;
+static unsigned int hdaps_mousedev;
+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) & HDAPS_READ_MASK;
+}
+
+/*
+ * __check_latch - Check a port latch for a given value.  Callers must hold
+ * hdaps_sem.  Returns zero if the port contains the given value.
+ */
+static inline unsigned 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 unsigned 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 -EINVAL;
+}
+
+/*
+ * __device_refresh - Request a refresh from the accelerometer.
+ *
+ * If sync is REFRESH_SYNC, we perform a synchronous refresh and will wait.
+ * Returns zero if successful and nonzero on error.
+ *
+ * If sync is REFRESH_ASYNC, we merely kick off a new refresh if the device is
+ * not up-to-date.  Always returns zero.
+ *
+ * Callers must hold hdaps_sem.
+ */
+static int __device_refresh(unsigned int sync)
+{
+	u8 state;
+
+	udelay(100);
+
+	state = inb(0x1604);
+	if (state == STATE_FRESH)
+		return 0;
+
+	outb(0x11, 0x1610);
+	outb(0x01, 0x161f);
+	if (sync == REFRESH_ASYNC)
+		return 0;
+
+	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(REFRESH_ASYNC);
+}
+
+static int __hdaps_readb_one(unsigned int port, u8 *val)
+{
+	/* do a sync refresh -- we need to be sure that we read fresh data */
+	if (__device_refresh(REFRESH_SYNC))
+		return -EIO;
+
+	*val = inb(port);
+	__device_complete();
+
+	return 0;
+}
+
+/*
+ * 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);
+	ret = __hdaps_readb_one(port, val);
+	up(&hdaps_sem);
+
+	return ret;
+}
+
+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(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;
+}
+
+/* initialize the accelerometer */
+static int hdaps_device_init(void)
+{
+	unsigned int total_msecs = INIT_TIMEOUT_MSECS;
+	int ret = -ENXIO;
+
+	down(&hdaps_sem);
+
+	outb(0x13, 0x1610);
+	outb(0x01, 0x161f);
+	if (__wait_latch(0x161f, 0x00))
+		goto out;
+
+	/*
+	 * The 0x03 value appears to only work on some thinkpads, such as the
+	 * T42p.  Others return 0x01.
+	 *
+	 * 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(REFRESH_SYNC))
+		goto out;
+	if (__wait_latch(0x1611, 0x00))
+		goto out;
+
+	/* we have done our dance, now let's wait for the applause */
+	while (total_msecs > 0) {
+		u8 ignored;
+
+		/* a read of the device helps push it into action */
+		__hdaps_readb_one(HDAPS_PORT_UNKNOWN, &ignored);
+		if (!__wait_latch(0x1611, 0x02)) {
+			ret = 0;
+			break;
+		}
+
+		msleep(INIT_WAIT_MSECS);
+		total_msecs -= INIT_WAIT_MSECS;
+	}
+
+out:
+	up(&hdaps_sem);
+	return ret;
+}
+
+
+/* Input class stuff */
+
+/*
+ * hdaps_calibrate - Zero out our "resting" values. Callers must hold hdaps_sem.
+ */
+static void hdaps_calibrate(void)
+{
+	int x, y;
+
+	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
+		return;
+
+	rest_x = x;
+	rest_y = 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+msecs_to_jiffies(hdaps_poll_ms));
+		return;
+	}
+
+	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
+		goto out;
+
+	x -= rest_x;
+	y -= rest_y;
+	if (abs(x) > hdaps_mousedev_threshold)
+		input_report_rel(&hdaps_idev, REL_X, x);
+	if (abs(y) > hdaps_mousedev_threshold)
+		input_report_rel(&hdaps_idev, REL_Y, y);
+	input_sync(&hdaps_idev);
+
+	mod_timer(&hdaps_timer, jiffies + msecs_to_jiffies(hdaps_poll_ms));
+
+out:
+	up(&hdaps_sem);
+}
+
+/*
+ * hdaps_mousedev_enable - enable the input class device.  Can sleep.
+ */
+static void hdaps_mousedev_enable(void)
+{
+	down(&hdaps_sem);
+
+	/* calibrate the device before enabling */
+	hdaps_calibrate();
+
+	/* initialize the input class */
+	init_input_dev(&hdaps_idev);
+	hdaps_idev.dev = &pdev->dev;
+	hdaps_idev.evbit[0] = BIT(EV_KEY) | BIT(EV_REL);
+	hdaps_idev.relbit[0] = BIT(REL_X) | BIT(REL_Y);
+	hdaps_idev.keybit[LONG(BTN_LEFT)] = BIT(BTN_LEFT);
+	input_register_device(&hdaps_idev);
+
+	/* start up our timer */
+	init_timer(&hdaps_timer);
+	hdaps_timer.function = hdaps_mousedev_poll;
+	hdaps_timer.expires = jiffies + msecs_to_jiffies(hdaps_poll_ms);
+	add_timer(&hdaps_timer);
+
+	hdaps_mousedev = 1;
+
+	up(&hdaps_sem);
+
+	printk(KERN_INFO "hdaps: input device enabled.\n");
+}
+
+/*
+ * hdaps_mousedev_disable - disable the input class device.  Caller must hold
+ * hdaps_sem.
+ */
+static void hdaps_mousedev_disable(void)
+{
+	down(&hdaps_sem);
+	if (hdaps_mousedev) {
+		hdaps_mousedev = 0;
+		del_timer_sync(&hdaps_timer);
+		input_unregister_device(&hdaps_idev);
+	}
+	up(&hdaps_sem);
+}
+
+
+/* Device model stuff */
+
+static int hdaps_probe(struct 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 device *dev, u32 level)
+{
+	if (level == RESUME_ENABLE)
+		return hdaps_device_init();
+	return 0;
+}
+
+static struct device_driver hdaps_driver = {
+	.name = "hdaps",
+	.bus = &platform_bus_type,
+	.owner = THIS_MODULE,
+	.probe = hdaps_probe,
+	.resume = hdaps_resume
+};
+
+
+/* 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 ssize_t hdaps_mousedev_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", hdaps_mousedev);
+}
+
+static ssize_t hdaps_mousedev_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	int enable;
+
+	if (sscanf(buf, "%d", &enable) != 1)
+		return -EINVAL;
+
+	if (enable == 1)
+		hdaps_mousedev_enable();
+	else if (enable == 0)
+		hdaps_mousedev_disable();
+	else
+		return -EINVAL;
+
+	return count;
+}
+
+static ssize_t hdaps_poll_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", hdaps_poll_ms);
+}
+
+static ssize_t hdaps_poll_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	unsigned int poll;
+
+	if (sscanf(buf, "%u", &poll) != 1 || poll == 0)
+		return -EINVAL;
+	hdaps_poll_ms = poll;
+
+	return count;
+}
+
+static ssize_t hdaps_threshold_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%u\n", hdaps_mousedev_threshold);
+}
+
+static ssize_t hdaps_threshold_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	unsigned int threshold;
+
+	if (sscanf(buf, "%u", &threshold) != 1 || threshold == 0)
+		return -EINVAL;
+	hdaps_mousedev_threshold = threshold;
+
+	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 DEVICE_ATTR(mousedev, 0644, hdaps_mousedev_show, hdaps_mousedev_store);
+static DEVICE_ATTR(mousedev_poll_ms, 0644, hdaps_poll_show, hdaps_poll_store);
+static DEVICE_ATTR(mousedev_threshold, 0644, hdaps_threshold_show,
+		   hdaps_threshold_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_mousedev.attr,
+	&dev_attr_mousedev_threshold.attr,
+	&dev_attr_mousedev_poll_ms.attr,
+	&dev_attr_invert.attr,
+	NULL,
+};
+
+static struct attribute_group hdaps_attribute_group = {
+	.attrs = hdaps_attributes,
+};
+
+
+/* Module stuff */
+
+/*
+ * XXX: We should be able to return nonzero and halt the detection process.
+ * But there is a bug in dmi_check_system() where a nonzero return from the
+ * first match will result in a return of failure from dmi_check_system().
+ * I fixed this; the patch is in 2.6-mm.  Once in Linus's tree we can make
+ * hdaps_dmi_match_invert() return hdaps_dmi_match(), which in turn returns 1.
+ */
+static int hdaps_dmi_match(struct dmi_system_id *id)
+{
+	printk(KERN_INFO "hdaps: %s detected.\n", id->ident);
+	return 0;
+}
+
+static int hdaps_dmi_match_invert(struct dmi_system_id *id)
+{
+	hdaps_invert = 1;
+	printk(KERN_INFO "hdaps: inverting axis readings.\n");
+	return 0;
+}
+
+#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)	\
+	}						\
+}
+
+static int __init hdaps_init(void)
+{
+	int ret;
+
+	/* Note that DMI_MATCH(...,"ThinkPad T42") will match "ThinkPad T42p" */
+	struct dmi_system_id hdaps_whitelist[] = {
+		HDAPS_DMI_MATCH_INVERT("ThinkPad R50p"),
+		HDAPS_DMI_MATCH_NORMAL("ThinkPad R50"),
+		HDAPS_DMI_MATCH_NORMAL("ThinkPad R51"),
+		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_NORMAL("ThinkPad X40"),
+		{ .ident = NULL }
+	};
+
+	if (!dmi_check_system(hdaps_whitelist)) {
+		printk(KERN_WARNING "hdaps: supported laptop not found!\n");
+		ret = -ENXIO;
+		goto out;
+	}
+
+	if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	ret = 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;
+
+	if (hdaps_mousedev)
+		hdaps_mousedev_enable();
+
+	printk(KERN_INFO "hdaps: driver successfully loaded.\n");
+	return 0;
+
+out_device:
+	platform_device_unregister(pdev);
+out_driver:
+	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)
+{
+	hdaps_mousedev_disable();
+
+	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
+	platform_device_unregister(pdev);
+	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(mousedev, hdaps_mousedev, bool, 0);
+MODULE_PARM_DESC(mousedev, "enable the input class device");
+
+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");