xref: /openbmc/linux/drivers/platform/x86/hdaps.c (revision b34e08d5)
1 /*
2  * hdaps.c - driver for IBM's Hard Drive Active Protection System
3  *
4  * Copyright (C) 2005 Robert Love <rml@novell.com>
5  * Copyright (C) 2005 Jesper Juhl <jj@chaosbits.net>
6  *
7  * The HardDisk Active Protection System (hdaps) is present in IBM ThinkPads
8  * starting with the R40, T41, and X40.  It provides a basic two-axis
9  * accelerometer and other data, such as the device's temperature.
10  *
11  * This driver is based on the document by Mark A. Smith available at
12  * http://www.almaden.ibm.com/cs/people/marksmith/tpaps.html and a lot of trial
13  * and error.
14  *
15  * This program is free software; you can redistribute it and/or modify it
16  * under the terms of the GNU General Public License v2 as published by the
17  * Free Software Foundation.
18  *
19  * This program is distributed in the hope that it will be useful, but WITHOUT
20  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
21  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
22  * more details.
23  *
24  * You should have received a copy of the GNU General Public License along with
25  * this program; if not, write to the Free Software Foundation, Inc.,
26  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
27  */
28 
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30 
31 #include <linux/delay.h>
32 #include <linux/platform_device.h>
33 #include <linux/input-polldev.h>
34 #include <linux/kernel.h>
35 #include <linux/mutex.h>
36 #include <linux/module.h>
37 #include <linux/timer.h>
38 #include <linux/dmi.h>
39 #include <linux/jiffies.h>
40 #include <linux/io.h>
41 
42 #define HDAPS_LOW_PORT		0x1600	/* first port used by hdaps */
43 #define HDAPS_NR_PORTS		0x30	/* number of ports: 0x1600 - 0x162f */
44 
45 #define HDAPS_PORT_STATE	0x1611	/* device state */
46 #define HDAPS_PORT_YPOS		0x1612	/* y-axis position */
47 #define	HDAPS_PORT_XPOS		0x1614	/* x-axis position */
48 #define HDAPS_PORT_TEMP1	0x1616	/* device temperature, in Celsius */
49 #define HDAPS_PORT_YVAR		0x1617	/* y-axis variance (what is this?) */
50 #define HDAPS_PORT_XVAR		0x1619	/* x-axis variance (what is this?) */
51 #define HDAPS_PORT_TEMP2	0x161b	/* device temperature (again?) */
52 #define HDAPS_PORT_UNKNOWN	0x161c	/* what is this? */
53 #define HDAPS_PORT_KMACT	0x161d	/* keyboard or mouse activity */
54 
55 #define STATE_FRESH		0x50	/* accelerometer data is fresh */
56 
57 #define KEYBD_MASK		0x20	/* set if keyboard activity */
58 #define MOUSE_MASK		0x40	/* set if mouse activity */
59 #define KEYBD_ISSET(n)		(!! (n & KEYBD_MASK))	/* keyboard used? */
60 #define MOUSE_ISSET(n)		(!! (n & MOUSE_MASK))	/* mouse used? */
61 
62 #define INIT_TIMEOUT_MSECS	4000	/* wait up to 4s for device init ... */
63 #define INIT_WAIT_MSECS		200	/* ... in 200ms increments */
64 
65 #define HDAPS_POLL_INTERVAL	50	/* poll for input every 1/20s (50 ms)*/
66 #define HDAPS_INPUT_FUZZ	4	/* input event threshold */
67 #define HDAPS_INPUT_FLAT	4
68 
69 #define HDAPS_X_AXIS		(1 << 0)
70 #define HDAPS_Y_AXIS		(1 << 1)
71 #define HDAPS_BOTH_AXES		(HDAPS_X_AXIS | HDAPS_Y_AXIS)
72 
73 static struct platform_device *pdev;
74 static struct input_polled_dev *hdaps_idev;
75 static unsigned int hdaps_invert;
76 static u8 km_activity;
77 static int rest_x;
78 static int rest_y;
79 
80 static DEFINE_MUTEX(hdaps_mtx);
81 
82 /*
83  * __get_latch - Get the value from a given port.  Callers must hold hdaps_mtx.
84  */
85 static inline u8 __get_latch(u16 port)
86 {
87 	return inb(port) & 0xff;
88 }
89 
90 /*
91  * __check_latch - Check a port latch for a given value.  Returns zero if the
92  * port contains the given value.  Callers must hold hdaps_mtx.
93  */
94 static inline int __check_latch(u16 port, u8 val)
95 {
96 	if (__get_latch(port) == val)
97 		return 0;
98 	return -EINVAL;
99 }
100 
101 /*
102  * __wait_latch - Wait up to 100us for a port latch to get a certain value,
103  * returning zero if the value is obtained.  Callers must hold hdaps_mtx.
104  */
105 static int __wait_latch(u16 port, u8 val)
106 {
107 	unsigned int i;
108 
109 	for (i = 0; i < 20; i++) {
110 		if (!__check_latch(port, val))
111 			return 0;
112 		udelay(5);
113 	}
114 
115 	return -EIO;
116 }
117 
118 /*
119  * __device_refresh - request a refresh from the accelerometer.  Does not wait
120  * for refresh to complete.  Callers must hold hdaps_mtx.
121  */
122 static void __device_refresh(void)
123 {
124 	udelay(200);
125 	if (inb(0x1604) != STATE_FRESH) {
126 		outb(0x11, 0x1610);
127 		outb(0x01, 0x161f);
128 	}
129 }
130 
131 /*
132  * __device_refresh_sync - request a synchronous refresh from the
133  * accelerometer.  We wait for the refresh to complete.  Returns zero if
134  * successful and nonzero on error.  Callers must hold hdaps_mtx.
135  */
136 static int __device_refresh_sync(void)
137 {
138 	__device_refresh();
139 	return __wait_latch(0x1604, STATE_FRESH);
140 }
141 
142 /*
143  * __device_complete - indicate to the accelerometer that we are done reading
144  * data, and then initiate an async refresh.  Callers must hold hdaps_mtx.
145  */
146 static inline void __device_complete(void)
147 {
148 	inb(0x161f);
149 	inb(0x1604);
150 	__device_refresh();
151 }
152 
153 /*
154  * hdaps_readb_one - reads a byte from a single I/O port, placing the value in
155  * the given pointer.  Returns zero on success or a negative error on failure.
156  * Can sleep.
157  */
158 static int hdaps_readb_one(unsigned int port, u8 *val)
159 {
160 	int ret;
161 
162 	mutex_lock(&hdaps_mtx);
163 
164 	/* do a sync refresh -- we need to be sure that we read fresh data */
165 	ret = __device_refresh_sync();
166 	if (ret)
167 		goto out;
168 
169 	*val = inb(port);
170 	__device_complete();
171 
172 out:
173 	mutex_unlock(&hdaps_mtx);
174 	return ret;
175 }
176 
177 /* __hdaps_read_pair - internal lockless helper for hdaps_read_pair(). */
178 static int __hdaps_read_pair(unsigned int port1, unsigned int port2,
179 			     int *x, int *y)
180 {
181 	/* do a sync refresh -- we need to be sure that we read fresh data */
182 	if (__device_refresh_sync())
183 		return -EIO;
184 
185 	*y = inw(port2);
186 	*x = inw(port1);
187 	km_activity = inb(HDAPS_PORT_KMACT);
188 	__device_complete();
189 
190 	/* hdaps_invert is a bitvector to negate the axes */
191 	if (hdaps_invert & HDAPS_X_AXIS)
192 		*x = -*x;
193 	if (hdaps_invert & HDAPS_Y_AXIS)
194 		*y = -*y;
195 
196 	return 0;
197 }
198 
199 /*
200  * hdaps_read_pair - reads the values from a pair of ports, placing the values
201  * in the given pointers.  Returns zero on success.  Can sleep.
202  */
203 static int hdaps_read_pair(unsigned int port1, unsigned int port2,
204 			   int *val1, int *val2)
205 {
206 	int ret;
207 
208 	mutex_lock(&hdaps_mtx);
209 	ret = __hdaps_read_pair(port1, port2, val1, val2);
210 	mutex_unlock(&hdaps_mtx);
211 
212 	return ret;
213 }
214 
215 /*
216  * hdaps_device_init - initialize the accelerometer.  Returns zero on success
217  * and negative error code on failure.  Can sleep.
218  */
219 static int hdaps_device_init(void)
220 {
221 	int total, ret = -ENXIO;
222 
223 	mutex_lock(&hdaps_mtx);
224 
225 	outb(0x13, 0x1610);
226 	outb(0x01, 0x161f);
227 	if (__wait_latch(0x161f, 0x00))
228 		goto out;
229 
230 	/*
231 	 * Most ThinkPads return 0x01.
232 	 *
233 	 * Others--namely the R50p, T41p, and T42p--return 0x03.  These laptops
234 	 * have "inverted" axises.
235 	 *
236 	 * The 0x02 value occurs when the chip has been previously initialized.
237 	 */
238 	if (__check_latch(0x1611, 0x03) &&
239 		     __check_latch(0x1611, 0x02) &&
240 		     __check_latch(0x1611, 0x01))
241 		goto out;
242 
243 	printk(KERN_DEBUG "hdaps: initial latch check good (0x%02x)\n",
244 	       __get_latch(0x1611));
245 
246 	outb(0x17, 0x1610);
247 	outb(0x81, 0x1611);
248 	outb(0x01, 0x161f);
249 	if (__wait_latch(0x161f, 0x00))
250 		goto out;
251 	if (__wait_latch(0x1611, 0x00))
252 		goto out;
253 	if (__wait_latch(0x1612, 0x60))
254 		goto out;
255 	if (__wait_latch(0x1613, 0x00))
256 		goto out;
257 	outb(0x14, 0x1610);
258 	outb(0x01, 0x1611);
259 	outb(0x01, 0x161f);
260 	if (__wait_latch(0x161f, 0x00))
261 		goto out;
262 	outb(0x10, 0x1610);
263 	outb(0xc8, 0x1611);
264 	outb(0x00, 0x1612);
265 	outb(0x02, 0x1613);
266 	outb(0x01, 0x161f);
267 	if (__wait_latch(0x161f, 0x00))
268 		goto out;
269 	if (__device_refresh_sync())
270 		goto out;
271 	if (__wait_latch(0x1611, 0x00))
272 		goto out;
273 
274 	/* we have done our dance, now let's wait for the applause */
275 	for (total = INIT_TIMEOUT_MSECS; total > 0; total -= INIT_WAIT_MSECS) {
276 		int x, y;
277 
278 		/* a read of the device helps push it into action */
279 		__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
280 		if (!__wait_latch(0x1611, 0x02)) {
281 			ret = 0;
282 			break;
283 		}
284 
285 		msleep(INIT_WAIT_MSECS);
286 	}
287 
288 out:
289 	mutex_unlock(&hdaps_mtx);
290 	return ret;
291 }
292 
293 
294 /* Device model stuff */
295 
296 static int hdaps_probe(struct platform_device *dev)
297 {
298 	int ret;
299 
300 	ret = hdaps_device_init();
301 	if (ret)
302 		return ret;
303 
304 	pr_info("device successfully initialized\n");
305 	return 0;
306 }
307 
308 #ifdef CONFIG_PM_SLEEP
309 static int hdaps_resume(struct device *dev)
310 {
311 	return hdaps_device_init();
312 }
313 #endif
314 
315 static SIMPLE_DEV_PM_OPS(hdaps_pm, NULL, hdaps_resume);
316 
317 static struct platform_driver hdaps_driver = {
318 	.probe = hdaps_probe,
319 	.driver	= {
320 		.name = "hdaps",
321 		.owner = THIS_MODULE,
322 		.pm = &hdaps_pm,
323 	},
324 };
325 
326 /*
327  * hdaps_calibrate - Set our "resting" values.  Callers must hold hdaps_mtx.
328  */
329 static void hdaps_calibrate(void)
330 {
331 	__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y);
332 }
333 
334 static void hdaps_mousedev_poll(struct input_polled_dev *dev)
335 {
336 	struct input_dev *input_dev = dev->input;
337 	int x, y;
338 
339 	mutex_lock(&hdaps_mtx);
340 
341 	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
342 		goto out;
343 
344 	input_report_abs(input_dev, ABS_X, x - rest_x);
345 	input_report_abs(input_dev, ABS_Y, y - rest_y);
346 	input_sync(input_dev);
347 
348 out:
349 	mutex_unlock(&hdaps_mtx);
350 }
351 
352 
353 /* Sysfs Files */
354 
355 static ssize_t hdaps_position_show(struct device *dev,
356 				   struct device_attribute *attr, char *buf)
357 {
358 	int ret, x, y;
359 
360 	ret = hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
361 	if (ret)
362 		return ret;
363 
364 	return sprintf(buf, "(%d,%d)\n", x, y);
365 }
366 
367 static ssize_t hdaps_variance_show(struct device *dev,
368 				   struct device_attribute *attr, char *buf)
369 {
370 	int ret, x, y;
371 
372 	ret = hdaps_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y);
373 	if (ret)
374 		return ret;
375 
376 	return sprintf(buf, "(%d,%d)\n", x, y);
377 }
378 
379 static ssize_t hdaps_temp1_show(struct device *dev,
380 				struct device_attribute *attr, char *buf)
381 {
382 	u8 uninitialized_var(temp);
383 	int ret;
384 
385 	ret = hdaps_readb_one(HDAPS_PORT_TEMP1, &temp);
386 	if (ret)
387 		return ret;
388 
389 	return sprintf(buf, "%u\n", temp);
390 }
391 
392 static ssize_t hdaps_temp2_show(struct device *dev,
393 				struct device_attribute *attr, char *buf)
394 {
395 	u8 uninitialized_var(temp);
396 	int ret;
397 
398 	ret = hdaps_readb_one(HDAPS_PORT_TEMP2, &temp);
399 	if (ret)
400 		return ret;
401 
402 	return sprintf(buf, "%u\n", temp);
403 }
404 
405 static ssize_t hdaps_keyboard_activity_show(struct device *dev,
406 					    struct device_attribute *attr,
407 					    char *buf)
408 {
409 	return sprintf(buf, "%u\n", KEYBD_ISSET(km_activity));
410 }
411 
412 static ssize_t hdaps_mouse_activity_show(struct device *dev,
413 					 struct device_attribute *attr,
414 					 char *buf)
415 {
416 	return sprintf(buf, "%u\n", MOUSE_ISSET(km_activity));
417 }
418 
419 static ssize_t hdaps_calibrate_show(struct device *dev,
420 				    struct device_attribute *attr, char *buf)
421 {
422 	return sprintf(buf, "(%d,%d)\n", rest_x, rest_y);
423 }
424 
425 static ssize_t hdaps_calibrate_store(struct device *dev,
426 				     struct device_attribute *attr,
427 				     const char *buf, size_t count)
428 {
429 	mutex_lock(&hdaps_mtx);
430 	hdaps_calibrate();
431 	mutex_unlock(&hdaps_mtx);
432 
433 	return count;
434 }
435 
436 static ssize_t hdaps_invert_show(struct device *dev,
437 				 struct device_attribute *attr, char *buf)
438 {
439 	return sprintf(buf, "%u\n", hdaps_invert);
440 }
441 
442 static ssize_t hdaps_invert_store(struct device *dev,
443 				  struct device_attribute *attr,
444 				  const char *buf, size_t count)
445 {
446 	int invert;
447 
448 	if (sscanf(buf, "%d", &invert) != 1 ||
449 	    invert < 0 || invert > HDAPS_BOTH_AXES)
450 		return -EINVAL;
451 
452 	hdaps_invert = invert;
453 	hdaps_calibrate();
454 
455 	return count;
456 }
457 
458 static DEVICE_ATTR(position, 0444, hdaps_position_show, NULL);
459 static DEVICE_ATTR(variance, 0444, hdaps_variance_show, NULL);
460 static DEVICE_ATTR(temp1, 0444, hdaps_temp1_show, NULL);
461 static DEVICE_ATTR(temp2, 0444, hdaps_temp2_show, NULL);
462 static DEVICE_ATTR(keyboard_activity, 0444, hdaps_keyboard_activity_show, NULL);
463 static DEVICE_ATTR(mouse_activity, 0444, hdaps_mouse_activity_show, NULL);
464 static DEVICE_ATTR(calibrate, 0644, hdaps_calibrate_show,hdaps_calibrate_store);
465 static DEVICE_ATTR(invert, 0644, hdaps_invert_show, hdaps_invert_store);
466 
467 static struct attribute *hdaps_attributes[] = {
468 	&dev_attr_position.attr,
469 	&dev_attr_variance.attr,
470 	&dev_attr_temp1.attr,
471 	&dev_attr_temp2.attr,
472 	&dev_attr_keyboard_activity.attr,
473 	&dev_attr_mouse_activity.attr,
474 	&dev_attr_calibrate.attr,
475 	&dev_attr_invert.attr,
476 	NULL,
477 };
478 
479 static struct attribute_group hdaps_attribute_group = {
480 	.attrs = hdaps_attributes,
481 };
482 
483 
484 /* Module stuff */
485 
486 /* hdaps_dmi_match - found a match.  return one, short-circuiting the hunt. */
487 static int __init hdaps_dmi_match(const struct dmi_system_id *id)
488 {
489 	pr_info("%s detected\n", id->ident);
490 	return 1;
491 }
492 
493 /* hdaps_dmi_match_invert - found an inverted match. */
494 static int __init hdaps_dmi_match_invert(const struct dmi_system_id *id)
495 {
496 	hdaps_invert = (unsigned long)id->driver_data;
497 	pr_info("inverting axis (%u) readings\n", hdaps_invert);
498 	return hdaps_dmi_match(id);
499 }
500 
501 #define HDAPS_DMI_MATCH_INVERT(vendor, model, axes) {	\
502 	.ident = vendor " " model,			\
503 	.callback = hdaps_dmi_match_invert,		\
504 	.driver_data = (void *)axes,			\
505 	.matches = {					\
506 		DMI_MATCH(DMI_BOARD_VENDOR, vendor),	\
507 		DMI_MATCH(DMI_PRODUCT_VERSION, model)	\
508 	}						\
509 }
510 
511 #define HDAPS_DMI_MATCH_NORMAL(vendor, model)		\
512 	HDAPS_DMI_MATCH_INVERT(vendor, model, 0)
513 
514 /* Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match
515    "ThinkPad T42p", so the order of the entries matters.
516    If your ThinkPad is not recognized, please update to latest
517    BIOS. This is especially the case for some R52 ThinkPads. */
518 static struct dmi_system_id __initdata hdaps_whitelist[] = {
519 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad R50p", HDAPS_BOTH_AXES),
520 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R50"),
521 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R51"),
522 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R52"),
523 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61i", HDAPS_BOTH_AXES),
524 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61", HDAPS_BOTH_AXES),
525 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T41p", HDAPS_BOTH_AXES),
526 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T41"),
527 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T42p", HDAPS_BOTH_AXES),
528 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T42"),
529 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T43"),
530 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T400", HDAPS_BOTH_AXES),
531 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T60", HDAPS_BOTH_AXES),
532 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61p", HDAPS_BOTH_AXES),
533 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61", HDAPS_BOTH_AXES),
534 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad X40"),
535 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad X41", HDAPS_Y_AXIS),
536 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60", HDAPS_BOTH_AXES),
537 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61s", HDAPS_BOTH_AXES),
538 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61", HDAPS_BOTH_AXES),
539 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad Z60m"),
540 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61m", HDAPS_BOTH_AXES),
541 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61p", HDAPS_BOTH_AXES),
542 	{ .ident = NULL }
543 };
544 
545 static int __init hdaps_init(void)
546 {
547 	struct input_dev *idev;
548 	int ret;
549 
550 	if (!dmi_check_system(hdaps_whitelist)) {
551 		pr_warn("supported laptop not found!\n");
552 		ret = -ENODEV;
553 		goto out;
554 	}
555 
556 	if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) {
557 		ret = -ENXIO;
558 		goto out;
559 	}
560 
561 	ret = platform_driver_register(&hdaps_driver);
562 	if (ret)
563 		goto out_region;
564 
565 	pdev = platform_device_register_simple("hdaps", -1, NULL, 0);
566 	if (IS_ERR(pdev)) {
567 		ret = PTR_ERR(pdev);
568 		goto out_driver;
569 	}
570 
571 	ret = sysfs_create_group(&pdev->dev.kobj, &hdaps_attribute_group);
572 	if (ret)
573 		goto out_device;
574 
575 	hdaps_idev = input_allocate_polled_device();
576 	if (!hdaps_idev) {
577 		ret = -ENOMEM;
578 		goto out_group;
579 	}
580 
581 	hdaps_idev->poll = hdaps_mousedev_poll;
582 	hdaps_idev->poll_interval = HDAPS_POLL_INTERVAL;
583 
584 	/* initial calibrate for the input device */
585 	hdaps_calibrate();
586 
587 	/* initialize the input class */
588 	idev = hdaps_idev->input;
589 	idev->name = "hdaps";
590 	idev->phys = "isa1600/input0";
591 	idev->id.bustype = BUS_ISA;
592 	idev->dev.parent = &pdev->dev;
593 	idev->evbit[0] = BIT_MASK(EV_ABS);
594 	input_set_abs_params(idev, ABS_X,
595 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
596 	input_set_abs_params(idev, ABS_Y,
597 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
598 
599 	ret = input_register_polled_device(hdaps_idev);
600 	if (ret)
601 		goto out_idev;
602 
603 	pr_info("driver successfully loaded\n");
604 	return 0;
605 
606 out_idev:
607 	input_free_polled_device(hdaps_idev);
608 out_group:
609 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
610 out_device:
611 	platform_device_unregister(pdev);
612 out_driver:
613 	platform_driver_unregister(&hdaps_driver);
614 out_region:
615 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
616 out:
617 	pr_warn("driver init failed (ret=%d)!\n", ret);
618 	return ret;
619 }
620 
621 static void __exit hdaps_exit(void)
622 {
623 	input_unregister_polled_device(hdaps_idev);
624 	input_free_polled_device(hdaps_idev);
625 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
626 	platform_device_unregister(pdev);
627 	platform_driver_unregister(&hdaps_driver);
628 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
629 
630 	pr_info("driver unloaded\n");
631 }
632 
633 module_init(hdaps_init);
634 module_exit(hdaps_exit);
635 
636 module_param_named(invert, hdaps_invert, int, 0);
637 MODULE_PARM_DESC(invert, "invert data along each axis. 1 invert x-axis, "
638 		 "2 invert y-axis, 3 invert both axes.");
639 
640 MODULE_AUTHOR("Robert Love");
641 MODULE_DESCRIPTION("IBM Hard Drive Active Protection System (HDAPS) driver");
642 MODULE_LICENSE("GPL v2");
643