xref: /openbmc/linux/drivers/platform/x86/hdaps.c (revision 9b93eb47)
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 		.pm = &hdaps_pm,
322 	},
323 };
324 
325 /*
326  * hdaps_calibrate - Set our "resting" values.  Callers must hold hdaps_mtx.
327  */
328 static void hdaps_calibrate(void)
329 {
330 	__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y);
331 }
332 
333 static void hdaps_mousedev_poll(struct input_polled_dev *dev)
334 {
335 	struct input_dev *input_dev = dev->input;
336 	int x, y;
337 
338 	mutex_lock(&hdaps_mtx);
339 
340 	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
341 		goto out;
342 
343 	input_report_abs(input_dev, ABS_X, x - rest_x);
344 	input_report_abs(input_dev, ABS_Y, y - rest_y);
345 	input_sync(input_dev);
346 
347 out:
348 	mutex_unlock(&hdaps_mtx);
349 }
350 
351 
352 /* Sysfs Files */
353 
354 static ssize_t hdaps_position_show(struct device *dev,
355 				   struct device_attribute *attr, char *buf)
356 {
357 	int ret, x, y;
358 
359 	ret = hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
360 	if (ret)
361 		return ret;
362 
363 	return sprintf(buf, "(%d,%d)\n", x, y);
364 }
365 
366 static ssize_t hdaps_variance_show(struct device *dev,
367 				   struct device_attribute *attr, char *buf)
368 {
369 	int ret, x, y;
370 
371 	ret = hdaps_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y);
372 	if (ret)
373 		return ret;
374 
375 	return sprintf(buf, "(%d,%d)\n", x, y);
376 }
377 
378 static ssize_t hdaps_temp1_show(struct device *dev,
379 				struct device_attribute *attr, char *buf)
380 {
381 	u8 uninitialized_var(temp);
382 	int ret;
383 
384 	ret = hdaps_readb_one(HDAPS_PORT_TEMP1, &temp);
385 	if (ret)
386 		return ret;
387 
388 	return sprintf(buf, "%u\n", temp);
389 }
390 
391 static ssize_t hdaps_temp2_show(struct device *dev,
392 				struct device_attribute *attr, char *buf)
393 {
394 	u8 uninitialized_var(temp);
395 	int ret;
396 
397 	ret = hdaps_readb_one(HDAPS_PORT_TEMP2, &temp);
398 	if (ret)
399 		return ret;
400 
401 	return sprintf(buf, "%u\n", temp);
402 }
403 
404 static ssize_t hdaps_keyboard_activity_show(struct device *dev,
405 					    struct device_attribute *attr,
406 					    char *buf)
407 {
408 	return sprintf(buf, "%u\n", KEYBD_ISSET(km_activity));
409 }
410 
411 static ssize_t hdaps_mouse_activity_show(struct device *dev,
412 					 struct device_attribute *attr,
413 					 char *buf)
414 {
415 	return sprintf(buf, "%u\n", MOUSE_ISSET(km_activity));
416 }
417 
418 static ssize_t hdaps_calibrate_show(struct device *dev,
419 				    struct device_attribute *attr, char *buf)
420 {
421 	return sprintf(buf, "(%d,%d)\n", rest_x, rest_y);
422 }
423 
424 static ssize_t hdaps_calibrate_store(struct device *dev,
425 				     struct device_attribute *attr,
426 				     const char *buf, size_t count)
427 {
428 	mutex_lock(&hdaps_mtx);
429 	hdaps_calibrate();
430 	mutex_unlock(&hdaps_mtx);
431 
432 	return count;
433 }
434 
435 static ssize_t hdaps_invert_show(struct device *dev,
436 				 struct device_attribute *attr, char *buf)
437 {
438 	return sprintf(buf, "%u\n", hdaps_invert);
439 }
440 
441 static ssize_t hdaps_invert_store(struct device *dev,
442 				  struct device_attribute *attr,
443 				  const char *buf, size_t count)
444 {
445 	int invert;
446 
447 	if (sscanf(buf, "%d", &invert) != 1 ||
448 	    invert < 0 || invert > HDAPS_BOTH_AXES)
449 		return -EINVAL;
450 
451 	hdaps_invert = invert;
452 	hdaps_calibrate();
453 
454 	return count;
455 }
456 
457 static DEVICE_ATTR(position, 0444, hdaps_position_show, NULL);
458 static DEVICE_ATTR(variance, 0444, hdaps_variance_show, NULL);
459 static DEVICE_ATTR(temp1, 0444, hdaps_temp1_show, NULL);
460 static DEVICE_ATTR(temp2, 0444, hdaps_temp2_show, NULL);
461 static DEVICE_ATTR(keyboard_activity, 0444, hdaps_keyboard_activity_show, NULL);
462 static DEVICE_ATTR(mouse_activity, 0444, hdaps_mouse_activity_show, NULL);
463 static DEVICE_ATTR(calibrate, 0644, hdaps_calibrate_show,hdaps_calibrate_store);
464 static DEVICE_ATTR(invert, 0644, hdaps_invert_show, hdaps_invert_store);
465 
466 static struct attribute *hdaps_attributes[] = {
467 	&dev_attr_position.attr,
468 	&dev_attr_variance.attr,
469 	&dev_attr_temp1.attr,
470 	&dev_attr_temp2.attr,
471 	&dev_attr_keyboard_activity.attr,
472 	&dev_attr_mouse_activity.attr,
473 	&dev_attr_calibrate.attr,
474 	&dev_attr_invert.attr,
475 	NULL,
476 };
477 
478 static struct attribute_group hdaps_attribute_group = {
479 	.attrs = hdaps_attributes,
480 };
481 
482 
483 /* Module stuff */
484 
485 /* hdaps_dmi_match - found a match.  return one, short-circuiting the hunt. */
486 static int __init hdaps_dmi_match(const struct dmi_system_id *id)
487 {
488 	pr_info("%s detected\n", id->ident);
489 	return 1;
490 }
491 
492 /* hdaps_dmi_match_invert - found an inverted match. */
493 static int __init hdaps_dmi_match_invert(const struct dmi_system_id *id)
494 {
495 	hdaps_invert = (unsigned long)id->driver_data;
496 	pr_info("inverting axis (%u) readings\n", hdaps_invert);
497 	return hdaps_dmi_match(id);
498 }
499 
500 #define HDAPS_DMI_MATCH_INVERT(vendor, model, axes) {	\
501 	.ident = vendor " " model,			\
502 	.callback = hdaps_dmi_match_invert,		\
503 	.driver_data = (void *)axes,			\
504 	.matches = {					\
505 		DMI_MATCH(DMI_BOARD_VENDOR, vendor),	\
506 		DMI_MATCH(DMI_PRODUCT_VERSION, model)	\
507 	}						\
508 }
509 
510 #define HDAPS_DMI_MATCH_NORMAL(vendor, model)		\
511 	HDAPS_DMI_MATCH_INVERT(vendor, model, 0)
512 
513 /* Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match
514    "ThinkPad T42p", so the order of the entries matters.
515    If your ThinkPad is not recognized, please update to latest
516    BIOS. This is especially the case for some R52 ThinkPads. */
517 static const struct dmi_system_id hdaps_whitelist[] __initconst = {
518 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad R50p", HDAPS_BOTH_AXES),
519 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R50"),
520 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R51"),
521 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R52"),
522 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61i", HDAPS_BOTH_AXES),
523 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61", HDAPS_BOTH_AXES),
524 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T41p", HDAPS_BOTH_AXES),
525 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T41"),
526 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T42p", HDAPS_BOTH_AXES),
527 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T42"),
528 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T43"),
529 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T400", HDAPS_BOTH_AXES),
530 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T60", HDAPS_BOTH_AXES),
531 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61p", HDAPS_BOTH_AXES),
532 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61", HDAPS_BOTH_AXES),
533 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad X40"),
534 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad X41", HDAPS_Y_AXIS),
535 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60", HDAPS_BOTH_AXES),
536 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61s", HDAPS_BOTH_AXES),
537 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61", HDAPS_BOTH_AXES),
538 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad Z60m"),
539 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61m", HDAPS_BOTH_AXES),
540 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61p", HDAPS_BOTH_AXES),
541 	{ .ident = NULL }
542 };
543 
544 static int __init hdaps_init(void)
545 {
546 	struct input_dev *idev;
547 	int ret;
548 
549 	if (!dmi_check_system(hdaps_whitelist)) {
550 		pr_warn("supported laptop not found!\n");
551 		ret = -ENODEV;
552 		goto out;
553 	}
554 
555 	if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) {
556 		ret = -ENXIO;
557 		goto out;
558 	}
559 
560 	ret = platform_driver_register(&hdaps_driver);
561 	if (ret)
562 		goto out_region;
563 
564 	pdev = platform_device_register_simple("hdaps", -1, NULL, 0);
565 	if (IS_ERR(pdev)) {
566 		ret = PTR_ERR(pdev);
567 		goto out_driver;
568 	}
569 
570 	ret = sysfs_create_group(&pdev->dev.kobj, &hdaps_attribute_group);
571 	if (ret)
572 		goto out_device;
573 
574 	hdaps_idev = input_allocate_polled_device();
575 	if (!hdaps_idev) {
576 		ret = -ENOMEM;
577 		goto out_group;
578 	}
579 
580 	hdaps_idev->poll = hdaps_mousedev_poll;
581 	hdaps_idev->poll_interval = HDAPS_POLL_INTERVAL;
582 
583 	/* initial calibrate for the input device */
584 	hdaps_calibrate();
585 
586 	/* initialize the input class */
587 	idev = hdaps_idev->input;
588 	idev->name = "hdaps";
589 	idev->phys = "isa1600/input0";
590 	idev->id.bustype = BUS_ISA;
591 	idev->dev.parent = &pdev->dev;
592 	idev->evbit[0] = BIT_MASK(EV_ABS);
593 	input_set_abs_params(idev, ABS_X,
594 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
595 	input_set_abs_params(idev, ABS_Y,
596 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
597 
598 	ret = input_register_polled_device(hdaps_idev);
599 	if (ret)
600 		goto out_idev;
601 
602 	pr_info("driver successfully loaded\n");
603 	return 0;
604 
605 out_idev:
606 	input_free_polled_device(hdaps_idev);
607 out_group:
608 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
609 out_device:
610 	platform_device_unregister(pdev);
611 out_driver:
612 	platform_driver_unregister(&hdaps_driver);
613 out_region:
614 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
615 out:
616 	pr_warn("driver init failed (ret=%d)!\n", ret);
617 	return ret;
618 }
619 
620 static void __exit hdaps_exit(void)
621 {
622 	input_unregister_polled_device(hdaps_idev);
623 	input_free_polled_device(hdaps_idev);
624 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
625 	platform_device_unregister(pdev);
626 	platform_driver_unregister(&hdaps_driver);
627 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
628 
629 	pr_info("driver unloaded\n");
630 }
631 
632 module_init(hdaps_init);
633 module_exit(hdaps_exit);
634 
635 module_param_named(invert, hdaps_invert, int, 0);
636 MODULE_PARM_DESC(invert, "invert data along each axis. 1 invert x-axis, "
637 		 "2 invert y-axis, 3 invert both axes.");
638 
639 MODULE_AUTHOR("Robert Love");
640 MODULE_DESCRIPTION("IBM Hard Drive Active Protection System (HDAPS) driver");
641 MODULE_LICENSE("GPL v2");
642