xref: /openbmc/linux/drivers/input/mouse/appletouch.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
1 /*
2  * Apple USB Touchpad (for post-February 2005 PowerBooks and MacBooks) driver
3  *
4  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
5  * Copyright (C) 2005-2008 Johannes Berg (johannes@sipsolutions.net)
6  * Copyright (C) 2005-2008 Stelian Pop (stelian@popies.net)
7  * Copyright (C) 2005      Frank Arnold (frank@scirocco-5v-turbo.de)
8  * Copyright (C) 2005      Peter Osterlund (petero2@telia.com)
9  * Copyright (C) 2005      Michael Hanselmann (linux-kernel@hansmi.ch)
10  * Copyright (C) 2006      Nicolas Boichat (nicolas@boichat.ch)
11  * Copyright (C) 2007-2008 Sven Anders (anders@anduras.de)
12  *
13  * Thanks to Alex Harper <basilisk@foobox.net> for his inputs.
14  *
15  * This program is free software; you can redistribute it and/or modify
16  * it under the terms of the GNU General Public License as published by
17  * the Free Software Foundation; either version 2 of the License, or
18  * (at your option) any later version.
19  *
20  * This program is distributed in the hope that it will be useful,
21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
23  * GNU General Public License for more details.
24  *
25  * You should have received a copy of the GNU General Public License
26  * along with this program; if not, write to the Free Software
27  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28  *
29  */
30 
31 #include <linux/kernel.h>
32 #include <linux/errno.h>
33 #include <linux/init.h>
34 #include <linux/slab.h>
35 #include <linux/module.h>
36 #include <linux/usb/input.h>
37 
38 /*
39  * Note: We try to keep the touchpad aspect ratio while still doing only
40  * simple arithmetics:
41  *	0 <= x <= (xsensors - 1) * xfact
42  *	0 <= y <= (ysensors - 1) * yfact
43  */
44 struct atp_info {
45 	int xsensors;				/* number of X sensors */
46 	int xsensors_17;			/* 17" models have more sensors */
47 	int ysensors;				/* number of Y sensors */
48 	int xfact;				/* X multiplication factor */
49 	int yfact;				/* Y multiplication factor */
50 	int datalen;				/* size of USB transfers */
51 	void (*callback)(struct urb *);		/* callback function */
52 };
53 
54 static void atp_complete_geyser_1_2(struct urb *urb);
55 static void atp_complete_geyser_3_4(struct urb *urb);
56 
57 static const struct atp_info fountain_info = {
58 	.xsensors	= 16,
59 	.xsensors_17	= 26,
60 	.ysensors	= 16,
61 	.xfact		= 64,
62 	.yfact		= 43,
63 	.datalen	= 81,
64 	.callback	= atp_complete_geyser_1_2,
65 };
66 
67 static const struct atp_info geyser1_info = {
68 	.xsensors	= 16,
69 	.xsensors_17	= 26,
70 	.ysensors	= 16,
71 	.xfact		= 64,
72 	.yfact		= 43,
73 	.datalen	= 81,
74 	.callback	= atp_complete_geyser_1_2,
75 };
76 
77 static const struct atp_info geyser2_info = {
78 	.xsensors	= 15,
79 	.xsensors_17	= 20,
80 	.ysensors	= 9,
81 	.xfact		= 64,
82 	.yfact		= 43,
83 	.datalen	= 64,
84 	.callback	= atp_complete_geyser_1_2,
85 };
86 
87 static const struct atp_info geyser3_info = {
88 	.xsensors	= 20,
89 	.ysensors	= 10,
90 	.xfact		= 64,
91 	.yfact		= 64,
92 	.datalen	= 64,
93 	.callback	= atp_complete_geyser_3_4,
94 };
95 
96 static const struct atp_info geyser4_info = {
97 	.xsensors	= 20,
98 	.ysensors	= 10,
99 	.xfact		= 64,
100 	.yfact		= 64,
101 	.datalen	= 64,
102 	.callback	= atp_complete_geyser_3_4,
103 };
104 
105 #define ATP_DEVICE(prod, info)					\
106 {								\
107 	.match_flags = USB_DEVICE_ID_MATCH_DEVICE |		\
108 		       USB_DEVICE_ID_MATCH_INT_CLASS |		\
109 		       USB_DEVICE_ID_MATCH_INT_PROTOCOL,	\
110 	.idVendor = 0x05ac, /* Apple */				\
111 	.idProduct = (prod),					\
112 	.bInterfaceClass = 0x03,				\
113 	.bInterfaceProtocol = 0x02,				\
114 	.driver_info = (unsigned long) &info,			\
115 }
116 
117 /*
118  * Table of devices (Product IDs) that work with this driver.
119  * (The names come from Info.plist in AppleUSBTrackpad.kext,
120  *  According to Info.plist Geyser IV is the same as Geyser III.)
121  */
122 
123 static struct usb_device_id atp_table[] = {
124 	/* PowerBooks Feb 2005, iBooks G4 */
125 	ATP_DEVICE(0x020e, fountain_info),	/* FOUNTAIN ANSI */
126 	ATP_DEVICE(0x020f, fountain_info),	/* FOUNTAIN ISO */
127 	ATP_DEVICE(0x030a, fountain_info),	/* FOUNTAIN TP ONLY */
128 	ATP_DEVICE(0x030b, geyser1_info),	/* GEYSER 1 TP ONLY */
129 
130 	/* PowerBooks Oct 2005 */
131 	ATP_DEVICE(0x0214, geyser2_info),	/* GEYSER 2 ANSI */
132 	ATP_DEVICE(0x0215, geyser2_info),	/* GEYSER 2 ISO */
133 	ATP_DEVICE(0x0216, geyser2_info),	/* GEYSER 2 JIS */
134 
135 	/* Core Duo MacBook & MacBook Pro */
136 	ATP_DEVICE(0x0217, geyser3_info),	/* GEYSER 3 ANSI */
137 	ATP_DEVICE(0x0218, geyser3_info),	/* GEYSER 3 ISO */
138 	ATP_DEVICE(0x0219, geyser3_info),	/* GEYSER 3 JIS */
139 
140 	/* Core2 Duo MacBook & MacBook Pro */
141 	ATP_DEVICE(0x021a, geyser4_info),	/* GEYSER 4 ANSI */
142 	ATP_DEVICE(0x021b, geyser4_info),	/* GEYSER 4 ISO */
143 	ATP_DEVICE(0x021c, geyser4_info),	/* GEYSER 4 JIS */
144 
145 	/* Core2 Duo MacBook3,1 */
146 	ATP_DEVICE(0x0229, geyser4_info),	/* GEYSER 4 HF ANSI */
147 	ATP_DEVICE(0x022a, geyser4_info),	/* GEYSER 4 HF ISO */
148 	ATP_DEVICE(0x022b, geyser4_info),	/* GEYSER 4 HF JIS */
149 
150 	/* Terminating entry */
151 	{ }
152 };
153 MODULE_DEVICE_TABLE(usb, atp_table);
154 
155 /* maximum number of sensors */
156 #define ATP_XSENSORS	26
157 #define ATP_YSENSORS	16
158 
159 /* amount of fuzz this touchpad generates */
160 #define ATP_FUZZ	16
161 
162 /* maximum pressure this driver will report */
163 #define ATP_PRESSURE	300
164 
165 /*
166  * Threshold for the touchpad sensors. Any change less than ATP_THRESHOLD is
167  * ignored.
168  */
169 #define ATP_THRESHOLD	 5
170 
171 /* Geyser initialization constants */
172 #define ATP_GEYSER_MODE_READ_REQUEST_ID		1
173 #define ATP_GEYSER_MODE_WRITE_REQUEST_ID	9
174 #define ATP_GEYSER_MODE_REQUEST_VALUE		0x300
175 #define ATP_GEYSER_MODE_REQUEST_INDEX		0
176 #define ATP_GEYSER_MODE_VENDOR_VALUE		0x04
177 
178 /**
179  * enum atp_status_bits - status bit meanings
180  *
181  * These constants represent the meaning of the status bits.
182  * (only Geyser 3/4)
183  *
184  * @ATP_STATUS_BUTTON: The button was pressed
185  * @ATP_STATUS_BASE_UPDATE: Update of the base values (untouched pad)
186  * @ATP_STATUS_FROM_RESET: Reset previously performed
187  */
188 enum atp_status_bits {
189 	ATP_STATUS_BUTTON	= BIT(0),
190 	ATP_STATUS_BASE_UPDATE	= BIT(2),
191 	ATP_STATUS_FROM_RESET	= BIT(4),
192 };
193 
194 /* Structure to hold all of our device specific stuff */
195 struct atp {
196 	char			phys[64];
197 	struct usb_device	*udev;		/* usb device */
198 	struct urb		*urb;		/* usb request block */
199 	u8			*data;		/* transferred data */
200 	struct input_dev	*input;		/* input dev */
201 	const struct atp_info	*info;		/* touchpad model */
202 	bool			open;
203 	bool			valid;		/* are the samples valid? */
204 	bool			size_detect_done;
205 	bool			overflow_warned;
206 	int			x_old;		/* last reported x/y, */
207 	int			y_old;		/* used for smoothing */
208 	signed char		xy_cur[ATP_XSENSORS + ATP_YSENSORS];
209 	signed char		xy_old[ATP_XSENSORS + ATP_YSENSORS];
210 	int			xy_acc[ATP_XSENSORS + ATP_YSENSORS];
211 	int			idlecount;	/* number of empty packets */
212 	struct work_struct	work;
213 };
214 
215 #define dbg_dump(msg, tab) \
216 	if (debug > 1) {						\
217 		int __i;						\
218 		printk(KERN_DEBUG "appletouch: %s", msg);		\
219 		for (__i = 0; __i < ATP_XSENSORS + ATP_YSENSORS; __i++)	\
220 			printk(" %02x", tab[__i]);			\
221 		printk("\n");						\
222 	}
223 
224 #define dprintk(format, a...)						\
225 	do {								\
226 		if (debug)						\
227 			printk(KERN_DEBUG format, ##a);			\
228 	} while (0)
229 
230 MODULE_AUTHOR("Johannes Berg");
231 MODULE_AUTHOR("Stelian Pop");
232 MODULE_AUTHOR("Frank Arnold");
233 MODULE_AUTHOR("Michael Hanselmann");
234 MODULE_AUTHOR("Sven Anders");
235 MODULE_DESCRIPTION("Apple PowerBook and MacBook USB touchpad driver");
236 MODULE_LICENSE("GPL");
237 
238 /*
239  * Make the threshold a module parameter
240  */
241 static int threshold = ATP_THRESHOLD;
242 module_param(threshold, int, 0644);
243 MODULE_PARM_DESC(threshold, "Discard any change in data from a sensor"
244 			    " (the trackpad has many of these sensors)"
245 			    " less than this value.");
246 
247 static int debug;
248 module_param(debug, int, 0644);
249 MODULE_PARM_DESC(debug, "Activate debugging output");
250 
251 /*
252  * By default newer Geyser devices send standard USB HID mouse
253  * packets (Report ID 2). This code changes device mode, so it
254  * sends raw sensor reports (Report ID 5).
255  */
256 static int atp_geyser_init(struct usb_device *udev)
257 {
258 	char *data;
259 	int size;
260 	int i;
261 	int ret;
262 
263 	data = kmalloc(8, GFP_KERNEL);
264 	if (!data) {
265 		err("Out of memory");
266 		return -ENOMEM;
267 	}
268 
269 	size = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
270 			ATP_GEYSER_MODE_READ_REQUEST_ID,
271 			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
272 			ATP_GEYSER_MODE_REQUEST_VALUE,
273 			ATP_GEYSER_MODE_REQUEST_INDEX, data, 8, 5000);
274 
275 	if (size != 8) {
276 		dprintk("atp_geyser_init: read error\n");
277 		for (i = 0; i < 8; i++)
278 			dprintk("appletouch[%d]: %d\n", i, data[i]);
279 
280 		err("Failed to read mode from device.");
281 		ret = -EIO;
282 		goto out_free;
283 	}
284 
285 	/* Apply the mode switch */
286 	data[0] = ATP_GEYSER_MODE_VENDOR_VALUE;
287 
288 	size = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
289 			ATP_GEYSER_MODE_WRITE_REQUEST_ID,
290 			USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
291 			ATP_GEYSER_MODE_REQUEST_VALUE,
292 			ATP_GEYSER_MODE_REQUEST_INDEX, data, 8, 5000);
293 
294 	if (size != 8) {
295 		dprintk("atp_geyser_init: write error\n");
296 		for (i = 0; i < 8; i++)
297 			dprintk("appletouch[%d]: %d\n", i, data[i]);
298 
299 		err("Failed to request geyser raw mode");
300 		ret = -EIO;
301 		goto out_free;
302 	}
303 	ret = 0;
304 out_free:
305 	kfree(data);
306 	return ret;
307 }
308 
309 /*
310  * Reinitialise the device. This usually stops stream of empty packets
311  * coming from it.
312  */
313 static void atp_reinit(struct work_struct *work)
314 {
315 	struct atp *dev = container_of(work, struct atp, work);
316 	struct usb_device *udev = dev->udev;
317 	int retval;
318 
319 	dprintk("appletouch: putting appletouch to sleep (reinit)\n");
320 	atp_geyser_init(udev);
321 
322 	retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
323 	if (retval)
324 		err("atp_reinit: usb_submit_urb failed with error %d",
325 		    retval);
326 }
327 
328 static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
329 			     int *z, int *fingers)
330 {
331 	int i;
332 	/* values to calculate mean */
333 	int pcum = 0, psum = 0;
334 	int is_increasing = 0;
335 
336 	*fingers = 0;
337 
338 	for (i = 0; i < nb_sensors; i++) {
339 		if (xy_sensors[i] < threshold) {
340 			if (is_increasing)
341 				is_increasing = 0;
342 
343 			continue;
344 		}
345 
346 		/*
347 		 * Makes the finger detection more versatile.  For example,
348 		 * two fingers with no gap will be detected.  Also, my
349 		 * tests show it less likely to have intermittent loss
350 		 * of multiple finger readings while moving around (scrolling).
351 		 *
352 		 * Changes the multiple finger detection to counting humps on
353 		 * sensors (transitions from nonincreasing to increasing)
354 		 * instead of counting transitions from low sensors (no
355 		 * finger reading) to high sensors (finger above
356 		 * sensor)
357 		 *
358 		 * - Jason Parekh <jasonparekh@gmail.com>
359 		 */
360 		if (i < 1 ||
361 		    (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) {
362 			(*fingers)++;
363 			is_increasing = 1;
364 		} else if (i > 0 && (xy_sensors[i - 1] - xy_sensors[i] > threshold)) {
365 			is_increasing = 0;
366 		}
367 
368 		/*
369 		 * Subtracts threshold so a high sensor that just passes the
370 		 * threshold won't skew the calculated absolute coordinate.
371 		 * Fixes an issue where slowly moving the mouse would
372 		 * occasionally jump a number of pixels (slowly moving the
373 		 * finger makes this issue most apparent.)
374 		 */
375 		pcum += (xy_sensors[i] - threshold) * i;
376 		psum += (xy_sensors[i] - threshold);
377 	}
378 
379 	if (psum > 0) {
380 		*z = psum;
381 		return pcum * fact / psum;
382 	}
383 
384 	return 0;
385 }
386 
387 static inline void atp_report_fingers(struct input_dev *input, int fingers)
388 {
389 	input_report_key(input, BTN_TOOL_FINGER, fingers == 1);
390 	input_report_key(input, BTN_TOOL_DOUBLETAP, fingers == 2);
391 	input_report_key(input, BTN_TOOL_TRIPLETAP, fingers > 2);
392 }
393 
394 /* Check URB status and for correct length of data package */
395 
396 #define ATP_URB_STATUS_SUCCESS		0
397 #define ATP_URB_STATUS_ERROR		1
398 #define ATP_URB_STATUS_ERROR_FATAL	2
399 
400 static int atp_status_check(struct urb *urb)
401 {
402 	struct atp *dev = urb->context;
403 
404 	switch (urb->status) {
405 	case 0:
406 		/* success */
407 		break;
408 	case -EOVERFLOW:
409 		if (!dev->overflow_warned) {
410 			printk(KERN_WARNING "appletouch: OVERFLOW with data "
411 				"length %d, actual length is %d\n",
412 				dev->info->datalen, dev->urb->actual_length);
413 			dev->overflow_warned = true;
414 		}
415 	case -ECONNRESET:
416 	case -ENOENT:
417 	case -ESHUTDOWN:
418 		/* This urb is terminated, clean up */
419 		dbg("atp_complete: urb shutting down with status: %d",
420 		    urb->status);
421 		return ATP_URB_STATUS_ERROR_FATAL;
422 
423 	default:
424 		dbg("atp_complete: nonzero urb status received: %d",
425 		    urb->status);
426 		return ATP_URB_STATUS_ERROR;
427 	}
428 
429 	/* drop incomplete datasets */
430 	if (dev->urb->actual_length != dev->info->datalen) {
431 		dprintk("appletouch: incomplete data package"
432 			" (first byte: %d, length: %d).\n",
433 			dev->data[0], dev->urb->actual_length);
434 		return ATP_URB_STATUS_ERROR;
435 	}
436 
437 	return ATP_URB_STATUS_SUCCESS;
438 }
439 
440 static void atp_detect_size(struct atp *dev)
441 {
442 	int i;
443 
444 	/* 17" Powerbooks have extra X sensors */
445 	for (i = dev->info->xsensors; i < ATP_XSENSORS; i++) {
446 		if (dev->xy_cur[i]) {
447 
448 			printk(KERN_INFO "appletouch: 17\" model detected.\n");
449 
450 			input_set_abs_params(dev->input, ABS_X, 0,
451 					     (dev->info->xsensors_17 - 1) *
452 							dev->info->xfact - 1,
453 					     ATP_FUZZ, 0);
454 			break;
455 		}
456 	}
457 }
458 
459 /*
460  * USB interrupt callback functions
461  */
462 
463 /* Interrupt function for older touchpads: FOUNTAIN/GEYSER1/GEYSER2 */
464 
465 static void atp_complete_geyser_1_2(struct urb *urb)
466 {
467 	int x, y, x_z, y_z, x_f, y_f;
468 	int retval, i, j;
469 	int key;
470 	struct atp *dev = urb->context;
471 	int status = atp_status_check(urb);
472 
473 	if (status == ATP_URB_STATUS_ERROR_FATAL)
474 		return;
475 	else if (status == ATP_URB_STATUS_ERROR)
476 		goto exit;
477 
478 	/* reorder the sensors values */
479 	if (dev->info == &geyser2_info) {
480 		memset(dev->xy_cur, 0, sizeof(dev->xy_cur));
481 
482 		/*
483 		 * The values are laid out like this:
484 		 * Y1, Y2, -, Y3, Y4, -, ..., X1, X2, -, X3, X4, -, ...
485 		 * '-' is an unused value.
486 		 */
487 
488 		/* read X values */
489 		for (i = 0, j = 19; i < 20; i += 2, j += 3) {
490 			dev->xy_cur[i] = dev->data[j];
491 			dev->xy_cur[i + 1] = dev->data[j + 1];
492 		}
493 
494 		/* read Y values */
495 		for (i = 0, j = 1; i < 9; i += 2, j += 3) {
496 			dev->xy_cur[ATP_XSENSORS + i] = dev->data[j];
497 			dev->xy_cur[ATP_XSENSORS + i + 1] = dev->data[j + 1];
498 		}
499 	} else {
500 		for (i = 0; i < 8; i++) {
501 			/* X values */
502 			dev->xy_cur[i +  0] = dev->data[5 * i +  2];
503 			dev->xy_cur[i +  8] = dev->data[5 * i +  4];
504 			dev->xy_cur[i + 16] = dev->data[5 * i + 42];
505 			if (i < 2)
506 				dev->xy_cur[i + 24] = dev->data[5 * i + 44];
507 
508 			/* Y values */
509 			dev->xy_cur[ATP_XSENSORS + i] = dev->data[5 * i +  1];
510 			dev->xy_cur[ATP_XSENSORS + i + 8] = dev->data[5 * i + 3];
511 		}
512 	}
513 
514 	dbg_dump("sample", dev->xy_cur);
515 
516 	if (!dev->valid) {
517 		/* first sample */
518 		dev->valid = true;
519 		dev->x_old = dev->y_old = -1;
520 
521 		/* Store first sample */
522 		memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));
523 
524 		/* Perform size detection, if not done already */
525 		if (unlikely(!dev->size_detect_done)) {
526 			atp_detect_size(dev);
527 			dev->size_detect_done = 1;
528 			goto exit;
529 		}
530 	}
531 
532 	for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++) {
533 		/* accumulate the change */
534 		signed char change = dev->xy_old[i] - dev->xy_cur[i];
535 		dev->xy_acc[i] -= change;
536 
537 		/* prevent down drifting */
538 		if (dev->xy_acc[i] < 0)
539 			dev->xy_acc[i] = 0;
540 	}
541 
542 	memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));
543 
544 	dbg_dump("accumulator", dev->xy_acc);
545 
546 	x = atp_calculate_abs(dev->xy_acc, ATP_XSENSORS,
547 			      dev->info->xfact, &x_z, &x_f);
548 	y = atp_calculate_abs(dev->xy_acc + ATP_XSENSORS, ATP_YSENSORS,
549 			      dev->info->yfact, &y_z, &y_f);
550 	key = dev->data[dev->info->datalen - 1] & ATP_STATUS_BUTTON;
551 
552 	if (x && y) {
553 		if (dev->x_old != -1) {
554 			x = (dev->x_old * 3 + x) >> 2;
555 			y = (dev->y_old * 3 + y) >> 2;
556 			dev->x_old = x;
557 			dev->y_old = y;
558 
559 			if (debug > 1)
560 				printk(KERN_DEBUG "appletouch: "
561 					"X: %3d Y: %3d Xz: %3d Yz: %3d\n",
562 					x, y, x_z, y_z);
563 
564 			input_report_key(dev->input, BTN_TOUCH, 1);
565 			input_report_abs(dev->input, ABS_X, x);
566 			input_report_abs(dev->input, ABS_Y, y);
567 			input_report_abs(dev->input, ABS_PRESSURE,
568 					 min(ATP_PRESSURE, x_z + y_z));
569 			atp_report_fingers(dev->input, max(x_f, y_f));
570 		}
571 		dev->x_old = x;
572 		dev->y_old = y;
573 
574 	} else if (!x && !y) {
575 
576 		dev->x_old = dev->y_old = -1;
577 		input_report_key(dev->input, BTN_TOUCH, 0);
578 		input_report_abs(dev->input, ABS_PRESSURE, 0);
579 		atp_report_fingers(dev->input, 0);
580 
581 		/* reset the accumulator on release */
582 		memset(dev->xy_acc, 0, sizeof(dev->xy_acc));
583 	}
584 
585 	input_report_key(dev->input, BTN_LEFT, key);
586 	input_sync(dev->input);
587 
588  exit:
589 	retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
590 	if (retval)
591 		err("atp_complete: usb_submit_urb failed with result %d",
592 		    retval);
593 }
594 
595 /* Interrupt function for older touchpads: GEYSER3/GEYSER4 */
596 
597 static void atp_complete_geyser_3_4(struct urb *urb)
598 {
599 	int x, y, x_z, y_z, x_f, y_f;
600 	int retval, i, j;
601 	int key;
602 	struct atp *dev = urb->context;
603 	int status = atp_status_check(urb);
604 
605 	if (status == ATP_URB_STATUS_ERROR_FATAL)
606 		return;
607 	else if (status == ATP_URB_STATUS_ERROR)
608 		goto exit;
609 
610 	/* Reorder the sensors values:
611 	 *
612 	 * The values are laid out like this:
613 	 * -, Y1, Y2, -, Y3, Y4, -, ..., -, X1, X2, -, X3, X4, ...
614 	 * '-' is an unused value.
615 	 */
616 
617 	/* read X values */
618 	for (i = 0, j = 19; i < 20; i += 2, j += 3) {
619 		dev->xy_cur[i] = dev->data[j + 1];
620 		dev->xy_cur[i + 1] = dev->data[j + 2];
621 	}
622 	/* read Y values */
623 	for (i = 0, j = 1; i < 9; i += 2, j += 3) {
624 		dev->xy_cur[ATP_XSENSORS + i] = dev->data[j + 1];
625 		dev->xy_cur[ATP_XSENSORS + i + 1] = dev->data[j + 2];
626 	}
627 
628 	dbg_dump("sample", dev->xy_cur);
629 
630 	/* Just update the base values (i.e. touchpad in untouched state) */
631 	if (dev->data[dev->info->datalen - 1] & ATP_STATUS_BASE_UPDATE) {
632 
633 		dprintk("appletouch: updated base values\n");
634 
635 		memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));
636 		goto exit;
637 	}
638 
639 	for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++) {
640 		/* calculate the change */
641 		dev->xy_acc[i] = dev->xy_cur[i] - dev->xy_old[i];
642 
643 		/* this is a round-robin value, so couple with that */
644 		if (dev->xy_acc[i] > 127)
645 			dev->xy_acc[i] -= 256;
646 
647 		if (dev->xy_acc[i] < -127)
648 			dev->xy_acc[i] += 256;
649 
650 		/* prevent down drifting */
651 		if (dev->xy_acc[i] < 0)
652 			dev->xy_acc[i] = 0;
653 	}
654 
655 	dbg_dump("accumulator", dev->xy_acc);
656 
657 	x = atp_calculate_abs(dev->xy_acc, ATP_XSENSORS,
658 			      dev->info->xfact, &x_z, &x_f);
659 	y = atp_calculate_abs(dev->xy_acc + ATP_XSENSORS, ATP_YSENSORS,
660 			      dev->info->yfact, &y_z, &y_f);
661 	key = dev->data[dev->info->datalen - 1] & ATP_STATUS_BUTTON;
662 
663 	if (x && y) {
664 		if (dev->x_old != -1) {
665 			x = (dev->x_old * 3 + x) >> 2;
666 			y = (dev->y_old * 3 + y) >> 2;
667 			dev->x_old = x;
668 			dev->y_old = y;
669 
670 			if (debug > 1)
671 				printk(KERN_DEBUG "appletouch: X: %3d Y: %3d "
672 				       "Xz: %3d Yz: %3d\n",
673 				       x, y, x_z, y_z);
674 
675 			input_report_key(dev->input, BTN_TOUCH, 1);
676 			input_report_abs(dev->input, ABS_X, x);
677 			input_report_abs(dev->input, ABS_Y, y);
678 			input_report_abs(dev->input, ABS_PRESSURE,
679 					 min(ATP_PRESSURE, x_z + y_z));
680 			atp_report_fingers(dev->input, max(x_f, y_f));
681 		}
682 		dev->x_old = x;
683 		dev->y_old = y;
684 
685 	} else if (!x && !y) {
686 
687 		dev->x_old = dev->y_old = -1;
688 		input_report_key(dev->input, BTN_TOUCH, 0);
689 		input_report_abs(dev->input, ABS_PRESSURE, 0);
690 		atp_report_fingers(dev->input, 0);
691 
692 		/* reset the accumulator on release */
693 		memset(dev->xy_acc, 0, sizeof(dev->xy_acc));
694 	}
695 
696 	input_report_key(dev->input, BTN_LEFT, key);
697 	input_sync(dev->input);
698 
699 	/*
700 	 * Geysers 3/4 will continue to send packets continually after
701 	 * the first touch unless reinitialised. Do so if it's been
702 	 * idle for a while in order to avoid waking the kernel up
703 	 * several hundred times a second.
704 	 */
705 
706 	/*
707 	 * Button must not be pressed when entering suspend,
708 	 * otherwise we will never release the button.
709 	 */
710 	if (!x && !y && !key) {
711 		dev->idlecount++;
712 		if (dev->idlecount == 10) {
713 			dev->x_old = dev->y_old = -1;
714 			dev->idlecount = 0;
715 			schedule_work(&dev->work);
716 			/* Don't resubmit urb here, wait for reinit */
717 			return;
718 		}
719 	} else
720 		dev->idlecount = 0;
721 
722  exit:
723 	retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
724 	if (retval)
725 		err("atp_complete: usb_submit_urb failed with result %d",
726 		    retval);
727 }
728 
729 static int atp_open(struct input_dev *input)
730 {
731 	struct atp *dev = input_get_drvdata(input);
732 
733 	if (usb_submit_urb(dev->urb, GFP_ATOMIC))
734 		return -EIO;
735 
736 	dev->open = 1;
737 	return 0;
738 }
739 
740 static void atp_close(struct input_dev *input)
741 {
742 	struct atp *dev = input_get_drvdata(input);
743 
744 	usb_kill_urb(dev->urb);
745 	cancel_work_sync(&dev->work);
746 	dev->open = 0;
747 }
748 
749 static int atp_handle_geyser(struct atp *dev)
750 {
751 	struct usb_device *udev = dev->udev;
752 
753 	if (dev->info != &fountain_info) {
754 		/* switch to raw sensor mode */
755 		if (atp_geyser_init(udev))
756 			return -EIO;
757 
758 		printk(KERN_INFO "appletouch: Geyser mode initialized.\n");
759 	}
760 
761 	return 0;
762 }
763 
764 static int atp_probe(struct usb_interface *iface,
765 		     const struct usb_device_id *id)
766 {
767 	struct atp *dev;
768 	struct input_dev *input_dev;
769 	struct usb_device *udev = interface_to_usbdev(iface);
770 	struct usb_host_interface *iface_desc;
771 	struct usb_endpoint_descriptor *endpoint;
772 	int int_in_endpointAddr = 0;
773 	int i, error = -ENOMEM;
774 	const struct atp_info *info = (const struct atp_info *)id->driver_info;
775 
776 	/* set up the endpoint information */
777 	/* use only the first interrupt-in endpoint */
778 	iface_desc = iface->cur_altsetting;
779 	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
780 		endpoint = &iface_desc->endpoint[i].desc;
781 		if (!int_in_endpointAddr && usb_endpoint_is_int_in(endpoint)) {
782 			/* we found an interrupt in endpoint */
783 			int_in_endpointAddr = endpoint->bEndpointAddress;
784 			break;
785 		}
786 	}
787 	if (!int_in_endpointAddr) {
788 		err("Could not find int-in endpoint");
789 		return -EIO;
790 	}
791 
792 	/* allocate memory for our device state and initialize it */
793 	dev = kzalloc(sizeof(struct atp), GFP_KERNEL);
794 	input_dev = input_allocate_device();
795 	if (!dev || !input_dev) {
796 		err("Out of memory");
797 		goto err_free_devs;
798 	}
799 
800 	dev->udev = udev;
801 	dev->input = input_dev;
802 	dev->info = info;
803 	dev->overflow_warned = false;
804 
805 	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
806 	if (!dev->urb)
807 		goto err_free_devs;
808 
809 	dev->data = usb_alloc_coherent(dev->udev, dev->info->datalen, GFP_KERNEL,
810 				       &dev->urb->transfer_dma);
811 	if (!dev->data)
812 		goto err_free_urb;
813 
814 	usb_fill_int_urb(dev->urb, udev,
815 			 usb_rcvintpipe(udev, int_in_endpointAddr),
816 			 dev->data, dev->info->datalen,
817 			 dev->info->callback, dev, 1);
818 
819 	error = atp_handle_geyser(dev);
820 	if (error)
821 		goto err_free_buffer;
822 
823 	usb_make_path(udev, dev->phys, sizeof(dev->phys));
824 	strlcat(dev->phys, "/input0", sizeof(dev->phys));
825 
826 	input_dev->name = "appletouch";
827 	input_dev->phys = dev->phys;
828 	usb_to_input_id(dev->udev, &input_dev->id);
829 	input_dev->dev.parent = &iface->dev;
830 
831 	input_set_drvdata(input_dev, dev);
832 
833 	input_dev->open = atp_open;
834 	input_dev->close = atp_close;
835 
836 	set_bit(EV_ABS, input_dev->evbit);
837 
838 	input_set_abs_params(input_dev, ABS_X, 0,
839 			     (dev->info->xsensors - 1) * dev->info->xfact - 1,
840 			     ATP_FUZZ, 0);
841 	input_set_abs_params(input_dev, ABS_Y, 0,
842 			     (dev->info->ysensors - 1) * dev->info->yfact - 1,
843 			     ATP_FUZZ, 0);
844 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, ATP_PRESSURE, 0, 0);
845 
846 	set_bit(EV_KEY, input_dev->evbit);
847 	set_bit(BTN_TOUCH, input_dev->keybit);
848 	set_bit(BTN_TOOL_FINGER, input_dev->keybit);
849 	set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
850 	set_bit(BTN_TOOL_TRIPLETAP, input_dev->keybit);
851 	set_bit(BTN_LEFT, input_dev->keybit);
852 
853 	error = input_register_device(dev->input);
854 	if (error)
855 		goto err_free_buffer;
856 
857 	/* save our data pointer in this interface device */
858 	usb_set_intfdata(iface, dev);
859 
860 	INIT_WORK(&dev->work, atp_reinit);
861 
862 	return 0;
863 
864  err_free_buffer:
865 	usb_free_coherent(dev->udev, dev->info->datalen,
866 			  dev->data, dev->urb->transfer_dma);
867  err_free_urb:
868 	usb_free_urb(dev->urb);
869  err_free_devs:
870 	usb_set_intfdata(iface, NULL);
871 	kfree(dev);
872 	input_free_device(input_dev);
873 	return error;
874 }
875 
876 static void atp_disconnect(struct usb_interface *iface)
877 {
878 	struct atp *dev = usb_get_intfdata(iface);
879 
880 	usb_set_intfdata(iface, NULL);
881 	if (dev) {
882 		usb_kill_urb(dev->urb);
883 		input_unregister_device(dev->input);
884 		usb_free_coherent(dev->udev, dev->info->datalen,
885 				  dev->data, dev->urb->transfer_dma);
886 		usb_free_urb(dev->urb);
887 		kfree(dev);
888 	}
889 	printk(KERN_INFO "input: appletouch disconnected\n");
890 }
891 
892 static int atp_recover(struct atp *dev)
893 {
894 	int error;
895 
896 	error = atp_handle_geyser(dev);
897 	if (error)
898 		return error;
899 
900 	if (dev->open && usb_submit_urb(dev->urb, GFP_ATOMIC))
901 		return -EIO;
902 
903 	return 0;
904 }
905 
906 static int atp_suspend(struct usb_interface *iface, pm_message_t message)
907 {
908 	struct atp *dev = usb_get_intfdata(iface);
909 
910 	usb_kill_urb(dev->urb);
911 	return 0;
912 }
913 
914 static int atp_resume(struct usb_interface *iface)
915 {
916 	struct atp *dev = usb_get_intfdata(iface);
917 
918 	if (dev->open && usb_submit_urb(dev->urb, GFP_ATOMIC))
919 		return -EIO;
920 
921 	return 0;
922 }
923 
924 static int atp_reset_resume(struct usb_interface *iface)
925 {
926 	struct atp *dev = usb_get_intfdata(iface);
927 
928 	return atp_recover(dev);
929 }
930 
931 static struct usb_driver atp_driver = {
932 	.name		= "appletouch",
933 	.probe		= atp_probe,
934 	.disconnect	= atp_disconnect,
935 	.suspend	= atp_suspend,
936 	.resume		= atp_resume,
937 	.reset_resume	= atp_reset_resume,
938 	.id_table	= atp_table,
939 };
940 
941 static int __init atp_init(void)
942 {
943 	return usb_register(&atp_driver);
944 }
945 
946 static void __exit atp_exit(void)
947 {
948 	usb_deregister(&atp_driver);
949 }
950 
951 module_init(atp_init);
952 module_exit(atp_exit);
953