1 /*
2 * ADS7846 based touchscreen and sensor driver
3 *
4 * Copyright (c) 2005 David Brownell
5 * Copyright (c) 2006 Nokia Corporation
6 * Various changes: Imre Deak <imre.deak@nokia.com>
7 *
8 * Using code from:
9 * - corgi_ts.c
10 * Copyright (C) 2004-2005 Richard Purdie
11 * - omap_ts.[hc], ads7846.h, ts_osk.c
12 * Copyright (C) 2002 MontaVista Software
13 * Copyright (C) 2004 Texas Instruments
14 * Copyright (C) 2005 Dirk Behme
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License version 2 as
18 * published by the Free Software Foundation.
19 */
20 #include <linux/types.h>
21 #include <linux/hwmon.h>
22 #include <linux/init.h>
23 #include <linux/err.h>
24 #include <linux/sched.h>
25 #include <linux/delay.h>
26 #include <linux/input.h>
27 #include <linux/interrupt.h>
28 #include <linux/slab.h>
29 #include <linux/pm.h>
30 #include <linux/gpio.h>
31 #include <linux/spi/spi.h>
32 #include <linux/spi/ads7846.h>
33 #include <linux/regulator/consumer.h>
34 #include <linux/module.h>
35 #include <asm/irq.h>
36
37 /*
38 * This code has been heavily tested on a Nokia 770, and lightly
39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
40 * TSC2046 is just newer ads7846 silicon.
41 * Support for ads7843 tested on Atmel at91sam926x-EK.
42 * Support for ads7845 has only been stubbed in.
43 * Support for Analog Devices AD7873 and AD7843 tested.
44 *
45 * IRQ handling needs a workaround because of a shortcoming in handling
46 * edge triggered IRQs on some platforms like the OMAP1/2. These
47 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
48 * have to maintain our own SW IRQ disabled status. This should be
49 * removed as soon as the affected platform's IRQ handling is fixed.
50 *
51 * App note sbaa036 talks in more detail about accurate sampling...
52 * that ought to help in situations like LCDs inducing noise (which
53 * can also be helped by using synch signals) and more generally.
54 * This driver tries to utilize the measures described in the app
55 * note. The strength of filtering can be set in the board-* specific
56 * files.
57 */
58
59 #define TS_POLL_DELAY 1 /* ms delay before the first sample */
60 #define TS_POLL_PERIOD 5 /* ms delay between samples */
61
62 /* this driver doesn't aim at the peak continuous sample rate */
63 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
64
65 struct ts_event {
66 /*
67 * For portability, we can't read 12 bit values using SPI (which
68 * would make the controller deliver them as native byte order u16
69 * with msbs zeroed). Instead, we read them as two 8-bit values,
70 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
71 */
72 u16 x;
73 u16 y;
74 u16 z1, z2;
75 bool ignore;
76 u8 x_buf[3];
77 u8 y_buf[3];
78 };
79
80 /*
81 * We allocate this separately to avoid cache line sharing issues when
82 * driver is used with DMA-based SPI controllers (like atmel_spi) on
83 * systems where main memory is not DMA-coherent (most non-x86 boards).
84 */
85 struct ads7846_packet {
86 u8 read_x, read_y, read_z1, read_z2, pwrdown;
87 u16 dummy; /* for the pwrdown read */
88 struct ts_event tc;
89 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
90 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
91 };
92
93 struct ads7846 {
94 struct input_dev *input;
95 char phys[32];
96 char name[32];
97
98 struct spi_device *spi;
99 struct regulator *reg;
100
101 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
102 struct attribute_group *attr_group;
103 struct device *hwmon;
104 #endif
105
106 u16 model;
107 u16 vref_mv;
108 u16 vref_delay_usecs;
109 u16 x_plate_ohms;
110 u16 pressure_max;
111
112 bool swap_xy;
113 bool use_internal;
114
115 struct ads7846_packet *packet;
116
117 struct spi_transfer xfer[18];
118 struct spi_message msg[5];
119 int msg_count;
120 wait_queue_head_t wait;
121
122 bool pendown;
123
124 int read_cnt;
125 int read_rep;
126 int last_read;
127
128 u16 debounce_max;
129 u16 debounce_tol;
130 u16 debounce_rep;
131
132 u16 penirq_recheck_delay_usecs;
133
134 struct mutex lock;
135 bool stopped; /* P: lock */
136 bool disabled; /* P: lock */
137 bool suspended; /* P: lock */
138
139 int (*filter)(void *data, int data_idx, int *val);
140 void *filter_data;
141 void (*filter_cleanup)(void *data);
142 int (*get_pendown_state)(void);
143 int gpio_pendown;
144
145 void (*wait_for_sync)(void);
146 };
147
148 /* leave chip selected when we're done, for quicker re-select? */
149 #if 0
150 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
151 #else
152 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
153 #endif
154
155 /*--------------------------------------------------------------------------*/
156
157 /* The ADS7846 has touchscreen and other sensors.
158 * Earlier ads784x chips are somewhat compatible.
159 */
160 #define ADS_START (1 << 7)
161 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
162 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
163 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
164 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
165 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
166 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
167 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
168 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
169 #define ADS_8_BIT (1 << 3)
170 #define ADS_12_BIT (0 << 3)
171 #define ADS_SER (1 << 2) /* non-differential */
172 #define ADS_DFR (0 << 2) /* differential */
173 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
174 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
175 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
176 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
177
178 #define MAX_12BIT ((1<<12)-1)
179
180 /* leave ADC powered up (disables penirq) between differential samples */
181 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
182 | ADS_12_BIT | ADS_DFR | \
183 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
184
185 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
186 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
187 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
188
189 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
190 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
191
192 /* single-ended samples need to first power up reference voltage;
193 * we leave both ADC and VREF powered
194 */
195 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
196 | ADS_12_BIT | ADS_SER)
197
198 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
199 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
200
201 /* Must be called with ts->lock held */
ads7846_stop(struct ads7846 * ts)202 static void ads7846_stop(struct ads7846 *ts)
203 {
204 if (!ts->disabled && !ts->suspended) {
205 /* Signal IRQ thread to stop polling and disable the handler. */
206 ts->stopped = true;
207 mb();
208 wake_up(&ts->wait);
209 disable_irq(ts->spi->irq);
210 }
211 }
212
213 /* Must be called with ts->lock held */
ads7846_restart(struct ads7846 * ts)214 static void ads7846_restart(struct ads7846 *ts)
215 {
216 if (!ts->disabled && !ts->suspended) {
217 /* Tell IRQ thread that it may poll the device. */
218 ts->stopped = false;
219 mb();
220 enable_irq(ts->spi->irq);
221 }
222 }
223
224 /* Must be called with ts->lock held */
__ads7846_disable(struct ads7846 * ts)225 static void __ads7846_disable(struct ads7846 *ts)
226 {
227 ads7846_stop(ts);
228 regulator_disable(ts->reg);
229
230 /*
231 * We know the chip's in low power mode since we always
232 * leave it that way after every request
233 */
234 }
235
236 /* Must be called with ts->lock held */
__ads7846_enable(struct ads7846 * ts)237 static void __ads7846_enable(struct ads7846 *ts)
238 {
239 regulator_enable(ts->reg);
240 ads7846_restart(ts);
241 }
242
ads7846_disable(struct ads7846 * ts)243 static void ads7846_disable(struct ads7846 *ts)
244 {
245 mutex_lock(&ts->lock);
246
247 if (!ts->disabled) {
248
249 if (!ts->suspended)
250 __ads7846_disable(ts);
251
252 ts->disabled = true;
253 }
254
255 mutex_unlock(&ts->lock);
256 }
257
ads7846_enable(struct ads7846 * ts)258 static void ads7846_enable(struct ads7846 *ts)
259 {
260 mutex_lock(&ts->lock);
261
262 if (ts->disabled) {
263
264 ts->disabled = false;
265
266 if (!ts->suspended)
267 __ads7846_enable(ts);
268 }
269
270 mutex_unlock(&ts->lock);
271 }
272
273 /*--------------------------------------------------------------------------*/
274
275 /*
276 * Non-touchscreen sensors only use single-ended conversions.
277 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
278 * ads7846 lets that pin be unconnected, to use internal vREF.
279 */
280
281 struct ser_req {
282 u8 ref_on;
283 u8 command;
284 u8 ref_off;
285 u16 scratch;
286 struct spi_message msg;
287 struct spi_transfer xfer[6];
288 /*
289 * DMA (thus cache coherency maintenance) requires the
290 * transfer buffers to live in their own cache lines.
291 */
292 __be16 sample ____cacheline_aligned;
293 };
294
295 struct ads7845_ser_req {
296 u8 command[3];
297 struct spi_message msg;
298 struct spi_transfer xfer[2];
299 /*
300 * DMA (thus cache coherency maintenance) requires the
301 * transfer buffers to live in their own cache lines.
302 */
303 u8 sample[3] ____cacheline_aligned;
304 };
305
ads7846_read12_ser(struct device * dev,unsigned command)306 static int ads7846_read12_ser(struct device *dev, unsigned command)
307 {
308 struct spi_device *spi = to_spi_device(dev);
309 struct ads7846 *ts = dev_get_drvdata(dev);
310 struct ser_req *req;
311 int status;
312
313 req = kzalloc(sizeof *req, GFP_KERNEL);
314 if (!req)
315 return -ENOMEM;
316
317 spi_message_init(&req->msg);
318
319 /* maybe turn on internal vREF, and let it settle */
320 if (ts->use_internal) {
321 req->ref_on = REF_ON;
322 req->xfer[0].tx_buf = &req->ref_on;
323 req->xfer[0].len = 1;
324 spi_message_add_tail(&req->xfer[0], &req->msg);
325
326 req->xfer[1].rx_buf = &req->scratch;
327 req->xfer[1].len = 2;
328
329 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
330 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
331 spi_message_add_tail(&req->xfer[1], &req->msg);
332
333 /* Enable reference voltage */
334 command |= ADS_PD10_REF_ON;
335 }
336
337 /* Enable ADC in every case */
338 command |= ADS_PD10_ADC_ON;
339
340 /* take sample */
341 req->command = (u8) command;
342 req->xfer[2].tx_buf = &req->command;
343 req->xfer[2].len = 1;
344 spi_message_add_tail(&req->xfer[2], &req->msg);
345
346 req->xfer[3].rx_buf = &req->sample;
347 req->xfer[3].len = 2;
348 spi_message_add_tail(&req->xfer[3], &req->msg);
349
350 /* REVISIT: take a few more samples, and compare ... */
351
352 /* converter in low power mode & enable PENIRQ */
353 req->ref_off = PWRDOWN;
354 req->xfer[4].tx_buf = &req->ref_off;
355 req->xfer[4].len = 1;
356 spi_message_add_tail(&req->xfer[4], &req->msg);
357
358 req->xfer[5].rx_buf = &req->scratch;
359 req->xfer[5].len = 2;
360 CS_CHANGE(req->xfer[5]);
361 spi_message_add_tail(&req->xfer[5], &req->msg);
362
363 mutex_lock(&ts->lock);
364 ads7846_stop(ts);
365 status = spi_sync(spi, &req->msg);
366 ads7846_restart(ts);
367 mutex_unlock(&ts->lock);
368
369 if (status == 0) {
370 /* on-wire is a must-ignore bit, a BE12 value, then padding */
371 status = be16_to_cpu(req->sample);
372 status = status >> 3;
373 status &= 0x0fff;
374 }
375
376 kfree(req);
377 return status;
378 }
379
ads7845_read12_ser(struct device * dev,unsigned command)380 static int ads7845_read12_ser(struct device *dev, unsigned command)
381 {
382 struct spi_device *spi = to_spi_device(dev);
383 struct ads7846 *ts = dev_get_drvdata(dev);
384 struct ads7845_ser_req *req;
385 int status;
386
387 req = kzalloc(sizeof *req, GFP_KERNEL);
388 if (!req)
389 return -ENOMEM;
390
391 spi_message_init(&req->msg);
392
393 req->command[0] = (u8) command;
394 req->xfer[0].tx_buf = req->command;
395 req->xfer[0].rx_buf = req->sample;
396 req->xfer[0].len = 3;
397 spi_message_add_tail(&req->xfer[0], &req->msg);
398
399 mutex_lock(&ts->lock);
400 ads7846_stop(ts);
401 status = spi_sync(spi, &req->msg);
402 ads7846_restart(ts);
403 mutex_unlock(&ts->lock);
404
405 if (status == 0) {
406 /* BE12 value, then padding */
407 status = be16_to_cpu(*((u16 *)&req->sample[1]));
408 status = status >> 3;
409 status &= 0x0fff;
410 }
411
412 kfree(req);
413 return status;
414 }
415
416 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
417
418 #define SHOW(name, var, adjust) static ssize_t \
419 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
420 { \
421 struct ads7846 *ts = dev_get_drvdata(dev); \
422 ssize_t v = ads7846_read12_ser(dev, \
423 READ_12BIT_SER(var)); \
424 if (v < 0) \
425 return v; \
426 return sprintf(buf, "%u\n", adjust(ts, v)); \
427 } \
428 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
429
430
431 /* Sysfs conventions report temperatures in millidegrees Celsius.
432 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
433 * accuracy scheme without calibration data. For now we won't try either;
434 * userspace sees raw sensor values, and must scale/calibrate appropriately.
435 */
null_adjust(struct ads7846 * ts,ssize_t v)436 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
437 {
438 return v;
439 }
440
SHOW(temp0,temp0,null_adjust)441 SHOW(temp0, temp0, null_adjust) /* temp1_input */
442 SHOW(temp1, temp1, null_adjust) /* temp2_input */
443
444
445 /* sysfs conventions report voltages in millivolts. We can convert voltages
446 * if we know vREF. userspace may need to scale vAUX to match the board's
447 * external resistors; we assume that vBATT only uses the internal ones.
448 */
449 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
450 {
451 unsigned retval = v;
452
453 /* external resistors may scale vAUX into 0..vREF */
454 retval *= ts->vref_mv;
455 retval = retval >> 12;
456
457 return retval;
458 }
459
vbatt_adjust(struct ads7846 * ts,ssize_t v)460 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
461 {
462 unsigned retval = vaux_adjust(ts, v);
463
464 /* ads7846 has a resistor ladder to scale this signal down */
465 if (ts->model == 7846)
466 retval *= 4;
467
468 return retval;
469 }
470
471 SHOW(in0_input, vaux, vaux_adjust)
472 SHOW(in1_input, vbatt, vbatt_adjust)
473
474 static struct attribute *ads7846_attributes[] = {
475 &dev_attr_temp0.attr,
476 &dev_attr_temp1.attr,
477 &dev_attr_in0_input.attr,
478 &dev_attr_in1_input.attr,
479 NULL,
480 };
481
482 static struct attribute_group ads7846_attr_group = {
483 .attrs = ads7846_attributes,
484 };
485
486 static struct attribute *ads7843_attributes[] = {
487 &dev_attr_in0_input.attr,
488 &dev_attr_in1_input.attr,
489 NULL,
490 };
491
492 static struct attribute_group ads7843_attr_group = {
493 .attrs = ads7843_attributes,
494 };
495
496 static struct attribute *ads7845_attributes[] = {
497 &dev_attr_in0_input.attr,
498 NULL,
499 };
500
501 static struct attribute_group ads7845_attr_group = {
502 .attrs = ads7845_attributes,
503 };
504
ads784x_hwmon_register(struct spi_device * spi,struct ads7846 * ts)505 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
506 {
507 struct device *hwmon;
508 int err;
509
510 /* hwmon sensors need a reference voltage */
511 switch (ts->model) {
512 case 7846:
513 if (!ts->vref_mv) {
514 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
515 ts->vref_mv = 2500;
516 ts->use_internal = true;
517 }
518 break;
519 case 7845:
520 case 7843:
521 if (!ts->vref_mv) {
522 dev_warn(&spi->dev,
523 "external vREF for ADS%d not specified\n",
524 ts->model);
525 return 0;
526 }
527 break;
528 }
529
530 /* different chips have different sensor groups */
531 switch (ts->model) {
532 case 7846:
533 ts->attr_group = &ads7846_attr_group;
534 break;
535 case 7845:
536 ts->attr_group = &ads7845_attr_group;
537 break;
538 case 7843:
539 ts->attr_group = &ads7843_attr_group;
540 break;
541 default:
542 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
543 return 0;
544 }
545
546 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
547 if (err)
548 return err;
549
550 hwmon = hwmon_device_register(&spi->dev);
551 if (IS_ERR(hwmon)) {
552 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
553 return PTR_ERR(hwmon);
554 }
555
556 ts->hwmon = hwmon;
557 return 0;
558 }
559
ads784x_hwmon_unregister(struct spi_device * spi,struct ads7846 * ts)560 static void ads784x_hwmon_unregister(struct spi_device *spi,
561 struct ads7846 *ts)
562 {
563 if (ts->hwmon) {
564 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
565 hwmon_device_unregister(ts->hwmon);
566 }
567 }
568
569 #else
ads784x_hwmon_register(struct spi_device * spi,struct ads7846 * ts)570 static inline int ads784x_hwmon_register(struct spi_device *spi,
571 struct ads7846 *ts)
572 {
573 return 0;
574 }
575
ads784x_hwmon_unregister(struct spi_device * spi,struct ads7846 * ts)576 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
577 struct ads7846 *ts)
578 {
579 }
580 #endif
581
ads7846_pen_down_show(struct device * dev,struct device_attribute * attr,char * buf)582 static ssize_t ads7846_pen_down_show(struct device *dev,
583 struct device_attribute *attr, char *buf)
584 {
585 struct ads7846 *ts = dev_get_drvdata(dev);
586
587 return sprintf(buf, "%u\n", ts->pendown);
588 }
589
590 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
591
ads7846_disable_show(struct device * dev,struct device_attribute * attr,char * buf)592 static ssize_t ads7846_disable_show(struct device *dev,
593 struct device_attribute *attr, char *buf)
594 {
595 struct ads7846 *ts = dev_get_drvdata(dev);
596
597 return sprintf(buf, "%u\n", ts->disabled);
598 }
599
ads7846_disable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)600 static ssize_t ads7846_disable_store(struct device *dev,
601 struct device_attribute *attr,
602 const char *buf, size_t count)
603 {
604 struct ads7846 *ts = dev_get_drvdata(dev);
605 unsigned int i;
606 int err;
607
608 err = kstrtouint(buf, 10, &i);
609 if (err)
610 return err;
611
612 if (i)
613 ads7846_disable(ts);
614 else
615 ads7846_enable(ts);
616
617 return count;
618 }
619
620 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
621
622 static struct attribute *ads784x_attributes[] = {
623 &dev_attr_pen_down.attr,
624 &dev_attr_disable.attr,
625 NULL,
626 };
627
628 static struct attribute_group ads784x_attr_group = {
629 .attrs = ads784x_attributes,
630 };
631
632 /*--------------------------------------------------------------------------*/
633
get_pendown_state(struct ads7846 * ts)634 static int get_pendown_state(struct ads7846 *ts)
635 {
636 if (ts->get_pendown_state)
637 return ts->get_pendown_state();
638
639 return !gpio_get_value(ts->gpio_pendown);
640 }
641
null_wait_for_sync(void)642 static void null_wait_for_sync(void)
643 {
644 }
645
ads7846_debounce_filter(void * ads,int data_idx,int * val)646 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
647 {
648 struct ads7846 *ts = ads;
649
650 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
651 /* Start over collecting consistent readings. */
652 ts->read_rep = 0;
653 /*
654 * Repeat it, if this was the first read or the read
655 * wasn't consistent enough.
656 */
657 if (ts->read_cnt < ts->debounce_max) {
658 ts->last_read = *val;
659 ts->read_cnt++;
660 return ADS7846_FILTER_REPEAT;
661 } else {
662 /*
663 * Maximum number of debouncing reached and still
664 * not enough number of consistent readings. Abort
665 * the whole sample, repeat it in the next sampling
666 * period.
667 */
668 ts->read_cnt = 0;
669 return ADS7846_FILTER_IGNORE;
670 }
671 } else {
672 if (++ts->read_rep > ts->debounce_rep) {
673 /*
674 * Got a good reading for this coordinate,
675 * go for the next one.
676 */
677 ts->read_cnt = 0;
678 ts->read_rep = 0;
679 return ADS7846_FILTER_OK;
680 } else {
681 /* Read more values that are consistent. */
682 ts->read_cnt++;
683 return ADS7846_FILTER_REPEAT;
684 }
685 }
686 }
687
ads7846_no_filter(void * ads,int data_idx,int * val)688 static int ads7846_no_filter(void *ads, int data_idx, int *val)
689 {
690 return ADS7846_FILTER_OK;
691 }
692
ads7846_get_value(struct ads7846 * ts,struct spi_message * m)693 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
694 {
695 struct spi_transfer *t =
696 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
697
698 if (ts->model == 7845) {
699 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
700 } else {
701 /*
702 * adjust: on-wire is a must-ignore bit, a BE12 value, then
703 * padding; built from two 8 bit values written msb-first.
704 */
705 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
706 }
707 }
708
ads7846_update_value(struct spi_message * m,int val)709 static void ads7846_update_value(struct spi_message *m, int val)
710 {
711 struct spi_transfer *t =
712 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
713
714 *(u16 *)t->rx_buf = val;
715 }
716
ads7846_read_state(struct ads7846 * ts)717 static void ads7846_read_state(struct ads7846 *ts)
718 {
719 struct ads7846_packet *packet = ts->packet;
720 struct spi_message *m;
721 int msg_idx = 0;
722 int val;
723 int action;
724 int error;
725
726 while (msg_idx < ts->msg_count) {
727
728 ts->wait_for_sync();
729
730 m = &ts->msg[msg_idx];
731 error = spi_sync(ts->spi, m);
732 if (error) {
733 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
734 packet->tc.ignore = true;
735 return;
736 }
737
738 /*
739 * Last message is power down request, no need to convert
740 * or filter the value.
741 */
742 if (msg_idx < ts->msg_count - 1) {
743
744 val = ads7846_get_value(ts, m);
745
746 action = ts->filter(ts->filter_data, msg_idx, &val);
747 switch (action) {
748 case ADS7846_FILTER_REPEAT:
749 continue;
750
751 case ADS7846_FILTER_IGNORE:
752 packet->tc.ignore = true;
753 msg_idx = ts->msg_count - 1;
754 continue;
755
756 case ADS7846_FILTER_OK:
757 ads7846_update_value(m, val);
758 packet->tc.ignore = false;
759 msg_idx++;
760 break;
761
762 default:
763 BUG();
764 }
765 } else {
766 msg_idx++;
767 }
768 }
769 }
770
ads7846_report_state(struct ads7846 * ts)771 static void ads7846_report_state(struct ads7846 *ts)
772 {
773 struct ads7846_packet *packet = ts->packet;
774 unsigned int Rt;
775 u16 x, y, z1, z2;
776
777 /*
778 * ads7846_get_value() does in-place conversion (including byte swap)
779 * from on-the-wire format as part of debouncing to get stable
780 * readings.
781 */
782 if (ts->model == 7845) {
783 x = *(u16 *)packet->tc.x_buf;
784 y = *(u16 *)packet->tc.y_buf;
785 z1 = 0;
786 z2 = 0;
787 } else {
788 x = packet->tc.x;
789 y = packet->tc.y;
790 z1 = packet->tc.z1;
791 z2 = packet->tc.z2;
792 }
793
794 /* range filtering */
795 if (x == MAX_12BIT)
796 x = 0;
797
798 if (ts->model == 7843) {
799 Rt = ts->pressure_max / 2;
800 } else if (ts->model == 7845) {
801 if (get_pendown_state(ts))
802 Rt = ts->pressure_max / 2;
803 else
804 Rt = 0;
805 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
806 } else if (likely(x && z1)) {
807 /* compute touch pressure resistance using equation #2 */
808 Rt = z2;
809 Rt -= z1;
810 Rt *= x;
811 Rt *= ts->x_plate_ohms;
812 Rt /= z1;
813 Rt = (Rt + 2047) >> 12;
814 } else {
815 Rt = 0;
816 }
817
818 /*
819 * Sample found inconsistent by debouncing or pressure is beyond
820 * the maximum. Don't report it to user space, repeat at least
821 * once more the measurement
822 */
823 if (packet->tc.ignore || Rt > ts->pressure_max) {
824 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
825 packet->tc.ignore, Rt);
826 return;
827 }
828
829 /*
830 * Maybe check the pendown state before reporting. This discards
831 * false readings when the pen is lifted.
832 */
833 if (ts->penirq_recheck_delay_usecs) {
834 udelay(ts->penirq_recheck_delay_usecs);
835 if (!get_pendown_state(ts))
836 Rt = 0;
837 }
838
839 /*
840 * NOTE: We can't rely on the pressure to determine the pen down
841 * state, even this controller has a pressure sensor. The pressure
842 * value can fluctuate for quite a while after lifting the pen and
843 * in some cases may not even settle at the expected value.
844 *
845 * The only safe way to check for the pen up condition is in the
846 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
847 */
848 if (Rt) {
849 struct input_dev *input = ts->input;
850
851 if (ts->swap_xy)
852 swap(x, y);
853
854 if (!ts->pendown) {
855 input_report_key(input, BTN_TOUCH, 1);
856 ts->pendown = true;
857 dev_vdbg(&ts->spi->dev, "DOWN\n");
858 }
859
860 input_report_abs(input, ABS_X, x);
861 input_report_abs(input, ABS_Y, y);
862 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
863
864 input_sync(input);
865 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
866 }
867 }
868
ads7846_hard_irq(int irq,void * handle)869 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
870 {
871 struct ads7846 *ts = handle;
872
873 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
874 }
875
876
ads7846_irq(int irq,void * handle)877 static irqreturn_t ads7846_irq(int irq, void *handle)
878 {
879 struct ads7846 *ts = handle;
880
881 /* Start with a small delay before checking pendown state */
882 msleep(TS_POLL_DELAY);
883
884 while (!ts->stopped && get_pendown_state(ts)) {
885
886 /* pen is down, continue with the measurement */
887 ads7846_read_state(ts);
888
889 if (!ts->stopped)
890 ads7846_report_state(ts);
891
892 wait_event_timeout(ts->wait, ts->stopped,
893 msecs_to_jiffies(TS_POLL_PERIOD));
894 }
895
896 if (ts->pendown) {
897 struct input_dev *input = ts->input;
898
899 input_report_key(input, BTN_TOUCH, 0);
900 input_report_abs(input, ABS_PRESSURE, 0);
901 input_sync(input);
902
903 ts->pendown = false;
904 dev_vdbg(&ts->spi->dev, "UP\n");
905 }
906
907 return IRQ_HANDLED;
908 }
909
910 #ifdef CONFIG_PM_SLEEP
ads7846_suspend(struct device * dev)911 static int ads7846_suspend(struct device *dev)
912 {
913 struct ads7846 *ts = dev_get_drvdata(dev);
914
915 mutex_lock(&ts->lock);
916
917 if (!ts->suspended) {
918
919 if (!ts->disabled)
920 __ads7846_disable(ts);
921
922 if (device_may_wakeup(&ts->spi->dev))
923 enable_irq_wake(ts->spi->irq);
924
925 ts->suspended = true;
926 }
927
928 mutex_unlock(&ts->lock);
929
930 return 0;
931 }
932
ads7846_resume(struct device * dev)933 static int ads7846_resume(struct device *dev)
934 {
935 struct ads7846 *ts = dev_get_drvdata(dev);
936
937 mutex_lock(&ts->lock);
938
939 if (ts->suspended) {
940
941 ts->suspended = false;
942
943 if (device_may_wakeup(&ts->spi->dev))
944 disable_irq_wake(ts->spi->irq);
945
946 if (!ts->disabled)
947 __ads7846_enable(ts);
948 }
949
950 mutex_unlock(&ts->lock);
951
952 return 0;
953 }
954 #endif
955
956 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
957
ads7846_setup_pendown(struct spi_device * spi,struct ads7846 * ts)958 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
959 {
960 struct ads7846_platform_data *pdata = spi->dev.platform_data;
961 int err;
962
963 /*
964 * REVISIT when the irq can be triggered active-low, or if for some
965 * reason the touchscreen isn't hooked up, we don't need to access
966 * the pendown state.
967 */
968
969 if (pdata->get_pendown_state) {
970 ts->get_pendown_state = pdata->get_pendown_state;
971 } else if (gpio_is_valid(pdata->gpio_pendown)) {
972
973 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
974 "ads7846_pendown");
975 if (err) {
976 dev_err(&spi->dev,
977 "failed to request/setup pendown GPIO%d: %d\n",
978 pdata->gpio_pendown, err);
979 return err;
980 }
981
982 ts->gpio_pendown = pdata->gpio_pendown;
983
984 } else {
985 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
986 return -EINVAL;
987 }
988
989 return 0;
990 }
991
992 /*
993 * Set up the transfers to read touchscreen state; this assumes we
994 * use formula #2 for pressure, not #3.
995 */
ads7846_setup_spi_msg(struct ads7846 * ts,const struct ads7846_platform_data * pdata)996 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
997 const struct ads7846_platform_data *pdata)
998 {
999 struct spi_message *m = &ts->msg[0];
1000 struct spi_transfer *x = ts->xfer;
1001 struct ads7846_packet *packet = ts->packet;
1002 int vref = pdata->keep_vref_on;
1003
1004 if (ts->model == 7873) {
1005 /*
1006 * The AD7873 is almost identical to the ADS7846
1007 * keep VREF off during differential/ratiometric
1008 * conversion modes.
1009 */
1010 ts->model = 7846;
1011 vref = 0;
1012 }
1013
1014 ts->msg_count = 1;
1015 spi_message_init(m);
1016 m->context = ts;
1017
1018 if (ts->model == 7845) {
1019 packet->read_y_cmd[0] = READ_Y(vref);
1020 packet->read_y_cmd[1] = 0;
1021 packet->read_y_cmd[2] = 0;
1022 x->tx_buf = &packet->read_y_cmd[0];
1023 x->rx_buf = &packet->tc.y_buf[0];
1024 x->len = 3;
1025 spi_message_add_tail(x, m);
1026 } else {
1027 /* y- still on; turn on only y+ (and ADC) */
1028 packet->read_y = READ_Y(vref);
1029 x->tx_buf = &packet->read_y;
1030 x->len = 1;
1031 spi_message_add_tail(x, m);
1032
1033 x++;
1034 x->rx_buf = &packet->tc.y;
1035 x->len = 2;
1036 spi_message_add_tail(x, m);
1037 }
1038
1039 /*
1040 * The first sample after switching drivers can be low quality;
1041 * optionally discard it, using a second one after the signals
1042 * have had enough time to stabilize.
1043 */
1044 if (pdata->settle_delay_usecs) {
1045 x->delay_usecs = pdata->settle_delay_usecs;
1046
1047 x++;
1048 x->tx_buf = &packet->read_y;
1049 x->len = 1;
1050 spi_message_add_tail(x, m);
1051
1052 x++;
1053 x->rx_buf = &packet->tc.y;
1054 x->len = 2;
1055 spi_message_add_tail(x, m);
1056 }
1057
1058 ts->msg_count++;
1059 m++;
1060 spi_message_init(m);
1061 m->context = ts;
1062
1063 if (ts->model == 7845) {
1064 x++;
1065 packet->read_x_cmd[0] = READ_X(vref);
1066 packet->read_x_cmd[1] = 0;
1067 packet->read_x_cmd[2] = 0;
1068 x->tx_buf = &packet->read_x_cmd[0];
1069 x->rx_buf = &packet->tc.x_buf[0];
1070 x->len = 3;
1071 spi_message_add_tail(x, m);
1072 } else {
1073 /* turn y- off, x+ on, then leave in lowpower */
1074 x++;
1075 packet->read_x = READ_X(vref);
1076 x->tx_buf = &packet->read_x;
1077 x->len = 1;
1078 spi_message_add_tail(x, m);
1079
1080 x++;
1081 x->rx_buf = &packet->tc.x;
1082 x->len = 2;
1083 spi_message_add_tail(x, m);
1084 }
1085
1086 /* ... maybe discard first sample ... */
1087 if (pdata->settle_delay_usecs) {
1088 x->delay_usecs = pdata->settle_delay_usecs;
1089
1090 x++;
1091 x->tx_buf = &packet->read_x;
1092 x->len = 1;
1093 spi_message_add_tail(x, m);
1094
1095 x++;
1096 x->rx_buf = &packet->tc.x;
1097 x->len = 2;
1098 spi_message_add_tail(x, m);
1099 }
1100
1101 /* turn y+ off, x- on; we'll use formula #2 */
1102 if (ts->model == 7846) {
1103 ts->msg_count++;
1104 m++;
1105 spi_message_init(m);
1106 m->context = ts;
1107
1108 x++;
1109 packet->read_z1 = READ_Z1(vref);
1110 x->tx_buf = &packet->read_z1;
1111 x->len = 1;
1112 spi_message_add_tail(x, m);
1113
1114 x++;
1115 x->rx_buf = &packet->tc.z1;
1116 x->len = 2;
1117 spi_message_add_tail(x, m);
1118
1119 /* ... maybe discard first sample ... */
1120 if (pdata->settle_delay_usecs) {
1121 x->delay_usecs = pdata->settle_delay_usecs;
1122
1123 x++;
1124 x->tx_buf = &packet->read_z1;
1125 x->len = 1;
1126 spi_message_add_tail(x, m);
1127
1128 x++;
1129 x->rx_buf = &packet->tc.z1;
1130 x->len = 2;
1131 spi_message_add_tail(x, m);
1132 }
1133
1134 ts->msg_count++;
1135 m++;
1136 spi_message_init(m);
1137 m->context = ts;
1138
1139 x++;
1140 packet->read_z2 = READ_Z2(vref);
1141 x->tx_buf = &packet->read_z2;
1142 x->len = 1;
1143 spi_message_add_tail(x, m);
1144
1145 x++;
1146 x->rx_buf = &packet->tc.z2;
1147 x->len = 2;
1148 spi_message_add_tail(x, m);
1149
1150 /* ... maybe discard first sample ... */
1151 if (pdata->settle_delay_usecs) {
1152 x->delay_usecs = pdata->settle_delay_usecs;
1153
1154 x++;
1155 x->tx_buf = &packet->read_z2;
1156 x->len = 1;
1157 spi_message_add_tail(x, m);
1158
1159 x++;
1160 x->rx_buf = &packet->tc.z2;
1161 x->len = 2;
1162 spi_message_add_tail(x, m);
1163 }
1164 }
1165
1166 /* power down */
1167 ts->msg_count++;
1168 m++;
1169 spi_message_init(m);
1170 m->context = ts;
1171
1172 if (ts->model == 7845) {
1173 x++;
1174 packet->pwrdown_cmd[0] = PWRDOWN;
1175 packet->pwrdown_cmd[1] = 0;
1176 packet->pwrdown_cmd[2] = 0;
1177 x->tx_buf = &packet->pwrdown_cmd[0];
1178 x->len = 3;
1179 } else {
1180 x++;
1181 packet->pwrdown = PWRDOWN;
1182 x->tx_buf = &packet->pwrdown;
1183 x->len = 1;
1184 spi_message_add_tail(x, m);
1185
1186 x++;
1187 x->rx_buf = &packet->dummy;
1188 x->len = 2;
1189 }
1190
1191 CS_CHANGE(*x);
1192 spi_message_add_tail(x, m);
1193 }
1194
ads7846_probe(struct spi_device * spi)1195 static int __devinit ads7846_probe(struct spi_device *spi)
1196 {
1197 struct ads7846 *ts;
1198 struct ads7846_packet *packet;
1199 struct input_dev *input_dev;
1200 struct ads7846_platform_data *pdata = spi->dev.platform_data;
1201 unsigned long irq_flags;
1202 int err;
1203
1204 if (!spi->irq) {
1205 dev_dbg(&spi->dev, "no IRQ?\n");
1206 return -ENODEV;
1207 }
1208
1209 if (!pdata) {
1210 dev_dbg(&spi->dev, "no platform data?\n");
1211 return -ENODEV;
1212 }
1213
1214 /* don't exceed max specified sample rate */
1215 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1216 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1217 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1218 return -EINVAL;
1219 }
1220
1221 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1222 * that even if the hardware can do that, the SPI controller driver
1223 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1224 */
1225 spi->bits_per_word = 8;
1226 spi->mode = SPI_MODE_0;
1227 err = spi_setup(spi);
1228 if (err < 0)
1229 return err;
1230
1231 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1232 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1233 input_dev = input_allocate_device();
1234 if (!ts || !packet || !input_dev) {
1235 err = -ENOMEM;
1236 goto err_free_mem;
1237 }
1238
1239 dev_set_drvdata(&spi->dev, ts);
1240
1241 ts->packet = packet;
1242 ts->spi = spi;
1243 ts->input = input_dev;
1244 ts->vref_mv = pdata->vref_mv;
1245 ts->swap_xy = pdata->swap_xy;
1246
1247 mutex_init(&ts->lock);
1248 init_waitqueue_head(&ts->wait);
1249
1250 ts->model = pdata->model ? : 7846;
1251 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1252 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1253 ts->pressure_max = pdata->pressure_max ? : ~0;
1254
1255 if (pdata->filter != NULL) {
1256 if (pdata->filter_init != NULL) {
1257 err = pdata->filter_init(pdata, &ts->filter_data);
1258 if (err < 0)
1259 goto err_free_mem;
1260 }
1261 ts->filter = pdata->filter;
1262 ts->filter_cleanup = pdata->filter_cleanup;
1263 } else if (pdata->debounce_max) {
1264 ts->debounce_max = pdata->debounce_max;
1265 if (ts->debounce_max < 2)
1266 ts->debounce_max = 2;
1267 ts->debounce_tol = pdata->debounce_tol;
1268 ts->debounce_rep = pdata->debounce_rep;
1269 ts->filter = ads7846_debounce_filter;
1270 ts->filter_data = ts;
1271 } else {
1272 ts->filter = ads7846_no_filter;
1273 }
1274
1275 err = ads7846_setup_pendown(spi, ts);
1276 if (err)
1277 goto err_cleanup_filter;
1278
1279 if (pdata->penirq_recheck_delay_usecs)
1280 ts->penirq_recheck_delay_usecs =
1281 pdata->penirq_recheck_delay_usecs;
1282
1283 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1284
1285 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1286 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1287
1288 input_dev->name = ts->name;
1289 input_dev->phys = ts->phys;
1290 input_dev->dev.parent = &spi->dev;
1291
1292 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1293 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1294 input_set_abs_params(input_dev, ABS_X,
1295 pdata->x_min ? : 0,
1296 pdata->x_max ? : MAX_12BIT,
1297 0, 0);
1298 input_set_abs_params(input_dev, ABS_Y,
1299 pdata->y_min ? : 0,
1300 pdata->y_max ? : MAX_12BIT,
1301 0, 0);
1302 input_set_abs_params(input_dev, ABS_PRESSURE,
1303 pdata->pressure_min, pdata->pressure_max, 0, 0);
1304
1305 ads7846_setup_spi_msg(ts, pdata);
1306
1307 ts->reg = regulator_get(&spi->dev, "vcc");
1308 if (IS_ERR(ts->reg)) {
1309 err = PTR_ERR(ts->reg);
1310 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1311 goto err_free_gpio;
1312 }
1313
1314 err = regulator_enable(ts->reg);
1315 if (err) {
1316 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1317 goto err_put_regulator;
1318 }
1319
1320 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1321 irq_flags |= IRQF_ONESHOT;
1322
1323 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1324 irq_flags, spi->dev.driver->name, ts);
1325 if (err && !pdata->irq_flags) {
1326 dev_info(&spi->dev,
1327 "trying pin change workaround on irq %d\n", spi->irq);
1328 irq_flags |= IRQF_TRIGGER_RISING;
1329 err = request_threaded_irq(spi->irq,
1330 ads7846_hard_irq, ads7846_irq,
1331 irq_flags, spi->dev.driver->name, ts);
1332 }
1333
1334 if (err) {
1335 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1336 goto err_disable_regulator;
1337 }
1338
1339 err = ads784x_hwmon_register(spi, ts);
1340 if (err)
1341 goto err_free_irq;
1342
1343 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1344
1345 /*
1346 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1347 * the touchscreen, in case it's not connected.
1348 */
1349 if (ts->model == 7845)
1350 ads7845_read12_ser(&spi->dev, PWRDOWN);
1351 else
1352 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1353
1354 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1355 if (err)
1356 goto err_remove_hwmon;
1357
1358 err = input_register_device(input_dev);
1359 if (err)
1360 goto err_remove_attr_group;
1361
1362 device_init_wakeup(&spi->dev, pdata->wakeup);
1363
1364 return 0;
1365
1366 err_remove_attr_group:
1367 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1368 err_remove_hwmon:
1369 ads784x_hwmon_unregister(spi, ts);
1370 err_free_irq:
1371 free_irq(spi->irq, ts);
1372 err_disable_regulator:
1373 regulator_disable(ts->reg);
1374 err_put_regulator:
1375 regulator_put(ts->reg);
1376 err_free_gpio:
1377 if (!ts->get_pendown_state)
1378 gpio_free(ts->gpio_pendown);
1379 err_cleanup_filter:
1380 if (ts->filter_cleanup)
1381 ts->filter_cleanup(ts->filter_data);
1382 err_free_mem:
1383 input_free_device(input_dev);
1384 kfree(packet);
1385 kfree(ts);
1386 return err;
1387 }
1388
ads7846_remove(struct spi_device * spi)1389 static int __devexit ads7846_remove(struct spi_device *spi)
1390 {
1391 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1392
1393 device_init_wakeup(&spi->dev, false);
1394
1395 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1396
1397 ads7846_disable(ts);
1398 free_irq(ts->spi->irq, ts);
1399
1400 input_unregister_device(ts->input);
1401
1402 ads784x_hwmon_unregister(spi, ts);
1403
1404 regulator_disable(ts->reg);
1405 regulator_put(ts->reg);
1406
1407 if (!ts->get_pendown_state) {
1408 /*
1409 * If we are not using specialized pendown method we must
1410 * have been relying on gpio we set up ourselves.
1411 */
1412 gpio_free(ts->gpio_pendown);
1413 }
1414
1415 if (ts->filter_cleanup)
1416 ts->filter_cleanup(ts->filter_data);
1417
1418 kfree(ts->packet);
1419 kfree(ts);
1420
1421 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1422
1423 return 0;
1424 }
1425
1426 static struct spi_driver ads7846_driver = {
1427 .driver = {
1428 .name = "ads7846",
1429 .owner = THIS_MODULE,
1430 .pm = &ads7846_pm,
1431 },
1432 .probe = ads7846_probe,
1433 .remove = __devexit_p(ads7846_remove),
1434 };
1435
1436 module_spi_driver(ads7846_driver);
1437
1438 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1439 MODULE_LICENSE("GPL");
1440 MODULE_ALIAS("spi:ads7846");
1441