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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/err.h>
23#include <linux/sched.h>
24#include <linux/delay.h>
25#include <linux/input.h>
26#include <linux/interrupt.h>
27#include <linux/slab.h>
28#include <linux/pm.h>
29#include <linux/of.h>
30#include <linux/of_gpio.h>
31#include <linux/of_device.h>
32#include <linux/gpio.h>
33#include <linux/spi/spi.h>
34#include <linux/spi/ads7846.h>
35#include <linux/regulator/consumer.h>
36#include <linux/module.h>
37#include <asm/irq.h>
38
39/*
40 * This code has been heavily tested on a Nokia 770, and lightly
41 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
42 * TSC2046 is just newer ads7846 silicon.
43 * Support for ads7843 tested on Atmel at91sam926x-EK.
44 * Support for ads7845 has only been stubbed in.
45 * Support for Analog Devices AD7873 and AD7843 tested.
46 *
47 * IRQ handling needs a workaround because of a shortcoming in handling
48 * edge triggered IRQs on some platforms like the OMAP1/2. These
49 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
50 * have to maintain our own SW IRQ disabled status. This should be
51 * removed as soon as the affected platform's IRQ handling is fixed.
52 *
53 * App note sbaa036 talks in more detail about accurate sampling...
54 * that ought to help in situations like LCDs inducing noise (which
55 * can also be helped by using synch signals) and more generally.
56 * This driver tries to utilize the measures described in the app
57 * note. The strength of filtering can be set in the board-* specific
58 * files.
59 */
60
61#define TS_POLL_DELAY 1 /* ms delay before the first sample */
62#define TS_POLL_PERIOD 5 /* ms delay between samples */
63
64/* this driver doesn't aim at the peak continuous sample rate */
65#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
66
67struct ts_event {
68 /*
69 * For portability, we can't read 12 bit values using SPI (which
70 * would make the controller deliver them as native byte order u16
71 * with msbs zeroed). Instead, we read them as two 8-bit values,
72 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
73 */
74 u16 x;
75 u16 y;
76 u16 z1, z2;
77 bool ignore;
78 u8 x_buf[3];
79 u8 y_buf[3];
80};
81
82/*
83 * We allocate this separately to avoid cache line sharing issues when
84 * driver is used with DMA-based SPI controllers (like atmel_spi) on
85 * systems where main memory is not DMA-coherent (most non-x86 boards).
86 */
87struct ads7846_packet {
88 u8 read_x, read_y, read_z1, read_z2, pwrdown;
89 u16 dummy; /* for the pwrdown read */
90 struct ts_event tc;
91 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
92 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
93};
94
95struct ads7846 {
96 struct input_dev *input;
97 char phys[32];
98 char name[32];
99
100 struct spi_device *spi;
101 struct regulator *reg;
102
103#if IS_ENABLED(CONFIG_HWMON)
104 struct device *hwmon;
105#endif
106
107 u16 model;
108 u16 vref_mv;
109 u16 vref_delay_usecs;
110 u16 x_plate_ohms;
111 u16 pressure_max;
112
113 bool swap_xy;
114 bool use_internal;
115
116 struct ads7846_packet *packet;
117
118 struct spi_transfer xfer[18];
119 struct spi_message msg[5];
120 int msg_count;
121 wait_queue_head_t wait;
122
123 bool pendown;
124
125 int read_cnt;
126 int read_rep;
127 int last_read;
128
129 u16 debounce_max;
130 u16 debounce_tol;
131 u16 debounce_rep;
132
133 u16 penirq_recheck_delay_usecs;
134
135 struct mutex lock;
136 bool stopped; /* P: lock */
137 bool disabled; /* P: lock */
138 bool suspended; /* P: lock */
139
140 int (*filter)(void *data, int data_idx, int *val);
141 void *filter_data;
142 void (*filter_cleanup)(void *data);
143 int (*get_pendown_state)(void);
144 int gpio_pendown;
145
146 void (*wait_for_sync)(void);
147};
148
149/* leave chip selected when we're done, for quicker re-select? */
150#if 0
151#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
152#else
153#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
154#endif
155
156/*--------------------------------------------------------------------------*/
157
158/* The ADS7846 has touchscreen and other sensors.
159 * Earlier ads784x chips are somewhat compatible.
160 */
161#define ADS_START (1 << 7)
162#define ADS_A2A1A0_d_y (1 << 4) /* differential */
163#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
164#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
165#define ADS_A2A1A0_d_x (5 << 4) /* differential */
166#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
167#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
168#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
169#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
170#define ADS_8_BIT (1 << 3)
171#define ADS_12_BIT (0 << 3)
172#define ADS_SER (1 << 2) /* non-differential */
173#define ADS_DFR (0 << 2) /* differential */
174#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
175#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
176#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
177#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
178
179#define MAX_12BIT ((1<<12)-1)
180
181/* leave ADC powered up (disables penirq) between differential samples */
182#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
183 | ADS_12_BIT | ADS_DFR | \
184 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
185
186#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
187#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
188#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
189
190#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
191#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
192
193/* single-ended samples need to first power up reference voltage;
194 * we leave both ADC and VREF powered
195 */
196#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
197 | ADS_12_BIT | ADS_SER)
198
199#define REF_ON (READ_12BIT_DFR(x, 1, 1))
200#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
201
202/* Must be called with ts->lock held */
203static void ads7846_stop(struct ads7846 *ts)
204{
205 if (!ts->disabled && !ts->suspended) {
206 /* Signal IRQ thread to stop polling and disable the handler. */
207 ts->stopped = true;
208 mb();
209 wake_up(&ts->wait);
210 disable_irq(ts->spi->irq);
211 }
212}
213
214/* Must be called with ts->lock held */
215static void ads7846_restart(struct ads7846 *ts)
216{
217 if (!ts->disabled && !ts->suspended) {
218 /* Tell IRQ thread that it may poll the device. */
219 ts->stopped = false;
220 mb();
221 enable_irq(ts->spi->irq);
222 }
223}
224
225/* Must be called with ts->lock held */
226static void __ads7846_disable(struct ads7846 *ts)
227{
228 ads7846_stop(ts);
229 regulator_disable(ts->reg);
230
231 /*
232 * We know the chip's in low power mode since we always
233 * leave it that way after every request
234 */
235}
236
237/* Must be called with ts->lock held */
238static void __ads7846_enable(struct ads7846 *ts)
239{
240 int error;
241
242 error = regulator_enable(ts->reg);
243 if (error != 0)
244 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
245
246 ads7846_restart(ts);
247}
248
249static void ads7846_disable(struct ads7846 *ts)
250{
251 mutex_lock(&ts->lock);
252
253 if (!ts->disabled) {
254
255 if (!ts->suspended)
256 __ads7846_disable(ts);
257
258 ts->disabled = true;
259 }
260
261 mutex_unlock(&ts->lock);
262}
263
264static void ads7846_enable(struct ads7846 *ts)
265{
266 mutex_lock(&ts->lock);
267
268 if (ts->disabled) {
269
270 ts->disabled = false;
271
272 if (!ts->suspended)
273 __ads7846_enable(ts);
274 }
275
276 mutex_unlock(&ts->lock);
277}
278
279/*--------------------------------------------------------------------------*/
280
281/*
282 * Non-touchscreen sensors only use single-ended conversions.
283 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
284 * ads7846 lets that pin be unconnected, to use internal vREF.
285 */
286
287struct ser_req {
288 u8 ref_on;
289 u8 command;
290 u8 ref_off;
291 u16 scratch;
292 struct spi_message msg;
293 struct spi_transfer xfer[6];
294 /*
295 * DMA (thus cache coherency maintenance) requires the
296 * transfer buffers to live in their own cache lines.
297 */
298 __be16 sample ____cacheline_aligned;
299};
300
301struct ads7845_ser_req {
302 u8 command[3];
303 struct spi_message msg;
304 struct spi_transfer xfer[2];
305 /*
306 * DMA (thus cache coherency maintenance) requires the
307 * transfer buffers to live in their own cache lines.
308 */
309 u8 sample[3] ____cacheline_aligned;
310};
311
312static int ads7846_read12_ser(struct device *dev, unsigned command)
313{
314 struct spi_device *spi = to_spi_device(dev);
315 struct ads7846 *ts = dev_get_drvdata(dev);
316 struct ser_req *req;
317 int status;
318
319 req = kzalloc(sizeof *req, GFP_KERNEL);
320 if (!req)
321 return -ENOMEM;
322
323 spi_message_init(&req->msg);
324
325 /* maybe turn on internal vREF, and let it settle */
326 if (ts->use_internal) {
327 req->ref_on = REF_ON;
328 req->xfer[0].tx_buf = &req->ref_on;
329 req->xfer[0].len = 1;
330 spi_message_add_tail(&req->xfer[0], &req->msg);
331
332 req->xfer[1].rx_buf = &req->scratch;
333 req->xfer[1].len = 2;
334
335 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
336 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
337 spi_message_add_tail(&req->xfer[1], &req->msg);
338
339 /* Enable reference voltage */
340 command |= ADS_PD10_REF_ON;
341 }
342
343 /* Enable ADC in every case */
344 command |= ADS_PD10_ADC_ON;
345
346 /* take sample */
347 req->command = (u8) command;
348 req->xfer[2].tx_buf = &req->command;
349 req->xfer[2].len = 1;
350 spi_message_add_tail(&req->xfer[2], &req->msg);
351
352 req->xfer[3].rx_buf = &req->sample;
353 req->xfer[3].len = 2;
354 spi_message_add_tail(&req->xfer[3], &req->msg);
355
356 /* REVISIT: take a few more samples, and compare ... */
357
358 /* converter in low power mode & enable PENIRQ */
359 req->ref_off = PWRDOWN;
360 req->xfer[4].tx_buf = &req->ref_off;
361 req->xfer[4].len = 1;
362 spi_message_add_tail(&req->xfer[4], &req->msg);
363
364 req->xfer[5].rx_buf = &req->scratch;
365 req->xfer[5].len = 2;
366 CS_CHANGE(req->xfer[5]);
367 spi_message_add_tail(&req->xfer[5], &req->msg);
368
369 mutex_lock(&ts->lock);
370 ads7846_stop(ts);
371 status = spi_sync(spi, &req->msg);
372 ads7846_restart(ts);
373 mutex_unlock(&ts->lock);
374
375 if (status == 0) {
376 /* on-wire is a must-ignore bit, a BE12 value, then padding */
377 status = be16_to_cpu(req->sample);
378 status = status >> 3;
379 status &= 0x0fff;
380 }
381
382 kfree(req);
383 return status;
384}
385
386static int ads7845_read12_ser(struct device *dev, unsigned command)
387{
388 struct spi_device *spi = to_spi_device(dev);
389 struct ads7846 *ts = dev_get_drvdata(dev);
390 struct ads7845_ser_req *req;
391 int status;
392
393 req = kzalloc(sizeof *req, GFP_KERNEL);
394 if (!req)
395 return -ENOMEM;
396
397 spi_message_init(&req->msg);
398
399 req->command[0] = (u8) command;
400 req->xfer[0].tx_buf = req->command;
401 req->xfer[0].rx_buf = req->sample;
402 req->xfer[0].len = 3;
403 spi_message_add_tail(&req->xfer[0], &req->msg);
404
405 mutex_lock(&ts->lock);
406 ads7846_stop(ts);
407 status = spi_sync(spi, &req->msg);
408 ads7846_restart(ts);
409 mutex_unlock(&ts->lock);
410
411 if (status == 0) {
412 /* BE12 value, then padding */
413 status = be16_to_cpu(*((u16 *)&req->sample[1]));
414 status = status >> 3;
415 status &= 0x0fff;
416 }
417
418 kfree(req);
419 return status;
420}
421
422#if IS_ENABLED(CONFIG_HWMON)
423
424#define SHOW(name, var, adjust) static ssize_t \
425name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
426{ \
427 struct ads7846 *ts = dev_get_drvdata(dev); \
428 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
429 READ_12BIT_SER(var)); \
430 if (v < 0) \
431 return v; \
432 return sprintf(buf, "%u\n", adjust(ts, v)); \
433} \
434static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
435
436
437/* Sysfs conventions report temperatures in millidegrees Celsius.
438 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
439 * accuracy scheme without calibration data. For now we won't try either;
440 * userspace sees raw sensor values, and must scale/calibrate appropriately.
441 */
442static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
443{
444 return v;
445}
446
447SHOW(temp0, temp0, null_adjust) /* temp1_input */
448SHOW(temp1, temp1, null_adjust) /* temp2_input */
449
450
451/* sysfs conventions report voltages in millivolts. We can convert voltages
452 * if we know vREF. userspace may need to scale vAUX to match the board's
453 * external resistors; we assume that vBATT only uses the internal ones.
454 */
455static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
456{
457 unsigned retval = v;
458
459 /* external resistors may scale vAUX into 0..vREF */
460 retval *= ts->vref_mv;
461 retval = retval >> 12;
462
463 return retval;
464}
465
466static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
467{
468 unsigned retval = vaux_adjust(ts, v);
469
470 /* ads7846 has a resistor ladder to scale this signal down */
471 if (ts->model == 7846)
472 retval *= 4;
473
474 return retval;
475}
476
477SHOW(in0_input, vaux, vaux_adjust)
478SHOW(in1_input, vbatt, vbatt_adjust)
479
480static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
481 int index)
482{
483 struct device *dev = container_of(kobj, struct device, kobj);
484 struct ads7846 *ts = dev_get_drvdata(dev);
485
486 if (ts->model == 7843 && index < 2) /* in0, in1 */
487 return 0;
488 if (ts->model == 7845 && index != 2) /* in0 */
489 return 0;
490
491 return attr->mode;
492}
493
494static struct attribute *ads7846_attributes[] = {
495 &dev_attr_temp0.attr, /* 0 */
496 &dev_attr_temp1.attr, /* 1 */
497 &dev_attr_in0_input.attr, /* 2 */
498 &dev_attr_in1_input.attr, /* 3 */
499 NULL,
500};
501
502static struct attribute_group ads7846_attr_group = {
503 .attrs = ads7846_attributes,
504 .is_visible = ads7846_is_visible,
505};
506__ATTRIBUTE_GROUPS(ads7846_attr);
507
508static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
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 ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
531 ts, ads7846_attr_groups);
532 if (IS_ERR(ts->hwmon))
533 return PTR_ERR(ts->hwmon);
534
535 return 0;
536}
537
538static void ads784x_hwmon_unregister(struct spi_device *spi,
539 struct ads7846 *ts)
540{
541 if (ts->hwmon)
542 hwmon_device_unregister(ts->hwmon);
543}
544
545#else
546static inline int ads784x_hwmon_register(struct spi_device *spi,
547 struct ads7846 *ts)
548{
549 return 0;
550}
551
552static inline void ads784x_hwmon_unregister(struct spi_device *spi,
553 struct ads7846 *ts)
554{
555}
556#endif
557
558static ssize_t ads7846_pen_down_show(struct device *dev,
559 struct device_attribute *attr, char *buf)
560{
561 struct ads7846 *ts = dev_get_drvdata(dev);
562
563 return sprintf(buf, "%u\n", ts->pendown);
564}
565
566static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
567
568static ssize_t ads7846_disable_show(struct device *dev,
569 struct device_attribute *attr, char *buf)
570{
571 struct ads7846 *ts = dev_get_drvdata(dev);
572
573 return sprintf(buf, "%u\n", ts->disabled);
574}
575
576static ssize_t ads7846_disable_store(struct device *dev,
577 struct device_attribute *attr,
578 const char *buf, size_t count)
579{
580 struct ads7846 *ts = dev_get_drvdata(dev);
581 unsigned int i;
582 int err;
583
584 err = kstrtouint(buf, 10, &i);
585 if (err)
586 return err;
587
588 if (i)
589 ads7846_disable(ts);
590 else
591 ads7846_enable(ts);
592
593 return count;
594}
595
596static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
597
598static struct attribute *ads784x_attributes[] = {
599 &dev_attr_pen_down.attr,
600 &dev_attr_disable.attr,
601 NULL,
602};
603
604static struct attribute_group ads784x_attr_group = {
605 .attrs = ads784x_attributes,
606};
607
608/*--------------------------------------------------------------------------*/
609
610static int get_pendown_state(struct ads7846 *ts)
611{
612 if (ts->get_pendown_state)
613 return ts->get_pendown_state();
614
615 return !gpio_get_value(ts->gpio_pendown);
616}
617
618static void null_wait_for_sync(void)
619{
620}
621
622static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
623{
624 struct ads7846 *ts = ads;
625
626 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
627 /* Start over collecting consistent readings. */
628 ts->read_rep = 0;
629 /*
630 * Repeat it, if this was the first read or the read
631 * wasn't consistent enough.
632 */
633 if (ts->read_cnt < ts->debounce_max) {
634 ts->last_read = *val;
635 ts->read_cnt++;
636 return ADS7846_FILTER_REPEAT;
637 } else {
638 /*
639 * Maximum number of debouncing reached and still
640 * not enough number of consistent readings. Abort
641 * the whole sample, repeat it in the next sampling
642 * period.
643 */
644 ts->read_cnt = 0;
645 return ADS7846_FILTER_IGNORE;
646 }
647 } else {
648 if (++ts->read_rep > ts->debounce_rep) {
649 /*
650 * Got a good reading for this coordinate,
651 * go for the next one.
652 */
653 ts->read_cnt = 0;
654 ts->read_rep = 0;
655 return ADS7846_FILTER_OK;
656 } else {
657 /* Read more values that are consistent. */
658 ts->read_cnt++;
659 return ADS7846_FILTER_REPEAT;
660 }
661 }
662}
663
664static int ads7846_no_filter(void *ads, int data_idx, int *val)
665{
666 return ADS7846_FILTER_OK;
667}
668
669static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
670{
671 struct spi_transfer *t =
672 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
673
674 if (ts->model == 7845) {
675 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
676 } else {
677 /*
678 * adjust: on-wire is a must-ignore bit, a BE12 value, then
679 * padding; built from two 8 bit values written msb-first.
680 */
681 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
682 }
683}
684
685static void ads7846_update_value(struct spi_message *m, int val)
686{
687 struct spi_transfer *t =
688 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
689
690 *(u16 *)t->rx_buf = val;
691}
692
693static void ads7846_read_state(struct ads7846 *ts)
694{
695 struct ads7846_packet *packet = ts->packet;
696 struct spi_message *m;
697 int msg_idx = 0;
698 int val;
699 int action;
700 int error;
701
702 while (msg_idx < ts->msg_count) {
703
704 ts->wait_for_sync();
705
706 m = &ts->msg[msg_idx];
707 error = spi_sync(ts->spi, m);
708 if (error) {
709 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
710 packet->tc.ignore = true;
711 return;
712 }
713
714 /*
715 * Last message is power down request, no need to convert
716 * or filter the value.
717 */
718 if (msg_idx < ts->msg_count - 1) {
719
720 val = ads7846_get_value(ts, m);
721
722 action = ts->filter(ts->filter_data, msg_idx, &val);
723 switch (action) {
724 case ADS7846_FILTER_REPEAT:
725 continue;
726
727 case ADS7846_FILTER_IGNORE:
728 packet->tc.ignore = true;
729 msg_idx = ts->msg_count - 1;
730 continue;
731
732 case ADS7846_FILTER_OK:
733 ads7846_update_value(m, val);
734 packet->tc.ignore = false;
735 msg_idx++;
736 break;
737
738 default:
739 BUG();
740 }
741 } else {
742 msg_idx++;
743 }
744 }
745}
746
747static void ads7846_report_state(struct ads7846 *ts)
748{
749 struct ads7846_packet *packet = ts->packet;
750 unsigned int Rt;
751 u16 x, y, z1, z2;
752
753 /*
754 * ads7846_get_value() does in-place conversion (including byte swap)
755 * from on-the-wire format as part of debouncing to get stable
756 * readings.
757 */
758 if (ts->model == 7845) {
759 x = *(u16 *)packet->tc.x_buf;
760 y = *(u16 *)packet->tc.y_buf;
761 z1 = 0;
762 z2 = 0;
763 } else {
764 x = packet->tc.x;
765 y = packet->tc.y;
766 z1 = packet->tc.z1;
767 z2 = packet->tc.z2;
768 }
769
770 /* range filtering */
771 if (x == MAX_12BIT)
772 x = 0;
773
774 if (ts->model == 7843) {
775 Rt = ts->pressure_max / 2;
776 } else if (ts->model == 7845) {
777 if (get_pendown_state(ts))
778 Rt = ts->pressure_max / 2;
779 else
780 Rt = 0;
781 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
782 } else if (likely(x && z1)) {
783 /* compute touch pressure resistance using equation #2 */
784 Rt = z2;
785 Rt -= z1;
786 Rt *= x;
787 Rt *= ts->x_plate_ohms;
788 Rt /= z1;
789 Rt = (Rt + 2047) >> 12;
790 } else {
791 Rt = 0;
792 }
793
794 /*
795 * Sample found inconsistent by debouncing or pressure is beyond
796 * the maximum. Don't report it to user space, repeat at least
797 * once more the measurement
798 */
799 if (packet->tc.ignore || Rt > ts->pressure_max) {
800 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
801 packet->tc.ignore, Rt);
802 return;
803 }
804
805 /*
806 * Maybe check the pendown state before reporting. This discards
807 * false readings when the pen is lifted.
808 */
809 if (ts->penirq_recheck_delay_usecs) {
810 udelay(ts->penirq_recheck_delay_usecs);
811 if (!get_pendown_state(ts))
812 Rt = 0;
813 }
814
815 /*
816 * NOTE: We can't rely on the pressure to determine the pen down
817 * state, even this controller has a pressure sensor. The pressure
818 * value can fluctuate for quite a while after lifting the pen and
819 * in some cases may not even settle at the expected value.
820 *
821 * The only safe way to check for the pen up condition is in the
822 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
823 */
824 if (Rt) {
825 struct input_dev *input = ts->input;
826
827 if (ts->swap_xy)
828 swap(x, y);
829
830 if (!ts->pendown) {
831 input_report_key(input, BTN_TOUCH, 1);
832 ts->pendown = true;
833 dev_vdbg(&ts->spi->dev, "DOWN\n");
834 }
835
836 input_report_abs(input, ABS_X, x);
837 input_report_abs(input, ABS_Y, y);
838 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
839
840 input_sync(input);
841 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
842 }
843}
844
845static irqreturn_t ads7846_hard_irq(int irq, void *handle)
846{
847 struct ads7846 *ts = handle;
848
849 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
850}
851
852
853static irqreturn_t ads7846_irq(int irq, void *handle)
854{
855 struct ads7846 *ts = handle;
856
857 /* Start with a small delay before checking pendown state */
858 msleep(TS_POLL_DELAY);
859
860 while (!ts->stopped && get_pendown_state(ts)) {
861
862 /* pen is down, continue with the measurement */
863 ads7846_read_state(ts);
864
865 if (!ts->stopped)
866 ads7846_report_state(ts);
867
868 wait_event_timeout(ts->wait, ts->stopped,
869 msecs_to_jiffies(TS_POLL_PERIOD));
870 }
871
872 if (ts->pendown) {
873 struct input_dev *input = ts->input;
874
875 input_report_key(input, BTN_TOUCH, 0);
876 input_report_abs(input, ABS_PRESSURE, 0);
877 input_sync(input);
878
879 ts->pendown = false;
880 dev_vdbg(&ts->spi->dev, "UP\n");
881 }
882
883 return IRQ_HANDLED;
884}
885
886#ifdef CONFIG_PM_SLEEP
887static int ads7846_suspend(struct device *dev)
888{
889 struct ads7846 *ts = dev_get_drvdata(dev);
890
891 mutex_lock(&ts->lock);
892
893 if (!ts->suspended) {
894
895 if (!ts->disabled)
896 __ads7846_disable(ts);
897
898 if (device_may_wakeup(&ts->spi->dev))
899 enable_irq_wake(ts->spi->irq);
900
901 ts->suspended = true;
902 }
903
904 mutex_unlock(&ts->lock);
905
906 return 0;
907}
908
909static int ads7846_resume(struct device *dev)
910{
911 struct ads7846 *ts = dev_get_drvdata(dev);
912
913 mutex_lock(&ts->lock);
914
915 if (ts->suspended) {
916
917 ts->suspended = false;
918
919 if (device_may_wakeup(&ts->spi->dev))
920 disable_irq_wake(ts->spi->irq);
921
922 if (!ts->disabled)
923 __ads7846_enable(ts);
924 }
925
926 mutex_unlock(&ts->lock);
927
928 return 0;
929}
930#endif
931
932static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
933
934static int ads7846_setup_pendown(struct spi_device *spi,
935 struct ads7846 *ts,
936 const struct ads7846_platform_data *pdata)
937{
938 int err;
939
940 /*
941 * REVISIT when the irq can be triggered active-low, or if for some
942 * reason the touchscreen isn't hooked up, we don't need to access
943 * the pendown state.
944 */
945
946 if (pdata->get_pendown_state) {
947 ts->get_pendown_state = pdata->get_pendown_state;
948 } else if (gpio_is_valid(pdata->gpio_pendown)) {
949
950 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
951 "ads7846_pendown");
952 if (err) {
953 dev_err(&spi->dev,
954 "failed to request/setup pendown GPIO%d: %d\n",
955 pdata->gpio_pendown, err);
956 return err;
957 }
958
959 ts->gpio_pendown = pdata->gpio_pendown;
960
961 if (pdata->gpio_pendown_debounce)
962 gpio_set_debounce(pdata->gpio_pendown,
963 pdata->gpio_pendown_debounce);
964 } else {
965 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
966 return -EINVAL;
967 }
968
969 return 0;
970}
971
972/*
973 * Set up the transfers to read touchscreen state; this assumes we
974 * use formula #2 for pressure, not #3.
975 */
976static void ads7846_setup_spi_msg(struct ads7846 *ts,
977 const struct ads7846_platform_data *pdata)
978{
979 struct spi_message *m = &ts->msg[0];
980 struct spi_transfer *x = ts->xfer;
981 struct ads7846_packet *packet = ts->packet;
982 int vref = pdata->keep_vref_on;
983
984 if (ts->model == 7873) {
985 /*
986 * The AD7873 is almost identical to the ADS7846
987 * keep VREF off during differential/ratiometric
988 * conversion modes.
989 */
990 ts->model = 7846;
991 vref = 0;
992 }
993
994 ts->msg_count = 1;
995 spi_message_init(m);
996 m->context = ts;
997
998 if (ts->model == 7845) {
999 packet->read_y_cmd[0] = READ_Y(vref);
1000 packet->read_y_cmd[1] = 0;
1001 packet->read_y_cmd[2] = 0;
1002 x->tx_buf = &packet->read_y_cmd[0];
1003 x->rx_buf = &packet->tc.y_buf[0];
1004 x->len = 3;
1005 spi_message_add_tail(x, m);
1006 } else {
1007 /* y- still on; turn on only y+ (and ADC) */
1008 packet->read_y = READ_Y(vref);
1009 x->tx_buf = &packet->read_y;
1010 x->len = 1;
1011 spi_message_add_tail(x, m);
1012
1013 x++;
1014 x->rx_buf = &packet->tc.y;
1015 x->len = 2;
1016 spi_message_add_tail(x, m);
1017 }
1018
1019 /*
1020 * The first sample after switching drivers can be low quality;
1021 * optionally discard it, using a second one after the signals
1022 * have had enough time to stabilize.
1023 */
1024 if (pdata->settle_delay_usecs) {
1025 x->delay_usecs = pdata->settle_delay_usecs;
1026
1027 x++;
1028 x->tx_buf = &packet->read_y;
1029 x->len = 1;
1030 spi_message_add_tail(x, m);
1031
1032 x++;
1033 x->rx_buf = &packet->tc.y;
1034 x->len = 2;
1035 spi_message_add_tail(x, m);
1036 }
1037
1038 ts->msg_count++;
1039 m++;
1040 spi_message_init(m);
1041 m->context = ts;
1042
1043 if (ts->model == 7845) {
1044 x++;
1045 packet->read_x_cmd[0] = READ_X(vref);
1046 packet->read_x_cmd[1] = 0;
1047 packet->read_x_cmd[2] = 0;
1048 x->tx_buf = &packet->read_x_cmd[0];
1049 x->rx_buf = &packet->tc.x_buf[0];
1050 x->len = 3;
1051 spi_message_add_tail(x, m);
1052 } else {
1053 /* turn y- off, x+ on, then leave in lowpower */
1054 x++;
1055 packet->read_x = READ_X(vref);
1056 x->tx_buf = &packet->read_x;
1057 x->len = 1;
1058 spi_message_add_tail(x, m);
1059
1060 x++;
1061 x->rx_buf = &packet->tc.x;
1062 x->len = 2;
1063 spi_message_add_tail(x, m);
1064 }
1065
1066 /* ... maybe discard first sample ... */
1067 if (pdata->settle_delay_usecs) {
1068 x->delay_usecs = pdata->settle_delay_usecs;
1069
1070 x++;
1071 x->tx_buf = &packet->read_x;
1072 x->len = 1;
1073 spi_message_add_tail(x, m);
1074
1075 x++;
1076 x->rx_buf = &packet->tc.x;
1077 x->len = 2;
1078 spi_message_add_tail(x, m);
1079 }
1080
1081 /* turn y+ off, x- on; we'll use formula #2 */
1082 if (ts->model == 7846) {
1083 ts->msg_count++;
1084 m++;
1085 spi_message_init(m);
1086 m->context = ts;
1087
1088 x++;
1089 packet->read_z1 = READ_Z1(vref);
1090 x->tx_buf = &packet->read_z1;
1091 x->len = 1;
1092 spi_message_add_tail(x, m);
1093
1094 x++;
1095 x->rx_buf = &packet->tc.z1;
1096 x->len = 2;
1097 spi_message_add_tail(x, m);
1098
1099 /* ... maybe discard first sample ... */
1100 if (pdata->settle_delay_usecs) {
1101 x->delay_usecs = pdata->settle_delay_usecs;
1102
1103 x++;
1104 x->tx_buf = &packet->read_z1;
1105 x->len = 1;
1106 spi_message_add_tail(x, m);
1107
1108 x++;
1109 x->rx_buf = &packet->tc.z1;
1110 x->len = 2;
1111 spi_message_add_tail(x, m);
1112 }
1113
1114 ts->msg_count++;
1115 m++;
1116 spi_message_init(m);
1117 m->context = ts;
1118
1119 x++;
1120 packet->read_z2 = READ_Z2(vref);
1121 x->tx_buf = &packet->read_z2;
1122 x->len = 1;
1123 spi_message_add_tail(x, m);
1124
1125 x++;
1126 x->rx_buf = &packet->tc.z2;
1127 x->len = 2;
1128 spi_message_add_tail(x, m);
1129
1130 /* ... maybe discard first sample ... */
1131 if (pdata->settle_delay_usecs) {
1132 x->delay_usecs = pdata->settle_delay_usecs;
1133
1134 x++;
1135 x->tx_buf = &packet->read_z2;
1136 x->len = 1;
1137 spi_message_add_tail(x, m);
1138
1139 x++;
1140 x->rx_buf = &packet->tc.z2;
1141 x->len = 2;
1142 spi_message_add_tail(x, m);
1143 }
1144 }
1145
1146 /* power down */
1147 ts->msg_count++;
1148 m++;
1149 spi_message_init(m);
1150 m->context = ts;
1151
1152 if (ts->model == 7845) {
1153 x++;
1154 packet->pwrdown_cmd[0] = PWRDOWN;
1155 packet->pwrdown_cmd[1] = 0;
1156 packet->pwrdown_cmd[2] = 0;
1157 x->tx_buf = &packet->pwrdown_cmd[0];
1158 x->len = 3;
1159 } else {
1160 x++;
1161 packet->pwrdown = PWRDOWN;
1162 x->tx_buf = &packet->pwrdown;
1163 x->len = 1;
1164 spi_message_add_tail(x, m);
1165
1166 x++;
1167 x->rx_buf = &packet->dummy;
1168 x->len = 2;
1169 }
1170
1171 CS_CHANGE(*x);
1172 spi_message_add_tail(x, m);
1173}
1174
1175#ifdef CONFIG_OF
1176static const struct of_device_id ads7846_dt_ids[] = {
1177 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1178 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1179 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1180 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1181 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1182 { }
1183};
1184MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1185
1186static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1187{
1188 struct ads7846_platform_data *pdata;
1189 struct device_node *node = dev->of_node;
1190 const struct of_device_id *match;
1191
1192 if (!node) {
1193 dev_err(dev, "Device does not have associated DT data\n");
1194 return ERR_PTR(-EINVAL);
1195 }
1196
1197 match = of_match_device(ads7846_dt_ids, dev);
1198 if (!match) {
1199 dev_err(dev, "Unknown device model\n");
1200 return ERR_PTR(-EINVAL);
1201 }
1202
1203 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1204 if (!pdata)
1205 return ERR_PTR(-ENOMEM);
1206
1207 pdata->model = (unsigned long)match->data;
1208
1209 of_property_read_u16(node, "ti,vref-delay-usecs",
1210 &pdata->vref_delay_usecs);
1211 of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1212 pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1213
1214 pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1215
1216 of_property_read_u16(node, "ti,settle-delay-usec",
1217 &pdata->settle_delay_usecs);
1218 of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1219 &pdata->penirq_recheck_delay_usecs);
1220
1221 of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1222 of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1223
1224 of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1225 of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1226 of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1227 of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1228
1229 of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1230 of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1231
1232 of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1233 of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1234 of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1235
1236 of_property_read_u32(node, "ti,pendown-gpio-debounce",
1237 &pdata->gpio_pendown_debounce);
1238
1239 pdata->wakeup = of_property_read_bool(node, "linux,wakeup");
1240
1241 pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1242
1243 return pdata;
1244}
1245#else
1246static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1247{
1248 dev_err(dev, "no platform data defined\n");
1249 return ERR_PTR(-EINVAL);
1250}
1251#endif
1252
1253static int ads7846_probe(struct spi_device *spi)
1254{
1255 const struct ads7846_platform_data *pdata;
1256 struct ads7846 *ts;
1257 struct ads7846_packet *packet;
1258 struct input_dev *input_dev;
1259 unsigned long irq_flags;
1260 int err;
1261
1262 if (!spi->irq) {
1263 dev_dbg(&spi->dev, "no IRQ?\n");
1264 return -EINVAL;
1265 }
1266
1267 /* don't exceed max specified sample rate */
1268 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1269 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1270 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1271 return -EINVAL;
1272 }
1273
1274 /*
1275 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1276 * that even if the hardware can do that, the SPI controller driver
1277 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1278 */
1279 spi->bits_per_word = 8;
1280 spi->mode = SPI_MODE_0;
1281 err = spi_setup(spi);
1282 if (err < 0)
1283 return err;
1284
1285 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1286 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1287 input_dev = input_allocate_device();
1288 if (!ts || !packet || !input_dev) {
1289 err = -ENOMEM;
1290 goto err_free_mem;
1291 }
1292
1293 spi_set_drvdata(spi, ts);
1294
1295 ts->packet = packet;
1296 ts->spi = spi;
1297 ts->input = input_dev;
1298
1299 mutex_init(&ts->lock);
1300 init_waitqueue_head(&ts->wait);
1301
1302 pdata = dev_get_platdata(&spi->dev);
1303 if (!pdata) {
1304 pdata = ads7846_probe_dt(&spi->dev);
1305 if (IS_ERR(pdata))
1306 return PTR_ERR(pdata);
1307 }
1308
1309 ts->model = pdata->model ? : 7846;
1310 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1311 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1312 ts->pressure_max = pdata->pressure_max ? : ~0;
1313
1314 ts->vref_mv = pdata->vref_mv;
1315 ts->swap_xy = pdata->swap_xy;
1316
1317 if (pdata->filter != NULL) {
1318 if (pdata->filter_init != NULL) {
1319 err = pdata->filter_init(pdata, &ts->filter_data);
1320 if (err < 0)
1321 goto err_free_mem;
1322 }
1323 ts->filter = pdata->filter;
1324 ts->filter_cleanup = pdata->filter_cleanup;
1325 } else if (pdata->debounce_max) {
1326 ts->debounce_max = pdata->debounce_max;
1327 if (ts->debounce_max < 2)
1328 ts->debounce_max = 2;
1329 ts->debounce_tol = pdata->debounce_tol;
1330 ts->debounce_rep = pdata->debounce_rep;
1331 ts->filter = ads7846_debounce_filter;
1332 ts->filter_data = ts;
1333 } else {
1334 ts->filter = ads7846_no_filter;
1335 }
1336
1337 err = ads7846_setup_pendown(spi, ts, pdata);
1338 if (err)
1339 goto err_cleanup_filter;
1340
1341 if (pdata->penirq_recheck_delay_usecs)
1342 ts->penirq_recheck_delay_usecs =
1343 pdata->penirq_recheck_delay_usecs;
1344
1345 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1346
1347 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1348 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1349
1350 input_dev->name = ts->name;
1351 input_dev->phys = ts->phys;
1352 input_dev->dev.parent = &spi->dev;
1353
1354 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1355 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1356 input_set_abs_params(input_dev, ABS_X,
1357 pdata->x_min ? : 0,
1358 pdata->x_max ? : MAX_12BIT,
1359 0, 0);
1360 input_set_abs_params(input_dev, ABS_Y,
1361 pdata->y_min ? : 0,
1362 pdata->y_max ? : MAX_12BIT,
1363 0, 0);
1364 input_set_abs_params(input_dev, ABS_PRESSURE,
1365 pdata->pressure_min, pdata->pressure_max, 0, 0);
1366
1367 ads7846_setup_spi_msg(ts, pdata);
1368
1369 ts->reg = regulator_get(&spi->dev, "vcc");
1370 if (IS_ERR(ts->reg)) {
1371 err = PTR_ERR(ts->reg);
1372 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1373 goto err_free_gpio;
1374 }
1375
1376 err = regulator_enable(ts->reg);
1377 if (err) {
1378 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1379 goto err_put_regulator;
1380 }
1381
1382 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1383 irq_flags |= IRQF_ONESHOT;
1384
1385 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1386 irq_flags, spi->dev.driver->name, ts);
1387 if (err && !pdata->irq_flags) {
1388 dev_info(&spi->dev,
1389 "trying pin change workaround on irq %d\n", spi->irq);
1390 irq_flags |= IRQF_TRIGGER_RISING;
1391 err = request_threaded_irq(spi->irq,
1392 ads7846_hard_irq, ads7846_irq,
1393 irq_flags, spi->dev.driver->name, ts);
1394 }
1395
1396 if (err) {
1397 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1398 goto err_disable_regulator;
1399 }
1400
1401 err = ads784x_hwmon_register(spi, ts);
1402 if (err)
1403 goto err_free_irq;
1404
1405 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1406
1407 /*
1408 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1409 * the touchscreen, in case it's not connected.
1410 */
1411 if (ts->model == 7845)
1412 ads7845_read12_ser(&spi->dev, PWRDOWN);
1413 else
1414 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1415
1416 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1417 if (err)
1418 goto err_remove_hwmon;
1419
1420 err = input_register_device(input_dev);
1421 if (err)
1422 goto err_remove_attr_group;
1423
1424 device_init_wakeup(&spi->dev, pdata->wakeup);
1425
1426 /*
1427 * If device does not carry platform data we must have allocated it
1428 * when parsing DT data.
1429 */
1430 if (!dev_get_platdata(&spi->dev))
1431 devm_kfree(&spi->dev, (void *)pdata);
1432
1433 return 0;
1434
1435 err_remove_attr_group:
1436 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1437 err_remove_hwmon:
1438 ads784x_hwmon_unregister(spi, ts);
1439 err_free_irq:
1440 free_irq(spi->irq, ts);
1441 err_disable_regulator:
1442 regulator_disable(ts->reg);
1443 err_put_regulator:
1444 regulator_put(ts->reg);
1445 err_free_gpio:
1446 if (!ts->get_pendown_state)
1447 gpio_free(ts->gpio_pendown);
1448 err_cleanup_filter:
1449 if (ts->filter_cleanup)
1450 ts->filter_cleanup(ts->filter_data);
1451 err_free_mem:
1452 input_free_device(input_dev);
1453 kfree(packet);
1454 kfree(ts);
1455 return err;
1456}
1457
1458static int ads7846_remove(struct spi_device *spi)
1459{
1460 struct ads7846 *ts = spi_get_drvdata(spi);
1461
1462 device_init_wakeup(&spi->dev, false);
1463
1464 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1465
1466 ads7846_disable(ts);
1467 free_irq(ts->spi->irq, ts);
1468
1469 input_unregister_device(ts->input);
1470
1471 ads784x_hwmon_unregister(spi, ts);
1472
1473 regulator_disable(ts->reg);
1474 regulator_put(ts->reg);
1475
1476 if (!ts->get_pendown_state) {
1477 /*
1478 * If we are not using specialized pendown method we must
1479 * have been relying on gpio we set up ourselves.
1480 */
1481 gpio_free(ts->gpio_pendown);
1482 }
1483
1484 if (ts->filter_cleanup)
1485 ts->filter_cleanup(ts->filter_data);
1486
1487 kfree(ts->packet);
1488 kfree(ts);
1489
1490 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1491
1492 return 0;
1493}
1494
1495static struct spi_driver ads7846_driver = {
1496 .driver = {
1497 .name = "ads7846",
1498 .owner = THIS_MODULE,
1499 .pm = &ads7846_pm,
1500 .of_match_table = of_match_ptr(ads7846_dt_ids),
1501 },
1502 .probe = ads7846_probe,
1503 .remove = ads7846_remove,
1504};
1505
1506module_spi_driver(ads7846_driver);
1507
1508MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1509MODULE_LICENSE("GPL");
1510MODULE_ALIAS("spi:ads7846");
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 <asm/irq.h>
35
36/*
37 * This code has been heavily tested on a Nokia 770, and lightly
38 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
39 * TSC2046 is just newer ads7846 silicon.
40 * Support for ads7843 tested on Atmel at91sam926x-EK.
41 * Support for ads7845 has only been stubbed in.
42 * Support for Analog Devices AD7873 and AD7843 tested.
43 *
44 * IRQ handling needs a workaround because of a shortcoming in handling
45 * edge triggered IRQs on some platforms like the OMAP1/2. These
46 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
47 * have to maintain our own SW IRQ disabled status. This should be
48 * removed as soon as the affected platform's IRQ handling is fixed.
49 *
50 * App note sbaa036 talks in more detail about accurate sampling...
51 * that ought to help in situations like LCDs inducing noise (which
52 * can also be helped by using synch signals) and more generally.
53 * This driver tries to utilize the measures described in the app
54 * note. The strength of filtering can be set in the board-* specific
55 * files.
56 */
57
58#define TS_POLL_DELAY 1 /* ms delay before the first sample */
59#define TS_POLL_PERIOD 5 /* ms delay between samples */
60
61/* this driver doesn't aim at the peak continuous sample rate */
62#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
63
64struct ts_event {
65 /*
66 * For portability, we can't read 12 bit values using SPI (which
67 * would make the controller deliver them as native byte order u16
68 * with msbs zeroed). Instead, we read them as two 8-bit values,
69 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
70 */
71 u16 x;
72 u16 y;
73 u16 z1, z2;
74 bool ignore;
75 u8 x_buf[3];
76 u8 y_buf[3];
77};
78
79/*
80 * We allocate this separately to avoid cache line sharing issues when
81 * driver is used with DMA-based SPI controllers (like atmel_spi) on
82 * systems where main memory is not DMA-coherent (most non-x86 boards).
83 */
84struct ads7846_packet {
85 u8 read_x, read_y, read_z1, read_z2, pwrdown;
86 u16 dummy; /* for the pwrdown read */
87 struct ts_event tc;
88 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
89 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
90};
91
92struct ads7846 {
93 struct input_dev *input;
94 char phys[32];
95 char name[32];
96
97 struct spi_device *spi;
98 struct regulator *reg;
99
100#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
101 struct attribute_group *attr_group;
102 struct device *hwmon;
103#endif
104
105 u16 model;
106 u16 vref_mv;
107 u16 vref_delay_usecs;
108 u16 x_plate_ohms;
109 u16 pressure_max;
110
111 bool swap_xy;
112 bool use_internal;
113
114 struct ads7846_packet *packet;
115
116 struct spi_transfer xfer[18];
117 struct spi_message msg[5];
118 int msg_count;
119 wait_queue_head_t wait;
120
121 bool pendown;
122
123 int read_cnt;
124 int read_rep;
125 int last_read;
126
127 u16 debounce_max;
128 u16 debounce_tol;
129 u16 debounce_rep;
130
131 u16 penirq_recheck_delay_usecs;
132
133 struct mutex lock;
134 bool stopped; /* P: lock */
135 bool disabled; /* P: lock */
136 bool suspended; /* P: lock */
137
138 int (*filter)(void *data, int data_idx, int *val);
139 void *filter_data;
140 void (*filter_cleanup)(void *data);
141 int (*get_pendown_state)(void);
142 int gpio_pendown;
143
144 void (*wait_for_sync)(void);
145};
146
147/* leave chip selected when we're done, for quicker re-select? */
148#if 0
149#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
150#else
151#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
152#endif
153
154/*--------------------------------------------------------------------------*/
155
156/* The ADS7846 has touchscreen and other sensors.
157 * Earlier ads784x chips are somewhat compatible.
158 */
159#define ADS_START (1 << 7)
160#define ADS_A2A1A0_d_y (1 << 4) /* differential */
161#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
162#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
163#define ADS_A2A1A0_d_x (5 << 4) /* differential */
164#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
165#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
166#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
167#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
168#define ADS_8_BIT (1 << 3)
169#define ADS_12_BIT (0 << 3)
170#define ADS_SER (1 << 2) /* non-differential */
171#define ADS_DFR (0 << 2) /* differential */
172#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
173#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
174#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
175#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
176
177#define MAX_12BIT ((1<<12)-1)
178
179/* leave ADC powered up (disables penirq) between differential samples */
180#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
181 | ADS_12_BIT | ADS_DFR | \
182 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
183
184#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
185#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
186#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
187
188#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
189#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
190
191/* single-ended samples need to first power up reference voltage;
192 * we leave both ADC and VREF powered
193 */
194#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
195 | ADS_12_BIT | ADS_SER)
196
197#define REF_ON (READ_12BIT_DFR(x, 1, 1))
198#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
199
200/* Must be called with ts->lock held */
201static void ads7846_stop(struct ads7846 *ts)
202{
203 if (!ts->disabled && !ts->suspended) {
204 /* Signal IRQ thread to stop polling and disable the handler. */
205 ts->stopped = true;
206 mb();
207 wake_up(&ts->wait);
208 disable_irq(ts->spi->irq);
209 }
210}
211
212/* Must be called with ts->lock held */
213static void ads7846_restart(struct ads7846 *ts)
214{
215 if (!ts->disabled && !ts->suspended) {
216 /* Tell IRQ thread that it may poll the device. */
217 ts->stopped = false;
218 mb();
219 enable_irq(ts->spi->irq);
220 }
221}
222
223/* Must be called with ts->lock held */
224static void __ads7846_disable(struct ads7846 *ts)
225{
226 ads7846_stop(ts);
227 regulator_disable(ts->reg);
228
229 /*
230 * We know the chip's in low power mode since we always
231 * leave it that way after every request
232 */
233}
234
235/* Must be called with ts->lock held */
236static void __ads7846_enable(struct ads7846 *ts)
237{
238 regulator_enable(ts->reg);
239 ads7846_restart(ts);
240}
241
242static void ads7846_disable(struct ads7846 *ts)
243{
244 mutex_lock(&ts->lock);
245
246 if (!ts->disabled) {
247
248 if (!ts->suspended)
249 __ads7846_disable(ts);
250
251 ts->disabled = true;
252 }
253
254 mutex_unlock(&ts->lock);
255}
256
257static void ads7846_enable(struct ads7846 *ts)
258{
259 mutex_lock(&ts->lock);
260
261 if (ts->disabled) {
262
263 ts->disabled = false;
264
265 if (!ts->suspended)
266 __ads7846_enable(ts);
267 }
268
269 mutex_unlock(&ts->lock);
270}
271
272/*--------------------------------------------------------------------------*/
273
274/*
275 * Non-touchscreen sensors only use single-ended conversions.
276 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
277 * ads7846 lets that pin be unconnected, to use internal vREF.
278 */
279
280struct ser_req {
281 u8 ref_on;
282 u8 command;
283 u8 ref_off;
284 u16 scratch;
285 struct spi_message msg;
286 struct spi_transfer xfer[6];
287 /*
288 * DMA (thus cache coherency maintenance) requires the
289 * transfer buffers to live in their own cache lines.
290 */
291 __be16 sample ____cacheline_aligned;
292};
293
294struct ads7845_ser_req {
295 u8 command[3];
296 struct spi_message msg;
297 struct spi_transfer xfer[2];
298 /*
299 * DMA (thus cache coherency maintenance) requires the
300 * transfer buffers to live in their own cache lines.
301 */
302 u8 sample[3] ____cacheline_aligned;
303};
304
305static int ads7846_read12_ser(struct device *dev, unsigned command)
306{
307 struct spi_device *spi = to_spi_device(dev);
308 struct ads7846 *ts = dev_get_drvdata(dev);
309 struct ser_req *req;
310 int status;
311
312 req = kzalloc(sizeof *req, GFP_KERNEL);
313 if (!req)
314 return -ENOMEM;
315
316 spi_message_init(&req->msg);
317
318 /* maybe turn on internal vREF, and let it settle */
319 if (ts->use_internal) {
320 req->ref_on = REF_ON;
321 req->xfer[0].tx_buf = &req->ref_on;
322 req->xfer[0].len = 1;
323 spi_message_add_tail(&req->xfer[0], &req->msg);
324
325 req->xfer[1].rx_buf = &req->scratch;
326 req->xfer[1].len = 2;
327
328 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
329 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
330 spi_message_add_tail(&req->xfer[1], &req->msg);
331
332 /* Enable reference voltage */
333 command |= ADS_PD10_REF_ON;
334 }
335
336 /* Enable ADC in every case */
337 command |= ADS_PD10_ADC_ON;
338
339 /* take sample */
340 req->command = (u8) command;
341 req->xfer[2].tx_buf = &req->command;
342 req->xfer[2].len = 1;
343 spi_message_add_tail(&req->xfer[2], &req->msg);
344
345 req->xfer[3].rx_buf = &req->sample;
346 req->xfer[3].len = 2;
347 spi_message_add_tail(&req->xfer[3], &req->msg);
348
349 /* REVISIT: take a few more samples, and compare ... */
350
351 /* converter in low power mode & enable PENIRQ */
352 req->ref_off = PWRDOWN;
353 req->xfer[4].tx_buf = &req->ref_off;
354 req->xfer[4].len = 1;
355 spi_message_add_tail(&req->xfer[4], &req->msg);
356
357 req->xfer[5].rx_buf = &req->scratch;
358 req->xfer[5].len = 2;
359 CS_CHANGE(req->xfer[5]);
360 spi_message_add_tail(&req->xfer[5], &req->msg);
361
362 mutex_lock(&ts->lock);
363 ads7846_stop(ts);
364 status = spi_sync(spi, &req->msg);
365 ads7846_restart(ts);
366 mutex_unlock(&ts->lock);
367
368 if (status == 0) {
369 /* on-wire is a must-ignore bit, a BE12 value, then padding */
370 status = be16_to_cpu(req->sample);
371 status = status >> 3;
372 status &= 0x0fff;
373 }
374
375 kfree(req);
376 return status;
377}
378
379static int ads7845_read12_ser(struct device *dev, unsigned command)
380{
381 struct spi_device *spi = to_spi_device(dev);
382 struct ads7846 *ts = dev_get_drvdata(dev);
383 struct ads7845_ser_req *req;
384 int status;
385
386 req = kzalloc(sizeof *req, GFP_KERNEL);
387 if (!req)
388 return -ENOMEM;
389
390 spi_message_init(&req->msg);
391
392 req->command[0] = (u8) command;
393 req->xfer[0].tx_buf = req->command;
394 req->xfer[0].rx_buf = req->sample;
395 req->xfer[0].len = 3;
396 spi_message_add_tail(&req->xfer[0], &req->msg);
397
398 mutex_lock(&ts->lock);
399 ads7846_stop(ts);
400 status = spi_sync(spi, &req->msg);
401 ads7846_restart(ts);
402 mutex_unlock(&ts->lock);
403
404 if (status == 0) {
405 /* BE12 value, then padding */
406 status = be16_to_cpu(*((u16 *)&req->sample[1]));
407 status = status >> 3;
408 status &= 0x0fff;
409 }
410
411 kfree(req);
412 return status;
413}
414
415#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
416
417#define SHOW(name, var, adjust) static ssize_t \
418name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
419{ \
420 struct ads7846 *ts = dev_get_drvdata(dev); \
421 ssize_t v = ads7846_read12_ser(dev, \
422 READ_12BIT_SER(var)); \
423 if (v < 0) \
424 return v; \
425 return sprintf(buf, "%u\n", adjust(ts, v)); \
426} \
427static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
428
429
430/* Sysfs conventions report temperatures in millidegrees Celsius.
431 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
432 * accuracy scheme without calibration data. For now we won't try either;
433 * userspace sees raw sensor values, and must scale/calibrate appropriately.
434 */
435static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
436{
437 return v;
438}
439
440SHOW(temp0, temp0, null_adjust) /* temp1_input */
441SHOW(temp1, temp1, null_adjust) /* temp2_input */
442
443
444/* sysfs conventions report voltages in millivolts. We can convert voltages
445 * if we know vREF. userspace may need to scale vAUX to match the board's
446 * external resistors; we assume that vBATT only uses the internal ones.
447 */
448static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
449{
450 unsigned retval = v;
451
452 /* external resistors may scale vAUX into 0..vREF */
453 retval *= ts->vref_mv;
454 retval = retval >> 12;
455
456 return retval;
457}
458
459static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
460{
461 unsigned retval = vaux_adjust(ts, v);
462
463 /* ads7846 has a resistor ladder to scale this signal down */
464 if (ts->model == 7846)
465 retval *= 4;
466
467 return retval;
468}
469
470SHOW(in0_input, vaux, vaux_adjust)
471SHOW(in1_input, vbatt, vbatt_adjust)
472
473static struct attribute *ads7846_attributes[] = {
474 &dev_attr_temp0.attr,
475 &dev_attr_temp1.attr,
476 &dev_attr_in0_input.attr,
477 &dev_attr_in1_input.attr,
478 NULL,
479};
480
481static struct attribute_group ads7846_attr_group = {
482 .attrs = ads7846_attributes,
483};
484
485static struct attribute *ads7843_attributes[] = {
486 &dev_attr_in0_input.attr,
487 &dev_attr_in1_input.attr,
488 NULL,
489};
490
491static struct attribute_group ads7843_attr_group = {
492 .attrs = ads7843_attributes,
493};
494
495static struct attribute *ads7845_attributes[] = {
496 &dev_attr_in0_input.attr,
497 NULL,
498};
499
500static struct attribute_group ads7845_attr_group = {
501 .attrs = ads7845_attributes,
502};
503
504static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
505{
506 struct device *hwmon;
507 int err;
508
509 /* hwmon sensors need a reference voltage */
510 switch (ts->model) {
511 case 7846:
512 if (!ts->vref_mv) {
513 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
514 ts->vref_mv = 2500;
515 ts->use_internal = true;
516 }
517 break;
518 case 7845:
519 case 7843:
520 if (!ts->vref_mv) {
521 dev_warn(&spi->dev,
522 "external vREF for ADS%d not specified\n",
523 ts->model);
524 return 0;
525 }
526 break;
527 }
528
529 /* different chips have different sensor groups */
530 switch (ts->model) {
531 case 7846:
532 ts->attr_group = &ads7846_attr_group;
533 break;
534 case 7845:
535 ts->attr_group = &ads7845_attr_group;
536 break;
537 case 7843:
538 ts->attr_group = &ads7843_attr_group;
539 break;
540 default:
541 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
542 return 0;
543 }
544
545 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
546 if (err)
547 return err;
548
549 hwmon = hwmon_device_register(&spi->dev);
550 if (IS_ERR(hwmon)) {
551 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
552 return PTR_ERR(hwmon);
553 }
554
555 ts->hwmon = hwmon;
556 return 0;
557}
558
559static void ads784x_hwmon_unregister(struct spi_device *spi,
560 struct ads7846 *ts)
561{
562 if (ts->hwmon) {
563 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
564 hwmon_device_unregister(ts->hwmon);
565 }
566}
567
568#else
569static inline int ads784x_hwmon_register(struct spi_device *spi,
570 struct ads7846 *ts)
571{
572 return 0;
573}
574
575static inline void ads784x_hwmon_unregister(struct spi_device *spi,
576 struct ads7846 *ts)
577{
578}
579#endif
580
581static ssize_t ads7846_pen_down_show(struct device *dev,
582 struct device_attribute *attr, char *buf)
583{
584 struct ads7846 *ts = dev_get_drvdata(dev);
585
586 return sprintf(buf, "%u\n", ts->pendown);
587}
588
589static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
590
591static ssize_t ads7846_disable_show(struct device *dev,
592 struct device_attribute *attr, char *buf)
593{
594 struct ads7846 *ts = dev_get_drvdata(dev);
595
596 return sprintf(buf, "%u\n", ts->disabled);
597}
598
599static ssize_t ads7846_disable_store(struct device *dev,
600 struct device_attribute *attr,
601 const char *buf, size_t count)
602{
603 struct ads7846 *ts = dev_get_drvdata(dev);
604 unsigned long i;
605
606 if (strict_strtoul(buf, 10, &i))
607 return -EINVAL;
608
609 if (i)
610 ads7846_disable(ts);
611 else
612 ads7846_enable(ts);
613
614 return count;
615}
616
617static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
618
619static struct attribute *ads784x_attributes[] = {
620 &dev_attr_pen_down.attr,
621 &dev_attr_disable.attr,
622 NULL,
623};
624
625static struct attribute_group ads784x_attr_group = {
626 .attrs = ads784x_attributes,
627};
628
629/*--------------------------------------------------------------------------*/
630
631static int get_pendown_state(struct ads7846 *ts)
632{
633 if (ts->get_pendown_state)
634 return ts->get_pendown_state();
635
636 return !gpio_get_value(ts->gpio_pendown);
637}
638
639static void null_wait_for_sync(void)
640{
641}
642
643static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
644{
645 struct ads7846 *ts = ads;
646
647 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
648 /* Start over collecting consistent readings. */
649 ts->read_rep = 0;
650 /*
651 * Repeat it, if this was the first read or the read
652 * wasn't consistent enough.
653 */
654 if (ts->read_cnt < ts->debounce_max) {
655 ts->last_read = *val;
656 ts->read_cnt++;
657 return ADS7846_FILTER_REPEAT;
658 } else {
659 /*
660 * Maximum number of debouncing reached and still
661 * not enough number of consistent readings. Abort
662 * the whole sample, repeat it in the next sampling
663 * period.
664 */
665 ts->read_cnt = 0;
666 return ADS7846_FILTER_IGNORE;
667 }
668 } else {
669 if (++ts->read_rep > ts->debounce_rep) {
670 /*
671 * Got a good reading for this coordinate,
672 * go for the next one.
673 */
674 ts->read_cnt = 0;
675 ts->read_rep = 0;
676 return ADS7846_FILTER_OK;
677 } else {
678 /* Read more values that are consistent. */
679 ts->read_cnt++;
680 return ADS7846_FILTER_REPEAT;
681 }
682 }
683}
684
685static int ads7846_no_filter(void *ads, int data_idx, int *val)
686{
687 return ADS7846_FILTER_OK;
688}
689
690static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
691{
692 struct spi_transfer *t =
693 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
694
695 if (ts->model == 7845) {
696 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
697 } else {
698 /*
699 * adjust: on-wire is a must-ignore bit, a BE12 value, then
700 * padding; built from two 8 bit values written msb-first.
701 */
702 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
703 }
704}
705
706static void ads7846_update_value(struct spi_message *m, int val)
707{
708 struct spi_transfer *t =
709 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
710
711 *(u16 *)t->rx_buf = val;
712}
713
714static void ads7846_read_state(struct ads7846 *ts)
715{
716 struct ads7846_packet *packet = ts->packet;
717 struct spi_message *m;
718 int msg_idx = 0;
719 int val;
720 int action;
721 int error;
722
723 while (msg_idx < ts->msg_count) {
724
725 ts->wait_for_sync();
726
727 m = &ts->msg[msg_idx];
728 error = spi_sync(ts->spi, m);
729 if (error) {
730 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
731 packet->tc.ignore = true;
732 return;
733 }
734
735 /*
736 * Last message is power down request, no need to convert
737 * or filter the value.
738 */
739 if (msg_idx < ts->msg_count - 1) {
740
741 val = ads7846_get_value(ts, m);
742
743 action = ts->filter(ts->filter_data, msg_idx, &val);
744 switch (action) {
745 case ADS7846_FILTER_REPEAT:
746 continue;
747
748 case ADS7846_FILTER_IGNORE:
749 packet->tc.ignore = true;
750 msg_idx = ts->msg_count - 1;
751 continue;
752
753 case ADS7846_FILTER_OK:
754 ads7846_update_value(m, val);
755 packet->tc.ignore = false;
756 msg_idx++;
757 break;
758
759 default:
760 BUG();
761 }
762 } else {
763 msg_idx++;
764 }
765 }
766}
767
768static void ads7846_report_state(struct ads7846 *ts)
769{
770 struct ads7846_packet *packet = ts->packet;
771 unsigned int Rt;
772 u16 x, y, z1, z2;
773
774 /*
775 * ads7846_get_value() does in-place conversion (including byte swap)
776 * from on-the-wire format as part of debouncing to get stable
777 * readings.
778 */
779 if (ts->model == 7845) {
780 x = *(u16 *)packet->tc.x_buf;
781 y = *(u16 *)packet->tc.y_buf;
782 z1 = 0;
783 z2 = 0;
784 } else {
785 x = packet->tc.x;
786 y = packet->tc.y;
787 z1 = packet->tc.z1;
788 z2 = packet->tc.z2;
789 }
790
791 /* range filtering */
792 if (x == MAX_12BIT)
793 x = 0;
794
795 if (ts->model == 7843) {
796 Rt = ts->pressure_max / 2;
797 } else if (ts->model == 7845) {
798 if (get_pendown_state(ts))
799 Rt = ts->pressure_max / 2;
800 else
801 Rt = 0;
802 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
803 } else if (likely(x && z1)) {
804 /* compute touch pressure resistance using equation #2 */
805 Rt = z2;
806 Rt -= z1;
807 Rt *= x;
808 Rt *= ts->x_plate_ohms;
809 Rt /= z1;
810 Rt = (Rt + 2047) >> 12;
811 } else {
812 Rt = 0;
813 }
814
815 /*
816 * Sample found inconsistent by debouncing or pressure is beyond
817 * the maximum. Don't report it to user space, repeat at least
818 * once more the measurement
819 */
820 if (packet->tc.ignore || Rt > ts->pressure_max) {
821 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
822 packet->tc.ignore, Rt);
823 return;
824 }
825
826 /*
827 * Maybe check the pendown state before reporting. This discards
828 * false readings when the pen is lifted.
829 */
830 if (ts->penirq_recheck_delay_usecs) {
831 udelay(ts->penirq_recheck_delay_usecs);
832 if (!get_pendown_state(ts))
833 Rt = 0;
834 }
835
836 /*
837 * NOTE: We can't rely on the pressure to determine the pen down
838 * state, even this controller has a pressure sensor. The pressure
839 * value can fluctuate for quite a while after lifting the pen and
840 * in some cases may not even settle at the expected value.
841 *
842 * The only safe way to check for the pen up condition is in the
843 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
844 */
845 if (Rt) {
846 struct input_dev *input = ts->input;
847
848 if (ts->swap_xy)
849 swap(x, y);
850
851 if (!ts->pendown) {
852 input_report_key(input, BTN_TOUCH, 1);
853 ts->pendown = true;
854 dev_vdbg(&ts->spi->dev, "DOWN\n");
855 }
856
857 input_report_abs(input, ABS_X, x);
858 input_report_abs(input, ABS_Y, y);
859 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
860
861 input_sync(input);
862 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
863 }
864}
865
866static irqreturn_t ads7846_hard_irq(int irq, void *handle)
867{
868 struct ads7846 *ts = handle;
869
870 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
871}
872
873
874static irqreturn_t ads7846_irq(int irq, void *handle)
875{
876 struct ads7846 *ts = handle;
877
878 /* Start with a small delay before checking pendown state */
879 msleep(TS_POLL_DELAY);
880
881 while (!ts->stopped && get_pendown_state(ts)) {
882
883 /* pen is down, continue with the measurement */
884 ads7846_read_state(ts);
885
886 if (!ts->stopped)
887 ads7846_report_state(ts);
888
889 wait_event_timeout(ts->wait, ts->stopped,
890 msecs_to_jiffies(TS_POLL_PERIOD));
891 }
892
893 if (ts->pendown) {
894 struct input_dev *input = ts->input;
895
896 input_report_key(input, BTN_TOUCH, 0);
897 input_report_abs(input, ABS_PRESSURE, 0);
898 input_sync(input);
899
900 ts->pendown = false;
901 dev_vdbg(&ts->spi->dev, "UP\n");
902 }
903
904 return IRQ_HANDLED;
905}
906
907#ifdef CONFIG_PM_SLEEP
908static int ads7846_suspend(struct device *dev)
909{
910 struct ads7846 *ts = dev_get_drvdata(dev);
911
912 mutex_lock(&ts->lock);
913
914 if (!ts->suspended) {
915
916 if (!ts->disabled)
917 __ads7846_disable(ts);
918
919 if (device_may_wakeup(&ts->spi->dev))
920 enable_irq_wake(ts->spi->irq);
921
922 ts->suspended = true;
923 }
924
925 mutex_unlock(&ts->lock);
926
927 return 0;
928}
929
930static int ads7846_resume(struct device *dev)
931{
932 struct ads7846 *ts = dev_get_drvdata(dev);
933
934 mutex_lock(&ts->lock);
935
936 if (ts->suspended) {
937
938 ts->suspended = false;
939
940 if (device_may_wakeup(&ts->spi->dev))
941 disable_irq_wake(ts->spi->irq);
942
943 if (!ts->disabled)
944 __ads7846_enable(ts);
945 }
946
947 mutex_unlock(&ts->lock);
948
949 return 0;
950}
951#endif
952
953static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
954
955static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
956{
957 struct ads7846_platform_data *pdata = spi->dev.platform_data;
958 int err;
959
960 /*
961 * REVISIT when the irq can be triggered active-low, or if for some
962 * reason the touchscreen isn't hooked up, we don't need to access
963 * the pendown state.
964 */
965
966 if (pdata->get_pendown_state) {
967 ts->get_pendown_state = pdata->get_pendown_state;
968 } else if (gpio_is_valid(pdata->gpio_pendown)) {
969
970 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
971 "ads7846_pendown");
972 if (err) {
973 dev_err(&spi->dev,
974 "failed to request/setup pendown GPIO%d: %d\n",
975 pdata->gpio_pendown, err);
976 return err;
977 }
978
979 ts->gpio_pendown = pdata->gpio_pendown;
980
981 } else {
982 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
983 return -EINVAL;
984 }
985
986 return 0;
987}
988
989/*
990 * Set up the transfers to read touchscreen state; this assumes we
991 * use formula #2 for pressure, not #3.
992 */
993static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
994 const struct ads7846_platform_data *pdata)
995{
996 struct spi_message *m = &ts->msg[0];
997 struct spi_transfer *x = ts->xfer;
998 struct ads7846_packet *packet = ts->packet;
999 int vref = pdata->keep_vref_on;
1000
1001 if (ts->model == 7873) {
1002 /*
1003 * The AD7873 is almost identical to the ADS7846
1004 * keep VREF off during differential/ratiometric
1005 * conversion modes.
1006 */
1007 ts->model = 7846;
1008 vref = 0;
1009 }
1010
1011 ts->msg_count = 1;
1012 spi_message_init(m);
1013 m->context = ts;
1014
1015 if (ts->model == 7845) {
1016 packet->read_y_cmd[0] = READ_Y(vref);
1017 packet->read_y_cmd[1] = 0;
1018 packet->read_y_cmd[2] = 0;
1019 x->tx_buf = &packet->read_y_cmd[0];
1020 x->rx_buf = &packet->tc.y_buf[0];
1021 x->len = 3;
1022 spi_message_add_tail(x, m);
1023 } else {
1024 /* y- still on; turn on only y+ (and ADC) */
1025 packet->read_y = READ_Y(vref);
1026 x->tx_buf = &packet->read_y;
1027 x->len = 1;
1028 spi_message_add_tail(x, m);
1029
1030 x++;
1031 x->rx_buf = &packet->tc.y;
1032 x->len = 2;
1033 spi_message_add_tail(x, m);
1034 }
1035
1036 /*
1037 * The first sample after switching drivers can be low quality;
1038 * optionally discard it, using a second one after the signals
1039 * have had enough time to stabilize.
1040 */
1041 if (pdata->settle_delay_usecs) {
1042 x->delay_usecs = pdata->settle_delay_usecs;
1043
1044 x++;
1045 x->tx_buf = &packet->read_y;
1046 x->len = 1;
1047 spi_message_add_tail(x, m);
1048
1049 x++;
1050 x->rx_buf = &packet->tc.y;
1051 x->len = 2;
1052 spi_message_add_tail(x, m);
1053 }
1054
1055 ts->msg_count++;
1056 m++;
1057 spi_message_init(m);
1058 m->context = ts;
1059
1060 if (ts->model == 7845) {
1061 x++;
1062 packet->read_x_cmd[0] = READ_X(vref);
1063 packet->read_x_cmd[1] = 0;
1064 packet->read_x_cmd[2] = 0;
1065 x->tx_buf = &packet->read_x_cmd[0];
1066 x->rx_buf = &packet->tc.x_buf[0];
1067 x->len = 3;
1068 spi_message_add_tail(x, m);
1069 } else {
1070 /* turn y- off, x+ on, then leave in lowpower */
1071 x++;
1072 packet->read_x = READ_X(vref);
1073 x->tx_buf = &packet->read_x;
1074 x->len = 1;
1075 spi_message_add_tail(x, m);
1076
1077 x++;
1078 x->rx_buf = &packet->tc.x;
1079 x->len = 2;
1080 spi_message_add_tail(x, m);
1081 }
1082
1083 /* ... maybe discard first sample ... */
1084 if (pdata->settle_delay_usecs) {
1085 x->delay_usecs = pdata->settle_delay_usecs;
1086
1087 x++;
1088 x->tx_buf = &packet->read_x;
1089 x->len = 1;
1090 spi_message_add_tail(x, m);
1091
1092 x++;
1093 x->rx_buf = &packet->tc.x;
1094 x->len = 2;
1095 spi_message_add_tail(x, m);
1096 }
1097
1098 /* turn y+ off, x- on; we'll use formula #2 */
1099 if (ts->model == 7846) {
1100 ts->msg_count++;
1101 m++;
1102 spi_message_init(m);
1103 m->context = ts;
1104
1105 x++;
1106 packet->read_z1 = READ_Z1(vref);
1107 x->tx_buf = &packet->read_z1;
1108 x->len = 1;
1109 spi_message_add_tail(x, m);
1110
1111 x++;
1112 x->rx_buf = &packet->tc.z1;
1113 x->len = 2;
1114 spi_message_add_tail(x, m);
1115
1116 /* ... maybe discard first sample ... */
1117 if (pdata->settle_delay_usecs) {
1118 x->delay_usecs = pdata->settle_delay_usecs;
1119
1120 x++;
1121 x->tx_buf = &packet->read_z1;
1122 x->len = 1;
1123 spi_message_add_tail(x, m);
1124
1125 x++;
1126 x->rx_buf = &packet->tc.z1;
1127 x->len = 2;
1128 spi_message_add_tail(x, m);
1129 }
1130
1131 ts->msg_count++;
1132 m++;
1133 spi_message_init(m);
1134 m->context = ts;
1135
1136 x++;
1137 packet->read_z2 = READ_Z2(vref);
1138 x->tx_buf = &packet->read_z2;
1139 x->len = 1;
1140 spi_message_add_tail(x, m);
1141
1142 x++;
1143 x->rx_buf = &packet->tc.z2;
1144 x->len = 2;
1145 spi_message_add_tail(x, m);
1146
1147 /* ... maybe discard first sample ... */
1148 if (pdata->settle_delay_usecs) {
1149 x->delay_usecs = pdata->settle_delay_usecs;
1150
1151 x++;
1152 x->tx_buf = &packet->read_z2;
1153 x->len = 1;
1154 spi_message_add_tail(x, m);
1155
1156 x++;
1157 x->rx_buf = &packet->tc.z2;
1158 x->len = 2;
1159 spi_message_add_tail(x, m);
1160 }
1161 }
1162
1163 /* power down */
1164 ts->msg_count++;
1165 m++;
1166 spi_message_init(m);
1167 m->context = ts;
1168
1169 if (ts->model == 7845) {
1170 x++;
1171 packet->pwrdown_cmd[0] = PWRDOWN;
1172 packet->pwrdown_cmd[1] = 0;
1173 packet->pwrdown_cmd[2] = 0;
1174 x->tx_buf = &packet->pwrdown_cmd[0];
1175 x->len = 3;
1176 } else {
1177 x++;
1178 packet->pwrdown = PWRDOWN;
1179 x->tx_buf = &packet->pwrdown;
1180 x->len = 1;
1181 spi_message_add_tail(x, m);
1182
1183 x++;
1184 x->rx_buf = &packet->dummy;
1185 x->len = 2;
1186 }
1187
1188 CS_CHANGE(*x);
1189 spi_message_add_tail(x, m);
1190}
1191
1192static int __devinit ads7846_probe(struct spi_device *spi)
1193{
1194 struct ads7846 *ts;
1195 struct ads7846_packet *packet;
1196 struct input_dev *input_dev;
1197 struct ads7846_platform_data *pdata = spi->dev.platform_data;
1198 unsigned long irq_flags;
1199 int err;
1200
1201 if (!spi->irq) {
1202 dev_dbg(&spi->dev, "no IRQ?\n");
1203 return -ENODEV;
1204 }
1205
1206 if (!pdata) {
1207 dev_dbg(&spi->dev, "no platform data?\n");
1208 return -ENODEV;
1209 }
1210
1211 /* don't exceed max specified sample rate */
1212 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1213 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1214 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1215 return -EINVAL;
1216 }
1217
1218 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1219 * that even if the hardware can do that, the SPI controller driver
1220 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1221 */
1222 spi->bits_per_word = 8;
1223 spi->mode = SPI_MODE_0;
1224 err = spi_setup(spi);
1225 if (err < 0)
1226 return err;
1227
1228 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1229 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1230 input_dev = input_allocate_device();
1231 if (!ts || !packet || !input_dev) {
1232 err = -ENOMEM;
1233 goto err_free_mem;
1234 }
1235
1236 dev_set_drvdata(&spi->dev, ts);
1237
1238 ts->packet = packet;
1239 ts->spi = spi;
1240 ts->input = input_dev;
1241 ts->vref_mv = pdata->vref_mv;
1242 ts->swap_xy = pdata->swap_xy;
1243
1244 mutex_init(&ts->lock);
1245 init_waitqueue_head(&ts->wait);
1246
1247 ts->model = pdata->model ? : 7846;
1248 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1249 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1250 ts->pressure_max = pdata->pressure_max ? : ~0;
1251
1252 if (pdata->filter != NULL) {
1253 if (pdata->filter_init != NULL) {
1254 err = pdata->filter_init(pdata, &ts->filter_data);
1255 if (err < 0)
1256 goto err_free_mem;
1257 }
1258 ts->filter = pdata->filter;
1259 ts->filter_cleanup = pdata->filter_cleanup;
1260 } else if (pdata->debounce_max) {
1261 ts->debounce_max = pdata->debounce_max;
1262 if (ts->debounce_max < 2)
1263 ts->debounce_max = 2;
1264 ts->debounce_tol = pdata->debounce_tol;
1265 ts->debounce_rep = pdata->debounce_rep;
1266 ts->filter = ads7846_debounce_filter;
1267 ts->filter_data = ts;
1268 } else {
1269 ts->filter = ads7846_no_filter;
1270 }
1271
1272 err = ads7846_setup_pendown(spi, ts);
1273 if (err)
1274 goto err_cleanup_filter;
1275
1276 if (pdata->penirq_recheck_delay_usecs)
1277 ts->penirq_recheck_delay_usecs =
1278 pdata->penirq_recheck_delay_usecs;
1279
1280 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1281
1282 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1283 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1284
1285 input_dev->name = ts->name;
1286 input_dev->phys = ts->phys;
1287 input_dev->dev.parent = &spi->dev;
1288
1289 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1290 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1291 input_set_abs_params(input_dev, ABS_X,
1292 pdata->x_min ? : 0,
1293 pdata->x_max ? : MAX_12BIT,
1294 0, 0);
1295 input_set_abs_params(input_dev, ABS_Y,
1296 pdata->y_min ? : 0,
1297 pdata->y_max ? : MAX_12BIT,
1298 0, 0);
1299 input_set_abs_params(input_dev, ABS_PRESSURE,
1300 pdata->pressure_min, pdata->pressure_max, 0, 0);
1301
1302 ads7846_setup_spi_msg(ts, pdata);
1303
1304 ts->reg = regulator_get(&spi->dev, "vcc");
1305 if (IS_ERR(ts->reg)) {
1306 err = PTR_ERR(ts->reg);
1307 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1308 goto err_free_gpio;
1309 }
1310
1311 err = regulator_enable(ts->reg);
1312 if (err) {
1313 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1314 goto err_put_regulator;
1315 }
1316
1317 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1318 irq_flags |= IRQF_ONESHOT;
1319
1320 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1321 irq_flags, spi->dev.driver->name, ts);
1322 if (err && !pdata->irq_flags) {
1323 dev_info(&spi->dev,
1324 "trying pin change workaround on irq %d\n", spi->irq);
1325 irq_flags |= IRQF_TRIGGER_RISING;
1326 err = request_threaded_irq(spi->irq,
1327 ads7846_hard_irq, ads7846_irq,
1328 irq_flags, spi->dev.driver->name, ts);
1329 }
1330
1331 if (err) {
1332 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1333 goto err_disable_regulator;
1334 }
1335
1336 err = ads784x_hwmon_register(spi, ts);
1337 if (err)
1338 goto err_free_irq;
1339
1340 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1341
1342 /*
1343 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1344 * the touchscreen, in case it's not connected.
1345 */
1346 if (ts->model == 7845)
1347 ads7845_read12_ser(&spi->dev, PWRDOWN);
1348 else
1349 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1350
1351 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1352 if (err)
1353 goto err_remove_hwmon;
1354
1355 err = input_register_device(input_dev);
1356 if (err)
1357 goto err_remove_attr_group;
1358
1359 device_init_wakeup(&spi->dev, pdata->wakeup);
1360
1361 return 0;
1362
1363 err_remove_attr_group:
1364 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1365 err_remove_hwmon:
1366 ads784x_hwmon_unregister(spi, ts);
1367 err_free_irq:
1368 free_irq(spi->irq, ts);
1369 err_disable_regulator:
1370 regulator_disable(ts->reg);
1371 err_put_regulator:
1372 regulator_put(ts->reg);
1373 err_free_gpio:
1374 if (!ts->get_pendown_state)
1375 gpio_free(ts->gpio_pendown);
1376 err_cleanup_filter:
1377 if (ts->filter_cleanup)
1378 ts->filter_cleanup(ts->filter_data);
1379 err_free_mem:
1380 input_free_device(input_dev);
1381 kfree(packet);
1382 kfree(ts);
1383 return err;
1384}
1385
1386static int __devexit ads7846_remove(struct spi_device *spi)
1387{
1388 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1389
1390 device_init_wakeup(&spi->dev, false);
1391
1392 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1393
1394 ads7846_disable(ts);
1395 free_irq(ts->spi->irq, ts);
1396
1397 input_unregister_device(ts->input);
1398
1399 ads784x_hwmon_unregister(spi, ts);
1400
1401 regulator_disable(ts->reg);
1402 regulator_put(ts->reg);
1403
1404 if (!ts->get_pendown_state) {
1405 /*
1406 * If we are not using specialized pendown method we must
1407 * have been relying on gpio we set up ourselves.
1408 */
1409 gpio_free(ts->gpio_pendown);
1410 }
1411
1412 if (ts->filter_cleanup)
1413 ts->filter_cleanup(ts->filter_data);
1414
1415 kfree(ts->packet);
1416 kfree(ts);
1417
1418 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1419
1420 return 0;
1421}
1422
1423static struct spi_driver ads7846_driver = {
1424 .driver = {
1425 .name = "ads7846",
1426 .bus = &spi_bus_type,
1427 .owner = THIS_MODULE,
1428 .pm = &ads7846_pm,
1429 },
1430 .probe = ads7846_probe,
1431 .remove = __devexit_p(ads7846_remove),
1432};
1433
1434static int __init ads7846_init(void)
1435{
1436 return spi_register_driver(&ads7846_driver);
1437}
1438module_init(ads7846_init);
1439
1440static void __exit ads7846_exit(void)
1441{
1442 spi_unregister_driver(&ads7846_driver);
1443}
1444module_exit(ads7846_exit);
1445
1446MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1447MODULE_LICENSE("GPL");
1448MODULE_ALIAS("spi:ads7846");