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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/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");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ADS7846 based touchscreen and sensor driver
4 *
5 * Copyright (c) 2005 David Brownell
6 * Copyright (c) 2006 Nokia Corporation
7 * Various changes: Imre Deak <imre.deak@nokia.com>
8 *
9 * Using code from:
10 * - corgi_ts.c
11 * Copyright (C) 2004-2005 Richard Purdie
12 * - omap_ts.[hc], ads7846.h, ts_osk.c
13 * Copyright (C) 2002 MontaVista Software
14 * Copyright (C) 2004 Texas Instruments
15 * Copyright (C) 2005 Dirk Behme
16 */
17#include <linux/types.h>
18#include <linux/hwmon.h>
19#include <linux/err.h>
20#include <linux/sched.h>
21#include <linux/delay.h>
22#include <linux/input.h>
23#include <linux/input/touchscreen.h>
24#include <linux/interrupt.h>
25#include <linux/slab.h>
26#include <linux/pm.h>
27#include <linux/property.h>
28#include <linux/gpio/consumer.h>
29#include <linux/spi/spi.h>
30#include <linux/spi/ads7846.h>
31#include <linux/regulator/consumer.h>
32#include <linux/module.h>
33#include <asm/unaligned.h>
34
35/*
36 * This code has been heavily tested on a Nokia 770, and lightly
37 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
38 * TSC2046 is just newer ads7846 silicon.
39 * Support for ads7843 tested on Atmel at91sam926x-EK.
40 * Support for ads7845 has only been stubbed in.
41 * Support for Analog Devices AD7873 and AD7843 tested.
42 *
43 * IRQ handling needs a workaround because of a shortcoming in handling
44 * edge triggered IRQs on some platforms like the OMAP1/2. These
45 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
46 * have to maintain our own SW IRQ disabled status. This should be
47 * removed as soon as the affected platform's IRQ handling is fixed.
48 *
49 * App note sbaa036 talks in more detail about accurate sampling...
50 * that ought to help in situations like LCDs inducing noise (which
51 * can also be helped by using synch signals) and more generally.
52 * This driver tries to utilize the measures described in the app
53 * note. The strength of filtering can be set in the board-* specific
54 * files.
55 */
56
57#define TS_POLL_DELAY 1 /* ms delay before the first sample */
58#define TS_POLL_PERIOD 5 /* ms delay between samples */
59
60/* this driver doesn't aim at the peak continuous sample rate */
61#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
62
63struct ads7846_buf {
64 u8 cmd;
65 __be16 data;
66} __packed;
67
68struct ads7846_buf_layout {
69 unsigned int offset;
70 unsigned int count;
71 unsigned int skip;
72};
73
74/*
75 * We allocate this separately to avoid cache line sharing issues when
76 * driver is used with DMA-based SPI controllers (like atmel_spi) on
77 * systems where main memory is not DMA-coherent (most non-x86 boards).
78 */
79struct ads7846_packet {
80 unsigned int count;
81 unsigned int count_skip;
82 unsigned int cmds;
83 unsigned int last_cmd_idx;
84 struct ads7846_buf_layout l[5];
85 struct ads7846_buf *rx;
86 struct ads7846_buf *tx;
87
88 struct ads7846_buf pwrdown_cmd;
89
90 bool ignore;
91 u16 x, y, z1, z2;
92};
93
94struct ads7846 {
95 struct input_dev *input;
96 char phys[32];
97 char name[32];
98
99 struct spi_device *spi;
100 struct regulator *reg;
101
102 u16 model;
103 u16 vref_mv;
104 u16 vref_delay_usecs;
105 u16 x_plate_ohms;
106 u16 pressure_max;
107
108 bool swap_xy;
109 bool use_internal;
110
111 struct ads7846_packet *packet;
112
113 struct spi_transfer xfer[18];
114 struct spi_message msg[5];
115 int msg_count;
116 wait_queue_head_t wait;
117
118 bool pendown;
119
120 int read_cnt;
121 int read_rep;
122 int last_read;
123
124 u16 debounce_max;
125 u16 debounce_tol;
126 u16 debounce_rep;
127
128 u16 penirq_recheck_delay_usecs;
129
130 struct touchscreen_properties core_prop;
131
132 struct mutex lock;
133 bool stopped; /* P: lock */
134 bool disabled; /* P: lock */
135 bool suspended; /* P: lock */
136
137 int (*filter)(void *data, int data_idx, int *val);
138 void *filter_data;
139 int (*get_pendown_state)(void);
140 struct gpio_desc *gpio_pendown;
141
142 void (*wait_for_sync)(void);
143};
144
145enum ads7846_filter {
146 ADS7846_FILTER_OK,
147 ADS7846_FILTER_REPEAT,
148 ADS7846_FILTER_IGNORE,
149};
150
151/* leave chip selected when we're done, for quicker re-select? */
152#if 0
153#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
154#else
155#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
156#endif
157
158/*--------------------------------------------------------------------------*/
159
160/* The ADS7846 has touchscreen and other sensors.
161 * Earlier ads784x chips are somewhat compatible.
162 */
163#define ADS_START (1 << 7)
164#define ADS_A2A1A0_d_y (1 << 4) /* differential */
165#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
166#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
167#define ADS_A2A1A0_d_x (5 << 4) /* differential */
168#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
169#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
170#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
171#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
172#define ADS_8_BIT (1 << 3)
173#define ADS_12_BIT (0 << 3)
174#define ADS_SER (1 << 2) /* non-differential */
175#define ADS_DFR (0 << 2) /* differential */
176#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
177#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
178#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
179#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
180
181#define MAX_12BIT ((1<<12)-1)
182
183/* leave ADC powered up (disables penirq) between differential samples */
184#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
185 | ADS_12_BIT | ADS_DFR | \
186 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
187
188#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
189#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
190#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
191#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
192#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
193
194/* single-ended samples need to first power up reference voltage;
195 * we leave both ADC and VREF powered
196 */
197#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
198 | ADS_12_BIT | ADS_SER)
199
200#define REF_ON (READ_12BIT_DFR(x, 1, 1))
201#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
202
203/* Order commands in the most optimal way to reduce Vref switching and
204 * settling time:
205 * Measure: X; Vref: X+, X-; IN: Y+
206 * Measure: Y; Vref: Y+, Y-; IN: X+
207 * Measure: Z1; Vref: Y+, X-; IN: X+
208 * Measure: Z2; Vref: Y+, X-; IN: Y-
209 */
210enum ads7846_cmds {
211 ADS7846_X,
212 ADS7846_Y,
213 ADS7846_Z1,
214 ADS7846_Z2,
215 ADS7846_PWDOWN,
216};
217
218static int get_pendown_state(struct ads7846 *ts)
219{
220 if (ts->get_pendown_state)
221 return ts->get_pendown_state();
222
223 return gpiod_get_value(ts->gpio_pendown);
224}
225
226static void ads7846_report_pen_up(struct ads7846 *ts)
227{
228 struct input_dev *input = ts->input;
229
230 input_report_key(input, BTN_TOUCH, 0);
231 input_report_abs(input, ABS_PRESSURE, 0);
232 input_sync(input);
233
234 ts->pendown = false;
235 dev_vdbg(&ts->spi->dev, "UP\n");
236}
237
238/* Must be called with ts->lock held */
239static void ads7846_stop(struct ads7846 *ts)
240{
241 if (!ts->disabled && !ts->suspended) {
242 /* Signal IRQ thread to stop polling and disable the handler. */
243 ts->stopped = true;
244 mb();
245 wake_up(&ts->wait);
246 disable_irq(ts->spi->irq);
247 }
248}
249
250/* Must be called with ts->lock held */
251static void ads7846_restart(struct ads7846 *ts)
252{
253 if (!ts->disabled && !ts->suspended) {
254 /* Check if pen was released since last stop */
255 if (ts->pendown && !get_pendown_state(ts))
256 ads7846_report_pen_up(ts);
257
258 /* Tell IRQ thread that it may poll the device. */
259 ts->stopped = false;
260 mb();
261 enable_irq(ts->spi->irq);
262 }
263}
264
265/* Must be called with ts->lock held */
266static void __ads7846_disable(struct ads7846 *ts)
267{
268 ads7846_stop(ts);
269 regulator_disable(ts->reg);
270
271 /*
272 * We know the chip's in low power mode since we always
273 * leave it that way after every request
274 */
275}
276
277/* Must be called with ts->lock held */
278static void __ads7846_enable(struct ads7846 *ts)
279{
280 int error;
281
282 error = regulator_enable(ts->reg);
283 if (error != 0)
284 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
285
286 ads7846_restart(ts);
287}
288
289static void ads7846_disable(struct ads7846 *ts)
290{
291 mutex_lock(&ts->lock);
292
293 if (!ts->disabled) {
294
295 if (!ts->suspended)
296 __ads7846_disable(ts);
297
298 ts->disabled = true;
299 }
300
301 mutex_unlock(&ts->lock);
302}
303
304static void ads7846_enable(struct ads7846 *ts)
305{
306 mutex_lock(&ts->lock);
307
308 if (ts->disabled) {
309
310 ts->disabled = false;
311
312 if (!ts->suspended)
313 __ads7846_enable(ts);
314 }
315
316 mutex_unlock(&ts->lock);
317}
318
319/*--------------------------------------------------------------------------*/
320
321/*
322 * Non-touchscreen sensors only use single-ended conversions.
323 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
324 * ads7846 lets that pin be unconnected, to use internal vREF.
325 */
326
327struct ser_req {
328 u8 ref_on;
329 u8 command;
330 u8 ref_off;
331 u16 scratch;
332 struct spi_message msg;
333 struct spi_transfer xfer[6];
334 /*
335 * DMA (thus cache coherency maintenance) requires the
336 * transfer buffers to live in their own cache lines.
337 */
338 __be16 sample ____cacheline_aligned;
339};
340
341struct ads7845_ser_req {
342 u8 command[3];
343 struct spi_message msg;
344 struct spi_transfer xfer[2];
345 /*
346 * DMA (thus cache coherency maintenance) requires the
347 * transfer buffers to live in their own cache lines.
348 */
349 u8 sample[3] ____cacheline_aligned;
350};
351
352static int ads7846_read12_ser(struct device *dev, unsigned command)
353{
354 struct spi_device *spi = to_spi_device(dev);
355 struct ads7846 *ts = dev_get_drvdata(dev);
356 struct ser_req *req;
357 int status;
358
359 req = kzalloc(sizeof *req, GFP_KERNEL);
360 if (!req)
361 return -ENOMEM;
362
363 spi_message_init(&req->msg);
364
365 /* maybe turn on internal vREF, and let it settle */
366 if (ts->use_internal) {
367 req->ref_on = REF_ON;
368 req->xfer[0].tx_buf = &req->ref_on;
369 req->xfer[0].len = 1;
370 spi_message_add_tail(&req->xfer[0], &req->msg);
371
372 req->xfer[1].rx_buf = &req->scratch;
373 req->xfer[1].len = 2;
374
375 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
376 req->xfer[1].delay.value = ts->vref_delay_usecs;
377 req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
378 spi_message_add_tail(&req->xfer[1], &req->msg);
379
380 /* Enable reference voltage */
381 command |= ADS_PD10_REF_ON;
382 }
383
384 /* Enable ADC in every case */
385 command |= ADS_PD10_ADC_ON;
386
387 /* take sample */
388 req->command = (u8) command;
389 req->xfer[2].tx_buf = &req->command;
390 req->xfer[2].len = 1;
391 spi_message_add_tail(&req->xfer[2], &req->msg);
392
393 req->xfer[3].rx_buf = &req->sample;
394 req->xfer[3].len = 2;
395 spi_message_add_tail(&req->xfer[3], &req->msg);
396
397 /* REVISIT: take a few more samples, and compare ... */
398
399 /* converter in low power mode & enable PENIRQ */
400 req->ref_off = PWRDOWN;
401 req->xfer[4].tx_buf = &req->ref_off;
402 req->xfer[4].len = 1;
403 spi_message_add_tail(&req->xfer[4], &req->msg);
404
405 req->xfer[5].rx_buf = &req->scratch;
406 req->xfer[5].len = 2;
407 CS_CHANGE(req->xfer[5]);
408 spi_message_add_tail(&req->xfer[5], &req->msg);
409
410 mutex_lock(&ts->lock);
411 ads7846_stop(ts);
412 status = spi_sync(spi, &req->msg);
413 ads7846_restart(ts);
414 mutex_unlock(&ts->lock);
415
416 if (status == 0) {
417 /* on-wire is a must-ignore bit, a BE12 value, then padding */
418 status = be16_to_cpu(req->sample);
419 status = status >> 3;
420 status &= 0x0fff;
421 }
422
423 kfree(req);
424 return status;
425}
426
427static int ads7845_read12_ser(struct device *dev, unsigned command)
428{
429 struct spi_device *spi = to_spi_device(dev);
430 struct ads7846 *ts = dev_get_drvdata(dev);
431 struct ads7845_ser_req *req;
432 int status;
433
434 req = kzalloc(sizeof *req, GFP_KERNEL);
435 if (!req)
436 return -ENOMEM;
437
438 spi_message_init(&req->msg);
439
440 req->command[0] = (u8) command;
441 req->xfer[0].tx_buf = req->command;
442 req->xfer[0].rx_buf = req->sample;
443 req->xfer[0].len = 3;
444 spi_message_add_tail(&req->xfer[0], &req->msg);
445
446 mutex_lock(&ts->lock);
447 ads7846_stop(ts);
448 status = spi_sync(spi, &req->msg);
449 ads7846_restart(ts);
450 mutex_unlock(&ts->lock);
451
452 if (status == 0) {
453 /* BE12 value, then padding */
454 status = get_unaligned_be16(&req->sample[1]);
455 status = status >> 3;
456 status &= 0x0fff;
457 }
458
459 kfree(req);
460 return status;
461}
462
463#if IS_ENABLED(CONFIG_HWMON)
464
465#define SHOW(name, var, adjust) static ssize_t \
466name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
467{ \
468 struct ads7846 *ts = dev_get_drvdata(dev); \
469 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
470 READ_12BIT_SER(var)); \
471 if (v < 0) \
472 return v; \
473 return sprintf(buf, "%u\n", adjust(ts, v)); \
474} \
475static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
476
477
478/* Sysfs conventions report temperatures in millidegrees Celsius.
479 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
480 * accuracy scheme without calibration data. For now we won't try either;
481 * userspace sees raw sensor values, and must scale/calibrate appropriately.
482 */
483static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
484{
485 return v;
486}
487
488SHOW(temp0, temp0, null_adjust) /* temp1_input */
489SHOW(temp1, temp1, null_adjust) /* temp2_input */
490
491
492/* sysfs conventions report voltages in millivolts. We can convert voltages
493 * if we know vREF. userspace may need to scale vAUX to match the board's
494 * external resistors; we assume that vBATT only uses the internal ones.
495 */
496static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
497{
498 unsigned retval = v;
499
500 /* external resistors may scale vAUX into 0..vREF */
501 retval *= ts->vref_mv;
502 retval = retval >> 12;
503
504 return retval;
505}
506
507static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
508{
509 unsigned retval = vaux_adjust(ts, v);
510
511 /* ads7846 has a resistor ladder to scale this signal down */
512 if (ts->model == 7846)
513 retval *= 4;
514
515 return retval;
516}
517
518SHOW(in0_input, vaux, vaux_adjust)
519SHOW(in1_input, vbatt, vbatt_adjust)
520
521static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
522 int index)
523{
524 struct device *dev = kobj_to_dev(kobj);
525 struct ads7846 *ts = dev_get_drvdata(dev);
526
527 if (ts->model == 7843 && index < 2) /* in0, in1 */
528 return 0;
529 if (ts->model == 7845 && index != 2) /* in0 */
530 return 0;
531
532 return attr->mode;
533}
534
535static struct attribute *ads7846_attributes[] = {
536 &dev_attr_temp0.attr, /* 0 */
537 &dev_attr_temp1.attr, /* 1 */
538 &dev_attr_in0_input.attr, /* 2 */
539 &dev_attr_in1_input.attr, /* 3 */
540 NULL,
541};
542
543static const struct attribute_group ads7846_attr_group = {
544 .attrs = ads7846_attributes,
545 .is_visible = ads7846_is_visible,
546};
547__ATTRIBUTE_GROUPS(ads7846_attr);
548
549static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
550{
551 struct device *hwmon;
552
553 /* hwmon sensors need a reference voltage */
554 switch (ts->model) {
555 case 7846:
556 if (!ts->vref_mv) {
557 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
558 ts->vref_mv = 2500;
559 ts->use_internal = true;
560 }
561 break;
562 case 7845:
563 case 7843:
564 if (!ts->vref_mv) {
565 dev_warn(&spi->dev,
566 "external vREF for ADS%d not specified\n",
567 ts->model);
568 return 0;
569 }
570 break;
571 }
572
573 hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
574 spi->modalias, ts,
575 ads7846_attr_groups);
576
577 return PTR_ERR_OR_ZERO(hwmon);
578}
579
580#else
581static inline int ads784x_hwmon_register(struct spi_device *spi,
582 struct ads7846 *ts)
583{
584 return 0;
585}
586#endif
587
588static ssize_t ads7846_pen_down_show(struct device *dev,
589 struct device_attribute *attr, char *buf)
590{
591 struct ads7846 *ts = dev_get_drvdata(dev);
592
593 return sprintf(buf, "%u\n", ts->pendown);
594}
595
596static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
597
598static ssize_t ads7846_disable_show(struct device *dev,
599 struct device_attribute *attr, char *buf)
600{
601 struct ads7846 *ts = dev_get_drvdata(dev);
602
603 return sprintf(buf, "%u\n", ts->disabled);
604}
605
606static ssize_t ads7846_disable_store(struct device *dev,
607 struct device_attribute *attr,
608 const char *buf, size_t count)
609{
610 struct ads7846 *ts = dev_get_drvdata(dev);
611 unsigned int i;
612 int err;
613
614 err = kstrtouint(buf, 10, &i);
615 if (err)
616 return err;
617
618 if (i)
619 ads7846_disable(ts);
620 else
621 ads7846_enable(ts);
622
623 return count;
624}
625
626static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
627
628static struct attribute *ads784x_attrs[] = {
629 &dev_attr_pen_down.attr,
630 &dev_attr_disable.attr,
631 NULL,
632};
633ATTRIBUTE_GROUPS(ads784x);
634
635/*--------------------------------------------------------------------------*/
636
637static void null_wait_for_sync(void)
638{
639}
640
641static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
642{
643 struct ads7846 *ts = ads;
644
645 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
646 /* Start over collecting consistent readings. */
647 ts->read_rep = 0;
648 /*
649 * Repeat it, if this was the first read or the read
650 * wasn't consistent enough.
651 */
652 if (ts->read_cnt < ts->debounce_max) {
653 ts->last_read = *val;
654 ts->read_cnt++;
655 return ADS7846_FILTER_REPEAT;
656 } else {
657 /*
658 * Maximum number of debouncing reached and still
659 * not enough number of consistent readings. Abort
660 * the whole sample, repeat it in the next sampling
661 * period.
662 */
663 ts->read_cnt = 0;
664 return ADS7846_FILTER_IGNORE;
665 }
666 } else {
667 if (++ts->read_rep > ts->debounce_rep) {
668 /*
669 * Got a good reading for this coordinate,
670 * go for the next one.
671 */
672 ts->read_cnt = 0;
673 ts->read_rep = 0;
674 return ADS7846_FILTER_OK;
675 } else {
676 /* Read more values that are consistent. */
677 ts->read_cnt++;
678 return ADS7846_FILTER_REPEAT;
679 }
680 }
681}
682
683static int ads7846_no_filter(void *ads, int data_idx, int *val)
684{
685 return ADS7846_FILTER_OK;
686}
687
688static int ads7846_get_value(struct ads7846_buf *buf)
689{
690 int value;
691
692 value = be16_to_cpup(&buf->data);
693
694 /* enforce ADC output is 12 bits width */
695 return (value >> 3) & 0xfff;
696}
697
698static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
699 u16 val)
700{
701 struct ads7846_packet *packet = ts->packet;
702
703 switch (cmd_idx) {
704 case ADS7846_Y:
705 packet->y = val;
706 break;
707 case ADS7846_X:
708 packet->x = val;
709 break;
710 case ADS7846_Z1:
711 packet->z1 = val;
712 break;
713 case ADS7846_Z2:
714 packet->z2 = val;
715 break;
716 default:
717 WARN_ON_ONCE(1);
718 }
719}
720
721static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
722{
723 switch (cmd_idx) {
724 case ADS7846_Y:
725 return READ_Y(vref);
726 case ADS7846_X:
727 return READ_X(vref);
728
729 /* 7846 specific commands */
730 case ADS7846_Z1:
731 return READ_Z1(vref);
732 case ADS7846_Z2:
733 return READ_Z2(vref);
734 case ADS7846_PWDOWN:
735 return PWRDOWN;
736 default:
737 WARN_ON_ONCE(1);
738 }
739
740 return 0;
741}
742
743static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
744{
745 switch (cmd_idx) {
746 case ADS7846_X:
747 case ADS7846_Y:
748 case ADS7846_Z1:
749 case ADS7846_Z2:
750 return true;
751 case ADS7846_PWDOWN:
752 return false;
753 default:
754 WARN_ON_ONCE(1);
755 }
756
757 return false;
758}
759
760static int ads7846_filter(struct ads7846 *ts)
761{
762 struct ads7846_packet *packet = ts->packet;
763 int action;
764 int val;
765 unsigned int cmd_idx, b;
766
767 packet->ignore = false;
768 for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
769 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
770
771 packet->last_cmd_idx = cmd_idx;
772
773 for (b = l->skip; b < l->count; b++) {
774 val = ads7846_get_value(&packet->rx[l->offset + b]);
775
776 action = ts->filter(ts->filter_data, cmd_idx, &val);
777 if (action == ADS7846_FILTER_REPEAT) {
778 if (b == l->count - 1)
779 return -EAGAIN;
780 } else if (action == ADS7846_FILTER_OK) {
781 ads7846_set_cmd_val(ts, cmd_idx, val);
782 break;
783 } else {
784 packet->ignore = true;
785 return 0;
786 }
787 }
788 }
789
790 return 0;
791}
792
793static void ads7846_read_state(struct ads7846 *ts)
794{
795 struct ads7846_packet *packet = ts->packet;
796 struct spi_message *m;
797 int msg_idx = 0;
798 int error;
799
800 packet->last_cmd_idx = 0;
801
802 while (true) {
803 ts->wait_for_sync();
804
805 m = &ts->msg[msg_idx];
806 error = spi_sync(ts->spi, m);
807 if (error) {
808 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
809 packet->ignore = true;
810 return;
811 }
812
813 error = ads7846_filter(ts);
814 if (error)
815 continue;
816
817 return;
818 }
819}
820
821static void ads7846_report_state(struct ads7846 *ts)
822{
823 struct ads7846_packet *packet = ts->packet;
824 unsigned int Rt;
825 u16 x, y, z1, z2;
826
827 x = packet->x;
828 y = packet->y;
829 if (ts->model == 7845) {
830 z1 = 0;
831 z2 = 0;
832 } else {
833 z1 = packet->z1;
834 z2 = packet->z2;
835 }
836
837 /* range filtering */
838 if (x == MAX_12BIT)
839 x = 0;
840
841 if (ts->model == 7843 || ts->model == 7845) {
842 Rt = ts->pressure_max / 2;
843 } else if (likely(x && z1)) {
844 /* compute touch pressure resistance using equation #2 */
845 Rt = z2;
846 Rt -= z1;
847 Rt *= ts->x_plate_ohms;
848 Rt = DIV_ROUND_CLOSEST(Rt, 16);
849 Rt *= x;
850 Rt /= z1;
851 Rt = DIV_ROUND_CLOSEST(Rt, 256);
852 } else {
853 Rt = 0;
854 }
855
856 /*
857 * Sample found inconsistent by debouncing or pressure is beyond
858 * the maximum. Don't report it to user space, repeat at least
859 * once more the measurement
860 */
861 if (packet->ignore || Rt > ts->pressure_max) {
862 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
863 packet->ignore, Rt);
864 return;
865 }
866
867 /*
868 * Maybe check the pendown state before reporting. This discards
869 * false readings when the pen is lifted.
870 */
871 if (ts->penirq_recheck_delay_usecs) {
872 udelay(ts->penirq_recheck_delay_usecs);
873 if (!get_pendown_state(ts))
874 Rt = 0;
875 }
876
877 /*
878 * NOTE: We can't rely on the pressure to determine the pen down
879 * state, even this controller has a pressure sensor. The pressure
880 * value can fluctuate for quite a while after lifting the pen and
881 * in some cases may not even settle at the expected value.
882 *
883 * The only safe way to check for the pen up condition is in the
884 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
885 */
886 if (Rt) {
887 struct input_dev *input = ts->input;
888
889 if (!ts->pendown) {
890 input_report_key(input, BTN_TOUCH, 1);
891 ts->pendown = true;
892 dev_vdbg(&ts->spi->dev, "DOWN\n");
893 }
894
895 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
896 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
897
898 input_sync(input);
899 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
900 }
901}
902
903static irqreturn_t ads7846_hard_irq(int irq, void *handle)
904{
905 struct ads7846 *ts = handle;
906
907 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
908}
909
910
911static irqreturn_t ads7846_irq(int irq, void *handle)
912{
913 struct ads7846 *ts = handle;
914
915 /* Start with a small delay before checking pendown state */
916 msleep(TS_POLL_DELAY);
917
918 while (!ts->stopped && get_pendown_state(ts)) {
919
920 /* pen is down, continue with the measurement */
921 ads7846_read_state(ts);
922
923 if (!ts->stopped)
924 ads7846_report_state(ts);
925
926 wait_event_timeout(ts->wait, ts->stopped,
927 msecs_to_jiffies(TS_POLL_PERIOD));
928 }
929
930 if (ts->pendown && !ts->stopped)
931 ads7846_report_pen_up(ts);
932
933 return IRQ_HANDLED;
934}
935
936static int ads7846_suspend(struct device *dev)
937{
938 struct ads7846 *ts = dev_get_drvdata(dev);
939
940 mutex_lock(&ts->lock);
941
942 if (!ts->suspended) {
943
944 if (!ts->disabled)
945 __ads7846_disable(ts);
946
947 if (device_may_wakeup(&ts->spi->dev))
948 enable_irq_wake(ts->spi->irq);
949
950 ts->suspended = true;
951 }
952
953 mutex_unlock(&ts->lock);
954
955 return 0;
956}
957
958static int ads7846_resume(struct device *dev)
959{
960 struct ads7846 *ts = dev_get_drvdata(dev);
961
962 mutex_lock(&ts->lock);
963
964 if (ts->suspended) {
965
966 ts->suspended = false;
967
968 if (device_may_wakeup(&ts->spi->dev))
969 disable_irq_wake(ts->spi->irq);
970
971 if (!ts->disabled)
972 __ads7846_enable(ts);
973 }
974
975 mutex_unlock(&ts->lock);
976
977 return 0;
978}
979
980static DEFINE_SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
981
982static int ads7846_setup_pendown(struct spi_device *spi,
983 struct ads7846 *ts,
984 const struct ads7846_platform_data *pdata)
985{
986 /*
987 * REVISIT when the irq can be triggered active-low, or if for some
988 * reason the touchscreen isn't hooked up, we don't need to access
989 * the pendown state.
990 */
991
992 if (pdata->get_pendown_state) {
993 ts->get_pendown_state = pdata->get_pendown_state;
994 } else {
995 ts->gpio_pendown = gpiod_get(&spi->dev, "pendown", GPIOD_IN);
996 if (IS_ERR(ts->gpio_pendown)) {
997 dev_err(&spi->dev, "failed to request pendown GPIO\n");
998 return PTR_ERR(ts->gpio_pendown);
999 }
1000 if (pdata->gpio_pendown_debounce)
1001 gpiod_set_debounce(ts->gpio_pendown,
1002 pdata->gpio_pendown_debounce);
1003 }
1004
1005 return 0;
1006}
1007
1008/*
1009 * Set up the transfers to read touchscreen state; this assumes we
1010 * use formula #2 for pressure, not #3.
1011 */
1012static int ads7846_setup_spi_msg(struct ads7846 *ts,
1013 const struct ads7846_platform_data *pdata)
1014{
1015 struct spi_message *m = &ts->msg[0];
1016 struct spi_transfer *x = ts->xfer;
1017 struct ads7846_packet *packet = ts->packet;
1018 int vref = pdata->keep_vref_on;
1019 unsigned int count, offset = 0;
1020 unsigned int cmd_idx, b;
1021 unsigned long time;
1022 size_t size = 0;
1023
1024 /* time per bit */
1025 time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1026
1027 count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1028 packet->count_skip = DIV_ROUND_UP(count, 24);
1029
1030 if (ts->debounce_max && ts->debounce_rep)
1031 /* ads7846_debounce_filter() is making ts->debounce_rep + 2
1032 * reads. So we need to get all samples for normal case. */
1033 packet->count = ts->debounce_rep + 2;
1034 else
1035 packet->count = 1;
1036
1037 if (ts->model == 7846)
1038 packet->cmds = 5; /* x, y, z1, z2, pwdown */
1039 else
1040 packet->cmds = 3; /* x, y, pwdown */
1041
1042 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1043 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1044 unsigned int max_count;
1045
1046 if (cmd_idx == packet->cmds - 1)
1047 cmd_idx = ADS7846_PWDOWN;
1048
1049 if (ads7846_cmd_need_settle(cmd_idx))
1050 max_count = packet->count + packet->count_skip;
1051 else
1052 max_count = packet->count;
1053
1054 l->offset = offset;
1055 offset += max_count;
1056 l->count = max_count;
1057 l->skip = packet->count_skip;
1058 size += sizeof(*packet->tx) * max_count;
1059 }
1060
1061 packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1062 if (!packet->tx)
1063 return -ENOMEM;
1064
1065 packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1066 if (!packet->rx)
1067 return -ENOMEM;
1068
1069 if (ts->model == 7873) {
1070 /*
1071 * The AD7873 is almost identical to the ADS7846
1072 * keep VREF off during differential/ratiometric
1073 * conversion modes.
1074 */
1075 ts->model = 7846;
1076 vref = 0;
1077 }
1078
1079 ts->msg_count = 1;
1080 spi_message_init(m);
1081 m->context = ts;
1082
1083 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1084 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1085 u8 cmd;
1086
1087 if (cmd_idx == packet->cmds - 1)
1088 cmd_idx = ADS7846_PWDOWN;
1089
1090 cmd = ads7846_get_cmd(cmd_idx, vref);
1091
1092 for (b = 0; b < l->count; b++)
1093 packet->tx[l->offset + b].cmd = cmd;
1094 }
1095
1096 x->tx_buf = packet->tx;
1097 x->rx_buf = packet->rx;
1098 x->len = size;
1099 spi_message_add_tail(x, m);
1100
1101 return 0;
1102}
1103
1104static const struct of_device_id ads7846_dt_ids[] = {
1105 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1106 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1107 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1108 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1109 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1110 { }
1111};
1112MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1113
1114static const struct ads7846_platform_data *ads7846_get_props(struct device *dev)
1115{
1116 struct ads7846_platform_data *pdata;
1117 u32 value;
1118
1119 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1120 if (!pdata)
1121 return ERR_PTR(-ENOMEM);
1122
1123 pdata->model = (uintptr_t)device_get_match_data(dev);
1124
1125 device_property_read_u16(dev, "ti,vref-delay-usecs",
1126 &pdata->vref_delay_usecs);
1127 device_property_read_u16(dev, "ti,vref-mv", &pdata->vref_mv);
1128 pdata->keep_vref_on = device_property_read_bool(dev, "ti,keep-vref-on");
1129
1130 pdata->swap_xy = device_property_read_bool(dev, "ti,swap-xy");
1131
1132 device_property_read_u16(dev, "ti,settle-delay-usec",
1133 &pdata->settle_delay_usecs);
1134 device_property_read_u16(dev, "ti,penirq-recheck-delay-usecs",
1135 &pdata->penirq_recheck_delay_usecs);
1136
1137 device_property_read_u16(dev, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1138 device_property_read_u16(dev, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1139
1140 device_property_read_u16(dev, "ti,x-min", &pdata->x_min);
1141 device_property_read_u16(dev, "ti,y-min", &pdata->y_min);
1142 device_property_read_u16(dev, "ti,x-max", &pdata->x_max);
1143 device_property_read_u16(dev, "ti,y-max", &pdata->y_max);
1144
1145 /*
1146 * touchscreen-max-pressure gets parsed during
1147 * touchscreen_parse_properties()
1148 */
1149 device_property_read_u16(dev, "ti,pressure-min", &pdata->pressure_min);
1150 if (!device_property_read_u32(dev, "touchscreen-min-pressure", &value))
1151 pdata->pressure_min = (u16) value;
1152 device_property_read_u16(dev, "ti,pressure-max", &pdata->pressure_max);
1153
1154 device_property_read_u16(dev, "ti,debounce-max", &pdata->debounce_max);
1155 if (!device_property_read_u32(dev, "touchscreen-average-samples", &value))
1156 pdata->debounce_max = (u16) value;
1157 device_property_read_u16(dev, "ti,debounce-tol", &pdata->debounce_tol);
1158 device_property_read_u16(dev, "ti,debounce-rep", &pdata->debounce_rep);
1159
1160 device_property_read_u32(dev, "ti,pendown-gpio-debounce",
1161 &pdata->gpio_pendown_debounce);
1162
1163 pdata->wakeup = device_property_read_bool(dev, "wakeup-source") ||
1164 device_property_read_bool(dev, "linux,wakeup");
1165
1166 return pdata;
1167}
1168
1169static void ads7846_regulator_disable(void *regulator)
1170{
1171 regulator_disable(regulator);
1172}
1173
1174static int ads7846_probe(struct spi_device *spi)
1175{
1176 const struct ads7846_platform_data *pdata;
1177 struct ads7846 *ts;
1178 struct device *dev = &spi->dev;
1179 struct ads7846_packet *packet;
1180 struct input_dev *input_dev;
1181 unsigned long irq_flags;
1182 int err;
1183
1184 if (!spi->irq) {
1185 dev_dbg(dev, "no IRQ?\n");
1186 return -EINVAL;
1187 }
1188
1189 /* don't exceed max specified sample rate */
1190 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1191 dev_err(dev, "f(sample) %d KHz?\n",
1192 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1193 return -EINVAL;
1194 }
1195
1196 /*
1197 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1198 * that even if the hardware can do that, the SPI controller driver
1199 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1200 */
1201 spi->bits_per_word = 8;
1202 spi->mode &= ~SPI_MODE_X_MASK;
1203 spi->mode |= SPI_MODE_0;
1204 err = spi_setup(spi);
1205 if (err < 0)
1206 return err;
1207
1208 ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1209 if (!ts)
1210 return -ENOMEM;
1211
1212 packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1213 if (!packet)
1214 return -ENOMEM;
1215
1216 input_dev = devm_input_allocate_device(dev);
1217 if (!input_dev)
1218 return -ENOMEM;
1219
1220 spi_set_drvdata(spi, ts);
1221
1222 ts->packet = packet;
1223 ts->spi = spi;
1224 ts->input = input_dev;
1225
1226 mutex_init(&ts->lock);
1227 init_waitqueue_head(&ts->wait);
1228
1229 pdata = dev_get_platdata(dev);
1230 if (!pdata) {
1231 pdata = ads7846_get_props(dev);
1232 if (IS_ERR(pdata))
1233 return PTR_ERR(pdata);
1234 }
1235
1236 ts->model = pdata->model ? : 7846;
1237 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1238 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1239 ts->vref_mv = pdata->vref_mv;
1240
1241 if (pdata->debounce_max) {
1242 ts->debounce_max = pdata->debounce_max;
1243 if (ts->debounce_max < 2)
1244 ts->debounce_max = 2;
1245 ts->debounce_tol = pdata->debounce_tol;
1246 ts->debounce_rep = pdata->debounce_rep;
1247 ts->filter = ads7846_debounce_filter;
1248 ts->filter_data = ts;
1249 } else {
1250 ts->filter = ads7846_no_filter;
1251 }
1252
1253 err = ads7846_setup_pendown(spi, ts, pdata);
1254 if (err)
1255 return err;
1256
1257 if (pdata->penirq_recheck_delay_usecs)
1258 ts->penirq_recheck_delay_usecs =
1259 pdata->penirq_recheck_delay_usecs;
1260
1261 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1262
1263 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1264 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1265
1266 input_dev->name = ts->name;
1267 input_dev->phys = ts->phys;
1268
1269 input_dev->id.bustype = BUS_SPI;
1270 input_dev->id.product = pdata->model;
1271
1272 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1273 input_set_abs_params(input_dev, ABS_X,
1274 pdata->x_min ? : 0,
1275 pdata->x_max ? : MAX_12BIT,
1276 0, 0);
1277 input_set_abs_params(input_dev, ABS_Y,
1278 pdata->y_min ? : 0,
1279 pdata->y_max ? : MAX_12BIT,
1280 0, 0);
1281 if (ts->model != 7845)
1282 input_set_abs_params(input_dev, ABS_PRESSURE,
1283 pdata->pressure_min, pdata->pressure_max, 0, 0);
1284
1285 /*
1286 * Parse common framework properties. Must be done here to ensure the
1287 * correct behaviour in case of using the legacy vendor bindings. The
1288 * general binding value overrides the vendor specific one.
1289 */
1290 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1291 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1292
1293 /*
1294 * Check if legacy ti,swap-xy binding is used instead of
1295 * touchscreen-swapped-x-y
1296 */
1297 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1298 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1299 ts->core_prop.swap_x_y = true;
1300 }
1301
1302 ads7846_setup_spi_msg(ts, pdata);
1303
1304 ts->reg = devm_regulator_get(dev, "vcc");
1305 if (IS_ERR(ts->reg)) {
1306 err = PTR_ERR(ts->reg);
1307 dev_err(dev, "unable to get regulator: %d\n", err);
1308 return err;
1309 }
1310
1311 err = regulator_enable(ts->reg);
1312 if (err) {
1313 dev_err(dev, "unable to enable regulator: %d\n", err);
1314 return err;
1315 }
1316
1317 err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1318 if (err)
1319 return err;
1320
1321 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1322 irq_flags |= IRQF_ONESHOT;
1323
1324 err = devm_request_threaded_irq(dev, spi->irq,
1325 ads7846_hard_irq, ads7846_irq,
1326 irq_flags, dev->driver->name, ts);
1327 if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1328 dev_info(dev,
1329 "trying pin change workaround on irq %d\n", spi->irq);
1330 irq_flags |= IRQF_TRIGGER_RISING;
1331 err = devm_request_threaded_irq(dev, spi->irq,
1332 ads7846_hard_irq, ads7846_irq,
1333 irq_flags, dev->driver->name,
1334 ts);
1335 }
1336
1337 if (err) {
1338 dev_dbg(dev, "irq %d busy?\n", spi->irq);
1339 return err;
1340 }
1341
1342 err = ads784x_hwmon_register(spi, ts);
1343 if (err)
1344 return err;
1345
1346 dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1347
1348 /*
1349 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1350 * the touchscreen, in case it's not connected.
1351 */
1352 if (ts->model == 7845)
1353 ads7845_read12_ser(dev, PWRDOWN);
1354 else
1355 (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1356
1357 err = input_register_device(input_dev);
1358 if (err)
1359 return err;
1360
1361 device_init_wakeup(dev, pdata->wakeup);
1362
1363 /*
1364 * If device does not carry platform data we must have allocated it
1365 * when parsing DT data.
1366 */
1367 if (!dev_get_platdata(dev))
1368 devm_kfree(dev, (void *)pdata);
1369
1370 return 0;
1371}
1372
1373static void ads7846_remove(struct spi_device *spi)
1374{
1375 struct ads7846 *ts = spi_get_drvdata(spi);
1376
1377 ads7846_stop(ts);
1378}
1379
1380static struct spi_driver ads7846_driver = {
1381 .driver = {
1382 .name = "ads7846",
1383 .dev_groups = ads784x_groups,
1384 .pm = pm_sleep_ptr(&ads7846_pm),
1385 .of_match_table = ads7846_dt_ids,
1386 },
1387 .probe = ads7846_probe,
1388 .remove = ads7846_remove,
1389};
1390
1391module_spi_driver(ads7846_driver);
1392
1393MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1394MODULE_LICENSE("GPL");
1395MODULE_ALIAS("spi:ads7846");