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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 <linux/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 struct gpio_desc *gpio_hsync;
142
143 void (*wait_for_sync)(void);
144};
145
146enum ads7846_filter {
147 ADS7846_FILTER_OK,
148 ADS7846_FILTER_REPEAT,
149 ADS7846_FILTER_IGNORE,
150};
151
152/* leave chip selected when we're done, for quicker re-select? */
153#if 0
154#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
155#else
156#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
157#endif
158
159/*--------------------------------------------------------------------------*/
160
161/* The ADS7846 has touchscreen and other sensors.
162 * Earlier ads784x chips are somewhat compatible.
163 */
164#define ADS_START (1 << 7)
165#define ADS_A2A1A0_d_y (1 << 4) /* differential */
166#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
167#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
168#define ADS_A2A1A0_d_x (5 << 4) /* differential */
169#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
170#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
171#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
172#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
173#define ADS_8_BIT (1 << 3)
174#define ADS_12_BIT (0 << 3)
175#define ADS_SER (1 << 2) /* non-differential */
176#define ADS_DFR (0 << 2) /* differential */
177#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
178#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
179#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
180#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
181
182#define MAX_12BIT ((1<<12)-1)
183
184/* leave ADC powered up (disables penirq) between differential samples */
185#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
186 | ADS_12_BIT | ADS_DFR | \
187 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
188
189#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
190#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
191#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
192#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
193#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
194
195/* single-ended samples need to first power up reference voltage;
196 * we leave both ADC and VREF powered
197 */
198#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
199 | ADS_12_BIT | ADS_SER)
200
201#define REF_ON (READ_12BIT_DFR(x, 1, 1))
202#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
203
204/* Order commands in the most optimal way to reduce Vref switching and
205 * settling time:
206 * Measure: X; Vref: X+, X-; IN: Y+
207 * Measure: Y; Vref: Y+, Y-; IN: X+
208 * Measure: Z1; Vref: Y+, X-; IN: X+
209 * Measure: Z2; Vref: Y+, X-; IN: Y-
210 */
211enum ads7846_cmds {
212 ADS7846_X,
213 ADS7846_Y,
214 ADS7846_Z1,
215 ADS7846_Z2,
216 ADS7846_PWDOWN,
217};
218
219static int get_pendown_state(struct ads7846 *ts)
220{
221 if (ts->get_pendown_state)
222 return ts->get_pendown_state();
223
224 return gpiod_get_value(ts->gpio_pendown);
225}
226
227static void ads7846_report_pen_up(struct ads7846 *ts)
228{
229 struct input_dev *input = ts->input;
230
231 input_report_key(input, BTN_TOUCH, 0);
232 input_report_abs(input, ABS_PRESSURE, 0);
233 input_sync(input);
234
235 ts->pendown = false;
236 dev_vdbg(&ts->spi->dev, "UP\n");
237}
238
239/* Must be called with ts->lock held */
240static void ads7846_stop(struct ads7846 *ts)
241{
242 if (!ts->disabled && !ts->suspended) {
243 /* Signal IRQ thread to stop polling and disable the handler. */
244 ts->stopped = true;
245 mb();
246 wake_up(&ts->wait);
247 disable_irq(ts->spi->irq);
248 }
249}
250
251/* Must be called with ts->lock held */
252static void ads7846_restart(struct ads7846 *ts)
253{
254 if (!ts->disabled && !ts->suspended) {
255 /* Check if pen was released since last stop */
256 if (ts->pendown && !get_pendown_state(ts))
257 ads7846_report_pen_up(ts);
258
259 /* Tell IRQ thread that it may poll the device. */
260 ts->stopped = false;
261 mb();
262 enable_irq(ts->spi->irq);
263 }
264}
265
266/* Must be called with ts->lock held */
267static void __ads7846_disable(struct ads7846 *ts)
268{
269 ads7846_stop(ts);
270 regulator_disable(ts->reg);
271
272 /*
273 * We know the chip's in low power mode since we always
274 * leave it that way after every request
275 */
276}
277
278/* Must be called with ts->lock held */
279static void __ads7846_enable(struct ads7846 *ts)
280{
281 int error;
282
283 error = regulator_enable(ts->reg);
284 if (error != 0)
285 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
286
287 ads7846_restart(ts);
288}
289
290static void ads7846_disable(struct ads7846 *ts)
291{
292 mutex_lock(&ts->lock);
293
294 if (!ts->disabled) {
295
296 if (!ts->suspended)
297 __ads7846_disable(ts);
298
299 ts->disabled = true;
300 }
301
302 mutex_unlock(&ts->lock);
303}
304
305static void ads7846_enable(struct ads7846 *ts)
306{
307 mutex_lock(&ts->lock);
308
309 if (ts->disabled) {
310
311 ts->disabled = false;
312
313 if (!ts->suspended)
314 __ads7846_enable(ts);
315 }
316
317 mutex_unlock(&ts->lock);
318}
319
320/*--------------------------------------------------------------------------*/
321
322/*
323 * Non-touchscreen sensors only use single-ended conversions.
324 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
325 * ads7846 lets that pin be unconnected, to use internal vREF.
326 */
327
328struct ser_req {
329 u8 ref_on;
330 u8 command;
331 u8 ref_off;
332 u16 scratch;
333 struct spi_message msg;
334 struct spi_transfer xfer[8];
335 /*
336 * DMA (thus cache coherency maintenance) requires the
337 * transfer buffers to live in their own cache lines.
338 */
339 __be16 sample ____cacheline_aligned;
340};
341
342struct ads7845_ser_req {
343 u8 command[3];
344 struct spi_message msg;
345 struct spi_transfer xfer[2];
346 /*
347 * DMA (thus cache coherency maintenance) requires the
348 * transfer buffers to live in their own cache lines.
349 */
350 u8 sample[3] ____cacheline_aligned;
351};
352
353static int ads7846_read12_ser(struct device *dev, unsigned command)
354{
355 struct spi_device *spi = to_spi_device(dev);
356 struct ads7846 *ts = dev_get_drvdata(dev);
357 struct ser_req *req;
358 int status;
359
360 req = kzalloc(sizeof *req, GFP_KERNEL);
361 if (!req)
362 return -ENOMEM;
363
364 spi_message_init(&req->msg);
365
366 /* maybe turn on internal vREF, and let it settle */
367 if (ts->use_internal) {
368 req->ref_on = REF_ON;
369 req->xfer[0].tx_buf = &req->ref_on;
370 req->xfer[0].len = 1;
371 spi_message_add_tail(&req->xfer[0], &req->msg);
372
373 req->xfer[1].rx_buf = &req->scratch;
374 req->xfer[1].len = 2;
375
376 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
377 req->xfer[1].delay.value = ts->vref_delay_usecs;
378 req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
379 spi_message_add_tail(&req->xfer[1], &req->msg);
380
381 /* Enable reference voltage */
382 command |= ADS_PD10_REF_ON;
383 }
384
385 /* Enable ADC in every case */
386 command |= ADS_PD10_ADC_ON;
387
388 /* take sample */
389 req->command = (u8) command;
390 req->xfer[2].tx_buf = &req->command;
391 req->xfer[2].len = 1;
392 spi_message_add_tail(&req->xfer[2], &req->msg);
393
394 req->xfer[3].rx_buf = &req->sample;
395 req->xfer[3].len = 2;
396 spi_message_add_tail(&req->xfer[3], &req->msg);
397
398 /* REVISIT: take a few more samples, and compare ... */
399
400 /* converter in low power mode & enable PENIRQ */
401 req->ref_off = PWRDOWN;
402 req->xfer[4].tx_buf = &req->ref_off;
403 req->xfer[4].len = 1;
404 spi_message_add_tail(&req->xfer[4], &req->msg);
405
406 req->xfer[5].rx_buf = &req->scratch;
407 req->xfer[5].len = 2;
408 spi_message_add_tail(&req->xfer[5], &req->msg);
409
410 /* clear the command register */
411 req->scratch = 0;
412 req->xfer[6].tx_buf = &req->scratch;
413 req->xfer[6].len = 1;
414 spi_message_add_tail(&req->xfer[6], &req->msg);
415
416 req->xfer[7].rx_buf = &req->scratch;
417 req->xfer[7].len = 2;
418 CS_CHANGE(req->xfer[7]);
419 spi_message_add_tail(&req->xfer[7], &req->msg);
420
421 mutex_lock(&ts->lock);
422 ads7846_stop(ts);
423 status = spi_sync(spi, &req->msg);
424 ads7846_restart(ts);
425 mutex_unlock(&ts->lock);
426
427 if (status == 0) {
428 /* on-wire is a must-ignore bit, a BE12 value, then padding */
429 status = be16_to_cpu(req->sample);
430 status = status >> 3;
431 status &= 0x0fff;
432 }
433
434 kfree(req);
435 return status;
436}
437
438static int ads7845_read12_ser(struct device *dev, unsigned command)
439{
440 struct spi_device *spi = to_spi_device(dev);
441 struct ads7846 *ts = dev_get_drvdata(dev);
442 struct ads7845_ser_req *req;
443 int status;
444
445 req = kzalloc(sizeof *req, GFP_KERNEL);
446 if (!req)
447 return -ENOMEM;
448
449 spi_message_init(&req->msg);
450
451 req->command[0] = (u8) command;
452 req->xfer[0].tx_buf = req->command;
453 req->xfer[0].rx_buf = req->sample;
454 req->xfer[0].len = 3;
455 spi_message_add_tail(&req->xfer[0], &req->msg);
456
457 mutex_lock(&ts->lock);
458 ads7846_stop(ts);
459 status = spi_sync(spi, &req->msg);
460 ads7846_restart(ts);
461 mutex_unlock(&ts->lock);
462
463 if (status == 0) {
464 /* BE12 value, then padding */
465 status = get_unaligned_be16(&req->sample[1]);
466 status = status >> 3;
467 status &= 0x0fff;
468 }
469
470 kfree(req);
471 return status;
472}
473
474#if IS_ENABLED(CONFIG_HWMON)
475
476#define SHOW(name, var, adjust) static ssize_t \
477name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
478{ \
479 struct ads7846 *ts = dev_get_drvdata(dev); \
480 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
481 READ_12BIT_SER(var)); \
482 if (v < 0) \
483 return v; \
484 return sprintf(buf, "%u\n", adjust(ts, v)); \
485} \
486static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
487
488
489/* Sysfs conventions report temperatures in millidegrees Celsius.
490 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
491 * accuracy scheme without calibration data. For now we won't try either;
492 * userspace sees raw sensor values, and must scale/calibrate appropriately.
493 */
494static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
495{
496 return v;
497}
498
499SHOW(temp0, temp0, null_adjust) /* temp1_input */
500SHOW(temp1, temp1, null_adjust) /* temp2_input */
501
502
503/* sysfs conventions report voltages in millivolts. We can convert voltages
504 * if we know vREF. userspace may need to scale vAUX to match the board's
505 * external resistors; we assume that vBATT only uses the internal ones.
506 */
507static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
508{
509 unsigned retval = v;
510
511 /* external resistors may scale vAUX into 0..vREF */
512 retval *= ts->vref_mv;
513 retval = retval >> 12;
514
515 return retval;
516}
517
518static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
519{
520 unsigned retval = vaux_adjust(ts, v);
521
522 /* ads7846 has a resistor ladder to scale this signal down */
523 if (ts->model == 7846)
524 retval *= 4;
525
526 return retval;
527}
528
529SHOW(in0_input, vaux, vaux_adjust)
530SHOW(in1_input, vbatt, vbatt_adjust)
531
532static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
533 int index)
534{
535 struct device *dev = kobj_to_dev(kobj);
536 struct ads7846 *ts = dev_get_drvdata(dev);
537
538 if (ts->model == 7843 && index < 2) /* in0, in1 */
539 return 0;
540 if (ts->model == 7845 && index != 2) /* in0 */
541 return 0;
542
543 return attr->mode;
544}
545
546static struct attribute *ads7846_attributes[] = {
547 &dev_attr_temp0.attr, /* 0 */
548 &dev_attr_temp1.attr, /* 1 */
549 &dev_attr_in0_input.attr, /* 2 */
550 &dev_attr_in1_input.attr, /* 3 */
551 NULL,
552};
553
554static const struct attribute_group ads7846_attr_group = {
555 .attrs = ads7846_attributes,
556 .is_visible = ads7846_is_visible,
557};
558__ATTRIBUTE_GROUPS(ads7846_attr);
559
560static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
561{
562 struct device *hwmon;
563
564 /* hwmon sensors need a reference voltage */
565 switch (ts->model) {
566 case 7846:
567 if (!ts->vref_mv) {
568 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
569 ts->vref_mv = 2500;
570 ts->use_internal = true;
571 }
572 break;
573 case 7845:
574 case 7843:
575 if (!ts->vref_mv) {
576 dev_warn(&spi->dev,
577 "external vREF for ADS%d not specified\n",
578 ts->model);
579 return 0;
580 }
581 break;
582 }
583
584 hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
585 spi->modalias, ts,
586 ads7846_attr_groups);
587
588 return PTR_ERR_OR_ZERO(hwmon);
589}
590
591#else
592static inline int ads784x_hwmon_register(struct spi_device *spi,
593 struct ads7846 *ts)
594{
595 return 0;
596}
597#endif
598
599static ssize_t ads7846_pen_down_show(struct device *dev,
600 struct device_attribute *attr, char *buf)
601{
602 struct ads7846 *ts = dev_get_drvdata(dev);
603
604 return sprintf(buf, "%u\n", ts->pendown);
605}
606
607static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
608
609static ssize_t ads7846_disable_show(struct device *dev,
610 struct device_attribute *attr, char *buf)
611{
612 struct ads7846 *ts = dev_get_drvdata(dev);
613
614 return sprintf(buf, "%u\n", ts->disabled);
615}
616
617static ssize_t ads7846_disable_store(struct device *dev,
618 struct device_attribute *attr,
619 const char *buf, size_t count)
620{
621 struct ads7846 *ts = dev_get_drvdata(dev);
622 unsigned int i;
623 int err;
624
625 err = kstrtouint(buf, 10, &i);
626 if (err)
627 return err;
628
629 if (i)
630 ads7846_disable(ts);
631 else
632 ads7846_enable(ts);
633
634 return count;
635}
636
637static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
638
639static struct attribute *ads784x_attrs[] = {
640 &dev_attr_pen_down.attr,
641 &dev_attr_disable.attr,
642 NULL,
643};
644ATTRIBUTE_GROUPS(ads784x);
645
646/*--------------------------------------------------------------------------*/
647
648static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
649{
650 struct ads7846 *ts = ads;
651
652 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
653 /* Start over collecting consistent readings. */
654 ts->read_rep = 0;
655 /*
656 * Repeat it, if this was the first read or the read
657 * wasn't consistent enough.
658 */
659 if (ts->read_cnt < ts->debounce_max) {
660 ts->last_read = *val;
661 ts->read_cnt++;
662 return ADS7846_FILTER_REPEAT;
663 } else {
664 /*
665 * Maximum number of debouncing reached and still
666 * not enough number of consistent readings. Abort
667 * the whole sample, repeat it in the next sampling
668 * period.
669 */
670 ts->read_cnt = 0;
671 return ADS7846_FILTER_IGNORE;
672 }
673 } else {
674 if (++ts->read_rep > ts->debounce_rep) {
675 /*
676 * Got a good reading for this coordinate,
677 * go for the next one.
678 */
679 ts->read_cnt = 0;
680 ts->read_rep = 0;
681 return ADS7846_FILTER_OK;
682 } else {
683 /* Read more values that are consistent. */
684 ts->read_cnt++;
685 return ADS7846_FILTER_REPEAT;
686 }
687 }
688}
689
690static int ads7846_no_filter(void *ads, int data_idx, int *val)
691{
692 return ADS7846_FILTER_OK;
693}
694
695static int ads7846_get_value(struct ads7846_buf *buf)
696{
697 int value;
698
699 value = be16_to_cpup(&buf->data);
700
701 /* enforce ADC output is 12 bits width */
702 return (value >> 3) & 0xfff;
703}
704
705static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
706 u16 val)
707{
708 struct ads7846_packet *packet = ts->packet;
709
710 switch (cmd_idx) {
711 case ADS7846_Y:
712 packet->y = val;
713 break;
714 case ADS7846_X:
715 packet->x = val;
716 break;
717 case ADS7846_Z1:
718 packet->z1 = val;
719 break;
720 case ADS7846_Z2:
721 packet->z2 = val;
722 break;
723 default:
724 WARN_ON_ONCE(1);
725 }
726}
727
728static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
729{
730 switch (cmd_idx) {
731 case ADS7846_Y:
732 return READ_Y(vref);
733 case ADS7846_X:
734 return READ_X(vref);
735
736 /* 7846 specific commands */
737 case ADS7846_Z1:
738 return READ_Z1(vref);
739 case ADS7846_Z2:
740 return READ_Z2(vref);
741 case ADS7846_PWDOWN:
742 return PWRDOWN;
743 default:
744 WARN_ON_ONCE(1);
745 }
746
747 return 0;
748}
749
750static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
751{
752 switch (cmd_idx) {
753 case ADS7846_X:
754 case ADS7846_Y:
755 case ADS7846_Z1:
756 case ADS7846_Z2:
757 return true;
758 case ADS7846_PWDOWN:
759 return false;
760 default:
761 WARN_ON_ONCE(1);
762 }
763
764 return false;
765}
766
767static int ads7846_filter(struct ads7846 *ts)
768{
769 struct ads7846_packet *packet = ts->packet;
770 int action;
771 int val;
772 unsigned int cmd_idx, b;
773
774 packet->ignore = false;
775 for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
776 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
777
778 packet->last_cmd_idx = cmd_idx;
779
780 for (b = l->skip; b < l->count; b++) {
781 val = ads7846_get_value(&packet->rx[l->offset + b]);
782
783 action = ts->filter(ts->filter_data, cmd_idx, &val);
784 if (action == ADS7846_FILTER_REPEAT) {
785 if (b == l->count - 1)
786 return -EAGAIN;
787 } else if (action == ADS7846_FILTER_OK) {
788 ads7846_set_cmd_val(ts, cmd_idx, val);
789 break;
790 } else {
791 packet->ignore = true;
792 return 0;
793 }
794 }
795 }
796
797 return 0;
798}
799
800static void ads7846_wait_for_hsync(struct ads7846 *ts)
801{
802 if (ts->wait_for_sync) {
803 ts->wait_for_sync();
804 return;
805 }
806
807 if (!ts->gpio_hsync)
808 return;
809
810 /*
811 * Wait for HSYNC to assert the line should be flagged
812 * as active low so here we are waiting for it to assert
813 */
814 while (!gpiod_get_value(ts->gpio_hsync))
815 cpu_relax();
816
817 /* Then we wait for it do de-assert */
818 while (gpiod_get_value(ts->gpio_hsync))
819 cpu_relax();
820}
821
822static void ads7846_read_state(struct ads7846 *ts)
823{
824 struct ads7846_packet *packet = ts->packet;
825 struct spi_message *m;
826 int msg_idx = 0;
827 int error;
828
829 packet->last_cmd_idx = 0;
830
831 while (true) {
832 ads7846_wait_for_hsync(ts);
833
834 m = &ts->msg[msg_idx];
835 error = spi_sync(ts->spi, m);
836 if (error) {
837 dev_err_ratelimited(&ts->spi->dev, "spi_sync --> %d\n", error);
838 packet->ignore = true;
839 return;
840 }
841
842 error = ads7846_filter(ts);
843 if (error)
844 continue;
845
846 return;
847 }
848}
849
850static void ads7846_report_state(struct ads7846 *ts)
851{
852 struct ads7846_packet *packet = ts->packet;
853 unsigned int Rt;
854 u16 x, y, z1, z2;
855
856 x = packet->x;
857 y = packet->y;
858 if (ts->model == 7845) {
859 z1 = 0;
860 z2 = 0;
861 } else {
862 z1 = packet->z1;
863 z2 = packet->z2;
864 }
865
866 /* range filtering */
867 if (x == MAX_12BIT)
868 x = 0;
869
870 if (ts->model == 7843 || ts->model == 7845) {
871 Rt = ts->pressure_max / 2;
872 } else if (likely(x && z1)) {
873 /* compute touch pressure resistance using equation #2 */
874 Rt = z2;
875 Rt -= z1;
876 Rt *= ts->x_plate_ohms;
877 Rt = DIV_ROUND_CLOSEST(Rt, 16);
878 Rt *= x;
879 Rt /= z1;
880 Rt = DIV_ROUND_CLOSEST(Rt, 256);
881 } else {
882 Rt = 0;
883 }
884
885 /*
886 * Sample found inconsistent by debouncing or pressure is beyond
887 * the maximum. Don't report it to user space, repeat at least
888 * once more the measurement
889 */
890 if (packet->ignore || Rt > ts->pressure_max) {
891 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
892 packet->ignore, Rt);
893 return;
894 }
895
896 /*
897 * Maybe check the pendown state before reporting. This discards
898 * false readings when the pen is lifted.
899 */
900 if (ts->penirq_recheck_delay_usecs) {
901 udelay(ts->penirq_recheck_delay_usecs);
902 if (!get_pendown_state(ts))
903 Rt = 0;
904 }
905
906 /*
907 * NOTE: We can't rely on the pressure to determine the pen down
908 * state, even this controller has a pressure sensor. The pressure
909 * value can fluctuate for quite a while after lifting the pen and
910 * in some cases may not even settle at the expected value.
911 *
912 * The only safe way to check for the pen up condition is in the
913 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
914 */
915 if (Rt) {
916 struct input_dev *input = ts->input;
917
918 if (!ts->pendown) {
919 input_report_key(input, BTN_TOUCH, 1);
920 ts->pendown = true;
921 dev_vdbg(&ts->spi->dev, "DOWN\n");
922 }
923
924 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
925 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
926
927 input_sync(input);
928 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
929 }
930}
931
932static irqreturn_t ads7846_hard_irq(int irq, void *handle)
933{
934 struct ads7846 *ts = handle;
935
936 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
937}
938
939
940static irqreturn_t ads7846_irq(int irq, void *handle)
941{
942 struct ads7846 *ts = handle;
943
944 /* Start with a small delay before checking pendown state */
945 msleep(TS_POLL_DELAY);
946
947 while (!ts->stopped && get_pendown_state(ts)) {
948
949 /* pen is down, continue with the measurement */
950 ads7846_read_state(ts);
951
952 if (!ts->stopped)
953 ads7846_report_state(ts);
954
955 wait_event_timeout(ts->wait, ts->stopped,
956 msecs_to_jiffies(TS_POLL_PERIOD));
957 }
958
959 if (ts->pendown && !ts->stopped)
960 ads7846_report_pen_up(ts);
961
962 return IRQ_HANDLED;
963}
964
965static int ads7846_suspend(struct device *dev)
966{
967 struct ads7846 *ts = dev_get_drvdata(dev);
968
969 mutex_lock(&ts->lock);
970
971 if (!ts->suspended) {
972
973 if (!ts->disabled)
974 __ads7846_disable(ts);
975
976 if (device_may_wakeup(&ts->spi->dev))
977 enable_irq_wake(ts->spi->irq);
978
979 ts->suspended = true;
980 }
981
982 mutex_unlock(&ts->lock);
983
984 return 0;
985}
986
987static int ads7846_resume(struct device *dev)
988{
989 struct ads7846 *ts = dev_get_drvdata(dev);
990
991 mutex_lock(&ts->lock);
992
993 if (ts->suspended) {
994
995 ts->suspended = false;
996
997 if (device_may_wakeup(&ts->spi->dev))
998 disable_irq_wake(ts->spi->irq);
999
1000 if (!ts->disabled)
1001 __ads7846_enable(ts);
1002 }
1003
1004 mutex_unlock(&ts->lock);
1005
1006 return 0;
1007}
1008
1009static DEFINE_SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
1010
1011static int ads7846_setup_pendown(struct spi_device *spi,
1012 struct ads7846 *ts,
1013 const struct ads7846_platform_data *pdata)
1014{
1015 /*
1016 * REVISIT when the irq can be triggered active-low, or if for some
1017 * reason the touchscreen isn't hooked up, we don't need to access
1018 * the pendown state.
1019 */
1020
1021 if (pdata->get_pendown_state) {
1022 ts->get_pendown_state = pdata->get_pendown_state;
1023 } else {
1024 ts->gpio_pendown = gpiod_get(&spi->dev, "pendown", GPIOD_IN);
1025 if (IS_ERR(ts->gpio_pendown)) {
1026 dev_err(&spi->dev, "failed to request pendown GPIO\n");
1027 return PTR_ERR(ts->gpio_pendown);
1028 }
1029 if (pdata->gpio_pendown_debounce)
1030 gpiod_set_debounce(ts->gpio_pendown,
1031 pdata->gpio_pendown_debounce);
1032 }
1033
1034 return 0;
1035}
1036
1037/*
1038 * Set up the transfers to read touchscreen state; this assumes we
1039 * use formula #2 for pressure, not #3.
1040 */
1041static int ads7846_setup_spi_msg(struct ads7846 *ts,
1042 const struct ads7846_platform_data *pdata)
1043{
1044 struct spi_message *m = &ts->msg[0];
1045 struct spi_transfer *x = ts->xfer;
1046 struct ads7846_packet *packet = ts->packet;
1047 int vref = pdata->keep_vref_on;
1048 unsigned int count, offset = 0;
1049 unsigned int cmd_idx, b;
1050 unsigned long time;
1051 size_t size = 0;
1052
1053 /* time per bit */
1054 time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1055
1056 count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1057 packet->count_skip = DIV_ROUND_UP(count, 24);
1058
1059 if (ts->debounce_max && ts->debounce_rep)
1060 /* ads7846_debounce_filter() is making ts->debounce_rep + 2
1061 * reads. So we need to get all samples for normal case. */
1062 packet->count = ts->debounce_rep + 2;
1063 else
1064 packet->count = 1;
1065
1066 if (ts->model == 7846)
1067 packet->cmds = 5; /* x, y, z1, z2, pwdown */
1068 else
1069 packet->cmds = 3; /* x, y, pwdown */
1070
1071 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1072 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1073 unsigned int max_count;
1074
1075 if (cmd_idx == packet->cmds - 1)
1076 cmd_idx = ADS7846_PWDOWN;
1077
1078 if (ads7846_cmd_need_settle(cmd_idx))
1079 max_count = packet->count + packet->count_skip;
1080 else
1081 max_count = packet->count;
1082
1083 l->offset = offset;
1084 offset += max_count;
1085 l->count = max_count;
1086 l->skip = packet->count_skip;
1087 size += sizeof(*packet->tx) * max_count;
1088 }
1089
1090 packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1091 if (!packet->tx)
1092 return -ENOMEM;
1093
1094 packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1095 if (!packet->rx)
1096 return -ENOMEM;
1097
1098 if (ts->model == 7873) {
1099 /*
1100 * The AD7873 is almost identical to the ADS7846
1101 * keep VREF off during differential/ratiometric
1102 * conversion modes.
1103 */
1104 ts->model = 7846;
1105 vref = 0;
1106 }
1107
1108 ts->msg_count = 1;
1109 spi_message_init(m);
1110 m->context = ts;
1111
1112 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1113 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1114 u8 cmd;
1115
1116 if (cmd_idx == packet->cmds - 1)
1117 cmd_idx = ADS7846_PWDOWN;
1118
1119 cmd = ads7846_get_cmd(cmd_idx, vref);
1120
1121 for (b = 0; b < l->count; b++)
1122 packet->tx[l->offset + b].cmd = cmd;
1123 }
1124
1125 x->tx_buf = packet->tx;
1126 x->rx_buf = packet->rx;
1127 x->len = size;
1128 spi_message_add_tail(x, m);
1129
1130 return 0;
1131}
1132
1133static const struct of_device_id ads7846_dt_ids[] = {
1134 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1135 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1136 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1137 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1138 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1139 { }
1140};
1141MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1142
1143static const struct spi_device_id ads7846_spi_ids[] = {
1144 { "tsc2046", 7846 },
1145 { "ads7843", 7843 },
1146 { "ads7845", 7845 },
1147 { "ads7846", 7846 },
1148 { "ads7873", 7873 },
1149 { },
1150};
1151MODULE_DEVICE_TABLE(spi, ads7846_spi_ids);
1152
1153static const struct ads7846_platform_data *ads7846_get_props(struct device *dev)
1154{
1155 struct ads7846_platform_data *pdata;
1156 u32 value;
1157
1158 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1159 if (!pdata)
1160 return ERR_PTR(-ENOMEM);
1161
1162 pdata->model = (uintptr_t)device_get_match_data(dev);
1163
1164 device_property_read_u16(dev, "ti,vref-delay-usecs",
1165 &pdata->vref_delay_usecs);
1166 device_property_read_u16(dev, "ti,vref-mv", &pdata->vref_mv);
1167 pdata->keep_vref_on = device_property_read_bool(dev, "ti,keep-vref-on");
1168
1169 pdata->swap_xy = device_property_read_bool(dev, "ti,swap-xy");
1170
1171 device_property_read_u16(dev, "ti,settle-delay-usec",
1172 &pdata->settle_delay_usecs);
1173 device_property_read_u16(dev, "ti,penirq-recheck-delay-usecs",
1174 &pdata->penirq_recheck_delay_usecs);
1175
1176 device_property_read_u16(dev, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1177 device_property_read_u16(dev, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1178
1179 device_property_read_u16(dev, "ti,x-min", &pdata->x_min);
1180 device_property_read_u16(dev, "ti,y-min", &pdata->y_min);
1181 device_property_read_u16(dev, "ti,x-max", &pdata->x_max);
1182 device_property_read_u16(dev, "ti,y-max", &pdata->y_max);
1183
1184 /*
1185 * touchscreen-max-pressure gets parsed during
1186 * touchscreen_parse_properties()
1187 */
1188 device_property_read_u16(dev, "ti,pressure-min", &pdata->pressure_min);
1189 if (!device_property_read_u32(dev, "touchscreen-min-pressure", &value))
1190 pdata->pressure_min = (u16) value;
1191 device_property_read_u16(dev, "ti,pressure-max", &pdata->pressure_max);
1192
1193 device_property_read_u16(dev, "ti,debounce-max", &pdata->debounce_max);
1194 if (!device_property_read_u32(dev, "touchscreen-average-samples", &value))
1195 pdata->debounce_max = (u16) value;
1196 device_property_read_u16(dev, "ti,debounce-tol", &pdata->debounce_tol);
1197 device_property_read_u16(dev, "ti,debounce-rep", &pdata->debounce_rep);
1198
1199 device_property_read_u32(dev, "ti,pendown-gpio-debounce",
1200 &pdata->gpio_pendown_debounce);
1201
1202 pdata->wakeup = device_property_read_bool(dev, "wakeup-source") ||
1203 device_property_read_bool(dev, "linux,wakeup");
1204
1205 return pdata;
1206}
1207
1208static void ads7846_regulator_disable(void *regulator)
1209{
1210 regulator_disable(regulator);
1211}
1212
1213static int ads7846_probe(struct spi_device *spi)
1214{
1215 const struct ads7846_platform_data *pdata;
1216 struct ads7846 *ts;
1217 struct device *dev = &spi->dev;
1218 struct ads7846_packet *packet;
1219 struct input_dev *input_dev;
1220 unsigned long irq_flags;
1221 int err;
1222
1223 if (!spi->irq) {
1224 dev_dbg(dev, "no IRQ?\n");
1225 return -EINVAL;
1226 }
1227
1228 /* don't exceed max specified sample rate */
1229 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1230 dev_err(dev, "f(sample) %d KHz?\n",
1231 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1232 return -EINVAL;
1233 }
1234
1235 /*
1236 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1237 * that even if the hardware can do that, the SPI controller driver
1238 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1239 */
1240 spi->bits_per_word = 8;
1241 spi->mode &= ~SPI_MODE_X_MASK;
1242 spi->mode |= SPI_MODE_0;
1243 err = spi_setup(spi);
1244 if (err < 0)
1245 return err;
1246
1247 ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1248 if (!ts)
1249 return -ENOMEM;
1250
1251 packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1252 if (!packet)
1253 return -ENOMEM;
1254
1255 input_dev = devm_input_allocate_device(dev);
1256 if (!input_dev)
1257 return -ENOMEM;
1258
1259 spi_set_drvdata(spi, ts);
1260
1261 ts->packet = packet;
1262 ts->spi = spi;
1263 ts->input = input_dev;
1264
1265 mutex_init(&ts->lock);
1266 init_waitqueue_head(&ts->wait);
1267
1268 pdata = dev_get_platdata(dev);
1269 if (!pdata) {
1270 pdata = ads7846_get_props(dev);
1271 if (IS_ERR(pdata))
1272 return PTR_ERR(pdata);
1273 }
1274
1275 ts->model = pdata->model ? : 7846;
1276 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1277 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1278 ts->vref_mv = pdata->vref_mv;
1279
1280 if (pdata->debounce_max) {
1281 ts->debounce_max = pdata->debounce_max;
1282 if (ts->debounce_max < 2)
1283 ts->debounce_max = 2;
1284 ts->debounce_tol = pdata->debounce_tol;
1285 ts->debounce_rep = pdata->debounce_rep;
1286 ts->filter = ads7846_debounce_filter;
1287 ts->filter_data = ts;
1288 } else {
1289 ts->filter = ads7846_no_filter;
1290 }
1291
1292 err = ads7846_setup_pendown(spi, ts, pdata);
1293 if (err)
1294 return err;
1295
1296 if (pdata->penirq_recheck_delay_usecs)
1297 ts->penirq_recheck_delay_usecs =
1298 pdata->penirq_recheck_delay_usecs;
1299
1300 ts->wait_for_sync = pdata->wait_for_sync;
1301
1302 ts->gpio_hsync = devm_gpiod_get_optional(dev, "ti,hsync", GPIOD_IN);
1303 if (IS_ERR(ts->gpio_hsync))
1304 return PTR_ERR(ts->gpio_hsync);
1305
1306 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1307 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1308
1309 input_dev->name = ts->name;
1310 input_dev->phys = ts->phys;
1311
1312 input_dev->id.bustype = BUS_SPI;
1313 input_dev->id.product = pdata->model;
1314
1315 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1316 input_set_abs_params(input_dev, ABS_X,
1317 pdata->x_min ? : 0,
1318 pdata->x_max ? : MAX_12BIT,
1319 0, 0);
1320 input_set_abs_params(input_dev, ABS_Y,
1321 pdata->y_min ? : 0,
1322 pdata->y_max ? : MAX_12BIT,
1323 0, 0);
1324 if (ts->model != 7845)
1325 input_set_abs_params(input_dev, ABS_PRESSURE,
1326 pdata->pressure_min, pdata->pressure_max, 0, 0);
1327
1328 /*
1329 * Parse common framework properties. Must be done here to ensure the
1330 * correct behaviour in case of using the legacy vendor bindings. The
1331 * general binding value overrides the vendor specific one.
1332 */
1333 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1334 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1335
1336 /*
1337 * Check if legacy ti,swap-xy binding is used instead of
1338 * touchscreen-swapped-x-y
1339 */
1340 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1341 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1342 ts->core_prop.swap_x_y = true;
1343 }
1344
1345 ads7846_setup_spi_msg(ts, pdata);
1346
1347 ts->reg = devm_regulator_get(dev, "vcc");
1348 if (IS_ERR(ts->reg)) {
1349 err = PTR_ERR(ts->reg);
1350 dev_err(dev, "unable to get regulator: %d\n", err);
1351 return err;
1352 }
1353
1354 err = regulator_enable(ts->reg);
1355 if (err) {
1356 dev_err(dev, "unable to enable regulator: %d\n", err);
1357 return err;
1358 }
1359
1360 err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1361 if (err)
1362 return err;
1363
1364 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1365 irq_flags |= IRQF_ONESHOT;
1366
1367 err = devm_request_threaded_irq(dev, spi->irq,
1368 ads7846_hard_irq, ads7846_irq,
1369 irq_flags, dev->driver->name, ts);
1370 if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1371 dev_info(dev,
1372 "trying pin change workaround on irq %d\n", spi->irq);
1373 irq_flags |= IRQF_TRIGGER_RISING;
1374 err = devm_request_threaded_irq(dev, spi->irq,
1375 ads7846_hard_irq, ads7846_irq,
1376 irq_flags, dev->driver->name,
1377 ts);
1378 }
1379
1380 if (err) {
1381 dev_dbg(dev, "irq %d busy?\n", spi->irq);
1382 return err;
1383 }
1384
1385 err = ads784x_hwmon_register(spi, ts);
1386 if (err)
1387 return err;
1388
1389 dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1390
1391 /*
1392 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1393 * the touchscreen, in case it's not connected.
1394 */
1395 if (ts->model == 7845)
1396 ads7845_read12_ser(dev, PWRDOWN);
1397 else
1398 (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1399
1400 err = input_register_device(input_dev);
1401 if (err)
1402 return err;
1403
1404 device_init_wakeup(dev, pdata->wakeup);
1405
1406 /*
1407 * If device does not carry platform data we must have allocated it
1408 * when parsing DT data.
1409 */
1410 if (!dev_get_platdata(dev))
1411 devm_kfree(dev, (void *)pdata);
1412
1413 return 0;
1414}
1415
1416static void ads7846_remove(struct spi_device *spi)
1417{
1418 struct ads7846 *ts = spi_get_drvdata(spi);
1419
1420 ads7846_stop(ts);
1421}
1422
1423static struct spi_driver ads7846_driver = {
1424 .driver = {
1425 .name = "ads7846",
1426 .dev_groups = ads784x_groups,
1427 .pm = pm_sleep_ptr(&ads7846_pm),
1428 .of_match_table = ads7846_dt_ids,
1429 },
1430 .probe = ads7846_probe,
1431 .remove = ads7846_remove,
1432 .id_table = ads7846_spi_ids,
1433};
1434
1435module_spi_driver(ads7846_driver);
1436
1437MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1438MODULE_LICENSE("GPL");