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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");
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");