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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 <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");
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/of.h>
28#include <linux/of_gpio.h>
29#include <linux/of_device.h>
30#include <linux/gpio.h>
31#include <linux/spi/spi.h>
32#include <linux/spi/ads7846.h>
33#include <linux/regulator/consumer.h>
34#include <linux/module.h>
35#include <asm/irq.h>
36
37/*
38 * This code has been heavily tested on a Nokia 770, and lightly
39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
40 * TSC2046 is just newer ads7846 silicon.
41 * Support for ads7843 tested on Atmel at91sam926x-EK.
42 * Support for ads7845 has only been stubbed in.
43 * Support for Analog Devices AD7873 and AD7843 tested.
44 *
45 * IRQ handling needs a workaround because of a shortcoming in handling
46 * edge triggered IRQs on some platforms like the OMAP1/2. These
47 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
48 * have to maintain our own SW IRQ disabled status. This should be
49 * removed as soon as the affected platform's IRQ handling is fixed.
50 *
51 * App note sbaa036 talks in more detail about accurate sampling...
52 * that ought to help in situations like LCDs inducing noise (which
53 * can also be helped by using synch signals) and more generally.
54 * This driver tries to utilize the measures described in the app
55 * note. The strength of filtering can be set in the board-* specific
56 * files.
57 */
58
59#define TS_POLL_DELAY 1 /* ms delay before the first sample */
60#define TS_POLL_PERIOD 5 /* ms delay between samples */
61
62/* this driver doesn't aim at the peak continuous sample rate */
63#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
64
65struct ts_event {
66 /*
67 * For portability, we can't read 12 bit values using SPI (which
68 * would make the controller deliver them as native byte order u16
69 * with msbs zeroed). Instead, we read them as two 8-bit values,
70 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
71 */
72 u16 x;
73 u16 y;
74 u16 z1, z2;
75 bool ignore;
76 u8 x_buf[3];
77 u8 y_buf[3];
78};
79
80/*
81 * We allocate this separately to avoid cache line sharing issues when
82 * driver is used with DMA-based SPI controllers (like atmel_spi) on
83 * systems where main memory is not DMA-coherent (most non-x86 boards).
84 */
85struct ads7846_packet {
86 u8 read_x, read_y, read_z1, read_z2, pwrdown;
87 u16 dummy; /* for the pwrdown read */
88 struct ts_event tc;
89 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
90 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
91};
92
93struct ads7846 {
94 struct input_dev *input;
95 char phys[32];
96 char name[32];
97
98 struct spi_device *spi;
99 struct regulator *reg;
100
101#if IS_ENABLED(CONFIG_HWMON)
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 touchscreen_properties core_prop;
134
135 struct mutex lock;
136 bool stopped; /* P: lock */
137 bool disabled; /* P: lock */
138 bool suspended; /* P: lock */
139
140 int (*filter)(void *data, int data_idx, int *val);
141 void *filter_data;
142 void (*filter_cleanup)(void *data);
143 int (*get_pendown_state)(void);
144 int gpio_pendown;
145
146 void (*wait_for_sync)(void);
147};
148
149/* leave chip selected when we're done, for quicker re-select? */
150#if 0
151#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
152#else
153#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
154#endif
155
156/*--------------------------------------------------------------------------*/
157
158/* The ADS7846 has touchscreen and other sensors.
159 * Earlier ads784x chips are somewhat compatible.
160 */
161#define ADS_START (1 << 7)
162#define ADS_A2A1A0_d_y (1 << 4) /* differential */
163#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
164#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
165#define ADS_A2A1A0_d_x (5 << 4) /* differential */
166#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
167#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
168#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
169#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
170#define ADS_8_BIT (1 << 3)
171#define ADS_12_BIT (0 << 3)
172#define ADS_SER (1 << 2) /* non-differential */
173#define ADS_DFR (0 << 2) /* differential */
174#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
175#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
176#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
177#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
178
179#define MAX_12BIT ((1<<12)-1)
180
181/* leave ADC powered up (disables penirq) between differential samples */
182#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
183 | ADS_12_BIT | ADS_DFR | \
184 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
185
186#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
187#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
188#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
189
190#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
191#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
192
193/* single-ended samples need to first power up reference voltage;
194 * we leave both ADC and VREF powered
195 */
196#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
197 | ADS_12_BIT | ADS_SER)
198
199#define REF_ON (READ_12BIT_DFR(x, 1, 1))
200#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
201
202/* Must be called with ts->lock held */
203static void ads7846_stop(struct ads7846 *ts)
204{
205 if (!ts->disabled && !ts->suspended) {
206 /* Signal IRQ thread to stop polling and disable the handler. */
207 ts->stopped = true;
208 mb();
209 wake_up(&ts->wait);
210 disable_irq(ts->spi->irq);
211 }
212}
213
214/* Must be called with ts->lock held */
215static void ads7846_restart(struct ads7846 *ts)
216{
217 if (!ts->disabled && !ts->suspended) {
218 /* Tell IRQ thread that it may poll the device. */
219 ts->stopped = false;
220 mb();
221 enable_irq(ts->spi->irq);
222 }
223}
224
225/* Must be called with ts->lock held */
226static void __ads7846_disable(struct ads7846 *ts)
227{
228 ads7846_stop(ts);
229 regulator_disable(ts->reg);
230
231 /*
232 * We know the chip's in low power mode since we always
233 * leave it that way after every request
234 */
235}
236
237/* Must be called with ts->lock held */
238static void __ads7846_enable(struct ads7846 *ts)
239{
240 int error;
241
242 error = regulator_enable(ts->reg);
243 if (error != 0)
244 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
245
246 ads7846_restart(ts);
247}
248
249static void ads7846_disable(struct ads7846 *ts)
250{
251 mutex_lock(&ts->lock);
252
253 if (!ts->disabled) {
254
255 if (!ts->suspended)
256 __ads7846_disable(ts);
257
258 ts->disabled = true;
259 }
260
261 mutex_unlock(&ts->lock);
262}
263
264static void ads7846_enable(struct ads7846 *ts)
265{
266 mutex_lock(&ts->lock);
267
268 if (ts->disabled) {
269
270 ts->disabled = false;
271
272 if (!ts->suspended)
273 __ads7846_enable(ts);
274 }
275
276 mutex_unlock(&ts->lock);
277}
278
279/*--------------------------------------------------------------------------*/
280
281/*
282 * Non-touchscreen sensors only use single-ended conversions.
283 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
284 * ads7846 lets that pin be unconnected, to use internal vREF.
285 */
286
287struct ser_req {
288 u8 ref_on;
289 u8 command;
290 u8 ref_off;
291 u16 scratch;
292 struct spi_message msg;
293 struct spi_transfer xfer[6];
294 /*
295 * DMA (thus cache coherency maintenance) requires the
296 * transfer buffers to live in their own cache lines.
297 */
298 __be16 sample ____cacheline_aligned;
299};
300
301struct ads7845_ser_req {
302 u8 command[3];
303 struct spi_message msg;
304 struct spi_transfer xfer[2];
305 /*
306 * DMA (thus cache coherency maintenance) requires the
307 * transfer buffers to live in their own cache lines.
308 */
309 u8 sample[3] ____cacheline_aligned;
310};
311
312static int ads7846_read12_ser(struct device *dev, unsigned command)
313{
314 struct spi_device *spi = to_spi_device(dev);
315 struct ads7846 *ts = dev_get_drvdata(dev);
316 struct ser_req *req;
317 int status;
318
319 req = kzalloc(sizeof *req, GFP_KERNEL);
320 if (!req)
321 return -ENOMEM;
322
323 spi_message_init(&req->msg);
324
325 /* maybe turn on internal vREF, and let it settle */
326 if (ts->use_internal) {
327 req->ref_on = REF_ON;
328 req->xfer[0].tx_buf = &req->ref_on;
329 req->xfer[0].len = 1;
330 spi_message_add_tail(&req->xfer[0], &req->msg);
331
332 req->xfer[1].rx_buf = &req->scratch;
333 req->xfer[1].len = 2;
334
335 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
336 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
337 spi_message_add_tail(&req->xfer[1], &req->msg);
338
339 /* Enable reference voltage */
340 command |= ADS_PD10_REF_ON;
341 }
342
343 /* Enable ADC in every case */
344 command |= ADS_PD10_ADC_ON;
345
346 /* take sample */
347 req->command = (u8) command;
348 req->xfer[2].tx_buf = &req->command;
349 req->xfer[2].len = 1;
350 spi_message_add_tail(&req->xfer[2], &req->msg);
351
352 req->xfer[3].rx_buf = &req->sample;
353 req->xfer[3].len = 2;
354 spi_message_add_tail(&req->xfer[3], &req->msg);
355
356 /* REVISIT: take a few more samples, and compare ... */
357
358 /* converter in low power mode & enable PENIRQ */
359 req->ref_off = PWRDOWN;
360 req->xfer[4].tx_buf = &req->ref_off;
361 req->xfer[4].len = 1;
362 spi_message_add_tail(&req->xfer[4], &req->msg);
363
364 req->xfer[5].rx_buf = &req->scratch;
365 req->xfer[5].len = 2;
366 CS_CHANGE(req->xfer[5]);
367 spi_message_add_tail(&req->xfer[5], &req->msg);
368
369 mutex_lock(&ts->lock);
370 ads7846_stop(ts);
371 status = spi_sync(spi, &req->msg);
372 ads7846_restart(ts);
373 mutex_unlock(&ts->lock);
374
375 if (status == 0) {
376 /* on-wire is a must-ignore bit, a BE12 value, then padding */
377 status = be16_to_cpu(req->sample);
378 status = status >> 3;
379 status &= 0x0fff;
380 }
381
382 kfree(req);
383 return status;
384}
385
386static int ads7845_read12_ser(struct device *dev, unsigned command)
387{
388 struct spi_device *spi = to_spi_device(dev);
389 struct ads7846 *ts = dev_get_drvdata(dev);
390 struct ads7845_ser_req *req;
391 int status;
392
393 req = kzalloc(sizeof *req, GFP_KERNEL);
394 if (!req)
395 return -ENOMEM;
396
397 spi_message_init(&req->msg);
398
399 req->command[0] = (u8) command;
400 req->xfer[0].tx_buf = req->command;
401 req->xfer[0].rx_buf = req->sample;
402 req->xfer[0].len = 3;
403 spi_message_add_tail(&req->xfer[0], &req->msg);
404
405 mutex_lock(&ts->lock);
406 ads7846_stop(ts);
407 status = spi_sync(spi, &req->msg);
408 ads7846_restart(ts);
409 mutex_unlock(&ts->lock);
410
411 if (status == 0) {
412 /* BE12 value, then padding */
413 status = be16_to_cpu(*((u16 *)&req->sample[1]));
414 status = status >> 3;
415 status &= 0x0fff;
416 }
417
418 kfree(req);
419 return status;
420}
421
422#if IS_ENABLED(CONFIG_HWMON)
423
424#define SHOW(name, var, adjust) static ssize_t \
425name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
426{ \
427 struct ads7846 *ts = dev_get_drvdata(dev); \
428 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
429 READ_12BIT_SER(var)); \
430 if (v < 0) \
431 return v; \
432 return sprintf(buf, "%u\n", adjust(ts, v)); \
433} \
434static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
435
436
437/* Sysfs conventions report temperatures in millidegrees Celsius.
438 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
439 * accuracy scheme without calibration data. For now we won't try either;
440 * userspace sees raw sensor values, and must scale/calibrate appropriately.
441 */
442static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
443{
444 return v;
445}
446
447SHOW(temp0, temp0, null_adjust) /* temp1_input */
448SHOW(temp1, temp1, null_adjust) /* temp2_input */
449
450
451/* sysfs conventions report voltages in millivolts. We can convert voltages
452 * if we know vREF. userspace may need to scale vAUX to match the board's
453 * external resistors; we assume that vBATT only uses the internal ones.
454 */
455static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
456{
457 unsigned retval = v;
458
459 /* external resistors may scale vAUX into 0..vREF */
460 retval *= ts->vref_mv;
461 retval = retval >> 12;
462
463 return retval;
464}
465
466static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
467{
468 unsigned retval = vaux_adjust(ts, v);
469
470 /* ads7846 has a resistor ladder to scale this signal down */
471 if (ts->model == 7846)
472 retval *= 4;
473
474 return retval;
475}
476
477SHOW(in0_input, vaux, vaux_adjust)
478SHOW(in1_input, vbatt, vbatt_adjust)
479
480static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
481 int index)
482{
483 struct device *dev = container_of(kobj, struct device, kobj);
484 struct ads7846 *ts = dev_get_drvdata(dev);
485
486 if (ts->model == 7843 && index < 2) /* in0, in1 */
487 return 0;
488 if (ts->model == 7845 && index != 2) /* in0 */
489 return 0;
490
491 return attr->mode;
492}
493
494static struct attribute *ads7846_attributes[] = {
495 &dev_attr_temp0.attr, /* 0 */
496 &dev_attr_temp1.attr, /* 1 */
497 &dev_attr_in0_input.attr, /* 2 */
498 &dev_attr_in1_input.attr, /* 3 */
499 NULL,
500};
501
502static const struct attribute_group ads7846_attr_group = {
503 .attrs = ads7846_attributes,
504 .is_visible = ads7846_is_visible,
505};
506__ATTRIBUTE_GROUPS(ads7846_attr);
507
508static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
509{
510 /* hwmon sensors need a reference voltage */
511 switch (ts->model) {
512 case 7846:
513 if (!ts->vref_mv) {
514 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
515 ts->vref_mv = 2500;
516 ts->use_internal = true;
517 }
518 break;
519 case 7845:
520 case 7843:
521 if (!ts->vref_mv) {
522 dev_warn(&spi->dev,
523 "external vREF for ADS%d not specified\n",
524 ts->model);
525 return 0;
526 }
527 break;
528 }
529
530 ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
531 ts, ads7846_attr_groups);
532
533 return PTR_ERR_OR_ZERO(ts->hwmon);
534}
535
536static void ads784x_hwmon_unregister(struct spi_device *spi,
537 struct ads7846 *ts)
538{
539 if (ts->hwmon)
540 hwmon_device_unregister(ts->hwmon);
541}
542
543#else
544static inline int ads784x_hwmon_register(struct spi_device *spi,
545 struct ads7846 *ts)
546{
547 return 0;
548}
549
550static inline void ads784x_hwmon_unregister(struct spi_device *spi,
551 struct ads7846 *ts)
552{
553}
554#endif
555
556static ssize_t ads7846_pen_down_show(struct device *dev,
557 struct device_attribute *attr, char *buf)
558{
559 struct ads7846 *ts = dev_get_drvdata(dev);
560
561 return sprintf(buf, "%u\n", ts->pendown);
562}
563
564static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
565
566static ssize_t ads7846_disable_show(struct device *dev,
567 struct device_attribute *attr, char *buf)
568{
569 struct ads7846 *ts = dev_get_drvdata(dev);
570
571 return sprintf(buf, "%u\n", ts->disabled);
572}
573
574static ssize_t ads7846_disable_store(struct device *dev,
575 struct device_attribute *attr,
576 const char *buf, size_t count)
577{
578 struct ads7846 *ts = dev_get_drvdata(dev);
579 unsigned int i;
580 int err;
581
582 err = kstrtouint(buf, 10, &i);
583 if (err)
584 return err;
585
586 if (i)
587 ads7846_disable(ts);
588 else
589 ads7846_enable(ts);
590
591 return count;
592}
593
594static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
595
596static struct attribute *ads784x_attributes[] = {
597 &dev_attr_pen_down.attr,
598 &dev_attr_disable.attr,
599 NULL,
600};
601
602static const struct attribute_group ads784x_attr_group = {
603 .attrs = ads784x_attributes,
604};
605
606/*--------------------------------------------------------------------------*/
607
608static int get_pendown_state(struct ads7846 *ts)
609{
610 if (ts->get_pendown_state)
611 return ts->get_pendown_state();
612
613 return !gpio_get_value(ts->gpio_pendown);
614}
615
616static void null_wait_for_sync(void)
617{
618}
619
620static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
621{
622 struct ads7846 *ts = ads;
623
624 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
625 /* Start over collecting consistent readings. */
626 ts->read_rep = 0;
627 /*
628 * Repeat it, if this was the first read or the read
629 * wasn't consistent enough.
630 */
631 if (ts->read_cnt < ts->debounce_max) {
632 ts->last_read = *val;
633 ts->read_cnt++;
634 return ADS7846_FILTER_REPEAT;
635 } else {
636 /*
637 * Maximum number of debouncing reached and still
638 * not enough number of consistent readings. Abort
639 * the whole sample, repeat it in the next sampling
640 * period.
641 */
642 ts->read_cnt = 0;
643 return ADS7846_FILTER_IGNORE;
644 }
645 } else {
646 if (++ts->read_rep > ts->debounce_rep) {
647 /*
648 * Got a good reading for this coordinate,
649 * go for the next one.
650 */
651 ts->read_cnt = 0;
652 ts->read_rep = 0;
653 return ADS7846_FILTER_OK;
654 } else {
655 /* Read more values that are consistent. */
656 ts->read_cnt++;
657 return ADS7846_FILTER_REPEAT;
658 }
659 }
660}
661
662static int ads7846_no_filter(void *ads, int data_idx, int *val)
663{
664 return ADS7846_FILTER_OK;
665}
666
667static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
668{
669 int value;
670 struct spi_transfer *t =
671 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
672
673 if (ts->model == 7845) {
674 value = be16_to_cpup((__be16 *)&(((char *)t->rx_buf)[1]));
675 } else {
676 /*
677 * adjust: on-wire is a must-ignore bit, a BE12 value, then
678 * padding; built from two 8 bit values written msb-first.
679 */
680 value = be16_to_cpup((__be16 *)t->rx_buf);
681 }
682
683 /* enforce ADC output is 12 bits width */
684 return (value >> 3) & 0xfff;
685}
686
687static void ads7846_update_value(struct spi_message *m, int val)
688{
689 struct spi_transfer *t =
690 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
691
692 *(u16 *)t->rx_buf = val;
693}
694
695static void ads7846_read_state(struct ads7846 *ts)
696{
697 struct ads7846_packet *packet = ts->packet;
698 struct spi_message *m;
699 int msg_idx = 0;
700 int val;
701 int action;
702 int error;
703
704 while (msg_idx < ts->msg_count) {
705
706 ts->wait_for_sync();
707
708 m = &ts->msg[msg_idx];
709 error = spi_sync(ts->spi, m);
710 if (error) {
711 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
712 packet->tc.ignore = true;
713 return;
714 }
715
716 /*
717 * Last message is power down request, no need to convert
718 * or filter the value.
719 */
720 if (msg_idx < ts->msg_count - 1) {
721
722 val = ads7846_get_value(ts, m);
723
724 action = ts->filter(ts->filter_data, msg_idx, &val);
725 switch (action) {
726 case ADS7846_FILTER_REPEAT:
727 continue;
728
729 case ADS7846_FILTER_IGNORE:
730 packet->tc.ignore = true;
731 msg_idx = ts->msg_count - 1;
732 continue;
733
734 case ADS7846_FILTER_OK:
735 ads7846_update_value(m, val);
736 packet->tc.ignore = false;
737 msg_idx++;
738 break;
739
740 default:
741 BUG();
742 }
743 } else {
744 msg_idx++;
745 }
746 }
747}
748
749static void ads7846_report_state(struct ads7846 *ts)
750{
751 struct ads7846_packet *packet = ts->packet;
752 unsigned int Rt;
753 u16 x, y, z1, z2;
754
755 /*
756 * ads7846_get_value() does in-place conversion (including byte swap)
757 * from on-the-wire format as part of debouncing to get stable
758 * readings.
759 */
760 if (ts->model == 7845) {
761 x = *(u16 *)packet->tc.x_buf;
762 y = *(u16 *)packet->tc.y_buf;
763 z1 = 0;
764 z2 = 0;
765 } else {
766 x = packet->tc.x;
767 y = packet->tc.y;
768 z1 = packet->tc.z1;
769 z2 = packet->tc.z2;
770 }
771
772 /* range filtering */
773 if (x == MAX_12BIT)
774 x = 0;
775
776 if (ts->model == 7843) {
777 Rt = ts->pressure_max / 2;
778 } else if (ts->model == 7845) {
779 if (get_pendown_state(ts))
780 Rt = ts->pressure_max / 2;
781 else
782 Rt = 0;
783 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
784 } else if (likely(x && z1)) {
785 /* compute touch pressure resistance using equation #2 */
786 Rt = z2;
787 Rt -= z1;
788 Rt *= x;
789 Rt *= ts->x_plate_ohms;
790 Rt /= z1;
791 Rt = (Rt + 2047) >> 12;
792 } else {
793 Rt = 0;
794 }
795
796 /*
797 * Sample found inconsistent by debouncing or pressure is beyond
798 * the maximum. Don't report it to user space, repeat at least
799 * once more the measurement
800 */
801 if (packet->tc.ignore || Rt > ts->pressure_max) {
802 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
803 packet->tc.ignore, Rt);
804 return;
805 }
806
807 /*
808 * Maybe check the pendown state before reporting. This discards
809 * false readings when the pen is lifted.
810 */
811 if (ts->penirq_recheck_delay_usecs) {
812 udelay(ts->penirq_recheck_delay_usecs);
813 if (!get_pendown_state(ts))
814 Rt = 0;
815 }
816
817 /*
818 * NOTE: We can't rely on the pressure to determine the pen down
819 * state, even this controller has a pressure sensor. The pressure
820 * value can fluctuate for quite a while after lifting the pen and
821 * in some cases may not even settle at the expected value.
822 *
823 * The only safe way to check for the pen up condition is in the
824 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
825 */
826 if (Rt) {
827 struct input_dev *input = ts->input;
828
829 if (!ts->pendown) {
830 input_report_key(input, BTN_TOUCH, 1);
831 ts->pendown = true;
832 dev_vdbg(&ts->spi->dev, "DOWN\n");
833 }
834
835 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
836 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
837
838 input_sync(input);
839 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
840 }
841}
842
843static irqreturn_t ads7846_hard_irq(int irq, void *handle)
844{
845 struct ads7846 *ts = handle;
846
847 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
848}
849
850
851static irqreturn_t ads7846_irq(int irq, void *handle)
852{
853 struct ads7846 *ts = handle;
854
855 /* Start with a small delay before checking pendown state */
856 msleep(TS_POLL_DELAY);
857
858 while (!ts->stopped && get_pendown_state(ts)) {
859
860 /* pen is down, continue with the measurement */
861 ads7846_read_state(ts);
862
863 if (!ts->stopped)
864 ads7846_report_state(ts);
865
866 wait_event_timeout(ts->wait, ts->stopped,
867 msecs_to_jiffies(TS_POLL_PERIOD));
868 }
869
870 if (ts->pendown && !ts->stopped) {
871 struct input_dev *input = ts->input;
872
873 input_report_key(input, BTN_TOUCH, 0);
874 input_report_abs(input, ABS_PRESSURE, 0);
875 input_sync(input);
876
877 ts->pendown = false;
878 dev_vdbg(&ts->spi->dev, "UP\n");
879 }
880
881 return IRQ_HANDLED;
882}
883
884static int __maybe_unused ads7846_suspend(struct device *dev)
885{
886 struct ads7846 *ts = dev_get_drvdata(dev);
887
888 mutex_lock(&ts->lock);
889
890 if (!ts->suspended) {
891
892 if (!ts->disabled)
893 __ads7846_disable(ts);
894
895 if (device_may_wakeup(&ts->spi->dev))
896 enable_irq_wake(ts->spi->irq);
897
898 ts->suspended = true;
899 }
900
901 mutex_unlock(&ts->lock);
902
903 return 0;
904}
905
906static int __maybe_unused ads7846_resume(struct device *dev)
907{
908 struct ads7846 *ts = dev_get_drvdata(dev);
909
910 mutex_lock(&ts->lock);
911
912 if (ts->suspended) {
913
914 ts->suspended = false;
915
916 if (device_may_wakeup(&ts->spi->dev))
917 disable_irq_wake(ts->spi->irq);
918
919 if (!ts->disabled)
920 __ads7846_enable(ts);
921 }
922
923 mutex_unlock(&ts->lock);
924
925 return 0;
926}
927
928static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
929
930static int ads7846_setup_pendown(struct spi_device *spi,
931 struct ads7846 *ts,
932 const struct ads7846_platform_data *pdata)
933{
934 int err;
935
936 /*
937 * REVISIT when the irq can be triggered active-low, or if for some
938 * reason the touchscreen isn't hooked up, we don't need to access
939 * the pendown state.
940 */
941
942 if (pdata->get_pendown_state) {
943 ts->get_pendown_state = pdata->get_pendown_state;
944 } else if (gpio_is_valid(pdata->gpio_pendown)) {
945
946 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
947 "ads7846_pendown");
948 if (err) {
949 dev_err(&spi->dev,
950 "failed to request/setup pendown GPIO%d: %d\n",
951 pdata->gpio_pendown, err);
952 return err;
953 }
954
955 ts->gpio_pendown = pdata->gpio_pendown;
956
957 if (pdata->gpio_pendown_debounce)
958 gpio_set_debounce(pdata->gpio_pendown,
959 pdata->gpio_pendown_debounce);
960 } else {
961 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
962 return -EINVAL;
963 }
964
965 return 0;
966}
967
968/*
969 * Set up the transfers to read touchscreen state; this assumes we
970 * use formula #2 for pressure, not #3.
971 */
972static void ads7846_setup_spi_msg(struct ads7846 *ts,
973 const struct ads7846_platform_data *pdata)
974{
975 struct spi_message *m = &ts->msg[0];
976 struct spi_transfer *x = ts->xfer;
977 struct ads7846_packet *packet = ts->packet;
978 int vref = pdata->keep_vref_on;
979
980 if (ts->model == 7873) {
981 /*
982 * The AD7873 is almost identical to the ADS7846
983 * keep VREF off during differential/ratiometric
984 * conversion modes.
985 */
986 ts->model = 7846;
987 vref = 0;
988 }
989
990 ts->msg_count = 1;
991 spi_message_init(m);
992 m->context = ts;
993
994 if (ts->model == 7845) {
995 packet->read_y_cmd[0] = READ_Y(vref);
996 packet->read_y_cmd[1] = 0;
997 packet->read_y_cmd[2] = 0;
998 x->tx_buf = &packet->read_y_cmd[0];
999 x->rx_buf = &packet->tc.y_buf[0];
1000 x->len = 3;
1001 spi_message_add_tail(x, m);
1002 } else {
1003 /* y- still on; turn on only y+ (and ADC) */
1004 packet->read_y = READ_Y(vref);
1005 x->tx_buf = &packet->read_y;
1006 x->len = 1;
1007 spi_message_add_tail(x, m);
1008
1009 x++;
1010 x->rx_buf = &packet->tc.y;
1011 x->len = 2;
1012 spi_message_add_tail(x, m);
1013 }
1014
1015 /*
1016 * The first sample after switching drivers can be low quality;
1017 * optionally discard it, using a second one after the signals
1018 * have had enough time to stabilize.
1019 */
1020 if (pdata->settle_delay_usecs) {
1021 x->delay_usecs = pdata->settle_delay_usecs;
1022
1023 x++;
1024 x->tx_buf = &packet->read_y;
1025 x->len = 1;
1026 spi_message_add_tail(x, m);
1027
1028 x++;
1029 x->rx_buf = &packet->tc.y;
1030 x->len = 2;
1031 spi_message_add_tail(x, m);
1032 }
1033
1034 ts->msg_count++;
1035 m++;
1036 spi_message_init(m);
1037 m->context = ts;
1038
1039 if (ts->model == 7845) {
1040 x++;
1041 packet->read_x_cmd[0] = READ_X(vref);
1042 packet->read_x_cmd[1] = 0;
1043 packet->read_x_cmd[2] = 0;
1044 x->tx_buf = &packet->read_x_cmd[0];
1045 x->rx_buf = &packet->tc.x_buf[0];
1046 x->len = 3;
1047 spi_message_add_tail(x, m);
1048 } else {
1049 /* turn y- off, x+ on, then leave in lowpower */
1050 x++;
1051 packet->read_x = READ_X(vref);
1052 x->tx_buf = &packet->read_x;
1053 x->len = 1;
1054 spi_message_add_tail(x, m);
1055
1056 x++;
1057 x->rx_buf = &packet->tc.x;
1058 x->len = 2;
1059 spi_message_add_tail(x, m);
1060 }
1061
1062 /* ... maybe discard first sample ... */
1063 if (pdata->settle_delay_usecs) {
1064 x->delay_usecs = pdata->settle_delay_usecs;
1065
1066 x++;
1067 x->tx_buf = &packet->read_x;
1068 x->len = 1;
1069 spi_message_add_tail(x, m);
1070
1071 x++;
1072 x->rx_buf = &packet->tc.x;
1073 x->len = 2;
1074 spi_message_add_tail(x, m);
1075 }
1076
1077 /* turn y+ off, x- on; we'll use formula #2 */
1078 if (ts->model == 7846) {
1079 ts->msg_count++;
1080 m++;
1081 spi_message_init(m);
1082 m->context = ts;
1083
1084 x++;
1085 packet->read_z1 = READ_Z1(vref);
1086 x->tx_buf = &packet->read_z1;
1087 x->len = 1;
1088 spi_message_add_tail(x, m);
1089
1090 x++;
1091 x->rx_buf = &packet->tc.z1;
1092 x->len = 2;
1093 spi_message_add_tail(x, m);
1094
1095 /* ... maybe discard first sample ... */
1096 if (pdata->settle_delay_usecs) {
1097 x->delay_usecs = pdata->settle_delay_usecs;
1098
1099 x++;
1100 x->tx_buf = &packet->read_z1;
1101 x->len = 1;
1102 spi_message_add_tail(x, m);
1103
1104 x++;
1105 x->rx_buf = &packet->tc.z1;
1106 x->len = 2;
1107 spi_message_add_tail(x, m);
1108 }
1109
1110 ts->msg_count++;
1111 m++;
1112 spi_message_init(m);
1113 m->context = ts;
1114
1115 x++;
1116 packet->read_z2 = READ_Z2(vref);
1117 x->tx_buf = &packet->read_z2;
1118 x->len = 1;
1119 spi_message_add_tail(x, m);
1120
1121 x++;
1122 x->rx_buf = &packet->tc.z2;
1123 x->len = 2;
1124 spi_message_add_tail(x, m);
1125
1126 /* ... maybe discard first sample ... */
1127 if (pdata->settle_delay_usecs) {
1128 x->delay_usecs = pdata->settle_delay_usecs;
1129
1130 x++;
1131 x->tx_buf = &packet->read_z2;
1132 x->len = 1;
1133 spi_message_add_tail(x, m);
1134
1135 x++;
1136 x->rx_buf = &packet->tc.z2;
1137 x->len = 2;
1138 spi_message_add_tail(x, m);
1139 }
1140 }
1141
1142 /* power down */
1143 ts->msg_count++;
1144 m++;
1145 spi_message_init(m);
1146 m->context = ts;
1147
1148 if (ts->model == 7845) {
1149 x++;
1150 packet->pwrdown_cmd[0] = PWRDOWN;
1151 packet->pwrdown_cmd[1] = 0;
1152 packet->pwrdown_cmd[2] = 0;
1153 x->tx_buf = &packet->pwrdown_cmd[0];
1154 x->len = 3;
1155 } else {
1156 x++;
1157 packet->pwrdown = PWRDOWN;
1158 x->tx_buf = &packet->pwrdown;
1159 x->len = 1;
1160 spi_message_add_tail(x, m);
1161
1162 x++;
1163 x->rx_buf = &packet->dummy;
1164 x->len = 2;
1165 }
1166
1167 CS_CHANGE(*x);
1168 spi_message_add_tail(x, m);
1169}
1170
1171#ifdef CONFIG_OF
1172static const struct of_device_id ads7846_dt_ids[] = {
1173 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1174 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1175 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1176 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1177 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1178 { }
1179};
1180MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1181
1182static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1183{
1184 struct ads7846_platform_data *pdata;
1185 struct device_node *node = dev->of_node;
1186 const struct of_device_id *match;
1187 u32 value;
1188
1189 if (!node) {
1190 dev_err(dev, "Device does not have associated DT data\n");
1191 return ERR_PTR(-EINVAL);
1192 }
1193
1194 match = of_match_device(ads7846_dt_ids, dev);
1195 if (!match) {
1196 dev_err(dev, "Unknown device model\n");
1197 return ERR_PTR(-EINVAL);
1198 }
1199
1200 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1201 if (!pdata)
1202 return ERR_PTR(-ENOMEM);
1203
1204 pdata->model = (unsigned long)match->data;
1205
1206 of_property_read_u16(node, "ti,vref-delay-usecs",
1207 &pdata->vref_delay_usecs);
1208 of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1209 pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1210
1211 pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1212
1213 of_property_read_u16(node, "ti,settle-delay-usec",
1214 &pdata->settle_delay_usecs);
1215 of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1216 &pdata->penirq_recheck_delay_usecs);
1217
1218 of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1219 of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1220
1221 of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1222 of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1223 of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1224 of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1225
1226 /*
1227 * touchscreen-max-pressure gets parsed during
1228 * touchscreen_parse_properties()
1229 */
1230 of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1231 if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
1232 pdata->pressure_min = (u16) value;
1233 of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1234
1235 of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1236 if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
1237 pdata->debounce_max = (u16) value;
1238 of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1239 of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1240
1241 of_property_read_u32(node, "ti,pendown-gpio-debounce",
1242 &pdata->gpio_pendown_debounce);
1243
1244 pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1245 of_property_read_bool(node, "linux,wakeup");
1246
1247 pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1248
1249 return pdata;
1250}
1251#else
1252static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1253{
1254 dev_err(dev, "no platform data defined\n");
1255 return ERR_PTR(-EINVAL);
1256}
1257#endif
1258
1259static int ads7846_probe(struct spi_device *spi)
1260{
1261 const struct ads7846_platform_data *pdata;
1262 struct ads7846 *ts;
1263 struct ads7846_packet *packet;
1264 struct input_dev *input_dev;
1265 unsigned long irq_flags;
1266 int err;
1267
1268 if (!spi->irq) {
1269 dev_dbg(&spi->dev, "no IRQ?\n");
1270 return -EINVAL;
1271 }
1272
1273 /* don't exceed max specified sample rate */
1274 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1275 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1276 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1277 return -EINVAL;
1278 }
1279
1280 /*
1281 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1282 * that even if the hardware can do that, the SPI controller driver
1283 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1284 */
1285 spi->bits_per_word = 8;
1286 spi->mode = SPI_MODE_0;
1287 err = spi_setup(spi);
1288 if (err < 0)
1289 return err;
1290
1291 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1292 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1293 input_dev = input_allocate_device();
1294 if (!ts || !packet || !input_dev) {
1295 err = -ENOMEM;
1296 goto err_free_mem;
1297 }
1298
1299 spi_set_drvdata(spi, ts);
1300
1301 ts->packet = packet;
1302 ts->spi = spi;
1303 ts->input = input_dev;
1304
1305 mutex_init(&ts->lock);
1306 init_waitqueue_head(&ts->wait);
1307
1308 pdata = dev_get_platdata(&spi->dev);
1309 if (!pdata) {
1310 pdata = ads7846_probe_dt(&spi->dev);
1311 if (IS_ERR(pdata)) {
1312 err = PTR_ERR(pdata);
1313 goto err_free_mem;
1314 }
1315 }
1316
1317 ts->model = pdata->model ? : 7846;
1318 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1319 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1320 ts->vref_mv = pdata->vref_mv;
1321
1322 if (pdata->filter != NULL) {
1323 if (pdata->filter_init != NULL) {
1324 err = pdata->filter_init(pdata, &ts->filter_data);
1325 if (err < 0)
1326 goto err_free_mem;
1327 }
1328 ts->filter = pdata->filter;
1329 ts->filter_cleanup = pdata->filter_cleanup;
1330 } else if (pdata->debounce_max) {
1331 ts->debounce_max = pdata->debounce_max;
1332 if (ts->debounce_max < 2)
1333 ts->debounce_max = 2;
1334 ts->debounce_tol = pdata->debounce_tol;
1335 ts->debounce_rep = pdata->debounce_rep;
1336 ts->filter = ads7846_debounce_filter;
1337 ts->filter_data = ts;
1338 } else {
1339 ts->filter = ads7846_no_filter;
1340 }
1341
1342 err = ads7846_setup_pendown(spi, ts, pdata);
1343 if (err)
1344 goto err_cleanup_filter;
1345
1346 if (pdata->penirq_recheck_delay_usecs)
1347 ts->penirq_recheck_delay_usecs =
1348 pdata->penirq_recheck_delay_usecs;
1349
1350 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1351
1352 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1353 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1354
1355 input_dev->name = ts->name;
1356 input_dev->phys = ts->phys;
1357 input_dev->dev.parent = &spi->dev;
1358
1359 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1360 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1361 input_set_abs_params(input_dev, ABS_X,
1362 pdata->x_min ? : 0,
1363 pdata->x_max ? : MAX_12BIT,
1364 0, 0);
1365 input_set_abs_params(input_dev, ABS_Y,
1366 pdata->y_min ? : 0,
1367 pdata->y_max ? : MAX_12BIT,
1368 0, 0);
1369 input_set_abs_params(input_dev, ABS_PRESSURE,
1370 pdata->pressure_min, pdata->pressure_max, 0, 0);
1371
1372 /*
1373 * Parse common framework properties. Must be done here to ensure the
1374 * correct behaviour in case of using the legacy vendor bindings. The
1375 * general binding value overrides the vendor specific one.
1376 */
1377 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1378 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1379
1380 /*
1381 * Check if legacy ti,swap-xy binding is used instead of
1382 * touchscreen-swapped-x-y
1383 */
1384 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1385 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1386 ts->core_prop.swap_x_y = true;
1387 }
1388
1389 ads7846_setup_spi_msg(ts, pdata);
1390
1391 ts->reg = regulator_get(&spi->dev, "vcc");
1392 if (IS_ERR(ts->reg)) {
1393 err = PTR_ERR(ts->reg);
1394 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1395 goto err_free_gpio;
1396 }
1397
1398 err = regulator_enable(ts->reg);
1399 if (err) {
1400 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1401 goto err_put_regulator;
1402 }
1403
1404 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1405 irq_flags |= IRQF_ONESHOT;
1406
1407 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1408 irq_flags, spi->dev.driver->name, ts);
1409 if (err && !pdata->irq_flags) {
1410 dev_info(&spi->dev,
1411 "trying pin change workaround on irq %d\n", spi->irq);
1412 irq_flags |= IRQF_TRIGGER_RISING;
1413 err = request_threaded_irq(spi->irq,
1414 ads7846_hard_irq, ads7846_irq,
1415 irq_flags, spi->dev.driver->name, ts);
1416 }
1417
1418 if (err) {
1419 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1420 goto err_disable_regulator;
1421 }
1422
1423 err = ads784x_hwmon_register(spi, ts);
1424 if (err)
1425 goto err_free_irq;
1426
1427 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1428
1429 /*
1430 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1431 * the touchscreen, in case it's not connected.
1432 */
1433 if (ts->model == 7845)
1434 ads7845_read12_ser(&spi->dev, PWRDOWN);
1435 else
1436 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1437
1438 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1439 if (err)
1440 goto err_remove_hwmon;
1441
1442 err = input_register_device(input_dev);
1443 if (err)
1444 goto err_remove_attr_group;
1445
1446 device_init_wakeup(&spi->dev, pdata->wakeup);
1447
1448 /*
1449 * If device does not carry platform data we must have allocated it
1450 * when parsing DT data.
1451 */
1452 if (!dev_get_platdata(&spi->dev))
1453 devm_kfree(&spi->dev, (void *)pdata);
1454
1455 return 0;
1456
1457 err_remove_attr_group:
1458 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1459 err_remove_hwmon:
1460 ads784x_hwmon_unregister(spi, ts);
1461 err_free_irq:
1462 free_irq(spi->irq, ts);
1463 err_disable_regulator:
1464 regulator_disable(ts->reg);
1465 err_put_regulator:
1466 regulator_put(ts->reg);
1467 err_free_gpio:
1468 if (!ts->get_pendown_state)
1469 gpio_free(ts->gpio_pendown);
1470 err_cleanup_filter:
1471 if (ts->filter_cleanup)
1472 ts->filter_cleanup(ts->filter_data);
1473 err_free_mem:
1474 input_free_device(input_dev);
1475 kfree(packet);
1476 kfree(ts);
1477 return err;
1478}
1479
1480static int ads7846_remove(struct spi_device *spi)
1481{
1482 struct ads7846 *ts = spi_get_drvdata(spi);
1483
1484 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1485
1486 ads7846_disable(ts);
1487 free_irq(ts->spi->irq, ts);
1488
1489 input_unregister_device(ts->input);
1490
1491 ads784x_hwmon_unregister(spi, ts);
1492
1493 regulator_put(ts->reg);
1494
1495 if (!ts->get_pendown_state) {
1496 /*
1497 * If we are not using specialized pendown method we must
1498 * have been relying on gpio we set up ourselves.
1499 */
1500 gpio_free(ts->gpio_pendown);
1501 }
1502
1503 if (ts->filter_cleanup)
1504 ts->filter_cleanup(ts->filter_data);
1505
1506 kfree(ts->packet);
1507 kfree(ts);
1508
1509 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1510
1511 return 0;
1512}
1513
1514static struct spi_driver ads7846_driver = {
1515 .driver = {
1516 .name = "ads7846",
1517 .pm = &ads7846_pm,
1518 .of_match_table = of_match_ptr(ads7846_dt_ids),
1519 },
1520 .probe = ads7846_probe,
1521 .remove = ads7846_remove,
1522};
1523
1524module_spi_driver(ads7846_driver);
1525
1526MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1527MODULE_LICENSE("GPL");
1528MODULE_ALIAS("spi:ads7846");