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
63 struct ads7846_buf {
64 u8 cmd;
65 __be16 data;
66 } __packed;
67
68 struct 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 */
79 struct 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
94 struct 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
145 enum 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 */
210 enum ads7846_cmds {
211 ADS7846_X,
212 ADS7846_Y,
213 ADS7846_Z1,
214 ADS7846_Z2,
215 ADS7846_PWDOWN,
216 };
217
get_pendown_state(struct ads7846 * ts)218 static 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
ads7846_report_pen_up(struct ads7846 * ts)226 static 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 */
ads7846_stop(struct ads7846 * ts)239 static 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 */
ads7846_restart(struct ads7846 * ts)251 static 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 */
__ads7846_disable(struct ads7846 * ts)266 static 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 */
__ads7846_enable(struct ads7846 * ts)278 static 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
ads7846_disable(struct ads7846 * ts)289 static 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
ads7846_enable(struct ads7846 * ts)304 static 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
327 struct 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
341 struct 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
ads7846_read12_ser(struct device * dev,unsigned command)352 static 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
ads7845_read12_ser(struct device * dev,unsigned command)427 static 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 \
466 name ## _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 } \
475 static 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 */
null_adjust(struct ads7846 * ts,ssize_t v)483 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
484 {
485 return v;
486 }
487
SHOW(temp0,temp0,null_adjust)488 SHOW(temp0, temp0, null_adjust) /* temp1_input */
489 SHOW(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 */
496 static 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
vbatt_adjust(struct ads7846 * ts,ssize_t v)507 static 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
SHOW(in0_input,vaux,vaux_adjust)518 SHOW(in0_input, vaux, vaux_adjust)
519 SHOW(in1_input, vbatt, vbatt_adjust)
520
521 static 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
535 static 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
543 static const struct attribute_group ads7846_attr_group = {
544 .attrs = ads7846_attributes,
545 .is_visible = ads7846_is_visible,
546 };
547 __ATTRIBUTE_GROUPS(ads7846_attr);
548
ads784x_hwmon_register(struct spi_device * spi,struct ads7846 * ts)549 static 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
ads784x_hwmon_register(struct spi_device * spi,struct ads7846 * ts)581 static inline int ads784x_hwmon_register(struct spi_device *spi,
582 struct ads7846 *ts)
583 {
584 return 0;
585 }
586 #endif
587
ads7846_pen_down_show(struct device * dev,struct device_attribute * attr,char * buf)588 static 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
596 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
597
ads7846_disable_show(struct device * dev,struct device_attribute * attr,char * buf)598 static 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
ads7846_disable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)606 static 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
626 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
627
628 static struct attribute *ads784x_attributes[] = {
629 &dev_attr_pen_down.attr,
630 &dev_attr_disable.attr,
631 NULL,
632 };
633
634 static const struct attribute_group ads784x_attr_group = {
635 .attrs = ads784x_attributes,
636 };
637
638 /*--------------------------------------------------------------------------*/
639
null_wait_for_sync(void)640 static void null_wait_for_sync(void)
641 {
642 }
643
ads7846_debounce_filter(void * ads,int data_idx,int * val)644 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
645 {
646 struct ads7846 *ts = ads;
647
648 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
649 /* Start over collecting consistent readings. */
650 ts->read_rep = 0;
651 /*
652 * Repeat it, if this was the first read or the read
653 * wasn't consistent enough.
654 */
655 if (ts->read_cnt < ts->debounce_max) {
656 ts->last_read = *val;
657 ts->read_cnt++;
658 return ADS7846_FILTER_REPEAT;
659 } else {
660 /*
661 * Maximum number of debouncing reached and still
662 * not enough number of consistent readings. Abort
663 * the whole sample, repeat it in the next sampling
664 * period.
665 */
666 ts->read_cnt = 0;
667 return ADS7846_FILTER_IGNORE;
668 }
669 } else {
670 if (++ts->read_rep > ts->debounce_rep) {
671 /*
672 * Got a good reading for this coordinate,
673 * go for the next one.
674 */
675 ts->read_cnt = 0;
676 ts->read_rep = 0;
677 return ADS7846_FILTER_OK;
678 } else {
679 /* Read more values that are consistent. */
680 ts->read_cnt++;
681 return ADS7846_FILTER_REPEAT;
682 }
683 }
684 }
685
ads7846_no_filter(void * ads,int data_idx,int * val)686 static int ads7846_no_filter(void *ads, int data_idx, int *val)
687 {
688 return ADS7846_FILTER_OK;
689 }
690
ads7846_get_value(struct ads7846_buf * buf)691 static int ads7846_get_value(struct ads7846_buf *buf)
692 {
693 int value;
694
695 value = be16_to_cpup(&buf->data);
696
697 /* enforce ADC output is 12 bits width */
698 return (value >> 3) & 0xfff;
699 }
700
ads7846_set_cmd_val(struct ads7846 * ts,enum ads7846_cmds cmd_idx,u16 val)701 static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
702 u16 val)
703 {
704 struct ads7846_packet *packet = ts->packet;
705
706 switch (cmd_idx) {
707 case ADS7846_Y:
708 packet->y = val;
709 break;
710 case ADS7846_X:
711 packet->x = val;
712 break;
713 case ADS7846_Z1:
714 packet->z1 = val;
715 break;
716 case ADS7846_Z2:
717 packet->z2 = val;
718 break;
719 default:
720 WARN_ON_ONCE(1);
721 }
722 }
723
ads7846_get_cmd(enum ads7846_cmds cmd_idx,int vref)724 static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
725 {
726 switch (cmd_idx) {
727 case ADS7846_Y:
728 return READ_Y(vref);
729 case ADS7846_X:
730 return READ_X(vref);
731
732 /* 7846 specific commands */
733 case ADS7846_Z1:
734 return READ_Z1(vref);
735 case ADS7846_Z2:
736 return READ_Z2(vref);
737 case ADS7846_PWDOWN:
738 return PWRDOWN;
739 default:
740 WARN_ON_ONCE(1);
741 }
742
743 return 0;
744 }
745
ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)746 static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
747 {
748 switch (cmd_idx) {
749 case ADS7846_X:
750 case ADS7846_Y:
751 case ADS7846_Z1:
752 case ADS7846_Z2:
753 return true;
754 case ADS7846_PWDOWN:
755 return false;
756 default:
757 WARN_ON_ONCE(1);
758 }
759
760 return false;
761 }
762
ads7846_filter(struct ads7846 * ts)763 static int ads7846_filter(struct ads7846 *ts)
764 {
765 struct ads7846_packet *packet = ts->packet;
766 int action;
767 int val;
768 unsigned int cmd_idx, b;
769
770 packet->ignore = false;
771 for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
772 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
773
774 packet->last_cmd_idx = cmd_idx;
775
776 for (b = l->skip; b < l->count; b++) {
777 val = ads7846_get_value(&packet->rx[l->offset + b]);
778
779 action = ts->filter(ts->filter_data, cmd_idx, &val);
780 if (action == ADS7846_FILTER_REPEAT) {
781 if (b == l->count - 1)
782 return -EAGAIN;
783 } else if (action == ADS7846_FILTER_OK) {
784 ads7846_set_cmd_val(ts, cmd_idx, val);
785 break;
786 } else {
787 packet->ignore = true;
788 return 0;
789 }
790 }
791 }
792
793 return 0;
794 }
795
ads7846_read_state(struct ads7846 * ts)796 static void ads7846_read_state(struct ads7846 *ts)
797 {
798 struct ads7846_packet *packet = ts->packet;
799 struct spi_message *m;
800 int msg_idx = 0;
801 int error;
802
803 packet->last_cmd_idx = 0;
804
805 while (true) {
806 ts->wait_for_sync();
807
808 m = &ts->msg[msg_idx];
809 error = spi_sync(ts->spi, m);
810 if (error) {
811 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
812 packet->ignore = true;
813 return;
814 }
815
816 error = ads7846_filter(ts);
817 if (error)
818 continue;
819
820 return;
821 }
822 }
823
ads7846_report_state(struct ads7846 * ts)824 static void ads7846_report_state(struct ads7846 *ts)
825 {
826 struct ads7846_packet *packet = ts->packet;
827 unsigned int Rt;
828 u16 x, y, z1, z2;
829
830 x = packet->x;
831 y = packet->y;
832 if (ts->model == 7845) {
833 z1 = 0;
834 z2 = 0;
835 } else {
836 z1 = packet->z1;
837 z2 = packet->z2;
838 }
839
840 /* range filtering */
841 if (x == MAX_12BIT)
842 x = 0;
843
844 if (ts->model == 7843 || ts->model == 7845) {
845 Rt = ts->pressure_max / 2;
846 } else if (likely(x && z1)) {
847 /* compute touch pressure resistance using equation #2 */
848 Rt = z2;
849 Rt -= z1;
850 Rt *= ts->x_plate_ohms;
851 Rt = DIV_ROUND_CLOSEST(Rt, 16);
852 Rt *= x;
853 Rt /= z1;
854 Rt = DIV_ROUND_CLOSEST(Rt, 256);
855 } else {
856 Rt = 0;
857 }
858
859 /*
860 * Sample found inconsistent by debouncing or pressure is beyond
861 * the maximum. Don't report it to user space, repeat at least
862 * once more the measurement
863 */
864 if (packet->ignore || Rt > ts->pressure_max) {
865 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
866 packet->ignore, Rt);
867 return;
868 }
869
870 /*
871 * Maybe check the pendown state before reporting. This discards
872 * false readings when the pen is lifted.
873 */
874 if (ts->penirq_recheck_delay_usecs) {
875 udelay(ts->penirq_recheck_delay_usecs);
876 if (!get_pendown_state(ts))
877 Rt = 0;
878 }
879
880 /*
881 * NOTE: We can't rely on the pressure to determine the pen down
882 * state, even this controller has a pressure sensor. The pressure
883 * value can fluctuate for quite a while after lifting the pen and
884 * in some cases may not even settle at the expected value.
885 *
886 * The only safe way to check for the pen up condition is in the
887 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
888 */
889 if (Rt) {
890 struct input_dev *input = ts->input;
891
892 if (!ts->pendown) {
893 input_report_key(input, BTN_TOUCH, 1);
894 ts->pendown = true;
895 dev_vdbg(&ts->spi->dev, "DOWN\n");
896 }
897
898 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
899 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
900
901 input_sync(input);
902 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
903 }
904 }
905
ads7846_hard_irq(int irq,void * handle)906 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
907 {
908 struct ads7846 *ts = handle;
909
910 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
911 }
912
913
ads7846_irq(int irq,void * handle)914 static irqreturn_t ads7846_irq(int irq, void *handle)
915 {
916 struct ads7846 *ts = handle;
917
918 /* Start with a small delay before checking pendown state */
919 msleep(TS_POLL_DELAY);
920
921 while (!ts->stopped && get_pendown_state(ts)) {
922
923 /* pen is down, continue with the measurement */
924 ads7846_read_state(ts);
925
926 if (!ts->stopped)
927 ads7846_report_state(ts);
928
929 wait_event_timeout(ts->wait, ts->stopped,
930 msecs_to_jiffies(TS_POLL_PERIOD));
931 }
932
933 if (ts->pendown && !ts->stopped)
934 ads7846_report_pen_up(ts);
935
936 return IRQ_HANDLED;
937 }
938
ads7846_suspend(struct device * dev)939 static int ads7846_suspend(struct device *dev)
940 {
941 struct ads7846 *ts = dev_get_drvdata(dev);
942
943 mutex_lock(&ts->lock);
944
945 if (!ts->suspended) {
946
947 if (!ts->disabled)
948 __ads7846_disable(ts);
949
950 if (device_may_wakeup(&ts->spi->dev))
951 enable_irq_wake(ts->spi->irq);
952
953 ts->suspended = true;
954 }
955
956 mutex_unlock(&ts->lock);
957
958 return 0;
959 }
960
ads7846_resume(struct device * dev)961 static int ads7846_resume(struct device *dev)
962 {
963 struct ads7846 *ts = dev_get_drvdata(dev);
964
965 mutex_lock(&ts->lock);
966
967 if (ts->suspended) {
968
969 ts->suspended = false;
970
971 if (device_may_wakeup(&ts->spi->dev))
972 disable_irq_wake(ts->spi->irq);
973
974 if (!ts->disabled)
975 __ads7846_enable(ts);
976 }
977
978 mutex_unlock(&ts->lock);
979
980 return 0;
981 }
982
983 static DEFINE_SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
984
ads7846_setup_pendown(struct spi_device * spi,struct ads7846 * ts,const struct ads7846_platform_data * pdata)985 static int ads7846_setup_pendown(struct spi_device *spi,
986 struct ads7846 *ts,
987 const struct ads7846_platform_data *pdata)
988 {
989 /*
990 * REVISIT when the irq can be triggered active-low, or if for some
991 * reason the touchscreen isn't hooked up, we don't need to access
992 * the pendown state.
993 */
994
995 if (pdata->get_pendown_state) {
996 ts->get_pendown_state = pdata->get_pendown_state;
997 } else {
998 ts->gpio_pendown = gpiod_get(&spi->dev, "pendown", GPIOD_IN);
999 if (IS_ERR(ts->gpio_pendown)) {
1000 dev_err(&spi->dev, "failed to request pendown GPIO\n");
1001 return PTR_ERR(ts->gpio_pendown);
1002 }
1003 if (pdata->gpio_pendown_debounce)
1004 gpiod_set_debounce(ts->gpio_pendown,
1005 pdata->gpio_pendown_debounce);
1006 }
1007
1008 return 0;
1009 }
1010
1011 /*
1012 * Set up the transfers to read touchscreen state; this assumes we
1013 * use formula #2 for pressure, not #3.
1014 */
ads7846_setup_spi_msg(struct ads7846 * ts,const struct ads7846_platform_data * pdata)1015 static int ads7846_setup_spi_msg(struct ads7846 *ts,
1016 const struct ads7846_platform_data *pdata)
1017 {
1018 struct spi_message *m = &ts->msg[0];
1019 struct spi_transfer *x = ts->xfer;
1020 struct ads7846_packet *packet = ts->packet;
1021 int vref = pdata->keep_vref_on;
1022 unsigned int count, offset = 0;
1023 unsigned int cmd_idx, b;
1024 unsigned long time;
1025 size_t size = 0;
1026
1027 /* time per bit */
1028 time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1029
1030 count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1031 packet->count_skip = DIV_ROUND_UP(count, 24);
1032
1033 if (ts->debounce_max && ts->debounce_rep)
1034 /* ads7846_debounce_filter() is making ts->debounce_rep + 2
1035 * reads. So we need to get all samples for normal case. */
1036 packet->count = ts->debounce_rep + 2;
1037 else
1038 packet->count = 1;
1039
1040 if (ts->model == 7846)
1041 packet->cmds = 5; /* x, y, z1, z2, pwdown */
1042 else
1043 packet->cmds = 3; /* x, y, pwdown */
1044
1045 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1046 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1047 unsigned int max_count;
1048
1049 if (cmd_idx == packet->cmds - 1)
1050 cmd_idx = ADS7846_PWDOWN;
1051
1052 if (ads7846_cmd_need_settle(cmd_idx))
1053 max_count = packet->count + packet->count_skip;
1054 else
1055 max_count = packet->count;
1056
1057 l->offset = offset;
1058 offset += max_count;
1059 l->count = max_count;
1060 l->skip = packet->count_skip;
1061 size += sizeof(*packet->tx) * max_count;
1062 }
1063
1064 packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1065 if (!packet->tx)
1066 return -ENOMEM;
1067
1068 packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1069 if (!packet->rx)
1070 return -ENOMEM;
1071
1072 if (ts->model == 7873) {
1073 /*
1074 * The AD7873 is almost identical to the ADS7846
1075 * keep VREF off during differential/ratiometric
1076 * conversion modes.
1077 */
1078 ts->model = 7846;
1079 vref = 0;
1080 }
1081
1082 ts->msg_count = 1;
1083 spi_message_init(m);
1084 m->context = ts;
1085
1086 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1087 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1088 u8 cmd;
1089
1090 if (cmd_idx == packet->cmds - 1)
1091 cmd_idx = ADS7846_PWDOWN;
1092
1093 cmd = ads7846_get_cmd(cmd_idx, vref);
1094
1095 for (b = 0; b < l->count; b++)
1096 packet->tx[l->offset + b].cmd = cmd;
1097 }
1098
1099 x->tx_buf = packet->tx;
1100 x->rx_buf = packet->rx;
1101 x->len = size;
1102 spi_message_add_tail(x, m);
1103
1104 return 0;
1105 }
1106
1107 static const struct of_device_id ads7846_dt_ids[] = {
1108 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1109 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1110 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1111 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1112 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1113 { }
1114 };
1115 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1116
ads7846_get_props(struct device * dev)1117 static const struct ads7846_platform_data *ads7846_get_props(struct device *dev)
1118 {
1119 struct ads7846_platform_data *pdata;
1120 u32 value;
1121
1122 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1123 if (!pdata)
1124 return ERR_PTR(-ENOMEM);
1125
1126 pdata->model = (uintptr_t)device_get_match_data(dev);
1127
1128 device_property_read_u16(dev, "ti,vref-delay-usecs",
1129 &pdata->vref_delay_usecs);
1130 device_property_read_u16(dev, "ti,vref-mv", &pdata->vref_mv);
1131 pdata->keep_vref_on = device_property_read_bool(dev, "ti,keep-vref-on");
1132
1133 pdata->swap_xy = device_property_read_bool(dev, "ti,swap-xy");
1134
1135 device_property_read_u16(dev, "ti,settle-delay-usec",
1136 &pdata->settle_delay_usecs);
1137 device_property_read_u16(dev, "ti,penirq-recheck-delay-usecs",
1138 &pdata->penirq_recheck_delay_usecs);
1139
1140 device_property_read_u16(dev, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1141 device_property_read_u16(dev, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1142
1143 device_property_read_u16(dev, "ti,x-min", &pdata->x_min);
1144 device_property_read_u16(dev, "ti,y-min", &pdata->y_min);
1145 device_property_read_u16(dev, "ti,x-max", &pdata->x_max);
1146 device_property_read_u16(dev, "ti,y-max", &pdata->y_max);
1147
1148 /*
1149 * touchscreen-max-pressure gets parsed during
1150 * touchscreen_parse_properties()
1151 */
1152 device_property_read_u16(dev, "ti,pressure-min", &pdata->pressure_min);
1153 if (!device_property_read_u32(dev, "touchscreen-min-pressure", &value))
1154 pdata->pressure_min = (u16) value;
1155 device_property_read_u16(dev, "ti,pressure-max", &pdata->pressure_max);
1156
1157 device_property_read_u16(dev, "ti,debounce-max", &pdata->debounce_max);
1158 if (!device_property_read_u32(dev, "touchscreen-average-samples", &value))
1159 pdata->debounce_max = (u16) value;
1160 device_property_read_u16(dev, "ti,debounce-tol", &pdata->debounce_tol);
1161 device_property_read_u16(dev, "ti,debounce-rep", &pdata->debounce_rep);
1162
1163 device_property_read_u32(dev, "ti,pendown-gpio-debounce",
1164 &pdata->gpio_pendown_debounce);
1165
1166 pdata->wakeup = device_property_read_bool(dev, "wakeup-source") ||
1167 device_property_read_bool(dev, "linux,wakeup");
1168
1169 return pdata;
1170 }
1171
ads7846_regulator_disable(void * regulator)1172 static void ads7846_regulator_disable(void *regulator)
1173 {
1174 regulator_disable(regulator);
1175 }
1176
ads7846_probe(struct spi_device * spi)1177 static int ads7846_probe(struct spi_device *spi)
1178 {
1179 const struct ads7846_platform_data *pdata;
1180 struct ads7846 *ts;
1181 struct device *dev = &spi->dev;
1182 struct ads7846_packet *packet;
1183 struct input_dev *input_dev;
1184 unsigned long irq_flags;
1185 int err;
1186
1187 if (!spi->irq) {
1188 dev_dbg(dev, "no IRQ?\n");
1189 return -EINVAL;
1190 }
1191
1192 /* don't exceed max specified sample rate */
1193 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1194 dev_err(dev, "f(sample) %d KHz?\n",
1195 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1196 return -EINVAL;
1197 }
1198
1199 /*
1200 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1201 * that even if the hardware can do that, the SPI controller driver
1202 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1203 */
1204 spi->bits_per_word = 8;
1205 spi->mode &= ~SPI_MODE_X_MASK;
1206 spi->mode |= SPI_MODE_0;
1207 err = spi_setup(spi);
1208 if (err < 0)
1209 return err;
1210
1211 ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1212 if (!ts)
1213 return -ENOMEM;
1214
1215 packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1216 if (!packet)
1217 return -ENOMEM;
1218
1219 input_dev = devm_input_allocate_device(dev);
1220 if (!input_dev)
1221 return -ENOMEM;
1222
1223 spi_set_drvdata(spi, ts);
1224
1225 ts->packet = packet;
1226 ts->spi = spi;
1227 ts->input = input_dev;
1228
1229 mutex_init(&ts->lock);
1230 init_waitqueue_head(&ts->wait);
1231
1232 pdata = dev_get_platdata(dev);
1233 if (!pdata) {
1234 pdata = ads7846_get_props(dev);
1235 if (IS_ERR(pdata))
1236 return PTR_ERR(pdata);
1237 }
1238
1239 ts->model = pdata->model ? : 7846;
1240 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1241 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1242 ts->vref_mv = pdata->vref_mv;
1243
1244 if (pdata->debounce_max) {
1245 ts->debounce_max = pdata->debounce_max;
1246 if (ts->debounce_max < 2)
1247 ts->debounce_max = 2;
1248 ts->debounce_tol = pdata->debounce_tol;
1249 ts->debounce_rep = pdata->debounce_rep;
1250 ts->filter = ads7846_debounce_filter;
1251 ts->filter_data = ts;
1252 } else {
1253 ts->filter = ads7846_no_filter;
1254 }
1255
1256 err = ads7846_setup_pendown(spi, ts, pdata);
1257 if (err)
1258 return err;
1259
1260 if (pdata->penirq_recheck_delay_usecs)
1261 ts->penirq_recheck_delay_usecs =
1262 pdata->penirq_recheck_delay_usecs;
1263
1264 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1265
1266 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1267 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1268
1269 input_dev->name = ts->name;
1270 input_dev->phys = ts->phys;
1271
1272 input_dev->id.bustype = BUS_SPI;
1273 input_dev->id.product = pdata->model;
1274
1275 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1276 input_set_abs_params(input_dev, ABS_X,
1277 pdata->x_min ? : 0,
1278 pdata->x_max ? : MAX_12BIT,
1279 0, 0);
1280 input_set_abs_params(input_dev, ABS_Y,
1281 pdata->y_min ? : 0,
1282 pdata->y_max ? : MAX_12BIT,
1283 0, 0);
1284 if (ts->model != 7845)
1285 input_set_abs_params(input_dev, ABS_PRESSURE,
1286 pdata->pressure_min, pdata->pressure_max, 0, 0);
1287
1288 /*
1289 * Parse common framework properties. Must be done here to ensure the
1290 * correct behaviour in case of using the legacy vendor bindings. The
1291 * general binding value overrides the vendor specific one.
1292 */
1293 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1294 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1295
1296 /*
1297 * Check if legacy ti,swap-xy binding is used instead of
1298 * touchscreen-swapped-x-y
1299 */
1300 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1301 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1302 ts->core_prop.swap_x_y = true;
1303 }
1304
1305 ads7846_setup_spi_msg(ts, pdata);
1306
1307 ts->reg = devm_regulator_get(dev, "vcc");
1308 if (IS_ERR(ts->reg)) {
1309 err = PTR_ERR(ts->reg);
1310 dev_err(dev, "unable to get regulator: %d\n", err);
1311 return err;
1312 }
1313
1314 err = regulator_enable(ts->reg);
1315 if (err) {
1316 dev_err(dev, "unable to enable regulator: %d\n", err);
1317 return err;
1318 }
1319
1320 err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1321 if (err)
1322 return err;
1323
1324 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1325 irq_flags |= IRQF_ONESHOT;
1326
1327 err = devm_request_threaded_irq(dev, spi->irq,
1328 ads7846_hard_irq, ads7846_irq,
1329 irq_flags, dev->driver->name, ts);
1330 if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1331 dev_info(dev,
1332 "trying pin change workaround on irq %d\n", spi->irq);
1333 irq_flags |= IRQF_TRIGGER_RISING;
1334 err = devm_request_threaded_irq(dev, spi->irq,
1335 ads7846_hard_irq, ads7846_irq,
1336 irq_flags, dev->driver->name,
1337 ts);
1338 }
1339
1340 if (err) {
1341 dev_dbg(dev, "irq %d busy?\n", spi->irq);
1342 return err;
1343 }
1344
1345 err = ads784x_hwmon_register(spi, ts);
1346 if (err)
1347 return err;
1348
1349 dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1350
1351 /*
1352 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1353 * the touchscreen, in case it's not connected.
1354 */
1355 if (ts->model == 7845)
1356 ads7845_read12_ser(dev, PWRDOWN);
1357 else
1358 (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1359
1360 err = devm_device_add_group(dev, &ads784x_attr_group);
1361 if (err)
1362 return err;
1363
1364 err = input_register_device(input_dev);
1365 if (err)
1366 return err;
1367
1368 device_init_wakeup(dev, pdata->wakeup);
1369
1370 /*
1371 * If device does not carry platform data we must have allocated it
1372 * when parsing DT data.
1373 */
1374 if (!dev_get_platdata(dev))
1375 devm_kfree(dev, (void *)pdata);
1376
1377 return 0;
1378 }
1379
ads7846_remove(struct spi_device * spi)1380 static void ads7846_remove(struct spi_device *spi)
1381 {
1382 struct ads7846 *ts = spi_get_drvdata(spi);
1383
1384 ads7846_stop(ts);
1385 }
1386
1387 static struct spi_driver ads7846_driver = {
1388 .driver = {
1389 .name = "ads7846",
1390 .pm = pm_sleep_ptr(&ads7846_pm),
1391 .of_match_table = ads7846_dt_ids,
1392 },
1393 .probe = ads7846_probe,
1394 .remove = ads7846_remove,
1395 };
1396
1397 module_spi_driver(ads7846_driver);
1398
1399 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1400 MODULE_LICENSE("GPL");
1401 MODULE_ALIAS("spi:ads7846");
1402