1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Core Source for:
4 * Cypress TrueTouch(TM) Standard Product (TTSP) touchscreen drivers.
5 * For use with Cypress Txx3xx parts.
6 * Supported parts include:
7 * CY8CTST341
8 * CY8CTMA340
9 *
10 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
11 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
12 *
13 * Contact Cypress Semiconductor at www.cypress.com <kev@cypress.com>
14 */
15
16#include <linux/delay.h>
17#include <linux/input.h>
18#include <linux/input/mt.h>
19#include <linux/input/touchscreen.h>
20#include <linux/gpio.h>
21#include <linux/interrupt.h>
22#include <linux/slab.h>
23#include <linux/property.h>
24#include <linux/gpio/consumer.h>
25#include <linux/regulator/consumer.h>
26
27#include "cyttsp_core.h"
28
29/* Bootloader number of command keys */
30#define CY_NUM_BL_KEYS 8
31
32/* helpers */
33#define GET_NUM_TOUCHES(x) ((x) & 0x0F)
34#define IS_LARGE_AREA(x) (((x) & 0x10) >> 4)
35#define IS_BAD_PKT(x) ((x) & 0x20)
36#define IS_VALID_APP(x) ((x) & 0x01)
37#define IS_OPERATIONAL_ERR(x) ((x) & 0x3F)
38#define GET_HSTMODE(reg) (((reg) & 0x70) >> 4)
39#define GET_BOOTLOADERMODE(reg) (((reg) & 0x10) >> 4)
40
41#define CY_REG_BASE 0x00
42#define CY_REG_ACT_DIST 0x1E
43#define CY_REG_ACT_INTRVL 0x1D
44#define CY_REG_TCH_TMOUT (CY_REG_ACT_INTRVL + 1)
45#define CY_REG_LP_INTRVL (CY_REG_TCH_TMOUT + 1)
46#define CY_MAXZ 255
47#define CY_DELAY_DFLT 20 /* ms */
48#define CY_DELAY_MAX 500
49/* Active distance in pixels for a gesture to be reported */
50#define CY_ACT_DIST_DFLT 0xF8 /* pixels */
51#define CY_ACT_DIST_MASK 0x0F
52/* Active Power state scanning/processing refresh interval */
53#define CY_ACT_INTRVL_DFLT 0x00 /* ms */
54/* Low Power state scanning/processing refresh interval */
55#define CY_LP_INTRVL_DFLT 0x0A /* ms */
56/* touch timeout for the Active power */
57#define CY_TCH_TMOUT_DFLT 0xFF /* ms */
58#define CY_HNDSHK_BIT 0x80
59/* device mode bits */
60#define CY_OPERATE_MODE 0x00
61#define CY_SYSINFO_MODE 0x10
62/* power mode select bits */
63#define CY_SOFT_RESET_MODE 0x01 /* return to Bootloader mode */
64#define CY_DEEP_SLEEP_MODE 0x02
65#define CY_LOW_POWER_MODE 0x04
66
67/* Slots management */
68#define CY_MAX_FINGER 4
69#define CY_MAX_ID 16
70
71static const u8 bl_command[] = {
72 0x00, /* file offset */
73 0xFF, /* command */
74 0xA5, /* exit bootloader command */
75 0, 1, 2, 3, 4, 5, 6, 7 /* default keys */
76};
77
78static int ttsp_read_block_data(struct cyttsp *ts, u8 command,
79 u8 length, void *buf)
80{
81 int error;
82 int tries;
83
84 for (tries = 0; tries < CY_NUM_RETRY; tries++) {
85 error = ts->bus_ops->read(ts->dev, ts->xfer_buf, command,
86 length, buf);
87 if (!error)
88 return 0;
89
90 msleep(CY_DELAY_DFLT);
91 }
92
93 return -EIO;
94}
95
96static int ttsp_write_block_data(struct cyttsp *ts, u8 command,
97 u8 length, void *buf)
98{
99 int error;
100 int tries;
101
102 for (tries = 0; tries < CY_NUM_RETRY; tries++) {
103 error = ts->bus_ops->write(ts->dev, ts->xfer_buf, command,
104 length, buf);
105 if (!error)
106 return 0;
107
108 msleep(CY_DELAY_DFLT);
109 }
110
111 return -EIO;
112}
113
114static int ttsp_send_command(struct cyttsp *ts, u8 cmd)
115{
116 return ttsp_write_block_data(ts, CY_REG_BASE, length: sizeof(cmd), buf: &cmd);
117}
118
119static int cyttsp_handshake(struct cyttsp *ts)
120{
121 if (ts->use_hndshk)
122 return ttsp_send_command(ts,
123 cmd: ts->xy_data.hst_mode ^ CY_HNDSHK_BIT);
124
125 return 0;
126}
127
128static int cyttsp_load_bl_regs(struct cyttsp *ts)
129{
130 memset(&ts->bl_data, 0, sizeof(ts->bl_data));
131 ts->bl_data.bl_status = 0x10;
132
133 return ttsp_read_block_data(ts, CY_REG_BASE,
134 length: sizeof(ts->bl_data), buf: &ts->bl_data);
135}
136
137static int cyttsp_exit_bl_mode(struct cyttsp *ts)
138{
139 int error;
140 u8 bl_cmd[sizeof(bl_command)];
141
142 memcpy(bl_cmd, bl_command, sizeof(bl_command));
143 if (ts->bl_keys)
144 memcpy(&bl_cmd[sizeof(bl_command) - CY_NUM_BL_KEYS],
145 ts->bl_keys, CY_NUM_BL_KEYS);
146
147 error = ttsp_write_block_data(ts, CY_REG_BASE,
148 length: sizeof(bl_cmd), buf: bl_cmd);
149 if (error)
150 return error;
151
152 /* wait for TTSP Device to complete the operation */
153 msleep(CY_DELAY_DFLT);
154
155 error = cyttsp_load_bl_regs(ts);
156 if (error)
157 return error;
158
159 if (GET_BOOTLOADERMODE(ts->bl_data.bl_status))
160 return -EIO;
161
162 return 0;
163}
164
165static int cyttsp_set_operational_mode(struct cyttsp *ts)
166{
167 int error;
168
169 error = ttsp_send_command(ts, CY_OPERATE_MODE);
170 if (error)
171 return error;
172
173 /* wait for TTSP Device to complete switch to Operational mode */
174 error = ttsp_read_block_data(ts, CY_REG_BASE,
175 length: sizeof(ts->xy_data), buf: &ts->xy_data);
176 if (error)
177 return error;
178
179 error = cyttsp_handshake(ts);
180 if (error)
181 return error;
182
183 return ts->xy_data.act_dist == CY_ACT_DIST_DFLT ? -EIO : 0;
184}
185
186static int cyttsp_set_sysinfo_mode(struct cyttsp *ts)
187{
188 int error;
189
190 memset(&ts->sysinfo_data, 0, sizeof(ts->sysinfo_data));
191
192 /* switch to sysinfo mode */
193 error = ttsp_send_command(ts, CY_SYSINFO_MODE);
194 if (error)
195 return error;
196
197 /* read sysinfo registers */
198 msleep(CY_DELAY_DFLT);
199 error = ttsp_read_block_data(ts, CY_REG_BASE, length: sizeof(ts->sysinfo_data),
200 buf: &ts->sysinfo_data);
201 if (error)
202 return error;
203
204 error = cyttsp_handshake(ts);
205 if (error)
206 return error;
207
208 if (!ts->sysinfo_data.tts_verh && !ts->sysinfo_data.tts_verl)
209 return -EIO;
210
211 return 0;
212}
213
214static int cyttsp_set_sysinfo_regs(struct cyttsp *ts)
215{
216 int retval = 0;
217
218 if (ts->act_intrvl != CY_ACT_INTRVL_DFLT ||
219 ts->tch_tmout != CY_TCH_TMOUT_DFLT ||
220 ts->lp_intrvl != CY_LP_INTRVL_DFLT) {
221
222 u8 intrvl_ray[] = {
223 ts->act_intrvl,
224 ts->tch_tmout,
225 ts->lp_intrvl
226 };
227
228 /* set intrvl registers */
229 retval = ttsp_write_block_data(ts, CY_REG_ACT_INTRVL,
230 length: sizeof(intrvl_ray), buf: intrvl_ray);
231 msleep(CY_DELAY_DFLT);
232 }
233
234 return retval;
235}
236
237static void cyttsp_hard_reset(struct cyttsp *ts)
238{
239 if (ts->reset_gpio) {
240 /*
241 * According to the CY8CTMA340 datasheet page 21, the external
242 * reset pulse width should be >= 1 ms. The datasheet does not
243 * specify how long we have to wait after reset but a vendor
244 * tree specifies 5 ms here.
245 */
246 gpiod_set_value_cansleep(desc: ts->reset_gpio, value: 1);
247 usleep_range(min: 1000, max: 2000);
248 gpiod_set_value_cansleep(desc: ts->reset_gpio, value: 0);
249 usleep_range(min: 5000, max: 6000);
250 }
251}
252
253static int cyttsp_soft_reset(struct cyttsp *ts)
254{
255 int retval;
256
257 /* wait for interrupt to set ready completion */
258 reinit_completion(x: &ts->bl_ready);
259 ts->state = CY_BL_STATE;
260
261 enable_irq(irq: ts->irq);
262
263 retval = ttsp_send_command(ts, CY_SOFT_RESET_MODE);
264 if (retval) {
265 dev_err(ts->dev, "failed to send soft reset\n");
266 goto out;
267 }
268
269 if (!wait_for_completion_timeout(x: &ts->bl_ready,
270 timeout: msecs_to_jiffies(CY_DELAY_DFLT * CY_DELAY_MAX))) {
271 dev_err(ts->dev, "timeout waiting for soft reset\n");
272 retval = -EIO;
273 }
274
275out:
276 ts->state = CY_IDLE_STATE;
277 disable_irq(irq: ts->irq);
278 return retval;
279}
280
281static int cyttsp_act_dist_setup(struct cyttsp *ts)
282{
283 u8 act_dist_setup = ts->act_dist;
284
285 /* Init gesture; active distance setup */
286 return ttsp_write_block_data(ts, CY_REG_ACT_DIST,
287 length: sizeof(act_dist_setup), buf: &act_dist_setup);
288}
289
290static void cyttsp_extract_track_ids(struct cyttsp_xydata *xy_data, int *ids)
291{
292 ids[0] = xy_data->touch12_id >> 4;
293 ids[1] = xy_data->touch12_id & 0xF;
294 ids[2] = xy_data->touch34_id >> 4;
295 ids[3] = xy_data->touch34_id & 0xF;
296}
297
298static const struct cyttsp_tch *cyttsp_get_tch(struct cyttsp_xydata *xy_data,
299 int idx)
300{
301 switch (idx) {
302 case 0:
303 return &xy_data->tch1;
304 case 1:
305 return &xy_data->tch2;
306 case 2:
307 return &xy_data->tch3;
308 case 3:
309 return &xy_data->tch4;
310 default:
311 return NULL;
312 }
313}
314
315static void cyttsp_report_tchdata(struct cyttsp *ts)
316{
317 struct cyttsp_xydata *xy_data = &ts->xy_data;
318 struct input_dev *input = ts->input;
319 int num_tch = GET_NUM_TOUCHES(xy_data->tt_stat);
320 const struct cyttsp_tch *tch;
321 int ids[CY_MAX_ID];
322 int i;
323 DECLARE_BITMAP(used, CY_MAX_ID);
324
325 if (IS_LARGE_AREA(xy_data->tt_stat) == 1) {
326 /* terminate all active tracks */
327 num_tch = 0;
328 dev_dbg(ts->dev, "%s: Large area detected\n", __func__);
329 } else if (num_tch > CY_MAX_FINGER) {
330 /* terminate all active tracks */
331 num_tch = 0;
332 dev_dbg(ts->dev, "%s: Num touch error detected\n", __func__);
333 } else if (IS_BAD_PKT(xy_data->tt_mode)) {
334 /* terminate all active tracks */
335 num_tch = 0;
336 dev_dbg(ts->dev, "%s: Invalid buffer detected\n", __func__);
337 }
338
339 cyttsp_extract_track_ids(xy_data, ids);
340
341 bitmap_zero(dst: used, CY_MAX_ID);
342
343 for (i = 0; i < num_tch; i++) {
344 tch = cyttsp_get_tch(xy_data, idx: i);
345
346 input_mt_slot(dev: input, slot: ids[i]);
347 input_mt_report_slot_state(dev: input, MT_TOOL_FINGER, active: true);
348 input_report_abs(dev: input, ABS_MT_POSITION_X, be16_to_cpu(tch->x));
349 input_report_abs(dev: input, ABS_MT_POSITION_Y, be16_to_cpu(tch->y));
350 input_report_abs(dev: input, ABS_MT_TOUCH_MAJOR, value: tch->z);
351
352 __set_bit(ids[i], used);
353 }
354
355 for (i = 0; i < CY_MAX_ID; i++) {
356 if (test_bit(i, used))
357 continue;
358
359 input_mt_slot(dev: input, slot: i);
360 input_mt_report_slot_inactive(dev: input);
361 }
362
363 input_sync(dev: input);
364}
365
366static irqreturn_t cyttsp_irq(int irq, void *handle)
367{
368 struct cyttsp *ts = handle;
369 int error;
370
371 if (unlikely(ts->state == CY_BL_STATE)) {
372 complete(&ts->bl_ready);
373 goto out;
374 }
375
376 /* Get touch data from CYTTSP device */
377 error = ttsp_read_block_data(ts, CY_REG_BASE,
378 length: sizeof(struct cyttsp_xydata), buf: &ts->xy_data);
379 if (error)
380 goto out;
381
382 /* provide flow control handshake */
383 error = cyttsp_handshake(ts);
384 if (error)
385 goto out;
386
387 if (unlikely(ts->state == CY_IDLE_STATE))
388 goto out;
389
390 if (GET_BOOTLOADERMODE(ts->xy_data.tt_mode)) {
391 /*
392 * TTSP device has reset back to bootloader mode.
393 * Restore to operational mode.
394 */
395 error = cyttsp_exit_bl_mode(ts);
396 if (error) {
397 dev_err(ts->dev,
398 "Could not return to operational mode, err: %d\n",
399 error);
400 ts->state = CY_IDLE_STATE;
401 }
402 } else {
403 cyttsp_report_tchdata(ts);
404 }
405
406out:
407 return IRQ_HANDLED;
408}
409
410static int cyttsp_power_on(struct cyttsp *ts)
411{
412 int error;
413
414 error = cyttsp_soft_reset(ts);
415 if (error)
416 return error;
417
418 error = cyttsp_load_bl_regs(ts);
419 if (error)
420 return error;
421
422 if (GET_BOOTLOADERMODE(ts->bl_data.bl_status) &&
423 IS_VALID_APP(ts->bl_data.bl_status)) {
424 error = cyttsp_exit_bl_mode(ts);
425 if (error) {
426 dev_err(ts->dev, "failed to exit bootloader mode\n");
427 return error;
428 }
429 }
430
431 if (GET_HSTMODE(ts->bl_data.bl_file) != CY_OPERATE_MODE ||
432 IS_OPERATIONAL_ERR(ts->bl_data.bl_status)) {
433 return -ENODEV;
434 }
435
436 error = cyttsp_set_sysinfo_mode(ts);
437 if (error)
438 return error;
439
440 error = cyttsp_set_sysinfo_regs(ts);
441 if (error)
442 return error;
443
444 error = cyttsp_set_operational_mode(ts);
445 if (error)
446 return error;
447
448 /* init active distance */
449 error = cyttsp_act_dist_setup(ts);
450 if (error)
451 return error;
452
453 ts->state = CY_ACTIVE_STATE;
454
455 return 0;
456}
457
458static int cyttsp_enable(struct cyttsp *ts)
459{
460 int error;
461
462 /*
463 * The device firmware can wake on an I2C or SPI memory slave
464 * address match. So just reading a register is sufficient to
465 * wake up the device. The first read attempt will fail but it
466 * will wake it up making the second read attempt successful.
467 */
468 error = ttsp_read_block_data(ts, CY_REG_BASE,
469 length: sizeof(ts->xy_data), buf: &ts->xy_data);
470 if (error)
471 return error;
472
473 if (GET_HSTMODE(ts->xy_data.hst_mode))
474 return -EIO;
475
476 enable_irq(irq: ts->irq);
477
478 return 0;
479}
480
481static int cyttsp_disable(struct cyttsp *ts)
482{
483 int error;
484
485 error = ttsp_send_command(ts, CY_LOW_POWER_MODE);
486 if (error)
487 return error;
488
489 disable_irq(irq: ts->irq);
490
491 return 0;
492}
493
494static int cyttsp_suspend(struct device *dev)
495{
496 struct cyttsp *ts = dev_get_drvdata(dev);
497 int retval = 0;
498
499 mutex_lock(&ts->input->mutex);
500
501 if (input_device_enabled(dev: ts->input)) {
502 retval = cyttsp_disable(ts);
503 if (retval == 0)
504 ts->suspended = true;
505 }
506
507 mutex_unlock(lock: &ts->input->mutex);
508
509 return retval;
510}
511
512static int cyttsp_resume(struct device *dev)
513{
514 struct cyttsp *ts = dev_get_drvdata(dev);
515
516 mutex_lock(&ts->input->mutex);
517
518 if (input_device_enabled(dev: ts->input))
519 cyttsp_enable(ts);
520
521 ts->suspended = false;
522
523 mutex_unlock(lock: &ts->input->mutex);
524
525 return 0;
526}
527
528EXPORT_GPL_SIMPLE_DEV_PM_OPS(cyttsp_pm_ops, cyttsp_suspend, cyttsp_resume);
529
530static int cyttsp_open(struct input_dev *dev)
531{
532 struct cyttsp *ts = input_get_drvdata(dev);
533 int retval = 0;
534
535 if (!ts->suspended)
536 retval = cyttsp_enable(ts);
537
538 return retval;
539}
540
541static void cyttsp_close(struct input_dev *dev)
542{
543 struct cyttsp *ts = input_get_drvdata(dev);
544
545 if (!ts->suspended)
546 cyttsp_disable(ts);
547}
548
549static int cyttsp_parse_properties(struct cyttsp *ts)
550{
551 struct device *dev = ts->dev;
552 u32 dt_value;
553 int ret;
554
555 ts->bl_keys = devm_kzalloc(dev, CY_NUM_BL_KEYS, GFP_KERNEL);
556 if (!ts->bl_keys)
557 return -ENOMEM;
558
559 /* Set some default values */
560 ts->use_hndshk = false;
561 ts->act_dist = CY_ACT_DIST_DFLT;
562 ts->act_intrvl = CY_ACT_INTRVL_DFLT;
563 ts->tch_tmout = CY_TCH_TMOUT_DFLT;
564 ts->lp_intrvl = CY_LP_INTRVL_DFLT;
565
566 ret = device_property_read_u8_array(dev, propname: "bootloader-key",
567 val: ts->bl_keys, CY_NUM_BL_KEYS);
568 if (ret) {
569 dev_err(dev,
570 "bootloader-key property could not be retrieved\n");
571 return ret;
572 }
573
574 ts->use_hndshk = device_property_present(dev, propname: "use-handshake");
575
576 if (!device_property_read_u32(dev, propname: "active-distance", val: &dt_value)) {
577 if (dt_value > 15) {
578 dev_err(dev, "active-distance (%u) must be [0-15]\n",
579 dt_value);
580 return -EINVAL;
581 }
582 ts->act_dist &= ~CY_ACT_DIST_MASK;
583 ts->act_dist |= dt_value;
584 }
585
586 if (!device_property_read_u32(dev, propname: "active-interval-ms", val: &dt_value)) {
587 if (dt_value > 255) {
588 dev_err(dev, "active-interval-ms (%u) must be [0-255]\n",
589 dt_value);
590 return -EINVAL;
591 }
592 ts->act_intrvl = dt_value;
593 }
594
595 if (!device_property_read_u32(dev, propname: "lowpower-interval-ms", val: &dt_value)) {
596 if (dt_value > 2550) {
597 dev_err(dev, "lowpower-interval-ms (%u) must be [0-2550]\n",
598 dt_value);
599 return -EINVAL;
600 }
601 /* Register value is expressed in 0.01s / bit */
602 ts->lp_intrvl = dt_value / 10;
603 }
604
605 if (!device_property_read_u32(dev, propname: "touch-timeout-ms", val: &dt_value)) {
606 if (dt_value > 2550) {
607 dev_err(dev, "touch-timeout-ms (%u) must be [0-2550]\n",
608 dt_value);
609 return -EINVAL;
610 }
611 /* Register value is expressed in 0.01s / bit */
612 ts->tch_tmout = dt_value / 10;
613 }
614
615 return 0;
616}
617
618static void cyttsp_disable_regulators(void *_ts)
619{
620 struct cyttsp *ts = _ts;
621
622 regulator_bulk_disable(ARRAY_SIZE(ts->regulators),
623 consumers: ts->regulators);
624}
625
626struct cyttsp *cyttsp_probe(const struct cyttsp_bus_ops *bus_ops,
627 struct device *dev, int irq, size_t xfer_buf_size)
628{
629 struct cyttsp *ts;
630 struct input_dev *input_dev;
631 int error;
632
633 ts = devm_kzalloc(dev, size: sizeof(*ts) + xfer_buf_size, GFP_KERNEL);
634 if (!ts)
635 return ERR_PTR(error: -ENOMEM);
636
637 input_dev = devm_input_allocate_device(dev);
638 if (!input_dev)
639 return ERR_PTR(error: -ENOMEM);
640
641 ts->dev = dev;
642 ts->input = input_dev;
643 ts->bus_ops = bus_ops;
644 ts->irq = irq;
645
646 /*
647 * VCPIN is the analog voltage supply
648 * VDD is the digital voltage supply
649 */
650 ts->regulators[0].supply = "vcpin";
651 ts->regulators[1].supply = "vdd";
652 error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->regulators),
653 consumers: ts->regulators);
654 if (error) {
655 dev_err(dev, "Failed to get regulators: %d\n", error);
656 return ERR_PTR(error);
657 }
658
659 error = regulator_bulk_enable(ARRAY_SIZE(ts->regulators),
660 consumers: ts->regulators);
661 if (error) {
662 dev_err(dev, "Cannot enable regulators: %d\n", error);
663 return ERR_PTR(error);
664 }
665
666 error = devm_add_action_or_reset(dev, cyttsp_disable_regulators, ts);
667 if (error) {
668 dev_err(dev, "failed to install chip disable handler\n");
669 return ERR_PTR(error);
670 }
671
672 ts->reset_gpio = devm_gpiod_get_optional(dev, con_id: "reset", flags: GPIOD_OUT_LOW);
673 if (IS_ERR(ptr: ts->reset_gpio)) {
674 error = PTR_ERR(ptr: ts->reset_gpio);
675 dev_err(dev, "Failed to request reset gpio, error %d\n", error);
676 return ERR_PTR(error);
677 }
678
679 error = cyttsp_parse_properties(ts);
680 if (error)
681 return ERR_PTR(error);
682
683 init_completion(x: &ts->bl_ready);
684
685 input_dev->name = "Cypress TTSP TouchScreen";
686 input_dev->id.bustype = bus_ops->bustype;
687 input_dev->dev.parent = ts->dev;
688
689 input_dev->open = cyttsp_open;
690 input_dev->close = cyttsp_close;
691
692 input_set_drvdata(dev: input_dev, data: ts);
693
694 input_set_capability(dev: input_dev, EV_ABS, ABS_MT_POSITION_X);
695 input_set_capability(dev: input_dev, EV_ABS, ABS_MT_POSITION_Y);
696 /* One byte for width 0..255 so this is the limit */
697 input_set_abs_params(dev: input_dev, ABS_MT_TOUCH_MAJOR, min: 0, max: 255, fuzz: 0, flat: 0);
698
699 touchscreen_parse_properties(input: input_dev, multitouch: true, NULL);
700
701 error = input_mt_init_slots(dev: input_dev, CY_MAX_ID, INPUT_MT_DIRECT);
702 if (error) {
703 dev_err(dev, "Unable to init MT slots.\n");
704 return ERR_PTR(error);
705 }
706
707 error = devm_request_threaded_irq(dev, irq: ts->irq, NULL, thread_fn: cyttsp_irq,
708 IRQF_ONESHOT | IRQF_NO_AUTOEN,
709 devname: "cyttsp", dev_id: ts);
710 if (error) {
711 dev_err(ts->dev, "failed to request IRQ %d, err: %d\n",
712 ts->irq, error);
713 return ERR_PTR(error);
714 }
715
716 cyttsp_hard_reset(ts);
717
718 error = cyttsp_power_on(ts);
719 if (error)
720 return ERR_PTR(error);
721
722 error = input_register_device(input_dev);
723 if (error) {
724 dev_err(ts->dev, "failed to register input device: %d\n",
725 error);
726 return ERR_PTR(error);
727 }
728
729 return ts;
730}
731EXPORT_SYMBOL_GPL(cyttsp_probe);
732
733MODULE_LICENSE("GPL");
734MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard touchscreen driver core");
735MODULE_AUTHOR("Cypress");
736

source code of linux/drivers/input/touchscreen/cyttsp_core.c