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1/*
2 * ADS7846 based touchscreen and sensor driver
3 *
4 * Copyright (c) 2005 David Brownell
5 * Copyright (c) 2006 Nokia Corporation
6 * Various changes: Imre Deak <imre.deak@nokia.com>
7 *
8 * Using code from:
9 * - corgi_ts.c
10 * Copyright (C) 2004-2005 Richard Purdie
11 * - omap_ts.[hc], ads7846.h, ts_osk.c
12 * Copyright (C) 2002 MontaVista Software
13 * Copyright (C) 2004 Texas Instruments
14 * Copyright (C) 2005 Dirk Behme
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License version 2 as
18 * published by the Free Software Foundation.
19 */
20#include <linux/types.h>
21#include <linux/hwmon.h>
22#include <linux/init.h>
23#include <linux/err.h>
24#include <linux/sched.h>
25#include <linux/delay.h>
26#include <linux/input.h>
27#include <linux/interrupt.h>
28#include <linux/slab.h>
29#include <linux/pm.h>
30#include <linux/gpio.h>
31#include <linux/spi/spi.h>
32#include <linux/spi/ads7846.h>
33#include <linux/regulator/consumer.h>
34#include <asm/irq.h>
35
36/*
37 * This code has been heavily tested on a Nokia 770, and lightly
38 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
39 * TSC2046 is just newer ads7846 silicon.
40 * Support for ads7843 tested on Atmel at91sam926x-EK.
41 * Support for ads7845 has only been stubbed in.
42 * Support for Analog Devices AD7873 and AD7843 tested.
43 *
44 * IRQ handling needs a workaround because of a shortcoming in handling
45 * edge triggered IRQs on some platforms like the OMAP1/2. These
46 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
47 * have to maintain our own SW IRQ disabled status. This should be
48 * removed as soon as the affected platform's IRQ handling is fixed.
49 *
50 * App note sbaa036 talks in more detail about accurate sampling...
51 * that ought to help in situations like LCDs inducing noise (which
52 * can also be helped by using synch signals) and more generally.
53 * This driver tries to utilize the measures described in the app
54 * note. The strength of filtering can be set in the board-* specific
55 * files.
56 */
57
58#define TS_POLL_DELAY 1 /* ms delay before the first sample */
59#define TS_POLL_PERIOD 5 /* ms delay between samples */
60
61/* this driver doesn't aim at the peak continuous sample rate */
62#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
63
64struct ts_event {
65 /*
66 * For portability, we can't read 12 bit values using SPI (which
67 * would make the controller deliver them as native byte order u16
68 * with msbs zeroed). Instead, we read them as two 8-bit values,
69 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
70 */
71 u16 x;
72 u16 y;
73 u16 z1, z2;
74 bool ignore;
75 u8 x_buf[3];
76 u8 y_buf[3];
77};
78
79/*
80 * We allocate this separately to avoid cache line sharing issues when
81 * driver is used with DMA-based SPI controllers (like atmel_spi) on
82 * systems where main memory is not DMA-coherent (most non-x86 boards).
83 */
84struct ads7846_packet {
85 u8 read_x, read_y, read_z1, read_z2, pwrdown;
86 u16 dummy; /* for the pwrdown read */
87 struct ts_event tc;
88 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
89 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
90};
91
92struct ads7846 {
93 struct input_dev *input;
94 char phys[32];
95 char name[32];
96
97 struct spi_device *spi;
98 struct regulator *reg;
99
100#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
101 struct attribute_group *attr_group;
102 struct device *hwmon;
103#endif
104
105 u16 model;
106 u16 vref_mv;
107 u16 vref_delay_usecs;
108 u16 x_plate_ohms;
109 u16 pressure_max;
110
111 bool swap_xy;
112 bool use_internal;
113
114 struct ads7846_packet *packet;
115
116 struct spi_transfer xfer[18];
117 struct spi_message msg[5];
118 int msg_count;
119 wait_queue_head_t wait;
120
121 bool pendown;
122
123 int read_cnt;
124 int read_rep;
125 int last_read;
126
127 u16 debounce_max;
128 u16 debounce_tol;
129 u16 debounce_rep;
130
131 u16 penirq_recheck_delay_usecs;
132
133 struct mutex lock;
134 bool stopped; /* P: lock */
135 bool disabled; /* P: lock */
136 bool suspended; /* P: lock */
137
138 int (*filter)(void *data, int data_idx, int *val);
139 void *filter_data;
140 void (*filter_cleanup)(void *data);
141 int (*get_pendown_state)(void);
142 int gpio_pendown;
143
144 void (*wait_for_sync)(void);
145};
146
147/* leave chip selected when we're done, for quicker re-select? */
148#if 0
149#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
150#else
151#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
152#endif
153
154/*--------------------------------------------------------------------------*/
155
156/* The ADS7846 has touchscreen and other sensors.
157 * Earlier ads784x chips are somewhat compatible.
158 */
159#define ADS_START (1 << 7)
160#define ADS_A2A1A0_d_y (1 << 4) /* differential */
161#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
162#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
163#define ADS_A2A1A0_d_x (5 << 4) /* differential */
164#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
165#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
166#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
167#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
168#define ADS_8_BIT (1 << 3)
169#define ADS_12_BIT (0 << 3)
170#define ADS_SER (1 << 2) /* non-differential */
171#define ADS_DFR (0 << 2) /* differential */
172#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
173#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
174#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
175#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
176
177#define MAX_12BIT ((1<<12)-1)
178
179/* leave ADC powered up (disables penirq) between differential samples */
180#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
181 | ADS_12_BIT | ADS_DFR | \
182 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
183
184#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
185#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
186#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
187
188#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
189#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
190
191/* single-ended samples need to first power up reference voltage;
192 * we leave both ADC and VREF powered
193 */
194#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
195 | ADS_12_BIT | ADS_SER)
196
197#define REF_ON (READ_12BIT_DFR(x, 1, 1))
198#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
199
200/* Must be called with ts->lock held */
201static void ads7846_stop(struct ads7846 *ts)
202{
203 if (!ts->disabled && !ts->suspended) {
204 /* Signal IRQ thread to stop polling and disable the handler. */
205 ts->stopped = true;
206 mb();
207 wake_up(&ts->wait);
208 disable_irq(ts->spi->irq);
209 }
210}
211
212/* Must be called with ts->lock held */
213static void ads7846_restart(struct ads7846 *ts)
214{
215 if (!ts->disabled && !ts->suspended) {
216 /* Tell IRQ thread that it may poll the device. */
217 ts->stopped = false;
218 mb();
219 enable_irq(ts->spi->irq);
220 }
221}
222
223/* Must be called with ts->lock held */
224static void __ads7846_disable(struct ads7846 *ts)
225{
226 ads7846_stop(ts);
227 regulator_disable(ts->reg);
228
229 /*
230 * We know the chip's in low power mode since we always
231 * leave it that way after every request
232 */
233}
234
235/* Must be called with ts->lock held */
236static void __ads7846_enable(struct ads7846 *ts)
237{
238 regulator_enable(ts->reg);
239 ads7846_restart(ts);
240}
241
242static void ads7846_disable(struct ads7846 *ts)
243{
244 mutex_lock(&ts->lock);
245
246 if (!ts->disabled) {
247
248 if (!ts->suspended)
249 __ads7846_disable(ts);
250
251 ts->disabled = true;
252 }
253
254 mutex_unlock(&ts->lock);
255}
256
257static void ads7846_enable(struct ads7846 *ts)
258{
259 mutex_lock(&ts->lock);
260
261 if (ts->disabled) {
262
263 ts->disabled = false;
264
265 if (!ts->suspended)
266 __ads7846_enable(ts);
267 }
268
269 mutex_unlock(&ts->lock);
270}
271
272/*--------------------------------------------------------------------------*/
273
274/*
275 * Non-touchscreen sensors only use single-ended conversions.
276 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
277 * ads7846 lets that pin be unconnected, to use internal vREF.
278 */
279
280struct ser_req {
281 u8 ref_on;
282 u8 command;
283 u8 ref_off;
284 u16 scratch;
285 struct spi_message msg;
286 struct spi_transfer xfer[6];
287 /*
288 * DMA (thus cache coherency maintenance) requires the
289 * transfer buffers to live in their own cache lines.
290 */
291 __be16 sample ____cacheline_aligned;
292};
293
294struct ads7845_ser_req {
295 u8 command[3];
296 struct spi_message msg;
297 struct spi_transfer xfer[2];
298 /*
299 * DMA (thus cache coherency maintenance) requires the
300 * transfer buffers to live in their own cache lines.
301 */
302 u8 sample[3] ____cacheline_aligned;
303};
304
305static int ads7846_read12_ser(struct device *dev, unsigned command)
306{
307 struct spi_device *spi = to_spi_device(dev);
308 struct ads7846 *ts = dev_get_drvdata(dev);
309 struct ser_req *req;
310 int status;
311
312 req = kzalloc(sizeof *req, GFP_KERNEL);
313 if (!req)
314 return -ENOMEM;
315
316 spi_message_init(&req->msg);
317
318 /* maybe turn on internal vREF, and let it settle */
319 if (ts->use_internal) {
320 req->ref_on = REF_ON;
321 req->xfer[0].tx_buf = &req->ref_on;
322 req->xfer[0].len = 1;
323 spi_message_add_tail(&req->xfer[0], &req->msg);
324
325 req->xfer[1].rx_buf = &req->scratch;
326 req->xfer[1].len = 2;
327
328 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
329 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
330 spi_message_add_tail(&req->xfer[1], &req->msg);
331
332 /* Enable reference voltage */
333 command |= ADS_PD10_REF_ON;
334 }
335
336 /* Enable ADC in every case */
337 command |= ADS_PD10_ADC_ON;
338
339 /* take sample */
340 req->command = (u8) command;
341 req->xfer[2].tx_buf = &req->command;
342 req->xfer[2].len = 1;
343 spi_message_add_tail(&req->xfer[2], &req->msg);
344
345 req->xfer[3].rx_buf = &req->sample;
346 req->xfer[3].len = 2;
347 spi_message_add_tail(&req->xfer[3], &req->msg);
348
349 /* REVISIT: take a few more samples, and compare ... */
350
351 /* converter in low power mode & enable PENIRQ */
352 req->ref_off = PWRDOWN;
353 req->xfer[4].tx_buf = &req->ref_off;
354 req->xfer[4].len = 1;
355 spi_message_add_tail(&req->xfer[4], &req->msg);
356
357 req->xfer[5].rx_buf = &req->scratch;
358 req->xfer[5].len = 2;
359 CS_CHANGE(req->xfer[5]);
360 spi_message_add_tail(&req->xfer[5], &req->msg);
361
362 mutex_lock(&ts->lock);
363 ads7846_stop(ts);
364 status = spi_sync(spi, &req->msg);
365 ads7846_restart(ts);
366 mutex_unlock(&ts->lock);
367
368 if (status == 0) {
369 /* on-wire is a must-ignore bit, a BE12 value, then padding */
370 status = be16_to_cpu(req->sample);
371 status = status >> 3;
372 status &= 0x0fff;
373 }
374
375 kfree(req);
376 return status;
377}
378
379static int ads7845_read12_ser(struct device *dev, unsigned command)
380{
381 struct spi_device *spi = to_spi_device(dev);
382 struct ads7846 *ts = dev_get_drvdata(dev);
383 struct ads7845_ser_req *req;
384 int status;
385
386 req = kzalloc(sizeof *req, GFP_KERNEL);
387 if (!req)
388 return -ENOMEM;
389
390 spi_message_init(&req->msg);
391
392 req->command[0] = (u8) command;
393 req->xfer[0].tx_buf = req->command;
394 req->xfer[0].rx_buf = req->sample;
395 req->xfer[0].len = 3;
396 spi_message_add_tail(&req->xfer[0], &req->msg);
397
398 mutex_lock(&ts->lock);
399 ads7846_stop(ts);
400 status = spi_sync(spi, &req->msg);
401 ads7846_restart(ts);
402 mutex_unlock(&ts->lock);
403
404 if (status == 0) {
405 /* BE12 value, then padding */
406 status = be16_to_cpu(*((u16 *)&req->sample[1]));
407 status = status >> 3;
408 status &= 0x0fff;
409 }
410
411 kfree(req);
412 return status;
413}
414
415#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
416
417#define SHOW(name, var, adjust) static ssize_t \
418name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
419{ \
420 struct ads7846 *ts = dev_get_drvdata(dev); \
421 ssize_t v = ads7846_read12_ser(dev, \
422 READ_12BIT_SER(var)); \
423 if (v < 0) \
424 return v; \
425 return sprintf(buf, "%u\n", adjust(ts, v)); \
426} \
427static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
428
429
430/* Sysfs conventions report temperatures in millidegrees Celsius.
431 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
432 * accuracy scheme without calibration data. For now we won't try either;
433 * userspace sees raw sensor values, and must scale/calibrate appropriately.
434 */
435static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
436{
437 return v;
438}
439
440SHOW(temp0, temp0, null_adjust) /* temp1_input */
441SHOW(temp1, temp1, null_adjust) /* temp2_input */
442
443
444/* sysfs conventions report voltages in millivolts. We can convert voltages
445 * if we know vREF. userspace may need to scale vAUX to match the board's
446 * external resistors; we assume that vBATT only uses the internal ones.
447 */
448static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
449{
450 unsigned retval = v;
451
452 /* external resistors may scale vAUX into 0..vREF */
453 retval *= ts->vref_mv;
454 retval = retval >> 12;
455
456 return retval;
457}
458
459static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
460{
461 unsigned retval = vaux_adjust(ts, v);
462
463 /* ads7846 has a resistor ladder to scale this signal down */
464 if (ts->model == 7846)
465 retval *= 4;
466
467 return retval;
468}
469
470SHOW(in0_input, vaux, vaux_adjust)
471SHOW(in1_input, vbatt, vbatt_adjust)
472
473static struct attribute *ads7846_attributes[] = {
474 &dev_attr_temp0.attr,
475 &dev_attr_temp1.attr,
476 &dev_attr_in0_input.attr,
477 &dev_attr_in1_input.attr,
478 NULL,
479};
480
481static struct attribute_group ads7846_attr_group = {
482 .attrs = ads7846_attributes,
483};
484
485static struct attribute *ads7843_attributes[] = {
486 &dev_attr_in0_input.attr,
487 &dev_attr_in1_input.attr,
488 NULL,
489};
490
491static struct attribute_group ads7843_attr_group = {
492 .attrs = ads7843_attributes,
493};
494
495static struct attribute *ads7845_attributes[] = {
496 &dev_attr_in0_input.attr,
497 NULL,
498};
499
500static struct attribute_group ads7845_attr_group = {
501 .attrs = ads7845_attributes,
502};
503
504static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
505{
506 struct device *hwmon;
507 int err;
508
509 /* hwmon sensors need a reference voltage */
510 switch (ts->model) {
511 case 7846:
512 if (!ts->vref_mv) {
513 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
514 ts->vref_mv = 2500;
515 ts->use_internal = true;
516 }
517 break;
518 case 7845:
519 case 7843:
520 if (!ts->vref_mv) {
521 dev_warn(&spi->dev,
522 "external vREF for ADS%d not specified\n",
523 ts->model);
524 return 0;
525 }
526 break;
527 }
528
529 /* different chips have different sensor groups */
530 switch (ts->model) {
531 case 7846:
532 ts->attr_group = &ads7846_attr_group;
533 break;
534 case 7845:
535 ts->attr_group = &ads7845_attr_group;
536 break;
537 case 7843:
538 ts->attr_group = &ads7843_attr_group;
539 break;
540 default:
541 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
542 return 0;
543 }
544
545 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
546 if (err)
547 return err;
548
549 hwmon = hwmon_device_register(&spi->dev);
550 if (IS_ERR(hwmon)) {
551 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
552 return PTR_ERR(hwmon);
553 }
554
555 ts->hwmon = hwmon;
556 return 0;
557}
558
559static void ads784x_hwmon_unregister(struct spi_device *spi,
560 struct ads7846 *ts)
561{
562 if (ts->hwmon) {
563 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
564 hwmon_device_unregister(ts->hwmon);
565 }
566}
567
568#else
569static inline int ads784x_hwmon_register(struct spi_device *spi,
570 struct ads7846 *ts)
571{
572 return 0;
573}
574
575static inline void ads784x_hwmon_unregister(struct spi_device *spi,
576 struct ads7846 *ts)
577{
578}
579#endif
580
581static ssize_t ads7846_pen_down_show(struct device *dev,
582 struct device_attribute *attr, char *buf)
583{
584 struct ads7846 *ts = dev_get_drvdata(dev);
585
586 return sprintf(buf, "%u\n", ts->pendown);
587}
588
589static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
590
591static ssize_t ads7846_disable_show(struct device *dev,
592 struct device_attribute *attr, char *buf)
593{
594 struct ads7846 *ts = dev_get_drvdata(dev);
595
596 return sprintf(buf, "%u\n", ts->disabled);
597}
598
599static ssize_t ads7846_disable_store(struct device *dev,
600 struct device_attribute *attr,
601 const char *buf, size_t count)
602{
603 struct ads7846 *ts = dev_get_drvdata(dev);
604 unsigned long i;
605
606 if (strict_strtoul(buf, 10, &i))
607 return -EINVAL;
608
609 if (i)
610 ads7846_disable(ts);
611 else
612 ads7846_enable(ts);
613
614 return count;
615}
616
617static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
618
619static struct attribute *ads784x_attributes[] = {
620 &dev_attr_pen_down.attr,
621 &dev_attr_disable.attr,
622 NULL,
623};
624
625static struct attribute_group ads784x_attr_group = {
626 .attrs = ads784x_attributes,
627};
628
629/*--------------------------------------------------------------------------*/
630
631static int get_pendown_state(struct ads7846 *ts)
632{
633 if (ts->get_pendown_state)
634 return ts->get_pendown_state();
635
636 return !gpio_get_value(ts->gpio_pendown);
637}
638
639static void null_wait_for_sync(void)
640{
641}
642
643static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
644{
645 struct ads7846 *ts = ads;
646
647 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
648 /* Start over collecting consistent readings. */
649 ts->read_rep = 0;
650 /*
651 * Repeat it, if this was the first read or the read
652 * wasn't consistent enough.
653 */
654 if (ts->read_cnt < ts->debounce_max) {
655 ts->last_read = *val;
656 ts->read_cnt++;
657 return ADS7846_FILTER_REPEAT;
658 } else {
659 /*
660 * Maximum number of debouncing reached and still
661 * not enough number of consistent readings. Abort
662 * the whole sample, repeat it in the next sampling
663 * period.
664 */
665 ts->read_cnt = 0;
666 return ADS7846_FILTER_IGNORE;
667 }
668 } else {
669 if (++ts->read_rep > ts->debounce_rep) {
670 /*
671 * Got a good reading for this coordinate,
672 * go for the next one.
673 */
674 ts->read_cnt = 0;
675 ts->read_rep = 0;
676 return ADS7846_FILTER_OK;
677 } else {
678 /* Read more values that are consistent. */
679 ts->read_cnt++;
680 return ADS7846_FILTER_REPEAT;
681 }
682 }
683}
684
685static int ads7846_no_filter(void *ads, int data_idx, int *val)
686{
687 return ADS7846_FILTER_OK;
688}
689
690static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
691{
692 struct spi_transfer *t =
693 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
694
695 if (ts->model == 7845) {
696 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
697 } else {
698 /*
699 * adjust: on-wire is a must-ignore bit, a BE12 value, then
700 * padding; built from two 8 bit values written msb-first.
701 */
702 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
703 }
704}
705
706static void ads7846_update_value(struct spi_message *m, int val)
707{
708 struct spi_transfer *t =
709 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
710
711 *(u16 *)t->rx_buf = val;
712}
713
714static void ads7846_read_state(struct ads7846 *ts)
715{
716 struct ads7846_packet *packet = ts->packet;
717 struct spi_message *m;
718 int msg_idx = 0;
719 int val;
720 int action;
721 int error;
722
723 while (msg_idx < ts->msg_count) {
724
725 ts->wait_for_sync();
726
727 m = &ts->msg[msg_idx];
728 error = spi_sync(ts->spi, m);
729 if (error) {
730 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
731 packet->tc.ignore = true;
732 return;
733 }
734
735 /*
736 * Last message is power down request, no need to convert
737 * or filter the value.
738 */
739 if (msg_idx < ts->msg_count - 1) {
740
741 val = ads7846_get_value(ts, m);
742
743 action = ts->filter(ts->filter_data, msg_idx, &val);
744 switch (action) {
745 case ADS7846_FILTER_REPEAT:
746 continue;
747
748 case ADS7846_FILTER_IGNORE:
749 packet->tc.ignore = true;
750 msg_idx = ts->msg_count - 1;
751 continue;
752
753 case ADS7846_FILTER_OK:
754 ads7846_update_value(m, val);
755 packet->tc.ignore = false;
756 msg_idx++;
757 break;
758
759 default:
760 BUG();
761 }
762 } else {
763 msg_idx++;
764 }
765 }
766}
767
768static void ads7846_report_state(struct ads7846 *ts)
769{
770 struct ads7846_packet *packet = ts->packet;
771 unsigned int Rt;
772 u16 x, y, z1, z2;
773
774 /*
775 * ads7846_get_value() does in-place conversion (including byte swap)
776 * from on-the-wire format as part of debouncing to get stable
777 * readings.
778 */
779 if (ts->model == 7845) {
780 x = *(u16 *)packet->tc.x_buf;
781 y = *(u16 *)packet->tc.y_buf;
782 z1 = 0;
783 z2 = 0;
784 } else {
785 x = packet->tc.x;
786 y = packet->tc.y;
787 z1 = packet->tc.z1;
788 z2 = packet->tc.z2;
789 }
790
791 /* range filtering */
792 if (x == MAX_12BIT)
793 x = 0;
794
795 if (ts->model == 7843) {
796 Rt = ts->pressure_max / 2;
797 } else if (ts->model == 7845) {
798 if (get_pendown_state(ts))
799 Rt = ts->pressure_max / 2;
800 else
801 Rt = 0;
802 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
803 } else if (likely(x && z1)) {
804 /* compute touch pressure resistance using equation #2 */
805 Rt = z2;
806 Rt -= z1;
807 Rt *= x;
808 Rt *= ts->x_plate_ohms;
809 Rt /= z1;
810 Rt = (Rt + 2047) >> 12;
811 } else {
812 Rt = 0;
813 }
814
815 /*
816 * Sample found inconsistent by debouncing or pressure is beyond
817 * the maximum. Don't report it to user space, repeat at least
818 * once more the measurement
819 */
820 if (packet->tc.ignore || Rt > ts->pressure_max) {
821 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
822 packet->tc.ignore, Rt);
823 return;
824 }
825
826 /*
827 * Maybe check the pendown state before reporting. This discards
828 * false readings when the pen is lifted.
829 */
830 if (ts->penirq_recheck_delay_usecs) {
831 udelay(ts->penirq_recheck_delay_usecs);
832 if (!get_pendown_state(ts))
833 Rt = 0;
834 }
835
836 /*
837 * NOTE: We can't rely on the pressure to determine the pen down
838 * state, even this controller has a pressure sensor. The pressure
839 * value can fluctuate for quite a while after lifting the pen and
840 * in some cases may not even settle at the expected value.
841 *
842 * The only safe way to check for the pen up condition is in the
843 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
844 */
845 if (Rt) {
846 struct input_dev *input = ts->input;
847
848 if (ts->swap_xy)
849 swap(x, y);
850
851 if (!ts->pendown) {
852 input_report_key(input, BTN_TOUCH, 1);
853 ts->pendown = true;
854 dev_vdbg(&ts->spi->dev, "DOWN\n");
855 }
856
857 input_report_abs(input, ABS_X, x);
858 input_report_abs(input, ABS_Y, y);
859 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
860
861 input_sync(input);
862 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
863 }
864}
865
866static irqreturn_t ads7846_hard_irq(int irq, void *handle)
867{
868 struct ads7846 *ts = handle;
869
870 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
871}
872
873
874static irqreturn_t ads7846_irq(int irq, void *handle)
875{
876 struct ads7846 *ts = handle;
877
878 /* Start with a small delay before checking pendown state */
879 msleep(TS_POLL_DELAY);
880
881 while (!ts->stopped && get_pendown_state(ts)) {
882
883 /* pen is down, continue with the measurement */
884 ads7846_read_state(ts);
885
886 if (!ts->stopped)
887 ads7846_report_state(ts);
888
889 wait_event_timeout(ts->wait, ts->stopped,
890 msecs_to_jiffies(TS_POLL_PERIOD));
891 }
892
893 if (ts->pendown) {
894 struct input_dev *input = ts->input;
895
896 input_report_key(input, BTN_TOUCH, 0);
897 input_report_abs(input, ABS_PRESSURE, 0);
898 input_sync(input);
899
900 ts->pendown = false;
901 dev_vdbg(&ts->spi->dev, "UP\n");
902 }
903
904 return IRQ_HANDLED;
905}
906
907#ifdef CONFIG_PM_SLEEP
908static int ads7846_suspend(struct device *dev)
909{
910 struct ads7846 *ts = dev_get_drvdata(dev);
911
912 mutex_lock(&ts->lock);
913
914 if (!ts->suspended) {
915
916 if (!ts->disabled)
917 __ads7846_disable(ts);
918
919 if (device_may_wakeup(&ts->spi->dev))
920 enable_irq_wake(ts->spi->irq);
921
922 ts->suspended = true;
923 }
924
925 mutex_unlock(&ts->lock);
926
927 return 0;
928}
929
930static int ads7846_resume(struct device *dev)
931{
932 struct ads7846 *ts = dev_get_drvdata(dev);
933
934 mutex_lock(&ts->lock);
935
936 if (ts->suspended) {
937
938 ts->suspended = false;
939
940 if (device_may_wakeup(&ts->spi->dev))
941 disable_irq_wake(ts->spi->irq);
942
943 if (!ts->disabled)
944 __ads7846_enable(ts);
945 }
946
947 mutex_unlock(&ts->lock);
948
949 return 0;
950}
951#endif
952
953static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
954
955static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
956{
957 struct ads7846_platform_data *pdata = spi->dev.platform_data;
958 int err;
959
960 /*
961 * REVISIT when the irq can be triggered active-low, or if for some
962 * reason the touchscreen isn't hooked up, we don't need to access
963 * the pendown state.
964 */
965
966 if (pdata->get_pendown_state) {
967 ts->get_pendown_state = pdata->get_pendown_state;
968 } else if (gpio_is_valid(pdata->gpio_pendown)) {
969
970 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
971 "ads7846_pendown");
972 if (err) {
973 dev_err(&spi->dev,
974 "failed to request/setup pendown GPIO%d: %d\n",
975 pdata->gpio_pendown, err);
976 return err;
977 }
978
979 ts->gpio_pendown = pdata->gpio_pendown;
980
981 } else {
982 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
983 return -EINVAL;
984 }
985
986 return 0;
987}
988
989/*
990 * Set up the transfers to read touchscreen state; this assumes we
991 * use formula #2 for pressure, not #3.
992 */
993static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
994 const struct ads7846_platform_data *pdata)
995{
996 struct spi_message *m = &ts->msg[0];
997 struct spi_transfer *x = ts->xfer;
998 struct ads7846_packet *packet = ts->packet;
999 int vref = pdata->keep_vref_on;
1000
1001 if (ts->model == 7873) {
1002 /*
1003 * The AD7873 is almost identical to the ADS7846
1004 * keep VREF off during differential/ratiometric
1005 * conversion modes.
1006 */
1007 ts->model = 7846;
1008 vref = 0;
1009 }
1010
1011 ts->msg_count = 1;
1012 spi_message_init(m);
1013 m->context = ts;
1014
1015 if (ts->model == 7845) {
1016 packet->read_y_cmd[0] = READ_Y(vref);
1017 packet->read_y_cmd[1] = 0;
1018 packet->read_y_cmd[2] = 0;
1019 x->tx_buf = &packet->read_y_cmd[0];
1020 x->rx_buf = &packet->tc.y_buf[0];
1021 x->len = 3;
1022 spi_message_add_tail(x, m);
1023 } else {
1024 /* y- still on; turn on only y+ (and ADC) */
1025 packet->read_y = READ_Y(vref);
1026 x->tx_buf = &packet->read_y;
1027 x->len = 1;
1028 spi_message_add_tail(x, m);
1029
1030 x++;
1031 x->rx_buf = &packet->tc.y;
1032 x->len = 2;
1033 spi_message_add_tail(x, m);
1034 }
1035
1036 /*
1037 * The first sample after switching drivers can be low quality;
1038 * optionally discard it, using a second one after the signals
1039 * have had enough time to stabilize.
1040 */
1041 if (pdata->settle_delay_usecs) {
1042 x->delay_usecs = pdata->settle_delay_usecs;
1043
1044 x++;
1045 x->tx_buf = &packet->read_y;
1046 x->len = 1;
1047 spi_message_add_tail(x, m);
1048
1049 x++;
1050 x->rx_buf = &packet->tc.y;
1051 x->len = 2;
1052 spi_message_add_tail(x, m);
1053 }
1054
1055 ts->msg_count++;
1056 m++;
1057 spi_message_init(m);
1058 m->context = ts;
1059
1060 if (ts->model == 7845) {
1061 x++;
1062 packet->read_x_cmd[0] = READ_X(vref);
1063 packet->read_x_cmd[1] = 0;
1064 packet->read_x_cmd[2] = 0;
1065 x->tx_buf = &packet->read_x_cmd[0];
1066 x->rx_buf = &packet->tc.x_buf[0];
1067 x->len = 3;
1068 spi_message_add_tail(x, m);
1069 } else {
1070 /* turn y- off, x+ on, then leave in lowpower */
1071 x++;
1072 packet->read_x = READ_X(vref);
1073 x->tx_buf = &packet->read_x;
1074 x->len = 1;
1075 spi_message_add_tail(x, m);
1076
1077 x++;
1078 x->rx_buf = &packet->tc.x;
1079 x->len = 2;
1080 spi_message_add_tail(x, m);
1081 }
1082
1083 /* ... maybe discard first sample ... */
1084 if (pdata->settle_delay_usecs) {
1085 x->delay_usecs = pdata->settle_delay_usecs;
1086
1087 x++;
1088 x->tx_buf = &packet->read_x;
1089 x->len = 1;
1090 spi_message_add_tail(x, m);
1091
1092 x++;
1093 x->rx_buf = &packet->tc.x;
1094 x->len = 2;
1095 spi_message_add_tail(x, m);
1096 }
1097
1098 /* turn y+ off, x- on; we'll use formula #2 */
1099 if (ts->model == 7846) {
1100 ts->msg_count++;
1101 m++;
1102 spi_message_init(m);
1103 m->context = ts;
1104
1105 x++;
1106 packet->read_z1 = READ_Z1(vref);
1107 x->tx_buf = &packet->read_z1;
1108 x->len = 1;
1109 spi_message_add_tail(x, m);
1110
1111 x++;
1112 x->rx_buf = &packet->tc.z1;
1113 x->len = 2;
1114 spi_message_add_tail(x, m);
1115
1116 /* ... maybe discard first sample ... */
1117 if (pdata->settle_delay_usecs) {
1118 x->delay_usecs = pdata->settle_delay_usecs;
1119
1120 x++;
1121 x->tx_buf = &packet->read_z1;
1122 x->len = 1;
1123 spi_message_add_tail(x, m);
1124
1125 x++;
1126 x->rx_buf = &packet->tc.z1;
1127 x->len = 2;
1128 spi_message_add_tail(x, m);
1129 }
1130
1131 ts->msg_count++;
1132 m++;
1133 spi_message_init(m);
1134 m->context = ts;
1135
1136 x++;
1137 packet->read_z2 = READ_Z2(vref);
1138 x->tx_buf = &packet->read_z2;
1139 x->len = 1;
1140 spi_message_add_tail(x, m);
1141
1142 x++;
1143 x->rx_buf = &packet->tc.z2;
1144 x->len = 2;
1145 spi_message_add_tail(x, m);
1146
1147 /* ... maybe discard first sample ... */
1148 if (pdata->settle_delay_usecs) {
1149 x->delay_usecs = pdata->settle_delay_usecs;
1150
1151 x++;
1152 x->tx_buf = &packet->read_z2;
1153 x->len = 1;
1154 spi_message_add_tail(x, m);
1155
1156 x++;
1157 x->rx_buf = &packet->tc.z2;
1158 x->len = 2;
1159 spi_message_add_tail(x, m);
1160 }
1161 }
1162
1163 /* power down */
1164 ts->msg_count++;
1165 m++;
1166 spi_message_init(m);
1167 m->context = ts;
1168
1169 if (ts->model == 7845) {
1170 x++;
1171 packet->pwrdown_cmd[0] = PWRDOWN;
1172 packet->pwrdown_cmd[1] = 0;
1173 packet->pwrdown_cmd[2] = 0;
1174 x->tx_buf = &packet->pwrdown_cmd[0];
1175 x->len = 3;
1176 } else {
1177 x++;
1178 packet->pwrdown = PWRDOWN;
1179 x->tx_buf = &packet->pwrdown;
1180 x->len = 1;
1181 spi_message_add_tail(x, m);
1182
1183 x++;
1184 x->rx_buf = &packet->dummy;
1185 x->len = 2;
1186 }
1187
1188 CS_CHANGE(*x);
1189 spi_message_add_tail(x, m);
1190}
1191
1192static int __devinit ads7846_probe(struct spi_device *spi)
1193{
1194 struct ads7846 *ts;
1195 struct ads7846_packet *packet;
1196 struct input_dev *input_dev;
1197 struct ads7846_platform_data *pdata = spi->dev.platform_data;
1198 unsigned long irq_flags;
1199 int err;
1200
1201 if (!spi->irq) {
1202 dev_dbg(&spi->dev, "no IRQ?\n");
1203 return -ENODEV;
1204 }
1205
1206 if (!pdata) {
1207 dev_dbg(&spi->dev, "no platform data?\n");
1208 return -ENODEV;
1209 }
1210
1211 /* don't exceed max specified sample rate */
1212 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1213 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1214 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1215 return -EINVAL;
1216 }
1217
1218 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1219 * that even if the hardware can do that, the SPI controller driver
1220 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1221 */
1222 spi->bits_per_word = 8;
1223 spi->mode = SPI_MODE_0;
1224 err = spi_setup(spi);
1225 if (err < 0)
1226 return err;
1227
1228 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1229 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1230 input_dev = input_allocate_device();
1231 if (!ts || !packet || !input_dev) {
1232 err = -ENOMEM;
1233 goto err_free_mem;
1234 }
1235
1236 dev_set_drvdata(&spi->dev, ts);
1237
1238 ts->packet = packet;
1239 ts->spi = spi;
1240 ts->input = input_dev;
1241 ts->vref_mv = pdata->vref_mv;
1242 ts->swap_xy = pdata->swap_xy;
1243
1244 mutex_init(&ts->lock);
1245 init_waitqueue_head(&ts->wait);
1246
1247 ts->model = pdata->model ? : 7846;
1248 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1249 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1250 ts->pressure_max = pdata->pressure_max ? : ~0;
1251
1252 if (pdata->filter != NULL) {
1253 if (pdata->filter_init != NULL) {
1254 err = pdata->filter_init(pdata, &ts->filter_data);
1255 if (err < 0)
1256 goto err_free_mem;
1257 }
1258 ts->filter = pdata->filter;
1259 ts->filter_cleanup = pdata->filter_cleanup;
1260 } else if (pdata->debounce_max) {
1261 ts->debounce_max = pdata->debounce_max;
1262 if (ts->debounce_max < 2)
1263 ts->debounce_max = 2;
1264 ts->debounce_tol = pdata->debounce_tol;
1265 ts->debounce_rep = pdata->debounce_rep;
1266 ts->filter = ads7846_debounce_filter;
1267 ts->filter_data = ts;
1268 } else {
1269 ts->filter = ads7846_no_filter;
1270 }
1271
1272 err = ads7846_setup_pendown(spi, ts);
1273 if (err)
1274 goto err_cleanup_filter;
1275
1276 if (pdata->penirq_recheck_delay_usecs)
1277 ts->penirq_recheck_delay_usecs =
1278 pdata->penirq_recheck_delay_usecs;
1279
1280 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1281
1282 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1283 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1284
1285 input_dev->name = ts->name;
1286 input_dev->phys = ts->phys;
1287 input_dev->dev.parent = &spi->dev;
1288
1289 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1290 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1291 input_set_abs_params(input_dev, ABS_X,
1292 pdata->x_min ? : 0,
1293 pdata->x_max ? : MAX_12BIT,
1294 0, 0);
1295 input_set_abs_params(input_dev, ABS_Y,
1296 pdata->y_min ? : 0,
1297 pdata->y_max ? : MAX_12BIT,
1298 0, 0);
1299 input_set_abs_params(input_dev, ABS_PRESSURE,
1300 pdata->pressure_min, pdata->pressure_max, 0, 0);
1301
1302 ads7846_setup_spi_msg(ts, pdata);
1303
1304 ts->reg = regulator_get(&spi->dev, "vcc");
1305 if (IS_ERR(ts->reg)) {
1306 err = PTR_ERR(ts->reg);
1307 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1308 goto err_free_gpio;
1309 }
1310
1311 err = regulator_enable(ts->reg);
1312 if (err) {
1313 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1314 goto err_put_regulator;
1315 }
1316
1317 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1318 irq_flags |= IRQF_ONESHOT;
1319
1320 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1321 irq_flags, spi->dev.driver->name, ts);
1322 if (err && !pdata->irq_flags) {
1323 dev_info(&spi->dev,
1324 "trying pin change workaround on irq %d\n", spi->irq);
1325 irq_flags |= IRQF_TRIGGER_RISING;
1326 err = request_threaded_irq(spi->irq,
1327 ads7846_hard_irq, ads7846_irq,
1328 irq_flags, spi->dev.driver->name, ts);
1329 }
1330
1331 if (err) {
1332 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1333 goto err_disable_regulator;
1334 }
1335
1336 err = ads784x_hwmon_register(spi, ts);
1337 if (err)
1338 goto err_free_irq;
1339
1340 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1341
1342 /*
1343 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1344 * the touchscreen, in case it's not connected.
1345 */
1346 if (ts->model == 7845)
1347 ads7845_read12_ser(&spi->dev, PWRDOWN);
1348 else
1349 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1350
1351 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1352 if (err)
1353 goto err_remove_hwmon;
1354
1355 err = input_register_device(input_dev);
1356 if (err)
1357 goto err_remove_attr_group;
1358
1359 device_init_wakeup(&spi->dev, pdata->wakeup);
1360
1361 return 0;
1362
1363 err_remove_attr_group:
1364 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1365 err_remove_hwmon:
1366 ads784x_hwmon_unregister(spi, ts);
1367 err_free_irq:
1368 free_irq(spi->irq, ts);
1369 err_disable_regulator:
1370 regulator_disable(ts->reg);
1371 err_put_regulator:
1372 regulator_put(ts->reg);
1373 err_free_gpio:
1374 if (!ts->get_pendown_state)
1375 gpio_free(ts->gpio_pendown);
1376 err_cleanup_filter:
1377 if (ts->filter_cleanup)
1378 ts->filter_cleanup(ts->filter_data);
1379 err_free_mem:
1380 input_free_device(input_dev);
1381 kfree(packet);
1382 kfree(ts);
1383 return err;
1384}
1385
1386static int __devexit ads7846_remove(struct spi_device *spi)
1387{
1388 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1389
1390 device_init_wakeup(&spi->dev, false);
1391
1392 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1393
1394 ads7846_disable(ts);
1395 free_irq(ts->spi->irq, ts);
1396
1397 input_unregister_device(ts->input);
1398
1399 ads784x_hwmon_unregister(spi, ts);
1400
1401 regulator_disable(ts->reg);
1402 regulator_put(ts->reg);
1403
1404 if (!ts->get_pendown_state) {
1405 /*
1406 * If we are not using specialized pendown method we must
1407 * have been relying on gpio we set up ourselves.
1408 */
1409 gpio_free(ts->gpio_pendown);
1410 }
1411
1412 if (ts->filter_cleanup)
1413 ts->filter_cleanup(ts->filter_data);
1414
1415 kfree(ts->packet);
1416 kfree(ts);
1417
1418 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1419
1420 return 0;
1421}
1422
1423static struct spi_driver ads7846_driver = {
1424 .driver = {
1425 .name = "ads7846",
1426 .bus = &spi_bus_type,
1427 .owner = THIS_MODULE,
1428 .pm = &ads7846_pm,
1429 },
1430 .probe = ads7846_probe,
1431 .remove = __devexit_p(ads7846_remove),
1432};
1433
1434static int __init ads7846_init(void)
1435{
1436 return spi_register_driver(&ads7846_driver);
1437}
1438module_init(ads7846_init);
1439
1440static void __exit ads7846_exit(void)
1441{
1442 spi_unregister_driver(&ads7846_driver);
1443}
1444module_exit(ads7846_exit);
1445
1446MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1447MODULE_LICENSE("GPL");
1448MODULE_ALIAS("spi:ads7846");
1/*
2 * ADS7846 based touchscreen and sensor driver
3 *
4 * Copyright (c) 2005 David Brownell
5 * Copyright (c) 2006 Nokia Corporation
6 * Various changes: Imre Deak <imre.deak@nokia.com>
7 *
8 * Using code from:
9 * - corgi_ts.c
10 * Copyright (C) 2004-2005 Richard Purdie
11 * - omap_ts.[hc], ads7846.h, ts_osk.c
12 * Copyright (C) 2002 MontaVista Software
13 * Copyright (C) 2004 Texas Instruments
14 * Copyright (C) 2005 Dirk Behme
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License version 2 as
18 * published by the Free Software Foundation.
19 */
20#include <linux/types.h>
21#include <linux/hwmon.h>
22#include <linux/init.h>
23#include <linux/err.h>
24#include <linux/sched.h>
25#include <linux/delay.h>
26#include <linux/input.h>
27#include <linux/interrupt.h>
28#include <linux/slab.h>
29#include <linux/pm.h>
30#include <linux/gpio.h>
31#include <linux/spi/spi.h>
32#include <linux/spi/ads7846.h>
33#include <linux/regulator/consumer.h>
34#include <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 defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
102 struct attribute_group *attr_group;
103 struct device *hwmon;
104#endif
105
106 u16 model;
107 u16 vref_mv;
108 u16 vref_delay_usecs;
109 u16 x_plate_ohms;
110 u16 pressure_max;
111
112 bool swap_xy;
113 bool use_internal;
114
115 struct ads7846_packet *packet;
116
117 struct spi_transfer xfer[18];
118 struct spi_message msg[5];
119 int msg_count;
120 wait_queue_head_t wait;
121
122 bool pendown;
123
124 int read_cnt;
125 int read_rep;
126 int last_read;
127
128 u16 debounce_max;
129 u16 debounce_tol;
130 u16 debounce_rep;
131
132 u16 penirq_recheck_delay_usecs;
133
134 struct mutex lock;
135 bool stopped; /* P: lock */
136 bool disabled; /* P: lock */
137 bool suspended; /* P: lock */
138
139 int (*filter)(void *data, int data_idx, int *val);
140 void *filter_data;
141 void (*filter_cleanup)(void *data);
142 int (*get_pendown_state)(void);
143 int gpio_pendown;
144
145 void (*wait_for_sync)(void);
146};
147
148/* leave chip selected when we're done, for quicker re-select? */
149#if 0
150#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
151#else
152#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
153#endif
154
155/*--------------------------------------------------------------------------*/
156
157/* The ADS7846 has touchscreen and other sensors.
158 * Earlier ads784x chips are somewhat compatible.
159 */
160#define ADS_START (1 << 7)
161#define ADS_A2A1A0_d_y (1 << 4) /* differential */
162#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
163#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
164#define ADS_A2A1A0_d_x (5 << 4) /* differential */
165#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
166#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
167#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
168#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
169#define ADS_8_BIT (1 << 3)
170#define ADS_12_BIT (0 << 3)
171#define ADS_SER (1 << 2) /* non-differential */
172#define ADS_DFR (0 << 2) /* differential */
173#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
174#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
175#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
176#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
177
178#define MAX_12BIT ((1<<12)-1)
179
180/* leave ADC powered up (disables penirq) between differential samples */
181#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
182 | ADS_12_BIT | ADS_DFR | \
183 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
184
185#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
186#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
187#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
188
189#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
190#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
191
192/* single-ended samples need to first power up reference voltage;
193 * we leave both ADC and VREF powered
194 */
195#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
196 | ADS_12_BIT | ADS_SER)
197
198#define REF_ON (READ_12BIT_DFR(x, 1, 1))
199#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
200
201/* Must be called with ts->lock held */
202static void ads7846_stop(struct ads7846 *ts)
203{
204 if (!ts->disabled && !ts->suspended) {
205 /* Signal IRQ thread to stop polling and disable the handler. */
206 ts->stopped = true;
207 mb();
208 wake_up(&ts->wait);
209 disable_irq(ts->spi->irq);
210 }
211}
212
213/* Must be called with ts->lock held */
214static void ads7846_restart(struct ads7846 *ts)
215{
216 if (!ts->disabled && !ts->suspended) {
217 /* Tell IRQ thread that it may poll the device. */
218 ts->stopped = false;
219 mb();
220 enable_irq(ts->spi->irq);
221 }
222}
223
224/* Must be called with ts->lock held */
225static void __ads7846_disable(struct ads7846 *ts)
226{
227 ads7846_stop(ts);
228 regulator_disable(ts->reg);
229
230 /*
231 * We know the chip's in low power mode since we always
232 * leave it that way after every request
233 */
234}
235
236/* Must be called with ts->lock held */
237static void __ads7846_enable(struct ads7846 *ts)
238{
239 regulator_enable(ts->reg);
240 ads7846_restart(ts);
241}
242
243static void ads7846_disable(struct ads7846 *ts)
244{
245 mutex_lock(&ts->lock);
246
247 if (!ts->disabled) {
248
249 if (!ts->suspended)
250 __ads7846_disable(ts);
251
252 ts->disabled = true;
253 }
254
255 mutex_unlock(&ts->lock);
256}
257
258static void ads7846_enable(struct ads7846 *ts)
259{
260 mutex_lock(&ts->lock);
261
262 if (ts->disabled) {
263
264 ts->disabled = false;
265
266 if (!ts->suspended)
267 __ads7846_enable(ts);
268 }
269
270 mutex_unlock(&ts->lock);
271}
272
273/*--------------------------------------------------------------------------*/
274
275/*
276 * Non-touchscreen sensors only use single-ended conversions.
277 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
278 * ads7846 lets that pin be unconnected, to use internal vREF.
279 */
280
281struct ser_req {
282 u8 ref_on;
283 u8 command;
284 u8 ref_off;
285 u16 scratch;
286 struct spi_message msg;
287 struct spi_transfer xfer[6];
288 /*
289 * DMA (thus cache coherency maintenance) requires the
290 * transfer buffers to live in their own cache lines.
291 */
292 __be16 sample ____cacheline_aligned;
293};
294
295struct ads7845_ser_req {
296 u8 command[3];
297 struct spi_message msg;
298 struct spi_transfer xfer[2];
299 /*
300 * DMA (thus cache coherency maintenance) requires the
301 * transfer buffers to live in their own cache lines.
302 */
303 u8 sample[3] ____cacheline_aligned;
304};
305
306static int ads7846_read12_ser(struct device *dev, unsigned command)
307{
308 struct spi_device *spi = to_spi_device(dev);
309 struct ads7846 *ts = dev_get_drvdata(dev);
310 struct ser_req *req;
311 int status;
312
313 req = kzalloc(sizeof *req, GFP_KERNEL);
314 if (!req)
315 return -ENOMEM;
316
317 spi_message_init(&req->msg);
318
319 /* maybe turn on internal vREF, and let it settle */
320 if (ts->use_internal) {
321 req->ref_on = REF_ON;
322 req->xfer[0].tx_buf = &req->ref_on;
323 req->xfer[0].len = 1;
324 spi_message_add_tail(&req->xfer[0], &req->msg);
325
326 req->xfer[1].rx_buf = &req->scratch;
327 req->xfer[1].len = 2;
328
329 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
330 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
331 spi_message_add_tail(&req->xfer[1], &req->msg);
332
333 /* Enable reference voltage */
334 command |= ADS_PD10_REF_ON;
335 }
336
337 /* Enable ADC in every case */
338 command |= ADS_PD10_ADC_ON;
339
340 /* take sample */
341 req->command = (u8) command;
342 req->xfer[2].tx_buf = &req->command;
343 req->xfer[2].len = 1;
344 spi_message_add_tail(&req->xfer[2], &req->msg);
345
346 req->xfer[3].rx_buf = &req->sample;
347 req->xfer[3].len = 2;
348 spi_message_add_tail(&req->xfer[3], &req->msg);
349
350 /* REVISIT: take a few more samples, and compare ... */
351
352 /* converter in low power mode & enable PENIRQ */
353 req->ref_off = PWRDOWN;
354 req->xfer[4].tx_buf = &req->ref_off;
355 req->xfer[4].len = 1;
356 spi_message_add_tail(&req->xfer[4], &req->msg);
357
358 req->xfer[5].rx_buf = &req->scratch;
359 req->xfer[5].len = 2;
360 CS_CHANGE(req->xfer[5]);
361 spi_message_add_tail(&req->xfer[5], &req->msg);
362
363 mutex_lock(&ts->lock);
364 ads7846_stop(ts);
365 status = spi_sync(spi, &req->msg);
366 ads7846_restart(ts);
367 mutex_unlock(&ts->lock);
368
369 if (status == 0) {
370 /* on-wire is a must-ignore bit, a BE12 value, then padding */
371 status = be16_to_cpu(req->sample);
372 status = status >> 3;
373 status &= 0x0fff;
374 }
375
376 kfree(req);
377 return status;
378}
379
380static int ads7845_read12_ser(struct device *dev, unsigned command)
381{
382 struct spi_device *spi = to_spi_device(dev);
383 struct ads7846 *ts = dev_get_drvdata(dev);
384 struct ads7845_ser_req *req;
385 int status;
386
387 req = kzalloc(sizeof *req, GFP_KERNEL);
388 if (!req)
389 return -ENOMEM;
390
391 spi_message_init(&req->msg);
392
393 req->command[0] = (u8) command;
394 req->xfer[0].tx_buf = req->command;
395 req->xfer[0].rx_buf = req->sample;
396 req->xfer[0].len = 3;
397 spi_message_add_tail(&req->xfer[0], &req->msg);
398
399 mutex_lock(&ts->lock);
400 ads7846_stop(ts);
401 status = spi_sync(spi, &req->msg);
402 ads7846_restart(ts);
403 mutex_unlock(&ts->lock);
404
405 if (status == 0) {
406 /* BE12 value, then padding */
407 status = be16_to_cpu(*((u16 *)&req->sample[1]));
408 status = status >> 3;
409 status &= 0x0fff;
410 }
411
412 kfree(req);
413 return status;
414}
415
416#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
417
418#define SHOW(name, var, adjust) static ssize_t \
419name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
420{ \
421 struct ads7846 *ts = dev_get_drvdata(dev); \
422 ssize_t v = ads7846_read12_ser(dev, \
423 READ_12BIT_SER(var)); \
424 if (v < 0) \
425 return v; \
426 return sprintf(buf, "%u\n", adjust(ts, v)); \
427} \
428static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
429
430
431/* Sysfs conventions report temperatures in millidegrees Celsius.
432 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
433 * accuracy scheme without calibration data. For now we won't try either;
434 * userspace sees raw sensor values, and must scale/calibrate appropriately.
435 */
436static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
437{
438 return v;
439}
440
441SHOW(temp0, temp0, null_adjust) /* temp1_input */
442SHOW(temp1, temp1, null_adjust) /* temp2_input */
443
444
445/* sysfs conventions report voltages in millivolts. We can convert voltages
446 * if we know vREF. userspace may need to scale vAUX to match the board's
447 * external resistors; we assume that vBATT only uses the internal ones.
448 */
449static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
450{
451 unsigned retval = v;
452
453 /* external resistors may scale vAUX into 0..vREF */
454 retval *= ts->vref_mv;
455 retval = retval >> 12;
456
457 return retval;
458}
459
460static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
461{
462 unsigned retval = vaux_adjust(ts, v);
463
464 /* ads7846 has a resistor ladder to scale this signal down */
465 if (ts->model == 7846)
466 retval *= 4;
467
468 return retval;
469}
470
471SHOW(in0_input, vaux, vaux_adjust)
472SHOW(in1_input, vbatt, vbatt_adjust)
473
474static struct attribute *ads7846_attributes[] = {
475 &dev_attr_temp0.attr,
476 &dev_attr_temp1.attr,
477 &dev_attr_in0_input.attr,
478 &dev_attr_in1_input.attr,
479 NULL,
480};
481
482static struct attribute_group ads7846_attr_group = {
483 .attrs = ads7846_attributes,
484};
485
486static struct attribute *ads7843_attributes[] = {
487 &dev_attr_in0_input.attr,
488 &dev_attr_in1_input.attr,
489 NULL,
490};
491
492static struct attribute_group ads7843_attr_group = {
493 .attrs = ads7843_attributes,
494};
495
496static struct attribute *ads7845_attributes[] = {
497 &dev_attr_in0_input.attr,
498 NULL,
499};
500
501static struct attribute_group ads7845_attr_group = {
502 .attrs = ads7845_attributes,
503};
504
505static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
506{
507 struct device *hwmon;
508 int err;
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 /* different chips have different sensor groups */
531 switch (ts->model) {
532 case 7846:
533 ts->attr_group = &ads7846_attr_group;
534 break;
535 case 7845:
536 ts->attr_group = &ads7845_attr_group;
537 break;
538 case 7843:
539 ts->attr_group = &ads7843_attr_group;
540 break;
541 default:
542 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
543 return 0;
544 }
545
546 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
547 if (err)
548 return err;
549
550 hwmon = hwmon_device_register(&spi->dev);
551 if (IS_ERR(hwmon)) {
552 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
553 return PTR_ERR(hwmon);
554 }
555
556 ts->hwmon = hwmon;
557 return 0;
558}
559
560static void ads784x_hwmon_unregister(struct spi_device *spi,
561 struct ads7846 *ts)
562{
563 if (ts->hwmon) {
564 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
565 hwmon_device_unregister(ts->hwmon);
566 }
567}
568
569#else
570static inline int ads784x_hwmon_register(struct spi_device *spi,
571 struct ads7846 *ts)
572{
573 return 0;
574}
575
576static inline void ads784x_hwmon_unregister(struct spi_device *spi,
577 struct ads7846 *ts)
578{
579}
580#endif
581
582static ssize_t ads7846_pen_down_show(struct device *dev,
583 struct device_attribute *attr, char *buf)
584{
585 struct ads7846 *ts = dev_get_drvdata(dev);
586
587 return sprintf(buf, "%u\n", ts->pendown);
588}
589
590static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
591
592static ssize_t ads7846_disable_show(struct device *dev,
593 struct device_attribute *attr, char *buf)
594{
595 struct ads7846 *ts = dev_get_drvdata(dev);
596
597 return sprintf(buf, "%u\n", ts->disabled);
598}
599
600static ssize_t ads7846_disable_store(struct device *dev,
601 struct device_attribute *attr,
602 const char *buf, size_t count)
603{
604 struct ads7846 *ts = dev_get_drvdata(dev);
605 unsigned int i;
606 int err;
607
608 err = kstrtouint(buf, 10, &i);
609 if (err)
610 return err;
611
612 if (i)
613 ads7846_disable(ts);
614 else
615 ads7846_enable(ts);
616
617 return count;
618}
619
620static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
621
622static struct attribute *ads784x_attributes[] = {
623 &dev_attr_pen_down.attr,
624 &dev_attr_disable.attr,
625 NULL,
626};
627
628static struct attribute_group ads784x_attr_group = {
629 .attrs = ads784x_attributes,
630};
631
632/*--------------------------------------------------------------------------*/
633
634static int get_pendown_state(struct ads7846 *ts)
635{
636 if (ts->get_pendown_state)
637 return ts->get_pendown_state();
638
639 return !gpio_get_value(ts->gpio_pendown);
640}
641
642static void null_wait_for_sync(void)
643{
644}
645
646static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
647{
648 struct ads7846 *ts = ads;
649
650 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
651 /* Start over collecting consistent readings. */
652 ts->read_rep = 0;
653 /*
654 * Repeat it, if this was the first read or the read
655 * wasn't consistent enough.
656 */
657 if (ts->read_cnt < ts->debounce_max) {
658 ts->last_read = *val;
659 ts->read_cnt++;
660 return ADS7846_FILTER_REPEAT;
661 } else {
662 /*
663 * Maximum number of debouncing reached and still
664 * not enough number of consistent readings. Abort
665 * the whole sample, repeat it in the next sampling
666 * period.
667 */
668 ts->read_cnt = 0;
669 return ADS7846_FILTER_IGNORE;
670 }
671 } else {
672 if (++ts->read_rep > ts->debounce_rep) {
673 /*
674 * Got a good reading for this coordinate,
675 * go for the next one.
676 */
677 ts->read_cnt = 0;
678 ts->read_rep = 0;
679 return ADS7846_FILTER_OK;
680 } else {
681 /* Read more values that are consistent. */
682 ts->read_cnt++;
683 return ADS7846_FILTER_REPEAT;
684 }
685 }
686}
687
688static int ads7846_no_filter(void *ads, int data_idx, int *val)
689{
690 return ADS7846_FILTER_OK;
691}
692
693static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
694{
695 struct spi_transfer *t =
696 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
697
698 if (ts->model == 7845) {
699 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
700 } else {
701 /*
702 * adjust: on-wire is a must-ignore bit, a BE12 value, then
703 * padding; built from two 8 bit values written msb-first.
704 */
705 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
706 }
707}
708
709static void ads7846_update_value(struct spi_message *m, int val)
710{
711 struct spi_transfer *t =
712 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
713
714 *(u16 *)t->rx_buf = val;
715}
716
717static void ads7846_read_state(struct ads7846 *ts)
718{
719 struct ads7846_packet *packet = ts->packet;
720 struct spi_message *m;
721 int msg_idx = 0;
722 int val;
723 int action;
724 int error;
725
726 while (msg_idx < ts->msg_count) {
727
728 ts->wait_for_sync();
729
730 m = &ts->msg[msg_idx];
731 error = spi_sync(ts->spi, m);
732 if (error) {
733 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
734 packet->tc.ignore = true;
735 return;
736 }
737
738 /*
739 * Last message is power down request, no need to convert
740 * or filter the value.
741 */
742 if (msg_idx < ts->msg_count - 1) {
743
744 val = ads7846_get_value(ts, m);
745
746 action = ts->filter(ts->filter_data, msg_idx, &val);
747 switch (action) {
748 case ADS7846_FILTER_REPEAT:
749 continue;
750
751 case ADS7846_FILTER_IGNORE:
752 packet->tc.ignore = true;
753 msg_idx = ts->msg_count - 1;
754 continue;
755
756 case ADS7846_FILTER_OK:
757 ads7846_update_value(m, val);
758 packet->tc.ignore = false;
759 msg_idx++;
760 break;
761
762 default:
763 BUG();
764 }
765 } else {
766 msg_idx++;
767 }
768 }
769}
770
771static void ads7846_report_state(struct ads7846 *ts)
772{
773 struct ads7846_packet *packet = ts->packet;
774 unsigned int Rt;
775 u16 x, y, z1, z2;
776
777 /*
778 * ads7846_get_value() does in-place conversion (including byte swap)
779 * from on-the-wire format as part of debouncing to get stable
780 * readings.
781 */
782 if (ts->model == 7845) {
783 x = *(u16 *)packet->tc.x_buf;
784 y = *(u16 *)packet->tc.y_buf;
785 z1 = 0;
786 z2 = 0;
787 } else {
788 x = packet->tc.x;
789 y = packet->tc.y;
790 z1 = packet->tc.z1;
791 z2 = packet->tc.z2;
792 }
793
794 /* range filtering */
795 if (x == MAX_12BIT)
796 x = 0;
797
798 if (ts->model == 7843) {
799 Rt = ts->pressure_max / 2;
800 } else if (ts->model == 7845) {
801 if (get_pendown_state(ts))
802 Rt = ts->pressure_max / 2;
803 else
804 Rt = 0;
805 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
806 } else if (likely(x && z1)) {
807 /* compute touch pressure resistance using equation #2 */
808 Rt = z2;
809 Rt -= z1;
810 Rt *= x;
811 Rt *= ts->x_plate_ohms;
812 Rt /= z1;
813 Rt = (Rt + 2047) >> 12;
814 } else {
815 Rt = 0;
816 }
817
818 /*
819 * Sample found inconsistent by debouncing or pressure is beyond
820 * the maximum. Don't report it to user space, repeat at least
821 * once more the measurement
822 */
823 if (packet->tc.ignore || Rt > ts->pressure_max) {
824 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
825 packet->tc.ignore, Rt);
826 return;
827 }
828
829 /*
830 * Maybe check the pendown state before reporting. This discards
831 * false readings when the pen is lifted.
832 */
833 if (ts->penirq_recheck_delay_usecs) {
834 udelay(ts->penirq_recheck_delay_usecs);
835 if (!get_pendown_state(ts))
836 Rt = 0;
837 }
838
839 /*
840 * NOTE: We can't rely on the pressure to determine the pen down
841 * state, even this controller has a pressure sensor. The pressure
842 * value can fluctuate for quite a while after lifting the pen and
843 * in some cases may not even settle at the expected value.
844 *
845 * The only safe way to check for the pen up condition is in the
846 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
847 */
848 if (Rt) {
849 struct input_dev *input = ts->input;
850
851 if (ts->swap_xy)
852 swap(x, y);
853
854 if (!ts->pendown) {
855 input_report_key(input, BTN_TOUCH, 1);
856 ts->pendown = true;
857 dev_vdbg(&ts->spi->dev, "DOWN\n");
858 }
859
860 input_report_abs(input, ABS_X, x);
861 input_report_abs(input, ABS_Y, y);
862 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
863
864 input_sync(input);
865 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
866 }
867}
868
869static irqreturn_t ads7846_hard_irq(int irq, void *handle)
870{
871 struct ads7846 *ts = handle;
872
873 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
874}
875
876
877static irqreturn_t ads7846_irq(int irq, void *handle)
878{
879 struct ads7846 *ts = handle;
880
881 /* Start with a small delay before checking pendown state */
882 msleep(TS_POLL_DELAY);
883
884 while (!ts->stopped && get_pendown_state(ts)) {
885
886 /* pen is down, continue with the measurement */
887 ads7846_read_state(ts);
888
889 if (!ts->stopped)
890 ads7846_report_state(ts);
891
892 wait_event_timeout(ts->wait, ts->stopped,
893 msecs_to_jiffies(TS_POLL_PERIOD));
894 }
895
896 if (ts->pendown) {
897 struct input_dev *input = ts->input;
898
899 input_report_key(input, BTN_TOUCH, 0);
900 input_report_abs(input, ABS_PRESSURE, 0);
901 input_sync(input);
902
903 ts->pendown = false;
904 dev_vdbg(&ts->spi->dev, "UP\n");
905 }
906
907 return IRQ_HANDLED;
908}
909
910#ifdef CONFIG_PM_SLEEP
911static int ads7846_suspend(struct device *dev)
912{
913 struct ads7846 *ts = dev_get_drvdata(dev);
914
915 mutex_lock(&ts->lock);
916
917 if (!ts->suspended) {
918
919 if (!ts->disabled)
920 __ads7846_disable(ts);
921
922 if (device_may_wakeup(&ts->spi->dev))
923 enable_irq_wake(ts->spi->irq);
924
925 ts->suspended = true;
926 }
927
928 mutex_unlock(&ts->lock);
929
930 return 0;
931}
932
933static int ads7846_resume(struct device *dev)
934{
935 struct ads7846 *ts = dev_get_drvdata(dev);
936
937 mutex_lock(&ts->lock);
938
939 if (ts->suspended) {
940
941 ts->suspended = false;
942
943 if (device_may_wakeup(&ts->spi->dev))
944 disable_irq_wake(ts->spi->irq);
945
946 if (!ts->disabled)
947 __ads7846_enable(ts);
948 }
949
950 mutex_unlock(&ts->lock);
951
952 return 0;
953}
954#endif
955
956static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
957
958static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
959{
960 struct ads7846_platform_data *pdata = spi->dev.platform_data;
961 int err;
962
963 /*
964 * REVISIT when the irq can be triggered active-low, or if for some
965 * reason the touchscreen isn't hooked up, we don't need to access
966 * the pendown state.
967 */
968
969 if (pdata->get_pendown_state) {
970 ts->get_pendown_state = pdata->get_pendown_state;
971 } else if (gpio_is_valid(pdata->gpio_pendown)) {
972
973 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
974 "ads7846_pendown");
975 if (err) {
976 dev_err(&spi->dev,
977 "failed to request/setup pendown GPIO%d: %d\n",
978 pdata->gpio_pendown, err);
979 return err;
980 }
981
982 ts->gpio_pendown = pdata->gpio_pendown;
983
984 } else {
985 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
986 return -EINVAL;
987 }
988
989 return 0;
990}
991
992/*
993 * Set up the transfers to read touchscreen state; this assumes we
994 * use formula #2 for pressure, not #3.
995 */
996static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
997 const struct ads7846_platform_data *pdata)
998{
999 struct spi_message *m = &ts->msg[0];
1000 struct spi_transfer *x = ts->xfer;
1001 struct ads7846_packet *packet = ts->packet;
1002 int vref = pdata->keep_vref_on;
1003
1004 if (ts->model == 7873) {
1005 /*
1006 * The AD7873 is almost identical to the ADS7846
1007 * keep VREF off during differential/ratiometric
1008 * conversion modes.
1009 */
1010 ts->model = 7846;
1011 vref = 0;
1012 }
1013
1014 ts->msg_count = 1;
1015 spi_message_init(m);
1016 m->context = ts;
1017
1018 if (ts->model == 7845) {
1019 packet->read_y_cmd[0] = READ_Y(vref);
1020 packet->read_y_cmd[1] = 0;
1021 packet->read_y_cmd[2] = 0;
1022 x->tx_buf = &packet->read_y_cmd[0];
1023 x->rx_buf = &packet->tc.y_buf[0];
1024 x->len = 3;
1025 spi_message_add_tail(x, m);
1026 } else {
1027 /* y- still on; turn on only y+ (and ADC) */
1028 packet->read_y = READ_Y(vref);
1029 x->tx_buf = &packet->read_y;
1030 x->len = 1;
1031 spi_message_add_tail(x, m);
1032
1033 x++;
1034 x->rx_buf = &packet->tc.y;
1035 x->len = 2;
1036 spi_message_add_tail(x, m);
1037 }
1038
1039 /*
1040 * The first sample after switching drivers can be low quality;
1041 * optionally discard it, using a second one after the signals
1042 * have had enough time to stabilize.
1043 */
1044 if (pdata->settle_delay_usecs) {
1045 x->delay_usecs = pdata->settle_delay_usecs;
1046
1047 x++;
1048 x->tx_buf = &packet->read_y;
1049 x->len = 1;
1050 spi_message_add_tail(x, m);
1051
1052 x++;
1053 x->rx_buf = &packet->tc.y;
1054 x->len = 2;
1055 spi_message_add_tail(x, m);
1056 }
1057
1058 ts->msg_count++;
1059 m++;
1060 spi_message_init(m);
1061 m->context = ts;
1062
1063 if (ts->model == 7845) {
1064 x++;
1065 packet->read_x_cmd[0] = READ_X(vref);
1066 packet->read_x_cmd[1] = 0;
1067 packet->read_x_cmd[2] = 0;
1068 x->tx_buf = &packet->read_x_cmd[0];
1069 x->rx_buf = &packet->tc.x_buf[0];
1070 x->len = 3;
1071 spi_message_add_tail(x, m);
1072 } else {
1073 /* turn y- off, x+ on, then leave in lowpower */
1074 x++;
1075 packet->read_x = READ_X(vref);
1076 x->tx_buf = &packet->read_x;
1077 x->len = 1;
1078 spi_message_add_tail(x, m);
1079
1080 x++;
1081 x->rx_buf = &packet->tc.x;
1082 x->len = 2;
1083 spi_message_add_tail(x, m);
1084 }
1085
1086 /* ... maybe discard first sample ... */
1087 if (pdata->settle_delay_usecs) {
1088 x->delay_usecs = pdata->settle_delay_usecs;
1089
1090 x++;
1091 x->tx_buf = &packet->read_x;
1092 x->len = 1;
1093 spi_message_add_tail(x, m);
1094
1095 x++;
1096 x->rx_buf = &packet->tc.x;
1097 x->len = 2;
1098 spi_message_add_tail(x, m);
1099 }
1100
1101 /* turn y+ off, x- on; we'll use formula #2 */
1102 if (ts->model == 7846) {
1103 ts->msg_count++;
1104 m++;
1105 spi_message_init(m);
1106 m->context = ts;
1107
1108 x++;
1109 packet->read_z1 = READ_Z1(vref);
1110 x->tx_buf = &packet->read_z1;
1111 x->len = 1;
1112 spi_message_add_tail(x, m);
1113
1114 x++;
1115 x->rx_buf = &packet->tc.z1;
1116 x->len = 2;
1117 spi_message_add_tail(x, m);
1118
1119 /* ... maybe discard first sample ... */
1120 if (pdata->settle_delay_usecs) {
1121 x->delay_usecs = pdata->settle_delay_usecs;
1122
1123 x++;
1124 x->tx_buf = &packet->read_z1;
1125 x->len = 1;
1126 spi_message_add_tail(x, m);
1127
1128 x++;
1129 x->rx_buf = &packet->tc.z1;
1130 x->len = 2;
1131 spi_message_add_tail(x, m);
1132 }
1133
1134 ts->msg_count++;
1135 m++;
1136 spi_message_init(m);
1137 m->context = ts;
1138
1139 x++;
1140 packet->read_z2 = READ_Z2(vref);
1141 x->tx_buf = &packet->read_z2;
1142 x->len = 1;
1143 spi_message_add_tail(x, m);
1144
1145 x++;
1146 x->rx_buf = &packet->tc.z2;
1147 x->len = 2;
1148 spi_message_add_tail(x, m);
1149
1150 /* ... maybe discard first sample ... */
1151 if (pdata->settle_delay_usecs) {
1152 x->delay_usecs = pdata->settle_delay_usecs;
1153
1154 x++;
1155 x->tx_buf = &packet->read_z2;
1156 x->len = 1;
1157 spi_message_add_tail(x, m);
1158
1159 x++;
1160 x->rx_buf = &packet->tc.z2;
1161 x->len = 2;
1162 spi_message_add_tail(x, m);
1163 }
1164 }
1165
1166 /* power down */
1167 ts->msg_count++;
1168 m++;
1169 spi_message_init(m);
1170 m->context = ts;
1171
1172 if (ts->model == 7845) {
1173 x++;
1174 packet->pwrdown_cmd[0] = PWRDOWN;
1175 packet->pwrdown_cmd[1] = 0;
1176 packet->pwrdown_cmd[2] = 0;
1177 x->tx_buf = &packet->pwrdown_cmd[0];
1178 x->len = 3;
1179 } else {
1180 x++;
1181 packet->pwrdown = PWRDOWN;
1182 x->tx_buf = &packet->pwrdown;
1183 x->len = 1;
1184 spi_message_add_tail(x, m);
1185
1186 x++;
1187 x->rx_buf = &packet->dummy;
1188 x->len = 2;
1189 }
1190
1191 CS_CHANGE(*x);
1192 spi_message_add_tail(x, m);
1193}
1194
1195static int __devinit ads7846_probe(struct spi_device *spi)
1196{
1197 struct ads7846 *ts;
1198 struct ads7846_packet *packet;
1199 struct input_dev *input_dev;
1200 struct ads7846_platform_data *pdata = spi->dev.platform_data;
1201 unsigned long irq_flags;
1202 int err;
1203
1204 if (!spi->irq) {
1205 dev_dbg(&spi->dev, "no IRQ?\n");
1206 return -ENODEV;
1207 }
1208
1209 if (!pdata) {
1210 dev_dbg(&spi->dev, "no platform data?\n");
1211 return -ENODEV;
1212 }
1213
1214 /* don't exceed max specified sample rate */
1215 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1216 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1217 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1218 return -EINVAL;
1219 }
1220
1221 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1222 * that even if the hardware can do that, the SPI controller driver
1223 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1224 */
1225 spi->bits_per_word = 8;
1226 spi->mode = SPI_MODE_0;
1227 err = spi_setup(spi);
1228 if (err < 0)
1229 return err;
1230
1231 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1232 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1233 input_dev = input_allocate_device();
1234 if (!ts || !packet || !input_dev) {
1235 err = -ENOMEM;
1236 goto err_free_mem;
1237 }
1238
1239 dev_set_drvdata(&spi->dev, ts);
1240
1241 ts->packet = packet;
1242 ts->spi = spi;
1243 ts->input = input_dev;
1244 ts->vref_mv = pdata->vref_mv;
1245 ts->swap_xy = pdata->swap_xy;
1246
1247 mutex_init(&ts->lock);
1248 init_waitqueue_head(&ts->wait);
1249
1250 ts->model = pdata->model ? : 7846;
1251 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1252 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1253 ts->pressure_max = pdata->pressure_max ? : ~0;
1254
1255 if (pdata->filter != NULL) {
1256 if (pdata->filter_init != NULL) {
1257 err = pdata->filter_init(pdata, &ts->filter_data);
1258 if (err < 0)
1259 goto err_free_mem;
1260 }
1261 ts->filter = pdata->filter;
1262 ts->filter_cleanup = pdata->filter_cleanup;
1263 } else if (pdata->debounce_max) {
1264 ts->debounce_max = pdata->debounce_max;
1265 if (ts->debounce_max < 2)
1266 ts->debounce_max = 2;
1267 ts->debounce_tol = pdata->debounce_tol;
1268 ts->debounce_rep = pdata->debounce_rep;
1269 ts->filter = ads7846_debounce_filter;
1270 ts->filter_data = ts;
1271 } else {
1272 ts->filter = ads7846_no_filter;
1273 }
1274
1275 err = ads7846_setup_pendown(spi, ts);
1276 if (err)
1277 goto err_cleanup_filter;
1278
1279 if (pdata->penirq_recheck_delay_usecs)
1280 ts->penirq_recheck_delay_usecs =
1281 pdata->penirq_recheck_delay_usecs;
1282
1283 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1284
1285 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1286 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1287
1288 input_dev->name = ts->name;
1289 input_dev->phys = ts->phys;
1290 input_dev->dev.parent = &spi->dev;
1291
1292 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1293 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1294 input_set_abs_params(input_dev, ABS_X,
1295 pdata->x_min ? : 0,
1296 pdata->x_max ? : MAX_12BIT,
1297 0, 0);
1298 input_set_abs_params(input_dev, ABS_Y,
1299 pdata->y_min ? : 0,
1300 pdata->y_max ? : MAX_12BIT,
1301 0, 0);
1302 input_set_abs_params(input_dev, ABS_PRESSURE,
1303 pdata->pressure_min, pdata->pressure_max, 0, 0);
1304
1305 ads7846_setup_spi_msg(ts, pdata);
1306
1307 ts->reg = regulator_get(&spi->dev, "vcc");
1308 if (IS_ERR(ts->reg)) {
1309 err = PTR_ERR(ts->reg);
1310 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1311 goto err_free_gpio;
1312 }
1313
1314 err = regulator_enable(ts->reg);
1315 if (err) {
1316 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1317 goto err_put_regulator;
1318 }
1319
1320 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1321 irq_flags |= IRQF_ONESHOT;
1322
1323 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1324 irq_flags, spi->dev.driver->name, ts);
1325 if (err && !pdata->irq_flags) {
1326 dev_info(&spi->dev,
1327 "trying pin change workaround on irq %d\n", spi->irq);
1328 irq_flags |= IRQF_TRIGGER_RISING;
1329 err = request_threaded_irq(spi->irq,
1330 ads7846_hard_irq, ads7846_irq,
1331 irq_flags, spi->dev.driver->name, ts);
1332 }
1333
1334 if (err) {
1335 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1336 goto err_disable_regulator;
1337 }
1338
1339 err = ads784x_hwmon_register(spi, ts);
1340 if (err)
1341 goto err_free_irq;
1342
1343 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1344
1345 /*
1346 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1347 * the touchscreen, in case it's not connected.
1348 */
1349 if (ts->model == 7845)
1350 ads7845_read12_ser(&spi->dev, PWRDOWN);
1351 else
1352 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1353
1354 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1355 if (err)
1356 goto err_remove_hwmon;
1357
1358 err = input_register_device(input_dev);
1359 if (err)
1360 goto err_remove_attr_group;
1361
1362 device_init_wakeup(&spi->dev, pdata->wakeup);
1363
1364 return 0;
1365
1366 err_remove_attr_group:
1367 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1368 err_remove_hwmon:
1369 ads784x_hwmon_unregister(spi, ts);
1370 err_free_irq:
1371 free_irq(spi->irq, ts);
1372 err_disable_regulator:
1373 regulator_disable(ts->reg);
1374 err_put_regulator:
1375 regulator_put(ts->reg);
1376 err_free_gpio:
1377 if (!ts->get_pendown_state)
1378 gpio_free(ts->gpio_pendown);
1379 err_cleanup_filter:
1380 if (ts->filter_cleanup)
1381 ts->filter_cleanup(ts->filter_data);
1382 err_free_mem:
1383 input_free_device(input_dev);
1384 kfree(packet);
1385 kfree(ts);
1386 return err;
1387}
1388
1389static int __devexit ads7846_remove(struct spi_device *spi)
1390{
1391 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1392
1393 device_init_wakeup(&spi->dev, false);
1394
1395 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1396
1397 ads7846_disable(ts);
1398 free_irq(ts->spi->irq, ts);
1399
1400 input_unregister_device(ts->input);
1401
1402 ads784x_hwmon_unregister(spi, ts);
1403
1404 regulator_disable(ts->reg);
1405 regulator_put(ts->reg);
1406
1407 if (!ts->get_pendown_state) {
1408 /*
1409 * If we are not using specialized pendown method we must
1410 * have been relying on gpio we set up ourselves.
1411 */
1412 gpio_free(ts->gpio_pendown);
1413 }
1414
1415 if (ts->filter_cleanup)
1416 ts->filter_cleanup(ts->filter_data);
1417
1418 kfree(ts->packet);
1419 kfree(ts);
1420
1421 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1422
1423 return 0;
1424}
1425
1426static struct spi_driver ads7846_driver = {
1427 .driver = {
1428 .name = "ads7846",
1429 .owner = THIS_MODULE,
1430 .pm = &ads7846_pm,
1431 },
1432 .probe = ads7846_probe,
1433 .remove = __devexit_p(ads7846_remove),
1434};
1435
1436module_spi_driver(ads7846_driver);
1437
1438MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1439MODULE_LICENSE("GPL");
1440MODULE_ALIAS("spi:ads7846");