[ARM] S3C maintainer updates merge branch maintainers-updates into s3c-fixes
[linux-2.6] / drivers / input / touchscreen / ads7846.c
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/hwmon.h>
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/delay.h>
24 #include <linux/input.h>
25 #include <linux/interrupt.h>
26 #include <linux/slab.h>
27 #include <linux/gpio.h>
28 #include <linux/spi/spi.h>
29 #include <linux/spi/ads7846.h>
30 #include <asm/irq.h>
31
32
33 /*
34  * This code has been heavily tested on a Nokia 770, and lightly
35  * tested on other ads7846 devices (OSK/Mistral, Lubbock).
36  * TSC2046 is just newer ads7846 silicon.
37  * Support for ads7843 tested on Atmel at91sam926x-EK.
38  * Support for ads7845 has only been stubbed in.
39  *
40  * IRQ handling needs a workaround because of a shortcoming in handling
41  * edge triggered IRQs on some platforms like the OMAP1/2. These
42  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
43  * have to maintain our own SW IRQ disabled status. This should be
44  * removed as soon as the affected platform's IRQ handling is fixed.
45  *
46  * app note sbaa036 talks in more detail about accurate sampling...
47  * that ought to help in situations like LCDs inducing noise (which
48  * can also be helped by using synch signals) and more generally.
49  * This driver tries to utilize the measures described in the app
50  * note. The strength of filtering can be set in the board-* specific
51  * files.
52  */
53
54 #define TS_POLL_DELAY   (1 * 1000000)   /* ns delay before the first sample */
55 #define TS_POLL_PERIOD  (5 * 1000000)   /* ns delay between samples */
56
57 /* this driver doesn't aim at the peak continuous sample rate */
58 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
59
60 struct ts_event {
61         /* For portability, we can't read 12 bit values using SPI (which
62          * would make the controller deliver them as native byteorder u16
63          * with msbs zeroed).  Instead, we read them as two 8-bit values,
64          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
65          */
66         u16     x;
67         u16     y;
68         u16     z1, z2;
69         int     ignore;
70 };
71
72 /*
73  * We allocate this separately to avoid cache line sharing issues when
74  * driver is used with DMA-based SPI controllers (like atmel_spi) on
75  * systems where main memory is not DMA-coherent (most non-x86 boards).
76  */
77 struct ads7846_packet {
78         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
79         u16                     dummy;          /* for the pwrdown read */
80         struct ts_event         tc;
81 };
82
83 struct ads7846 {
84         struct input_dev        *input;
85         char                    phys[32];
86         char                    name[32];
87
88         struct spi_device       *spi;
89
90 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
91         struct attribute_group  *attr_group;
92         struct device           *hwmon;
93 #endif
94
95         u16                     model;
96         u16                     vref_mv;
97         u16                     vref_delay_usecs;
98         u16                     x_plate_ohms;
99         u16                     pressure_max;
100
101         bool                    swap_xy;
102
103         struct ads7846_packet   *packet;
104
105         struct spi_transfer     xfer[18];
106         struct spi_message      msg[5];
107         struct spi_message      *last_msg;
108         int                     msg_idx;
109         int                     read_cnt;
110         int                     read_rep;
111         int                     last_read;
112
113         u16                     debounce_max;
114         u16                     debounce_tol;
115         u16                     debounce_rep;
116
117         u16                     penirq_recheck_delay_usecs;
118
119         spinlock_t              lock;
120         struct hrtimer          timer;
121         unsigned                pendown:1;      /* P: lock */
122         unsigned                pending:1;      /* P: lock */
123 // FIXME remove "irq_disabled"
124         unsigned                irq_disabled:1; /* P: lock */
125         unsigned                disabled:1;
126         unsigned                is_suspended:1;
127
128         int                     (*filter)(void *data, int data_idx, int *val);
129         void                    *filter_data;
130         void                    (*filter_cleanup)(void *data);
131         int                     (*get_pendown_state)(void);
132         int                     gpio_pendown;
133
134         void                    (*wait_for_sync)(void);
135 };
136
137 /* leave chip selected when we're done, for quicker re-select? */
138 #if     0
139 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
140 #else
141 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
142 #endif
143
144 /*--------------------------------------------------------------------------*/
145
146 /* The ADS7846 has touchscreen and other sensors.
147  * Earlier ads784x chips are somewhat compatible.
148  */
149 #define ADS_START               (1 << 7)
150 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
151 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
152 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
153 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
154 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
155 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
156 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
157 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
158 #define ADS_8_BIT               (1 << 3)
159 #define ADS_12_BIT              (0 << 3)
160 #define ADS_SER                 (1 << 2)        /* non-differential */
161 #define ADS_DFR                 (0 << 2)        /* differential */
162 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
163 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
164 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
165 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
166
167 #define MAX_12BIT       ((1<<12)-1)
168
169 /* leave ADC powered up (disables penirq) between differential samples */
170 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
171         | ADS_12_BIT | ADS_DFR | \
172         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
173
174 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
175 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
176 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
177
178 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
179 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
180
181 /* single-ended samples need to first power up reference voltage;
182  * we leave both ADC and VREF powered
183  */
184 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
185         | ADS_12_BIT | ADS_SER)
186
187 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
188 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
189
190 /*--------------------------------------------------------------------------*/
191
192 /*
193  * Non-touchscreen sensors only use single-ended conversions.
194  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
195  * ads7846 lets that pin be unconnected, to use internal vREF.
196  */
197
198 struct ser_req {
199         u8                      ref_on;
200         u8                      command;
201         u8                      ref_off;
202         u16                     scratch;
203         __be16                  sample;
204         struct spi_message      msg;
205         struct spi_transfer     xfer[6];
206 };
207
208 static void ads7846_enable(struct ads7846 *ts);
209 static void ads7846_disable(struct ads7846 *ts);
210
211 static int device_suspended(struct device *dev)
212 {
213         struct ads7846 *ts = dev_get_drvdata(dev);
214         return ts->is_suspended || ts->disabled;
215 }
216
217 static int ads7846_read12_ser(struct device *dev, unsigned command)
218 {
219         struct spi_device       *spi = to_spi_device(dev);
220         struct ads7846          *ts = dev_get_drvdata(dev);
221         struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
222         int                     status;
223         int                     use_internal;
224
225         if (!req)
226                 return -ENOMEM;
227
228         spi_message_init(&req->msg);
229
230         /* FIXME boards with ads7846 might use external vref instead ... */
231         use_internal = (ts->model == 7846);
232
233         /* maybe turn on internal vREF, and let it settle */
234         if (use_internal) {
235                 req->ref_on = REF_ON;
236                 req->xfer[0].tx_buf = &req->ref_on;
237                 req->xfer[0].len = 1;
238                 spi_message_add_tail(&req->xfer[0], &req->msg);
239
240                 req->xfer[1].rx_buf = &req->scratch;
241                 req->xfer[1].len = 2;
242
243                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
244                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
245                 spi_message_add_tail(&req->xfer[1], &req->msg);
246         }
247
248         /* take sample */
249         req->command = (u8) command;
250         req->xfer[2].tx_buf = &req->command;
251         req->xfer[2].len = 1;
252         spi_message_add_tail(&req->xfer[2], &req->msg);
253
254         req->xfer[3].rx_buf = &req->sample;
255         req->xfer[3].len = 2;
256         spi_message_add_tail(&req->xfer[3], &req->msg);
257
258         /* REVISIT:  take a few more samples, and compare ... */
259
260         /* converter in low power mode & enable PENIRQ */
261         req->ref_off = PWRDOWN;
262         req->xfer[4].tx_buf = &req->ref_off;
263         req->xfer[4].len = 1;
264         spi_message_add_tail(&req->xfer[4], &req->msg);
265
266         req->xfer[5].rx_buf = &req->scratch;
267         req->xfer[5].len = 2;
268         CS_CHANGE(req->xfer[5]);
269         spi_message_add_tail(&req->xfer[5], &req->msg);
270
271         ts->irq_disabled = 1;
272         disable_irq(spi->irq);
273         status = spi_sync(spi, &req->msg);
274         ts->irq_disabled = 0;
275         enable_irq(spi->irq);
276
277         if (status == 0) {
278                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
279                 status = be16_to_cpu(req->sample);
280                 status = status >> 3;
281                 status &= 0x0fff;
282         }
283
284         kfree(req);
285         return status;
286 }
287
288 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
289
290 #define SHOW(name, var, adjust) static ssize_t \
291 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
292 { \
293         struct ads7846 *ts = dev_get_drvdata(dev); \
294         ssize_t v = ads7846_read12_ser(dev, \
295                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
296         if (v < 0) \
297                 return v; \
298         return sprintf(buf, "%u\n", adjust(ts, v)); \
299 } \
300 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
301
302
303 /* Sysfs conventions report temperatures in millidegrees Celsius.
304  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
305  * accuracy scheme without calibration data.  For now we won't try either;
306  * userspace sees raw sensor values, and must scale/calibrate appropriately.
307  */
308 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
309 {
310         return v;
311 }
312
313 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
314 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
315
316
317 /* sysfs conventions report voltages in millivolts.  We can convert voltages
318  * if we know vREF.  userspace may need to scale vAUX to match the board's
319  * external resistors; we assume that vBATT only uses the internal ones.
320  */
321 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
322 {
323         unsigned retval = v;
324
325         /* external resistors may scale vAUX into 0..vREF */
326         retval *= ts->vref_mv;
327         retval = retval >> 12;
328         return retval;
329 }
330
331 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
332 {
333         unsigned retval = vaux_adjust(ts, v);
334
335         /* ads7846 has a resistor ladder to scale this signal down */
336         if (ts->model == 7846)
337                 retval *= 4;
338         return retval;
339 }
340
341 SHOW(in0_input, vaux, vaux_adjust)
342 SHOW(in1_input, vbatt, vbatt_adjust)
343
344
345 static struct attribute *ads7846_attributes[] = {
346         &dev_attr_temp0.attr,
347         &dev_attr_temp1.attr,
348         &dev_attr_in0_input.attr,
349         &dev_attr_in1_input.attr,
350         NULL,
351 };
352
353 static struct attribute_group ads7846_attr_group = {
354         .attrs = ads7846_attributes,
355 };
356
357 static struct attribute *ads7843_attributes[] = {
358         &dev_attr_in0_input.attr,
359         &dev_attr_in1_input.attr,
360         NULL,
361 };
362
363 static struct attribute_group ads7843_attr_group = {
364         .attrs = ads7843_attributes,
365 };
366
367 static struct attribute *ads7845_attributes[] = {
368         &dev_attr_in0_input.attr,
369         NULL,
370 };
371
372 static struct attribute_group ads7845_attr_group = {
373         .attrs = ads7845_attributes,
374 };
375
376 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
377 {
378         struct device *hwmon;
379         int err;
380
381         /* hwmon sensors need a reference voltage */
382         switch (ts->model) {
383         case 7846:
384                 if (!ts->vref_mv) {
385                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
386                         ts->vref_mv = 2500;
387                 }
388                 break;
389         case 7845:
390         case 7843:
391                 if (!ts->vref_mv) {
392                         dev_warn(&spi->dev,
393                                 "external vREF for ADS%d not specified\n",
394                                 ts->model);
395                         return 0;
396                 }
397                 break;
398         }
399
400         /* different chips have different sensor groups */
401         switch (ts->model) {
402         case 7846:
403                 ts->attr_group = &ads7846_attr_group;
404                 break;
405         case 7845:
406                 ts->attr_group = &ads7845_attr_group;
407                 break;
408         case 7843:
409                 ts->attr_group = &ads7843_attr_group;
410                 break;
411         default:
412                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
413                 return 0;
414         }
415
416         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
417         if (err)
418                 return err;
419
420         hwmon = hwmon_device_register(&spi->dev);
421         if (IS_ERR(hwmon)) {
422                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
423                 return PTR_ERR(hwmon);
424         }
425
426         ts->hwmon = hwmon;
427         return 0;
428 }
429
430 static void ads784x_hwmon_unregister(struct spi_device *spi,
431                                      struct ads7846 *ts)
432 {
433         if (ts->hwmon) {
434                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
435                 hwmon_device_unregister(ts->hwmon);
436         }
437 }
438
439 #else
440 static inline int ads784x_hwmon_register(struct spi_device *spi,
441                                          struct ads7846 *ts)
442 {
443         return 0;
444 }
445
446 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
447                                             struct ads7846 *ts)
448 {
449 }
450 #endif
451
452 static int is_pen_down(struct device *dev)
453 {
454         struct ads7846  *ts = dev_get_drvdata(dev);
455
456         return ts->pendown;
457 }
458
459 static ssize_t ads7846_pen_down_show(struct device *dev,
460                                      struct device_attribute *attr, char *buf)
461 {
462         return sprintf(buf, "%u\n", is_pen_down(dev));
463 }
464
465 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
466
467 static ssize_t ads7846_disable_show(struct device *dev,
468                                      struct device_attribute *attr, char *buf)
469 {
470         struct ads7846  *ts = dev_get_drvdata(dev);
471
472         return sprintf(buf, "%u\n", ts->disabled);
473 }
474
475 static ssize_t ads7846_disable_store(struct device *dev,
476                                      struct device_attribute *attr,
477                                      const char *buf, size_t count)
478 {
479         struct ads7846 *ts = dev_get_drvdata(dev);
480         unsigned long i;
481
482         if (strict_strtoul(buf, 10, &i))
483                 return -EINVAL;
484
485         spin_lock_irq(&ts->lock);
486
487         if (i)
488                 ads7846_disable(ts);
489         else
490                 ads7846_enable(ts);
491
492         spin_unlock_irq(&ts->lock);
493
494         return count;
495 }
496
497 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
498
499 static struct attribute *ads784x_attributes[] = {
500         &dev_attr_pen_down.attr,
501         &dev_attr_disable.attr,
502         NULL,
503 };
504
505 static struct attribute_group ads784x_attr_group = {
506         .attrs = ads784x_attributes,
507 };
508
509 /*--------------------------------------------------------------------------*/
510
511 static int get_pendown_state(struct ads7846 *ts)
512 {
513         if (ts->get_pendown_state)
514                 return ts->get_pendown_state();
515
516         return !gpio_get_value(ts->gpio_pendown);
517 }
518
519 static void null_wait_for_sync(void)
520 {
521 }
522
523 /*
524  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
525  * to retrieve touchscreen status.
526  *
527  * The SPI transfer completion callback does the real work.  It reports
528  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
529  */
530
531 static void ads7846_rx(void *ads)
532 {
533         struct ads7846          *ts = ads;
534         struct ads7846_packet   *packet = ts->packet;
535         unsigned                Rt;
536         u16                     x, y, z1, z2;
537
538         /* ads7846_rx_val() did in-place conversion (including byteswap) from
539          * on-the-wire format as part of debouncing to get stable readings.
540          */
541         x = packet->tc.x;
542         y = packet->tc.y;
543         z1 = packet->tc.z1;
544         z2 = packet->tc.z2;
545
546         /* range filtering */
547         if (x == MAX_12BIT)
548                 x = 0;
549
550         if (ts->model == 7843) {
551                 Rt = ts->pressure_max / 2;
552         } else if (likely(x && z1)) {
553                 /* compute touch pressure resistance using equation #2 */
554                 Rt = z2;
555                 Rt -= z1;
556                 Rt *= x;
557                 Rt *= ts->x_plate_ohms;
558                 Rt /= z1;
559                 Rt = (Rt + 2047) >> 12;
560         } else {
561                 Rt = 0;
562         }
563
564         /* Sample found inconsistent by debouncing or pressure is beyond
565          * the maximum. Don't report it to user space, repeat at least
566          * once more the measurement
567          */
568         if (packet->tc.ignore || Rt > ts->pressure_max) {
569 #ifdef VERBOSE
570                 pr_debug("%s: ignored %d pressure %d\n",
571                         dev_name(&ts->spi->dev), packet->tc.ignore, Rt);
572 #endif
573                 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
574                               HRTIMER_MODE_REL);
575                 return;
576         }
577
578         /* Maybe check the pendown state before reporting. This discards
579          * false readings when the pen is lifted.
580          */
581         if (ts->penirq_recheck_delay_usecs) {
582                 udelay(ts->penirq_recheck_delay_usecs);
583                 if (!get_pendown_state(ts))
584                         Rt = 0;
585         }
586
587         /* NOTE: We can't rely on the pressure to determine the pen down
588          * state, even this controller has a pressure sensor.  The pressure
589          * value can fluctuate for quite a while after lifting the pen and
590          * in some cases may not even settle at the expected value.
591          *
592          * The only safe way to check for the pen up condition is in the
593          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
594          */
595         if (Rt) {
596                 struct input_dev *input = ts->input;
597
598                 if (!ts->pendown) {
599                         input_report_key(input, BTN_TOUCH, 1);
600                         ts->pendown = 1;
601 #ifdef VERBOSE
602                         dev_dbg(&ts->spi->dev, "DOWN\n");
603 #endif
604                 }
605
606                 if (ts->swap_xy)
607                         swap(x, y);
608
609                 input_report_abs(input, ABS_X, x);
610                 input_report_abs(input, ABS_Y, y);
611                 input_report_abs(input, ABS_PRESSURE, Rt);
612
613                 input_sync(input);
614 #ifdef VERBOSE
615                 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
616 #endif
617         }
618
619         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
620                         HRTIMER_MODE_REL);
621 }
622
623 static int ads7846_debounce(void *ads, int data_idx, int *val)
624 {
625         struct ads7846          *ts = ads;
626
627         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
628                 /* Start over collecting consistent readings. */
629                 ts->read_rep = 0;
630                 /* Repeat it, if this was the first read or the read
631                  * wasn't consistent enough. */
632                 if (ts->read_cnt < ts->debounce_max) {
633                         ts->last_read = *val;
634                         ts->read_cnt++;
635                         return ADS7846_FILTER_REPEAT;
636                 } else {
637                         /* Maximum number of debouncing reached and still
638                          * not enough number of consistent readings. Abort
639                          * the whole sample, repeat it in the next sampling
640                          * period.
641                          */
642                         ts->read_cnt = 0;
643                         return ADS7846_FILTER_IGNORE;
644                 }
645         } else {
646                 if (++ts->read_rep > ts->debounce_rep) {
647                         /* Got a good reading for this coordinate,
648                          * go for the next one. */
649                         ts->read_cnt = 0;
650                         ts->read_rep = 0;
651                         return ADS7846_FILTER_OK;
652                 } else {
653                         /* Read more values that are consistent. */
654                         ts->read_cnt++;
655                         return ADS7846_FILTER_REPEAT;
656                 }
657         }
658 }
659
660 static int ads7846_no_filter(void *ads, int data_idx, int *val)
661 {
662         return ADS7846_FILTER_OK;
663 }
664
665 static void ads7846_rx_val(void *ads)
666 {
667         struct ads7846 *ts = ads;
668         struct ads7846_packet *packet = ts->packet;
669         struct spi_message *m;
670         struct spi_transfer *t;
671         int val;
672         int action;
673         int status;
674
675         m = &ts->msg[ts->msg_idx];
676         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
677
678         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
679          * built from two 8 bit values written msb-first.
680          */
681         val = be16_to_cpup((__be16 *)t->rx_buf) >> 3;
682
683         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
684         switch (action) {
685         case ADS7846_FILTER_REPEAT:
686                 break;
687         case ADS7846_FILTER_IGNORE:
688                 packet->tc.ignore = 1;
689                 /* Last message will contain ads7846_rx() as the
690                  * completion function.
691                  */
692                 m = ts->last_msg;
693                 break;
694         case ADS7846_FILTER_OK:
695                 *(u16 *)t->rx_buf = val;
696                 packet->tc.ignore = 0;
697                 m = &ts->msg[++ts->msg_idx];
698                 break;
699         default:
700                 BUG();
701         }
702         ts->wait_for_sync();
703         status = spi_async(ts->spi, m);
704         if (status)
705                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
706                                 status);
707 }
708
709 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
710 {
711         struct ads7846  *ts = container_of(handle, struct ads7846, timer);
712         int             status = 0;
713
714         spin_lock(&ts->lock);
715
716         if (unlikely(!get_pendown_state(ts) ||
717                      device_suspended(&ts->spi->dev))) {
718                 if (ts->pendown) {
719                         struct input_dev *input = ts->input;
720
721                         input_report_key(input, BTN_TOUCH, 0);
722                         input_report_abs(input, ABS_PRESSURE, 0);
723                         input_sync(input);
724
725                         ts->pendown = 0;
726 #ifdef VERBOSE
727                         dev_dbg(&ts->spi->dev, "UP\n");
728 #endif
729                 }
730
731                 /* measurement cycle ended */
732                 if (!device_suspended(&ts->spi->dev)) {
733                         ts->irq_disabled = 0;
734                         enable_irq(ts->spi->irq);
735                 }
736                 ts->pending = 0;
737         } else {
738                 /* pen is still down, continue with the measurement */
739                 ts->msg_idx = 0;
740                 ts->wait_for_sync();
741                 status = spi_async(ts->spi, &ts->msg[0]);
742                 if (status)
743                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
744         }
745
746         spin_unlock(&ts->lock);
747         return HRTIMER_NORESTART;
748 }
749
750 static irqreturn_t ads7846_irq(int irq, void *handle)
751 {
752         struct ads7846 *ts = handle;
753         unsigned long flags;
754
755         spin_lock_irqsave(&ts->lock, flags);
756         if (likely(get_pendown_state(ts))) {
757                 if (!ts->irq_disabled) {
758                         /* The ARM do_simple_IRQ() dispatcher doesn't act
759                          * like the other dispatchers:  it will report IRQs
760                          * even after they've been disabled.  We work around
761                          * that here.  (The "generic irq" framework may help...)
762                          */
763                         ts->irq_disabled = 1;
764                         disable_irq_nosync(ts->spi->irq);
765                         ts->pending = 1;
766                         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
767                                         HRTIMER_MODE_REL);
768                 }
769         }
770         spin_unlock_irqrestore(&ts->lock, flags);
771
772         return IRQ_HANDLED;
773 }
774
775 /*--------------------------------------------------------------------------*/
776
777 /* Must be called with ts->lock held */
778 static void ads7846_disable(struct ads7846 *ts)
779 {
780         if (ts->disabled)
781                 return;
782
783         ts->disabled = 1;
784
785         /* are we waiting for IRQ, or polling? */
786         if (!ts->pending) {
787                 ts->irq_disabled = 1;
788                 disable_irq(ts->spi->irq);
789         } else {
790                 /* the timer will run at least once more, and
791                  * leave everything in a clean state, IRQ disabled
792                  */
793                 while (ts->pending) {
794                         spin_unlock_irq(&ts->lock);
795                         msleep(1);
796                         spin_lock_irq(&ts->lock);
797                 }
798         }
799
800         /* we know the chip's in lowpower mode since we always
801          * leave it that way after every request
802          */
803 }
804
805 /* Must be called with ts->lock held */
806 static void ads7846_enable(struct ads7846 *ts)
807 {
808         if (!ts->disabled)
809                 return;
810
811         ts->disabled = 0;
812         ts->irq_disabled = 0;
813         enable_irq(ts->spi->irq);
814 }
815
816 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
817 {
818         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
819
820         spin_lock_irq(&ts->lock);
821
822         ts->is_suspended = 1;
823         ads7846_disable(ts);
824
825         spin_unlock_irq(&ts->lock);
826
827         return 0;
828
829 }
830
831 static int ads7846_resume(struct spi_device *spi)
832 {
833         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
834
835         spin_lock_irq(&ts->lock);
836
837         ts->is_suspended = 0;
838         ads7846_enable(ts);
839
840         spin_unlock_irq(&ts->lock);
841
842         return 0;
843 }
844
845 static int __devinit setup_pendown(struct spi_device *spi, struct ads7846 *ts)
846 {
847         struct ads7846_platform_data *pdata = spi->dev.platform_data;
848         int err;
849
850         /* REVISIT when the irq can be triggered active-low, or if for some
851          * reason the touchscreen isn't hooked up, we don't need to access
852          * the pendown state.
853          */
854         if (!pdata->get_pendown_state && !gpio_is_valid(pdata->gpio_pendown)) {
855                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
856                 return -EINVAL;
857         }
858
859         if (pdata->get_pendown_state) {
860                 ts->get_pendown_state = pdata->get_pendown_state;
861                 return 0;
862         }
863
864         err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
865         if (err) {
866                 dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
867                                 pdata->gpio_pendown);
868                 return err;
869         }
870
871         ts->gpio_pendown = pdata->gpio_pendown;
872         return 0;
873 }
874
875 static int __devinit ads7846_probe(struct spi_device *spi)
876 {
877         struct ads7846                  *ts;
878         struct ads7846_packet           *packet;
879         struct input_dev                *input_dev;
880         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
881         struct spi_message              *m;
882         struct spi_transfer             *x;
883         int                             vref;
884         int                             err;
885
886         if (!spi->irq) {
887                 dev_dbg(&spi->dev, "no IRQ?\n");
888                 return -ENODEV;
889         }
890
891         if (!pdata) {
892                 dev_dbg(&spi->dev, "no platform data?\n");
893                 return -ENODEV;
894         }
895
896         /* don't exceed max specified sample rate */
897         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
898                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
899                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
900                 return -EINVAL;
901         }
902
903         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
904          * that even if the hardware can do that, the SPI controller driver
905          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
906          */
907         spi->bits_per_word = 8;
908         spi->mode = SPI_MODE_0;
909         err = spi_setup(spi);
910         if (err < 0)
911                 return err;
912
913         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
914         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
915         input_dev = input_allocate_device();
916         if (!ts || !packet || !input_dev) {
917                 err = -ENOMEM;
918                 goto err_free_mem;
919         }
920
921         dev_set_drvdata(&spi->dev, ts);
922
923         ts->packet = packet;
924         ts->spi = spi;
925         ts->input = input_dev;
926         ts->vref_mv = pdata->vref_mv;
927         ts->swap_xy = pdata->swap_xy;
928
929         hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
930         ts->timer.function = ads7846_timer;
931
932         spin_lock_init(&ts->lock);
933
934         ts->model = pdata->model ? : 7846;
935         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
936         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
937         ts->pressure_max = pdata->pressure_max ? : ~0;
938
939         if (pdata->filter != NULL) {
940                 if (pdata->filter_init != NULL) {
941                         err = pdata->filter_init(pdata, &ts->filter_data);
942                         if (err < 0)
943                                 goto err_free_mem;
944                 }
945                 ts->filter = pdata->filter;
946                 ts->filter_cleanup = pdata->filter_cleanup;
947         } else if (pdata->debounce_max) {
948                 ts->debounce_max = pdata->debounce_max;
949                 if (ts->debounce_max < 2)
950                         ts->debounce_max = 2;
951                 ts->debounce_tol = pdata->debounce_tol;
952                 ts->debounce_rep = pdata->debounce_rep;
953                 ts->filter = ads7846_debounce;
954                 ts->filter_data = ts;
955         } else
956                 ts->filter = ads7846_no_filter;
957
958         err = setup_pendown(spi, ts);
959         if (err)
960                 goto err_cleanup_filter;
961
962         if (pdata->penirq_recheck_delay_usecs)
963                 ts->penirq_recheck_delay_usecs =
964                                 pdata->penirq_recheck_delay_usecs;
965
966         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
967
968         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
969         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
970
971         input_dev->name = ts->name;
972         input_dev->phys = ts->phys;
973         input_dev->dev.parent = &spi->dev;
974
975         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
976         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
977         input_set_abs_params(input_dev, ABS_X,
978                         pdata->x_min ? : 0,
979                         pdata->x_max ? : MAX_12BIT,
980                         0, 0);
981         input_set_abs_params(input_dev, ABS_Y,
982                         pdata->y_min ? : 0,
983                         pdata->y_max ? : MAX_12BIT,
984                         0, 0);
985         input_set_abs_params(input_dev, ABS_PRESSURE,
986                         pdata->pressure_min, pdata->pressure_max, 0, 0);
987
988         vref = pdata->keep_vref_on;
989
990         /* set up the transfers to read touchscreen state; this assumes we
991          * use formula #2 for pressure, not #3.
992          */
993         m = &ts->msg[0];
994         x = ts->xfer;
995
996         spi_message_init(m);
997
998         /* y- still on; turn on only y+ (and ADC) */
999         packet->read_y = READ_Y(vref);
1000         x->tx_buf = &packet->read_y;
1001         x->len = 1;
1002         spi_message_add_tail(x, m);
1003
1004         x++;
1005         x->rx_buf = &packet->tc.y;
1006         x->len = 2;
1007         spi_message_add_tail(x, m);
1008
1009         /* the first sample after switching drivers can be low quality;
1010          * optionally discard it, using a second one after the signals
1011          * have had enough time to stabilize.
1012          */
1013         if (pdata->settle_delay_usecs) {
1014                 x->delay_usecs = pdata->settle_delay_usecs;
1015
1016                 x++;
1017                 x->tx_buf = &packet->read_y;
1018                 x->len = 1;
1019                 spi_message_add_tail(x, m);
1020
1021                 x++;
1022                 x->rx_buf = &packet->tc.y;
1023                 x->len = 2;
1024                 spi_message_add_tail(x, m);
1025         }
1026
1027         m->complete = ads7846_rx_val;
1028         m->context = ts;
1029
1030         m++;
1031         spi_message_init(m);
1032
1033         /* turn y- off, x+ on, then leave in lowpower */
1034         x++;
1035         packet->read_x = READ_X(vref);
1036         x->tx_buf = &packet->read_x;
1037         x->len = 1;
1038         spi_message_add_tail(x, m);
1039
1040         x++;
1041         x->rx_buf = &packet->tc.x;
1042         x->len = 2;
1043         spi_message_add_tail(x, m);
1044
1045         /* ... maybe discard first sample ... */
1046         if (pdata->settle_delay_usecs) {
1047                 x->delay_usecs = pdata->settle_delay_usecs;
1048
1049                 x++;
1050                 x->tx_buf = &packet->read_x;
1051                 x->len = 1;
1052                 spi_message_add_tail(x, m);
1053
1054                 x++;
1055                 x->rx_buf = &packet->tc.x;
1056                 x->len = 2;
1057                 spi_message_add_tail(x, m);
1058         }
1059
1060         m->complete = ads7846_rx_val;
1061         m->context = ts;
1062
1063         /* turn y+ off, x- on; we'll use formula #2 */
1064         if (ts->model == 7846) {
1065                 m++;
1066                 spi_message_init(m);
1067
1068                 x++;
1069                 packet->read_z1 = READ_Z1(vref);
1070                 x->tx_buf = &packet->read_z1;
1071                 x->len = 1;
1072                 spi_message_add_tail(x, m);
1073
1074                 x++;
1075                 x->rx_buf = &packet->tc.z1;
1076                 x->len = 2;
1077                 spi_message_add_tail(x, m);
1078
1079                 /* ... maybe discard first sample ... */
1080                 if (pdata->settle_delay_usecs) {
1081                         x->delay_usecs = pdata->settle_delay_usecs;
1082
1083                         x++;
1084                         x->tx_buf = &packet->read_z1;
1085                         x->len = 1;
1086                         spi_message_add_tail(x, m);
1087
1088                         x++;
1089                         x->rx_buf = &packet->tc.z1;
1090                         x->len = 2;
1091                         spi_message_add_tail(x, m);
1092                 }
1093
1094                 m->complete = ads7846_rx_val;
1095                 m->context = ts;
1096
1097                 m++;
1098                 spi_message_init(m);
1099
1100                 x++;
1101                 packet->read_z2 = READ_Z2(vref);
1102                 x->tx_buf = &packet->read_z2;
1103                 x->len = 1;
1104                 spi_message_add_tail(x, m);
1105
1106                 x++;
1107                 x->rx_buf = &packet->tc.z2;
1108                 x->len = 2;
1109                 spi_message_add_tail(x, m);
1110
1111                 /* ... maybe discard first sample ... */
1112                 if (pdata->settle_delay_usecs) {
1113                         x->delay_usecs = pdata->settle_delay_usecs;
1114
1115                         x++;
1116                         x->tx_buf = &packet->read_z2;
1117                         x->len = 1;
1118                         spi_message_add_tail(x, m);
1119
1120                         x++;
1121                         x->rx_buf = &packet->tc.z2;
1122                         x->len = 2;
1123                         spi_message_add_tail(x, m);
1124                 }
1125
1126                 m->complete = ads7846_rx_val;
1127                 m->context = ts;
1128         }
1129
1130         /* power down */
1131         m++;
1132         spi_message_init(m);
1133
1134         x++;
1135         packet->pwrdown = PWRDOWN;
1136         x->tx_buf = &packet->pwrdown;
1137         x->len = 1;
1138         spi_message_add_tail(x, m);
1139
1140         x++;
1141         x->rx_buf = &packet->dummy;
1142         x->len = 2;
1143         CS_CHANGE(*x);
1144         spi_message_add_tail(x, m);
1145
1146         m->complete = ads7846_rx;
1147         m->context = ts;
1148
1149         ts->last_msg = m;
1150
1151         if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
1152                         spi->dev.driver->name, ts)) {
1153                 dev_info(&spi->dev,
1154                         "trying pin change workaround on irq %d\n", spi->irq);
1155                 err = request_irq(spi->irq, ads7846_irq,
1156                                   IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
1157                                   spi->dev.driver->name, ts);
1158                 if (err) {
1159                         dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1160                         goto err_free_gpio;
1161                 }
1162         }
1163
1164         err = ads784x_hwmon_register(spi, ts);
1165         if (err)
1166                 goto err_free_irq;
1167
1168         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1169
1170         /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1171          * the touchscreen, in case it's not connected.
1172          */
1173         (void) ads7846_read12_ser(&spi->dev,
1174                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1175
1176         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1177         if (err)
1178                 goto err_remove_hwmon;
1179
1180         err = input_register_device(input_dev);
1181         if (err)
1182                 goto err_remove_attr_group;
1183
1184         return 0;
1185
1186  err_remove_attr_group:
1187         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1188  err_remove_hwmon:
1189         ads784x_hwmon_unregister(spi, ts);
1190  err_free_irq:
1191         free_irq(spi->irq, ts);
1192  err_free_gpio:
1193         if (ts->gpio_pendown != -1)
1194                 gpio_free(ts->gpio_pendown);
1195  err_cleanup_filter:
1196         if (ts->filter_cleanup)
1197                 ts->filter_cleanup(ts->filter_data);
1198  err_free_mem:
1199         input_free_device(input_dev);
1200         kfree(packet);
1201         kfree(ts);
1202         return err;
1203 }
1204
1205 static int __devexit ads7846_remove(struct spi_device *spi)
1206 {
1207         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
1208
1209         ads784x_hwmon_unregister(spi, ts);
1210         input_unregister_device(ts->input);
1211
1212         ads7846_suspend(spi, PMSG_SUSPEND);
1213
1214         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1215
1216         free_irq(ts->spi->irq, ts);
1217         /* suspend left the IRQ disabled */
1218         enable_irq(ts->spi->irq);
1219
1220         if (ts->gpio_pendown != -1)
1221                 gpio_free(ts->gpio_pendown);
1222
1223         if (ts->filter_cleanup)
1224                 ts->filter_cleanup(ts->filter_data);
1225
1226         kfree(ts->packet);
1227         kfree(ts);
1228
1229         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1230         return 0;
1231 }
1232
1233 static struct spi_driver ads7846_driver = {
1234         .driver = {
1235                 .name   = "ads7846",
1236                 .bus    = &spi_bus_type,
1237                 .owner  = THIS_MODULE,
1238         },
1239         .probe          = ads7846_probe,
1240         .remove         = __devexit_p(ads7846_remove),
1241         .suspend        = ads7846_suspend,
1242         .resume         = ads7846_resume,
1243 };
1244
1245 static int __init ads7846_init(void)
1246 {
1247         return spi_register_driver(&ads7846_driver);
1248 }
1249 module_init(ads7846_init);
1250
1251 static void __exit ads7846_exit(void)
1252 {
1253         spi_unregister_driver(&ads7846_driver);
1254 }
1255 module_exit(ads7846_exit);
1256
1257 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1258 MODULE_LICENSE("GPL");