Pull misc into release branch
[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/spi/spi.h>
28 #include <linux/spi/ads7846.h>
29 #include <asm/irq.h>
30
31 #ifdef  CONFIG_ARM
32 #include <asm/mach-types.h>
33 #ifdef  CONFIG_ARCH_OMAP
34 #include <asm/arch/gpio.h>
35 #endif
36 #endif
37
38
39 /*
40  * This code has been heavily tested on a Nokia 770, and lightly
41  * tested on other ads7846 devices (OSK/Mistral, Lubbock).
42  * TSC2046 is just newer ads7846 silicon.
43  * Support for ads7843 tested on Atmel at91sam926x-EK.
44  * Support for ads7845 has only been stubbed in.
45  *
46  * IRQ handling needs a workaround because of a shortcoming in handling
47  * edge triggered IRQs on some platforms like the OMAP1/2. These
48  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
49  * have to maintain our own SW IRQ disabled status. This should be
50  * removed as soon as the affected platform's IRQ handling is fixed.
51  *
52  * app note sbaa036 talks in more detail about accurate sampling...
53  * that ought to help in situations like LCDs inducing noise (which
54  * can also be helped by using synch signals) and more generally.
55  * This driver tries to utilize the measures described in the app
56  * note. The strength of filtering can be set in the board-* specific
57  * files.
58  */
59
60 #define TS_POLL_DELAY   (1 * 1000000)   /* ns delay before the first sample */
61 #define TS_POLL_PERIOD  (5 * 1000000)   /* ns delay between samples */
62
63 /* this driver doesn't aim at the peak continuous sample rate */
64 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
65
66 struct ts_event {
67         /* For portability, we can't read 12 bit values using SPI (which
68          * would make the controller deliver them as native byteorder 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         int     ignore;
76 };
77
78 struct ads7846 {
79         struct input_dev        *input;
80         char                    phys[32];
81
82         struct spi_device       *spi;
83
84 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
85         struct attribute_group  *attr_group;
86         struct class_device     *hwmon;
87 #endif
88
89         u16                     model;
90         u16                     vref_delay_usecs;
91         u16                     x_plate_ohms;
92         u16                     pressure_max;
93
94         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
95         u16                     dummy;          /* for the pwrdown read */
96         struct ts_event         tc;
97
98         struct spi_transfer     xfer[18];
99         struct spi_message      msg[5];
100         struct spi_message      *last_msg;
101         int                     msg_idx;
102         int                     read_cnt;
103         int                     read_rep;
104         int                     last_read;
105
106         u16                     debounce_max;
107         u16                     debounce_tol;
108         u16                     debounce_rep;
109
110         u16                     penirq_recheck_delay_usecs;
111
112         spinlock_t              lock;
113         struct hrtimer          timer;
114         unsigned                pendown:1;      /* P: lock */
115         unsigned                pending:1;      /* P: lock */
116 // FIXME remove "irq_disabled"
117         unsigned                irq_disabled:1; /* P: lock */
118         unsigned                disabled:1;
119
120         int                     (*filter)(void *data, int data_idx, int *val);
121         void                    *filter_data;
122         void                    (*filter_cleanup)(void *data);
123         int                     (*get_pendown_state)(void);
124 };
125
126 /* leave chip selected when we're done, for quicker re-select? */
127 #if     0
128 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
129 #else
130 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
131 #endif
132
133 /*--------------------------------------------------------------------------*/
134
135 /* The ADS7846 has touchscreen and other sensors.
136  * Earlier ads784x chips are somewhat compatible.
137  */
138 #define ADS_START               (1 << 7)
139 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
140 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
141 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
142 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
143 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
144 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
145 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
146 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
147 #define ADS_8_BIT               (1 << 3)
148 #define ADS_12_BIT              (0 << 3)
149 #define ADS_SER                 (1 << 2)        /* non-differential */
150 #define ADS_DFR                 (0 << 2)        /* differential */
151 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
152 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
153 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
154 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
155
156 #define MAX_12BIT       ((1<<12)-1)
157
158 /* leave ADC powered up (disables penirq) between differential samples */
159 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
160         | ADS_12_BIT | ADS_DFR | \
161         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
162
163 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
164 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
165 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
166
167 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
168 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
169
170 /* single-ended samples need to first power up reference voltage;
171  * we leave both ADC and VREF powered
172  */
173 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
174         | ADS_12_BIT | ADS_SER)
175
176 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
177 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
178
179 /*--------------------------------------------------------------------------*/
180
181 /*
182  * Non-touchscreen sensors only use single-ended conversions.
183  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
184  * ads7846 lets that pin be unconnected, to use internal vREF.
185  */
186 static unsigned vREF_mV;
187 module_param(vREF_mV, uint, 0);
188 MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts");
189
190 struct ser_req {
191         u8                      ref_on;
192         u8                      command;
193         u8                      ref_off;
194         u16                     scratch;
195         __be16                  sample;
196         struct spi_message      msg;
197         struct spi_transfer     xfer[6];
198 };
199
200 static void ads7846_enable(struct ads7846 *ts);
201 static void ads7846_disable(struct ads7846 *ts);
202
203 static int device_suspended(struct device *dev)
204 {
205         struct ads7846 *ts = dev_get_drvdata(dev);
206         return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
207 }
208
209 static int ads7846_read12_ser(struct device *dev, unsigned command)
210 {
211         struct spi_device       *spi = to_spi_device(dev);
212         struct ads7846          *ts = dev_get_drvdata(dev);
213         struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
214         int                     status;
215         int                     sample;
216         int                     use_internal;
217
218         if (!req)
219                 return -ENOMEM;
220
221         spi_message_init(&req->msg);
222
223         /* FIXME boards with ads7846 might use external vref instead ... */
224         use_internal = (ts->model == 7846);
225
226         /* maybe turn on internal vREF, and let it settle */
227         if (use_internal) {
228                 req->ref_on = REF_ON;
229                 req->xfer[0].tx_buf = &req->ref_on;
230                 req->xfer[0].len = 1;
231                 spi_message_add_tail(&req->xfer[0], &req->msg);
232
233                 req->xfer[1].rx_buf = &req->scratch;
234                 req->xfer[1].len = 2;
235
236                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
237                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
238                 spi_message_add_tail(&req->xfer[1], &req->msg);
239         }
240
241         /* take sample */
242         req->command = (u8) command;
243         req->xfer[2].tx_buf = &req->command;
244         req->xfer[2].len = 1;
245         spi_message_add_tail(&req->xfer[2], &req->msg);
246
247         req->xfer[3].rx_buf = &req->sample;
248         req->xfer[3].len = 2;
249         spi_message_add_tail(&req->xfer[3], &req->msg);
250
251         /* REVISIT:  take a few more samples, and compare ... */
252
253         /* converter in low power mode & enable PENIRQ */
254         req->ref_off = PWRDOWN;
255         req->xfer[4].tx_buf = &req->ref_off;
256         req->xfer[4].len = 1;
257         spi_message_add_tail(&req->xfer[4], &req->msg);
258
259         req->xfer[5].rx_buf = &req->scratch;
260         req->xfer[5].len = 2;
261         CS_CHANGE(req->xfer[5]);
262         spi_message_add_tail(&req->xfer[5], &req->msg);
263
264         ts->irq_disabled = 1;
265         disable_irq(spi->irq);
266         status = spi_sync(spi, &req->msg);
267         ts->irq_disabled = 0;
268         enable_irq(spi->irq);
269
270         if (req->msg.status)
271                 status = req->msg.status;
272
273         /* on-wire is a must-ignore bit, a BE12 value, then padding */
274         sample = be16_to_cpu(req->sample);
275         sample = sample >> 3;
276         sample &= 0x0fff;
277
278         kfree(req);
279         return status ? status : sample;
280 }
281
282 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
283
284 #define SHOW(name, var, adjust) static ssize_t \
285 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
286 { \
287         struct ads7846 *ts = dev_get_drvdata(dev); \
288         ssize_t v = ads7846_read12_ser(dev, \
289                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
290         if (v < 0) \
291                 return v; \
292         return sprintf(buf, "%u\n", adjust(ts, v)); \
293 } \
294 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
295
296
297 /* Sysfs conventions report temperatures in millidegrees Celcius.
298  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
299  * accuracy scheme without calibration data.  For now we won't try either;
300  * userspace sees raw sensor values, and must scale/calibrate appropriately.
301  */
302 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
303 {
304         return v;
305 }
306
307 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
308 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
309
310
311 /* sysfs conventions report voltages in millivolts.  We can convert voltages
312  * if we know vREF.  userspace may need to scale vAUX to match the board's
313  * external resistors; we assume that vBATT only uses the internal ones.
314  */
315 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
316 {
317         unsigned retval = v;
318
319         /* external resistors may scale vAUX into 0..vREF */
320         retval *= vREF_mV;
321         retval = retval >> 12;
322         return retval;
323 }
324
325 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
326 {
327         unsigned retval = vaux_adjust(ts, v);
328
329         /* ads7846 has a resistor ladder to scale this signal down */
330         if (ts->model == 7846)
331                 retval *= 4;
332         return retval;
333 }
334
335 SHOW(in0_input, vaux, vaux_adjust)
336 SHOW(in1_input, vbatt, vbatt_adjust)
337
338
339 static struct attribute *ads7846_attributes[] = {
340         &dev_attr_temp0.attr,
341         &dev_attr_temp1.attr,
342         &dev_attr_in0_input.attr,
343         &dev_attr_in1_input.attr,
344         NULL,
345 };
346
347 static struct attribute_group ads7846_attr_group = {
348         .attrs = ads7846_attributes,
349 };
350
351 static struct attribute *ads7843_attributes[] = {
352         &dev_attr_in0_input.attr,
353         &dev_attr_in1_input.attr,
354         NULL,
355 };
356
357 static struct attribute_group ads7843_attr_group = {
358         .attrs = ads7843_attributes,
359 };
360
361 static struct attribute *ads7845_attributes[] = {
362         &dev_attr_in0_input.attr,
363         NULL,
364 };
365
366 static struct attribute_group ads7845_attr_group = {
367         .attrs = ads7845_attributes,
368 };
369
370 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
371 {
372         struct class_device *hwmon;
373         int err;
374
375         /* hwmon sensors need a reference voltage */
376         switch (ts->model) {
377         case 7846:
378                 if (!vREF_mV) {
379                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
380                         vREF_mV = 2500;
381                 }
382                 break;
383         case 7845:
384         case 7843:
385                 if (!vREF_mV) {
386                         dev_warn(&spi->dev,
387                                 "external vREF for ADS%d not specified\n",
388                                 ts->model);
389                         return 0;
390                 }
391                 break;
392         }
393
394         /* different chips have different sensor groups */
395         switch (ts->model) {
396         case 7846:
397                 ts->attr_group = &ads7846_attr_group;
398                 break;
399         case 7845:
400                 ts->attr_group = &ads7845_attr_group;
401                 break;
402         case 7843:
403                 ts->attr_group = &ads7843_attr_group;
404                 break;
405         default:
406                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
407                 return 0;
408         }
409
410         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
411         if (err)
412                 return err;
413
414         hwmon = hwmon_device_register(&spi->dev);
415         if (IS_ERR(hwmon)) {
416                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
417                 return PTR_ERR(hwmon);
418         }
419
420         ts->hwmon = hwmon;
421         return 0;
422 }
423
424 static void ads784x_hwmon_unregister(struct spi_device *spi,
425                                      struct ads7846 *ts)
426 {
427         if (ts->hwmon) {
428                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
429                 hwmon_device_unregister(ts->hwmon);
430         }
431 }
432
433 #else
434 static inline int ads784x_hwmon_register(struct spi_device *spi,
435                                          struct ads7846 *ts)
436 {
437         return 0;
438 }
439
440 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
441                                             struct ads7846 *ts)
442 {
443 }
444 #endif
445
446 static int is_pen_down(struct device *dev)
447 {
448         struct ads7846  *ts = dev_get_drvdata(dev);
449
450         return ts->pendown;
451 }
452
453 static ssize_t ads7846_pen_down_show(struct device *dev,
454                                      struct device_attribute *attr, char *buf)
455 {
456         return sprintf(buf, "%u\n", is_pen_down(dev));
457 }
458
459 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
460
461 static ssize_t ads7846_disable_show(struct device *dev,
462                                      struct device_attribute *attr, char *buf)
463 {
464         struct ads7846  *ts = dev_get_drvdata(dev);
465
466         return sprintf(buf, "%u\n", ts->disabled);
467 }
468
469 static ssize_t ads7846_disable_store(struct device *dev,
470                                      struct device_attribute *attr,
471                                      const char *buf, size_t count)
472 {
473         struct ads7846 *ts = dev_get_drvdata(dev);
474         char *endp;
475         int i;
476
477         i = simple_strtoul(buf, &endp, 10);
478         spin_lock_irq(&ts->lock);
479
480         if (i)
481                 ads7846_disable(ts);
482         else
483                 ads7846_enable(ts);
484
485         spin_unlock_irq(&ts->lock);
486
487         return count;
488 }
489
490 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
491
492 static struct attribute *ads784x_attributes[] = {
493         &dev_attr_pen_down.attr,
494         &dev_attr_disable.attr,
495         NULL,
496 };
497
498 static struct attribute_group ads784x_attr_group = {
499         .attrs = ads784x_attributes,
500 };
501
502 /*--------------------------------------------------------------------------*/
503
504 /*
505  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
506  * to retrieve touchscreen status.
507  *
508  * The SPI transfer completion callback does the real work.  It reports
509  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
510  */
511
512 static void ads7846_rx(void *ads)
513 {
514         struct ads7846          *ts = ads;
515         unsigned                Rt;
516         u16                     x, y, z1, z2;
517
518         /* ads7846_rx_val() did in-place conversion (including byteswap) from
519          * on-the-wire format as part of debouncing to get stable readings.
520          */
521         x = ts->tc.x;
522         y = ts->tc.y;
523         z1 = ts->tc.z1;
524         z2 = ts->tc.z2;
525
526         /* range filtering */
527         if (x == MAX_12BIT)
528                 x = 0;
529
530         if (likely(x && z1)) {
531                 /* compute touch pressure resistance using equation #2 */
532                 Rt = z2;
533                 Rt -= z1;
534                 Rt *= x;
535                 Rt *= ts->x_plate_ohms;
536                 Rt /= z1;
537                 Rt = (Rt + 2047) >> 12;
538         } else
539                 Rt = 0;
540
541         if (ts->model == 7843)
542                 Rt = ts->pressure_max / 2;
543
544         /* Sample found inconsistent by debouncing or pressure is beyond
545          * the maximum. Don't report it to user space, repeat at least
546          * once more the measurement
547          */
548         if (ts->tc.ignore || Rt > ts->pressure_max) {
549 #ifdef VERBOSE
550                 pr_debug("%s: ignored %d pressure %d\n",
551                         ts->spi->dev.bus_id, ts->tc.ignore, Rt);
552 #endif
553                 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
554                               HRTIMER_MODE_REL);
555                 return;
556         }
557
558         /* Maybe check the pendown state before reporting. This discards
559          * false readings when the pen is lifted.
560          */
561         if (ts->penirq_recheck_delay_usecs) {
562                 udelay(ts->penirq_recheck_delay_usecs);
563                 if (!ts->get_pendown_state())
564                         Rt = 0;
565         }
566
567         /* NOTE: We can't rely on the pressure to determine the pen down
568          * state, even this controller has a pressure sensor.  The pressure
569          * value can fluctuate for quite a while after lifting the pen and
570          * in some cases may not even settle at the expected value.
571          *
572          * The only safe way to check for the pen up condition is in the
573          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
574          */
575         if (Rt) {
576                 struct input_dev *input = ts->input;
577
578                 if (!ts->pendown) {
579                         input_report_key(input, BTN_TOUCH, 1);
580                         ts->pendown = 1;
581 #ifdef VERBOSE
582                         dev_dbg(&ts->spi->dev, "DOWN\n");
583 #endif
584                 }
585                 input_report_abs(input, ABS_X, x);
586                 input_report_abs(input, ABS_Y, y);
587                 input_report_abs(input, ABS_PRESSURE, Rt);
588
589                 input_sync(input);
590 #ifdef VERBOSE
591                 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
592 #endif
593         }
594
595         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
596                         HRTIMER_MODE_REL);
597 }
598
599 static int ads7846_debounce(void *ads, int data_idx, int *val)
600 {
601         struct ads7846          *ts = ads;
602
603         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
604                 /* Start over collecting consistent readings. */
605                 ts->read_rep = 0;
606                 /* Repeat it, if this was the first read or the read
607                  * wasn't consistent enough. */
608                 if (ts->read_cnt < ts->debounce_max) {
609                         ts->last_read = *val;
610                         ts->read_cnt++;
611                         return ADS7846_FILTER_REPEAT;
612                 } else {
613                         /* Maximum number of debouncing reached and still
614                          * not enough number of consistent readings. Abort
615                          * the whole sample, repeat it in the next sampling
616                          * period.
617                          */
618                         ts->read_cnt = 0;
619                         return ADS7846_FILTER_IGNORE;
620                 }
621         } else {
622                 if (++ts->read_rep > ts->debounce_rep) {
623                         /* Got a good reading for this coordinate,
624                          * go for the next one. */
625                         ts->read_cnt = 0;
626                         ts->read_rep = 0;
627                         return ADS7846_FILTER_OK;
628                 } else {
629                         /* Read more values that are consistent. */
630                         ts->read_cnt++;
631                         return ADS7846_FILTER_REPEAT;
632                 }
633         }
634 }
635
636 static int ads7846_no_filter(void *ads, int data_idx, int *val)
637 {
638         return ADS7846_FILTER_OK;
639 }
640
641 static void ads7846_rx_val(void *ads)
642 {
643         struct ads7846 *ts = ads;
644         struct spi_message *m;
645         struct spi_transfer *t;
646         u16 *rx_val;
647         int val;
648         int action;
649         int status;
650
651         m = &ts->msg[ts->msg_idx];
652         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
653         rx_val = t->rx_buf;
654
655         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
656          * built from two 8 bit values written msb-first.
657          */
658         val = be16_to_cpu(*rx_val) >> 3;
659
660         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
661         switch (action) {
662         case ADS7846_FILTER_REPEAT:
663                 break;
664         case ADS7846_FILTER_IGNORE:
665                 ts->tc.ignore = 1;
666                 /* Last message will contain ads7846_rx() as the
667                  * completion function.
668                  */
669                 m = ts->last_msg;
670                 break;
671         case ADS7846_FILTER_OK:
672                 *rx_val = val;
673                 ts->tc.ignore = 0;
674                 m = &ts->msg[++ts->msg_idx];
675                 break;
676         default:
677                 BUG();
678         }
679         status = spi_async(ts->spi, m);
680         if (status)
681                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
682                                 status);
683 }
684
685 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
686 {
687         struct ads7846  *ts = container_of(handle, struct ads7846, timer);
688         int             status = 0;
689
690         spin_lock_irq(&ts->lock);
691
692         if (unlikely(!ts->get_pendown_state() ||
693                      device_suspended(&ts->spi->dev))) {
694                 if (ts->pendown) {
695                         struct input_dev *input = ts->input;
696
697                         input_report_key(input, BTN_TOUCH, 0);
698                         input_report_abs(input, ABS_PRESSURE, 0);
699                         input_sync(input);
700
701                         ts->pendown = 0;
702 #ifdef VERBOSE
703                         dev_dbg(&ts->spi->dev, "UP\n");
704 #endif
705                 }
706
707                 /* measurement cycle ended */
708                 if (!device_suspended(&ts->spi->dev)) {
709                         ts->irq_disabled = 0;
710                         enable_irq(ts->spi->irq);
711                 }
712                 ts->pending = 0;
713         } else {
714                 /* pen is still down, continue with the measurement */
715                 ts->msg_idx = 0;
716                 status = spi_async(ts->spi, &ts->msg[0]);
717                 if (status)
718                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
719         }
720
721         spin_unlock_irq(&ts->lock);
722         return HRTIMER_NORESTART;
723 }
724
725 static irqreturn_t ads7846_irq(int irq, void *handle)
726 {
727         struct ads7846 *ts = handle;
728         unsigned long flags;
729
730         spin_lock_irqsave(&ts->lock, flags);
731         if (likely(ts->get_pendown_state())) {
732                 if (!ts->irq_disabled) {
733                         /* The ARM do_simple_IRQ() dispatcher doesn't act
734                          * like the other dispatchers:  it will report IRQs
735                          * even after they've been disabled.  We work around
736                          * that here.  (The "generic irq" framework may help...)
737                          */
738                         ts->irq_disabled = 1;
739                         disable_irq(ts->spi->irq);
740                         ts->pending = 1;
741                         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
742                                         HRTIMER_MODE_REL);
743                 }
744         }
745         spin_unlock_irqrestore(&ts->lock, flags);
746
747         return IRQ_HANDLED;
748 }
749
750 /*--------------------------------------------------------------------------*/
751
752 /* Must be called with ts->lock held */
753 static void ads7846_disable(struct ads7846 *ts)
754 {
755         if (ts->disabled)
756                 return;
757
758         ts->disabled = 1;
759
760         /* are we waiting for IRQ, or polling? */
761         if (!ts->pending) {
762                 ts->irq_disabled = 1;
763                 disable_irq(ts->spi->irq);
764         } else {
765                 /* the timer will run at least once more, and
766                  * leave everything in a clean state, IRQ disabled
767                  */
768                 while (ts->pending) {
769                         spin_unlock_irq(&ts->lock);
770                         msleep(1);
771                         spin_lock_irq(&ts->lock);
772                 }
773         }
774
775         /* we know the chip's in lowpower mode since we always
776          * leave it that way after every request
777          */
778
779 }
780
781 /* Must be called with ts->lock held */
782 static void ads7846_enable(struct ads7846 *ts)
783 {
784         if (!ts->disabled)
785                 return;
786
787         ts->disabled = 0;
788         ts->irq_disabled = 0;
789         enable_irq(ts->spi->irq);
790 }
791
792 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
793 {
794         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
795
796         spin_lock_irq(&ts->lock);
797
798         spi->dev.power.power_state = message;
799         ads7846_disable(ts);
800
801         spin_unlock_irq(&ts->lock);
802
803         return 0;
804
805 }
806
807 static int ads7846_resume(struct spi_device *spi)
808 {
809         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
810
811         spin_lock_irq(&ts->lock);
812
813         spi->dev.power.power_state = PMSG_ON;
814         ads7846_enable(ts);
815
816         spin_unlock_irq(&ts->lock);
817
818         return 0;
819 }
820
821 static int __devinit ads7846_probe(struct spi_device *spi)
822 {
823         struct ads7846                  *ts;
824         struct input_dev                *input_dev;
825         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
826         struct spi_message              *m;
827         struct spi_transfer             *x;
828         int                             vref;
829         int                             err;
830
831         if (!spi->irq) {
832                 dev_dbg(&spi->dev, "no IRQ?\n");
833                 return -ENODEV;
834         }
835
836         if (!pdata) {
837                 dev_dbg(&spi->dev, "no platform data?\n");
838                 return -ENODEV;
839         }
840
841         /* don't exceed max specified sample rate */
842         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
843                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
844                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
845                 return -EINVAL;
846         }
847
848         /* REVISIT when the irq can be triggered active-low, or if for some
849          * reason the touchscreen isn't hooked up, we don't need to access
850          * the pendown state.
851          */
852         if (pdata->get_pendown_state == NULL) {
853                 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
854                 return -EINVAL;
855         }
856
857         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
858          * that even if the hardware can do that, the SPI controller driver
859          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
860          */
861         spi->bits_per_word = 8;
862         spi->mode = SPI_MODE_0;
863         err = spi_setup(spi);
864         if (err < 0)
865                 return err;
866
867         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
868         input_dev = input_allocate_device();
869         if (!ts || !input_dev) {
870                 err = -ENOMEM;
871                 goto err_free_mem;
872         }
873
874         dev_set_drvdata(&spi->dev, ts);
875         spi->dev.power.power_state = PMSG_ON;
876
877         ts->spi = spi;
878         ts->input = input_dev;
879
880         hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
881         ts->timer.function = ads7846_timer;
882
883         spin_lock_init(&ts->lock);
884
885         ts->model = pdata->model ? : 7846;
886         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
887         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
888         ts->pressure_max = pdata->pressure_max ? : ~0;
889
890         if (pdata->filter != NULL) {
891                 if (pdata->filter_init != NULL) {
892                         err = pdata->filter_init(pdata, &ts->filter_data);
893                         if (err < 0)
894                                 goto err_free_mem;
895                 }
896                 ts->filter = pdata->filter;
897                 ts->filter_cleanup = pdata->filter_cleanup;
898         } else if (pdata->debounce_max) {
899                 ts->debounce_max = pdata->debounce_max;
900                 if (ts->debounce_max < 2)
901                         ts->debounce_max = 2;
902                 ts->debounce_tol = pdata->debounce_tol;
903                 ts->debounce_rep = pdata->debounce_rep;
904                 ts->filter = ads7846_debounce;
905                 ts->filter_data = ts;
906         } else
907                 ts->filter = ads7846_no_filter;
908         ts->get_pendown_state = pdata->get_pendown_state;
909
910         if (pdata->penirq_recheck_delay_usecs)
911                 ts->penirq_recheck_delay_usecs =
912                                 pdata->penirq_recheck_delay_usecs;
913
914         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
915
916         input_dev->name = "ADS784x Touchscreen";
917         input_dev->phys = ts->phys;
918         input_dev->dev.parent = &spi->dev;
919
920         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
921         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
922         input_set_abs_params(input_dev, ABS_X,
923                         pdata->x_min ? : 0,
924                         pdata->x_max ? : MAX_12BIT,
925                         0, 0);
926         input_set_abs_params(input_dev, ABS_Y,
927                         pdata->y_min ? : 0,
928                         pdata->y_max ? : MAX_12BIT,
929                         0, 0);
930         input_set_abs_params(input_dev, ABS_PRESSURE,
931                         pdata->pressure_min, pdata->pressure_max, 0, 0);
932
933         vref = pdata->keep_vref_on;
934
935         /* set up the transfers to read touchscreen state; this assumes we
936          * use formula #2 for pressure, not #3.
937          */
938         m = &ts->msg[0];
939         x = ts->xfer;
940
941         spi_message_init(m);
942
943         /* y- still on; turn on only y+ (and ADC) */
944         ts->read_y = READ_Y(vref);
945         x->tx_buf = &ts->read_y;
946         x->len = 1;
947         spi_message_add_tail(x, m);
948
949         x++;
950         x->rx_buf = &ts->tc.y;
951         x->len = 2;
952         spi_message_add_tail(x, m);
953
954         /* the first sample after switching drivers can be low quality;
955          * optionally discard it, using a second one after the signals
956          * have had enough time to stabilize.
957          */
958         if (pdata->settle_delay_usecs) {
959                 x->delay_usecs = pdata->settle_delay_usecs;
960
961                 x++;
962                 x->tx_buf = &ts->read_y;
963                 x->len = 1;
964                 spi_message_add_tail(x, m);
965
966                 x++;
967                 x->rx_buf = &ts->tc.y;
968                 x->len = 2;
969                 spi_message_add_tail(x, m);
970         }
971
972         m->complete = ads7846_rx_val;
973         m->context = ts;
974
975         m++;
976         spi_message_init(m);
977
978         /* turn y- off, x+ on, then leave in lowpower */
979         x++;
980         ts->read_x = READ_X(vref);
981         x->tx_buf = &ts->read_x;
982         x->len = 1;
983         spi_message_add_tail(x, m);
984
985         x++;
986         x->rx_buf = &ts->tc.x;
987         x->len = 2;
988         spi_message_add_tail(x, m);
989
990         /* ... maybe discard first sample ... */
991         if (pdata->settle_delay_usecs) {
992                 x->delay_usecs = pdata->settle_delay_usecs;
993
994                 x++;
995                 x->tx_buf = &ts->read_x;
996                 x->len = 1;
997                 spi_message_add_tail(x, m);
998
999                 x++;
1000                 x->rx_buf = &ts->tc.x;
1001                 x->len = 2;
1002                 spi_message_add_tail(x, m);
1003         }
1004
1005         m->complete = ads7846_rx_val;
1006         m->context = ts;
1007
1008         /* turn y+ off, x- on; we'll use formula #2 */
1009         if (ts->model == 7846) {
1010                 m++;
1011                 spi_message_init(m);
1012
1013                 x++;
1014                 ts->read_z1 = READ_Z1(vref);
1015                 x->tx_buf = &ts->read_z1;
1016                 x->len = 1;
1017                 spi_message_add_tail(x, m);
1018
1019                 x++;
1020                 x->rx_buf = &ts->tc.z1;
1021                 x->len = 2;
1022                 spi_message_add_tail(x, m);
1023
1024                 /* ... maybe discard first sample ... */
1025                 if (pdata->settle_delay_usecs) {
1026                         x->delay_usecs = pdata->settle_delay_usecs;
1027
1028                         x++;
1029                         x->tx_buf = &ts->read_z1;
1030                         x->len = 1;
1031                         spi_message_add_tail(x, m);
1032
1033                         x++;
1034                         x->rx_buf = &ts->tc.z1;
1035                         x->len = 2;
1036                         spi_message_add_tail(x, m);
1037                 }
1038
1039                 m->complete = ads7846_rx_val;
1040                 m->context = ts;
1041
1042                 m++;
1043                 spi_message_init(m);
1044
1045                 x++;
1046                 ts->read_z2 = READ_Z2(vref);
1047                 x->tx_buf = &ts->read_z2;
1048                 x->len = 1;
1049                 spi_message_add_tail(x, m);
1050
1051                 x++;
1052                 x->rx_buf = &ts->tc.z2;
1053                 x->len = 2;
1054                 spi_message_add_tail(x, m);
1055
1056                 /* ... maybe discard first sample ... */
1057                 if (pdata->settle_delay_usecs) {
1058                         x->delay_usecs = pdata->settle_delay_usecs;
1059
1060                         x++;
1061                         x->tx_buf = &ts->read_z2;
1062                         x->len = 1;
1063                         spi_message_add_tail(x, m);
1064
1065                         x++;
1066                         x->rx_buf = &ts->tc.z2;
1067                         x->len = 2;
1068                         spi_message_add_tail(x, m);
1069                 }
1070
1071                 m->complete = ads7846_rx_val;
1072                 m->context = ts;
1073         }
1074
1075         /* power down */
1076         m++;
1077         spi_message_init(m);
1078
1079         x++;
1080         ts->pwrdown = PWRDOWN;
1081         x->tx_buf = &ts->pwrdown;
1082         x->len = 1;
1083         spi_message_add_tail(x, m);
1084
1085         x++;
1086         x->rx_buf = &ts->dummy;
1087         x->len = 2;
1088         CS_CHANGE(*x);
1089         spi_message_add_tail(x, m);
1090
1091         m->complete = ads7846_rx;
1092         m->context = ts;
1093
1094         ts->last_msg = m;
1095
1096         if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
1097                         spi->dev.driver->name, ts)) {
1098                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1099                 err = -EBUSY;
1100                 goto err_cleanup_filter;
1101         }
1102
1103         err = ads784x_hwmon_register(spi, ts);
1104         if (err)
1105                 goto err_free_irq;
1106
1107         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1108
1109         /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1110          * the touchscreen, in case it's not connected.
1111          */
1112         (void) ads7846_read12_ser(&spi->dev,
1113                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1114
1115         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1116         if (err)
1117                 goto err_remove_hwmon;
1118
1119         err = input_register_device(input_dev);
1120         if (err)
1121                 goto err_remove_attr_group;
1122
1123         return 0;
1124
1125  err_remove_attr_group:
1126         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1127  err_remove_hwmon:
1128         ads784x_hwmon_unregister(spi, ts);
1129  err_free_irq:
1130         free_irq(spi->irq, ts);
1131  err_cleanup_filter:
1132         if (ts->filter_cleanup)
1133                 ts->filter_cleanup(ts->filter_data);
1134  err_free_mem:
1135         input_free_device(input_dev);
1136         kfree(ts);
1137         return err;
1138 }
1139
1140 static int __devexit ads7846_remove(struct spi_device *spi)
1141 {
1142         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
1143
1144         ads784x_hwmon_unregister(spi, ts);
1145         input_unregister_device(ts->input);
1146
1147         ads7846_suspend(spi, PMSG_SUSPEND);
1148
1149         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1150
1151         free_irq(ts->spi->irq, ts);
1152         /* suspend left the IRQ disabled */
1153         enable_irq(ts->spi->irq);
1154
1155         if (ts->filter_cleanup)
1156                 ts->filter_cleanup(ts->filter_data);
1157
1158         kfree(ts);
1159
1160         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1161         return 0;
1162 }
1163
1164 static struct spi_driver ads7846_driver = {
1165         .driver = {
1166                 .name   = "ads7846",
1167                 .bus    = &spi_bus_type,
1168                 .owner  = THIS_MODULE,
1169         },
1170         .probe          = ads7846_probe,
1171         .remove         = __devexit_p(ads7846_remove),
1172         .suspend        = ads7846_suspend,
1173         .resume         = ads7846_resume,
1174 };
1175
1176 static int __init ads7846_init(void)
1177 {
1178         /* grr, board-specific init should stay out of drivers!! */
1179
1180 #ifdef  CONFIG_ARCH_OMAP
1181         if (machine_is_omap_osk()) {
1182                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
1183                 omap_request_gpio(4);
1184                 omap_set_gpio_direction(4, 1);
1185                 omap_request_gpio(6);
1186                 omap_set_gpio_direction(6, 1);
1187         }
1188         // also TI 1510 Innovator, bitbanging through FPGA
1189         // also Nokia 770
1190         // also Palm Tungsten T2
1191 #endif
1192
1193         // PXA:
1194         // also Dell Axim X50
1195         // also HP iPaq H191x/H192x/H415x/H435x
1196         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
1197         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
1198
1199         // Atmel at91sam9261-EK uses ads7843
1200
1201         // also various AMD Au1x00 devel boards
1202
1203         return spi_register_driver(&ads7846_driver);
1204 }
1205 module_init(ads7846_init);
1206
1207 static void __exit ads7846_exit(void)
1208 {
1209         spi_unregister_driver(&ads7846_driver);
1210
1211 #ifdef  CONFIG_ARCH_OMAP
1212         if (machine_is_omap_osk()) {
1213                 omap_free_gpio(4);
1214                 omap_free_gpio(6);
1215         }
1216 #endif
1217
1218 }
1219 module_exit(ads7846_exit);
1220
1221 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1222 MODULE_LICENSE("GPL");