Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394...
[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 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 (status == 0) {
271                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
272                 sample = be16_to_cpu(req->sample);
273                 sample = sample >> 3;
274                 sample &= 0x0fff;
275         }
276
277         kfree(req);
278         return status ? status : sample;
279 }
280
281 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
282
283 #define SHOW(name, var, adjust) static ssize_t \
284 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
285 { \
286         struct ads7846 *ts = dev_get_drvdata(dev); \
287         ssize_t v = ads7846_read12_ser(dev, \
288                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
289         if (v < 0) \
290                 return v; \
291         return sprintf(buf, "%u\n", adjust(ts, v)); \
292 } \
293 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
294
295
296 /* Sysfs conventions report temperatures in millidegrees Celcius.
297  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
298  * accuracy scheme without calibration data.  For now we won't try either;
299  * userspace sees raw sensor values, and must scale/calibrate appropriately.
300  */
301 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
302 {
303         return v;
304 }
305
306 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
307 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
308
309
310 /* sysfs conventions report voltages in millivolts.  We can convert voltages
311  * if we know vREF.  userspace may need to scale vAUX to match the board's
312  * external resistors; we assume that vBATT only uses the internal ones.
313  */
314 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
315 {
316         unsigned retval = v;
317
318         /* external resistors may scale vAUX into 0..vREF */
319         retval *= vREF_mV;
320         retval = retval >> 12;
321         return retval;
322 }
323
324 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
325 {
326         unsigned retval = vaux_adjust(ts, v);
327
328         /* ads7846 has a resistor ladder to scale this signal down */
329         if (ts->model == 7846)
330                 retval *= 4;
331         return retval;
332 }
333
334 SHOW(in0_input, vaux, vaux_adjust)
335 SHOW(in1_input, vbatt, vbatt_adjust)
336
337
338 static struct attribute *ads7846_attributes[] = {
339         &dev_attr_temp0.attr,
340         &dev_attr_temp1.attr,
341         &dev_attr_in0_input.attr,
342         &dev_attr_in1_input.attr,
343         NULL,
344 };
345
346 static struct attribute_group ads7846_attr_group = {
347         .attrs = ads7846_attributes,
348 };
349
350 static struct attribute *ads7843_attributes[] = {
351         &dev_attr_in0_input.attr,
352         &dev_attr_in1_input.attr,
353         NULL,
354 };
355
356 static struct attribute_group ads7843_attr_group = {
357         .attrs = ads7843_attributes,
358 };
359
360 static struct attribute *ads7845_attributes[] = {
361         &dev_attr_in0_input.attr,
362         NULL,
363 };
364
365 static struct attribute_group ads7845_attr_group = {
366         .attrs = ads7845_attributes,
367 };
368
369 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
370 {
371         struct device *hwmon;
372         int err;
373
374         /* hwmon sensors need a reference voltage */
375         switch (ts->model) {
376         case 7846:
377                 if (!vREF_mV) {
378                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
379                         vREF_mV = 2500;
380                 }
381                 break;
382         case 7845:
383         case 7843:
384                 if (!vREF_mV) {
385                         dev_warn(&spi->dev,
386                                 "external vREF for ADS%d not specified\n",
387                                 ts->model);
388                         return 0;
389                 }
390                 break;
391         }
392
393         /* different chips have different sensor groups */
394         switch (ts->model) {
395         case 7846:
396                 ts->attr_group = &ads7846_attr_group;
397                 break;
398         case 7845:
399                 ts->attr_group = &ads7845_attr_group;
400                 break;
401         case 7843:
402                 ts->attr_group = &ads7843_attr_group;
403                 break;
404         default:
405                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
406                 return 0;
407         }
408
409         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
410         if (err)
411                 return err;
412
413         hwmon = hwmon_device_register(&spi->dev);
414         if (IS_ERR(hwmon)) {
415                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
416                 return PTR_ERR(hwmon);
417         }
418
419         ts->hwmon = hwmon;
420         return 0;
421 }
422
423 static void ads784x_hwmon_unregister(struct spi_device *spi,
424                                      struct ads7846 *ts)
425 {
426         if (ts->hwmon) {
427                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
428                 hwmon_device_unregister(ts->hwmon);
429         }
430 }
431
432 #else
433 static inline int ads784x_hwmon_register(struct spi_device *spi,
434                                          struct ads7846 *ts)
435 {
436         return 0;
437 }
438
439 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
440                                             struct ads7846 *ts)
441 {
442 }
443 #endif
444
445 static int is_pen_down(struct device *dev)
446 {
447         struct ads7846  *ts = dev_get_drvdata(dev);
448
449         return ts->pendown;
450 }
451
452 static ssize_t ads7846_pen_down_show(struct device *dev,
453                                      struct device_attribute *attr, char *buf)
454 {
455         return sprintf(buf, "%u\n", is_pen_down(dev));
456 }
457
458 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
459
460 static ssize_t ads7846_disable_show(struct device *dev,
461                                      struct device_attribute *attr, char *buf)
462 {
463         struct ads7846  *ts = dev_get_drvdata(dev);
464
465         return sprintf(buf, "%u\n", ts->disabled);
466 }
467
468 static ssize_t ads7846_disable_store(struct device *dev,
469                                      struct device_attribute *attr,
470                                      const char *buf, size_t count)
471 {
472         struct ads7846 *ts = dev_get_drvdata(dev);
473         char *endp;
474         int i;
475
476         i = simple_strtoul(buf, &endp, 10);
477         spin_lock_irq(&ts->lock);
478
479         if (i)
480                 ads7846_disable(ts);
481         else
482                 ads7846_enable(ts);
483
484         spin_unlock_irq(&ts->lock);
485
486         return count;
487 }
488
489 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
490
491 static struct attribute *ads784x_attributes[] = {
492         &dev_attr_pen_down.attr,
493         &dev_attr_disable.attr,
494         NULL,
495 };
496
497 static struct attribute_group ads784x_attr_group = {
498         .attrs = ads784x_attributes,
499 };
500
501 /*--------------------------------------------------------------------------*/
502
503 /*
504  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
505  * to retrieve touchscreen status.
506  *
507  * The SPI transfer completion callback does the real work.  It reports
508  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
509  */
510
511 static void ads7846_rx(void *ads)
512 {
513         struct ads7846          *ts = ads;
514         unsigned                Rt;
515         u16                     x, y, z1, z2;
516
517         /* ads7846_rx_val() did in-place conversion (including byteswap) from
518          * on-the-wire format as part of debouncing to get stable readings.
519          */
520         x = ts->tc.x;
521         y = ts->tc.y;
522         z1 = ts->tc.z1;
523         z2 = ts->tc.z2;
524
525         /* range filtering */
526         if (x == MAX_12BIT)
527                 x = 0;
528
529         if (likely(x && z1)) {
530                 /* compute touch pressure resistance using equation #2 */
531                 Rt = z2;
532                 Rt -= z1;
533                 Rt *= x;
534                 Rt *= ts->x_plate_ohms;
535                 Rt /= z1;
536                 Rt = (Rt + 2047) >> 12;
537         } else
538                 Rt = 0;
539
540         if (ts->model == 7843)
541                 Rt = ts->pressure_max / 2;
542
543         /* Sample found inconsistent by debouncing or pressure is beyond
544          * the maximum. Don't report it to user space, repeat at least
545          * once more the measurement
546          */
547         if (ts->tc.ignore || Rt > ts->pressure_max) {
548 #ifdef VERBOSE
549                 pr_debug("%s: ignored %d pressure %d\n",
550                         ts->spi->dev.bus_id, ts->tc.ignore, Rt);
551 #endif
552                 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
553                               HRTIMER_MODE_REL);
554                 return;
555         }
556
557         /* Maybe check the pendown state before reporting. This discards
558          * false readings when the pen is lifted.
559          */
560         if (ts->penirq_recheck_delay_usecs) {
561                 udelay(ts->penirq_recheck_delay_usecs);
562                 if (!ts->get_pendown_state())
563                         Rt = 0;
564         }
565
566         /* NOTE: We can't rely on the pressure to determine the pen down
567          * state, even this controller has a pressure sensor.  The pressure
568          * value can fluctuate for quite a while after lifting the pen and
569          * in some cases may not even settle at the expected value.
570          *
571          * The only safe way to check for the pen up condition is in the
572          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
573          */
574         if (Rt) {
575                 struct input_dev *input = ts->input;
576
577                 if (!ts->pendown) {
578                         input_report_key(input, BTN_TOUCH, 1);
579                         ts->pendown = 1;
580 #ifdef VERBOSE
581                         dev_dbg(&ts->spi->dev, "DOWN\n");
582 #endif
583                 }
584                 input_report_abs(input, ABS_X, x);
585                 input_report_abs(input, ABS_Y, y);
586                 input_report_abs(input, ABS_PRESSURE, Rt);
587
588                 input_sync(input);
589 #ifdef VERBOSE
590                 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
591 #endif
592         }
593
594         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
595                         HRTIMER_MODE_REL);
596 }
597
598 static int ads7846_debounce(void *ads, int data_idx, int *val)
599 {
600         struct ads7846          *ts = ads;
601
602         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
603                 /* Start over collecting consistent readings. */
604                 ts->read_rep = 0;
605                 /* Repeat it, if this was the first read or the read
606                  * wasn't consistent enough. */
607                 if (ts->read_cnt < ts->debounce_max) {
608                         ts->last_read = *val;
609                         ts->read_cnt++;
610                         return ADS7846_FILTER_REPEAT;
611                 } else {
612                         /* Maximum number of debouncing reached and still
613                          * not enough number of consistent readings. Abort
614                          * the whole sample, repeat it in the next sampling
615                          * period.
616                          */
617                         ts->read_cnt = 0;
618                         return ADS7846_FILTER_IGNORE;
619                 }
620         } else {
621                 if (++ts->read_rep > ts->debounce_rep) {
622                         /* Got a good reading for this coordinate,
623                          * go for the next one. */
624                         ts->read_cnt = 0;
625                         ts->read_rep = 0;
626                         return ADS7846_FILTER_OK;
627                 } else {
628                         /* Read more values that are consistent. */
629                         ts->read_cnt++;
630                         return ADS7846_FILTER_REPEAT;
631                 }
632         }
633 }
634
635 static int ads7846_no_filter(void *ads, int data_idx, int *val)
636 {
637         return ADS7846_FILTER_OK;
638 }
639
640 static void ads7846_rx_val(void *ads)
641 {
642         struct ads7846 *ts = ads;
643         struct spi_message *m;
644         struct spi_transfer *t;
645         u16 *rx_val;
646         int val;
647         int action;
648         int status;
649
650         m = &ts->msg[ts->msg_idx];
651         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
652         rx_val = t->rx_buf;
653
654         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
655          * built from two 8 bit values written msb-first.
656          */
657         val = be16_to_cpu(*rx_val) >> 3;
658
659         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
660         switch (action) {
661         case ADS7846_FILTER_REPEAT:
662                 break;
663         case ADS7846_FILTER_IGNORE:
664                 ts->tc.ignore = 1;
665                 /* Last message will contain ads7846_rx() as the
666                  * completion function.
667                  */
668                 m = ts->last_msg;
669                 break;
670         case ADS7846_FILTER_OK:
671                 *rx_val = val;
672                 ts->tc.ignore = 0;
673                 m = &ts->msg[++ts->msg_idx];
674                 break;
675         default:
676                 BUG();
677         }
678         status = spi_async(ts->spi, m);
679         if (status)
680                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
681                                 status);
682 }
683
684 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
685 {
686         struct ads7846  *ts = container_of(handle, struct ads7846, timer);
687         int             status = 0;
688
689         spin_lock_irq(&ts->lock);
690
691         if (unlikely(!ts->get_pendown_state() ||
692                      device_suspended(&ts->spi->dev))) {
693                 if (ts->pendown) {
694                         struct input_dev *input = ts->input;
695
696                         input_report_key(input, BTN_TOUCH, 0);
697                         input_report_abs(input, ABS_PRESSURE, 0);
698                         input_sync(input);
699
700                         ts->pendown = 0;
701 #ifdef VERBOSE
702                         dev_dbg(&ts->spi->dev, "UP\n");
703 #endif
704                 }
705
706                 /* measurement cycle ended */
707                 if (!device_suspended(&ts->spi->dev)) {
708                         ts->irq_disabled = 0;
709                         enable_irq(ts->spi->irq);
710                 }
711                 ts->pending = 0;
712         } else {
713                 /* pen is still down, continue with the measurement */
714                 ts->msg_idx = 0;
715                 status = spi_async(ts->spi, &ts->msg[0]);
716                 if (status)
717                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
718         }
719
720         spin_unlock_irq(&ts->lock);
721         return HRTIMER_NORESTART;
722 }
723
724 static irqreturn_t ads7846_irq(int irq, void *handle)
725 {
726         struct ads7846 *ts = handle;
727         unsigned long flags;
728
729         spin_lock_irqsave(&ts->lock, flags);
730         if (likely(ts->get_pendown_state())) {
731                 if (!ts->irq_disabled) {
732                         /* The ARM do_simple_IRQ() dispatcher doesn't act
733                          * like the other dispatchers:  it will report IRQs
734                          * even after they've been disabled.  We work around
735                          * that here.  (The "generic irq" framework may help...)
736                          */
737                         ts->irq_disabled = 1;
738                         disable_irq(ts->spi->irq);
739                         ts->pending = 1;
740                         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
741                                         HRTIMER_MODE_REL);
742                 }
743         }
744         spin_unlock_irqrestore(&ts->lock, flags);
745
746         return IRQ_HANDLED;
747 }
748
749 /*--------------------------------------------------------------------------*/
750
751 /* Must be called with ts->lock held */
752 static void ads7846_disable(struct ads7846 *ts)
753 {
754         if (ts->disabled)
755                 return;
756
757         ts->disabled = 1;
758
759         /* are we waiting for IRQ, or polling? */
760         if (!ts->pending) {
761                 ts->irq_disabled = 1;
762                 disable_irq(ts->spi->irq);
763         } else {
764                 /* the timer will run at least once more, and
765                  * leave everything in a clean state, IRQ disabled
766                  */
767                 while (ts->pending) {
768                         spin_unlock_irq(&ts->lock);
769                         msleep(1);
770                         spin_lock_irq(&ts->lock);
771                 }
772         }
773
774         /* we know the chip's in lowpower mode since we always
775          * leave it that way after every request
776          */
777
778 }
779
780 /* Must be called with ts->lock held */
781 static void ads7846_enable(struct ads7846 *ts)
782 {
783         if (!ts->disabled)
784                 return;
785
786         ts->disabled = 0;
787         ts->irq_disabled = 0;
788         enable_irq(ts->spi->irq);
789 }
790
791 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
792 {
793         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
794
795         spin_lock_irq(&ts->lock);
796
797         spi->dev.power.power_state = message;
798         ads7846_disable(ts);
799
800         spin_unlock_irq(&ts->lock);
801
802         return 0;
803
804 }
805
806 static int ads7846_resume(struct spi_device *spi)
807 {
808         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
809
810         spin_lock_irq(&ts->lock);
811
812         spi->dev.power.power_state = PMSG_ON;
813         ads7846_enable(ts);
814
815         spin_unlock_irq(&ts->lock);
816
817         return 0;
818 }
819
820 static int __devinit ads7846_probe(struct spi_device *spi)
821 {
822         struct ads7846                  *ts;
823         struct input_dev                *input_dev;
824         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
825         struct spi_message              *m;
826         struct spi_transfer             *x;
827         int                             vref;
828         int                             err;
829
830         if (!spi->irq) {
831                 dev_dbg(&spi->dev, "no IRQ?\n");
832                 return -ENODEV;
833         }
834
835         if (!pdata) {
836                 dev_dbg(&spi->dev, "no platform data?\n");
837                 return -ENODEV;
838         }
839
840         /* don't exceed max specified sample rate */
841         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
842                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
843                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
844                 return -EINVAL;
845         }
846
847         /* REVISIT when the irq can be triggered active-low, or if for some
848          * reason the touchscreen isn't hooked up, we don't need to access
849          * the pendown state.
850          */
851         if (pdata->get_pendown_state == NULL) {
852                 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
853                 return -EINVAL;
854         }
855
856         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
857          * that even if the hardware can do that, the SPI controller driver
858          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
859          */
860         spi->bits_per_word = 8;
861         spi->mode = SPI_MODE_0;
862         err = spi_setup(spi);
863         if (err < 0)
864                 return err;
865
866         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
867         input_dev = input_allocate_device();
868         if (!ts || !input_dev) {
869                 err = -ENOMEM;
870                 goto err_free_mem;
871         }
872
873         dev_set_drvdata(&spi->dev, ts);
874         spi->dev.power.power_state = PMSG_ON;
875
876         ts->spi = spi;
877         ts->input = input_dev;
878
879         hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
880         ts->timer.function = ads7846_timer;
881
882         spin_lock_init(&ts->lock);
883
884         ts->model = pdata->model ? : 7846;
885         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
886         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
887         ts->pressure_max = pdata->pressure_max ? : ~0;
888
889         if (pdata->filter != NULL) {
890                 if (pdata->filter_init != NULL) {
891                         err = pdata->filter_init(pdata, &ts->filter_data);
892                         if (err < 0)
893                                 goto err_free_mem;
894                 }
895                 ts->filter = pdata->filter;
896                 ts->filter_cleanup = pdata->filter_cleanup;
897         } else if (pdata->debounce_max) {
898                 ts->debounce_max = pdata->debounce_max;
899                 if (ts->debounce_max < 2)
900                         ts->debounce_max = 2;
901                 ts->debounce_tol = pdata->debounce_tol;
902                 ts->debounce_rep = pdata->debounce_rep;
903                 ts->filter = ads7846_debounce;
904                 ts->filter_data = ts;
905         } else
906                 ts->filter = ads7846_no_filter;
907         ts->get_pendown_state = pdata->get_pendown_state;
908
909         if (pdata->penirq_recheck_delay_usecs)
910                 ts->penirq_recheck_delay_usecs =
911                                 pdata->penirq_recheck_delay_usecs;
912
913         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
914
915         input_dev->name = "ADS784x Touchscreen";
916         input_dev->phys = ts->phys;
917         input_dev->dev.parent = &spi->dev;
918
919         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
920         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
921         input_set_abs_params(input_dev, ABS_X,
922                         pdata->x_min ? : 0,
923                         pdata->x_max ? : MAX_12BIT,
924                         0, 0);
925         input_set_abs_params(input_dev, ABS_Y,
926                         pdata->y_min ? : 0,
927                         pdata->y_max ? : MAX_12BIT,
928                         0, 0);
929         input_set_abs_params(input_dev, ABS_PRESSURE,
930                         pdata->pressure_min, pdata->pressure_max, 0, 0);
931
932         vref = pdata->keep_vref_on;
933
934         /* set up the transfers to read touchscreen state; this assumes we
935          * use formula #2 for pressure, not #3.
936          */
937         m = &ts->msg[0];
938         x = ts->xfer;
939
940         spi_message_init(m);
941
942         /* y- still on; turn on only y+ (and ADC) */
943         ts->read_y = READ_Y(vref);
944         x->tx_buf = &ts->read_y;
945         x->len = 1;
946         spi_message_add_tail(x, m);
947
948         x++;
949         x->rx_buf = &ts->tc.y;
950         x->len = 2;
951         spi_message_add_tail(x, m);
952
953         /* the first sample after switching drivers can be low quality;
954          * optionally discard it, using a second one after the signals
955          * have had enough time to stabilize.
956          */
957         if (pdata->settle_delay_usecs) {
958                 x->delay_usecs = pdata->settle_delay_usecs;
959
960                 x++;
961                 x->tx_buf = &ts->read_y;
962                 x->len = 1;
963                 spi_message_add_tail(x, m);
964
965                 x++;
966                 x->rx_buf = &ts->tc.y;
967                 x->len = 2;
968                 spi_message_add_tail(x, m);
969         }
970
971         m->complete = ads7846_rx_val;
972         m->context = ts;
973
974         m++;
975         spi_message_init(m);
976
977         /* turn y- off, x+ on, then leave in lowpower */
978         x++;
979         ts->read_x = READ_X(vref);
980         x->tx_buf = &ts->read_x;
981         x->len = 1;
982         spi_message_add_tail(x, m);
983
984         x++;
985         x->rx_buf = &ts->tc.x;
986         x->len = 2;
987         spi_message_add_tail(x, m);
988
989         /* ... maybe discard first sample ... */
990         if (pdata->settle_delay_usecs) {
991                 x->delay_usecs = pdata->settle_delay_usecs;
992
993                 x++;
994                 x->tx_buf = &ts->read_x;
995                 x->len = 1;
996                 spi_message_add_tail(x, m);
997
998                 x++;
999                 x->rx_buf = &ts->tc.x;
1000                 x->len = 2;
1001                 spi_message_add_tail(x, m);
1002         }
1003
1004         m->complete = ads7846_rx_val;
1005         m->context = ts;
1006
1007         /* turn y+ off, x- on; we'll use formula #2 */
1008         if (ts->model == 7846) {
1009                 m++;
1010                 spi_message_init(m);
1011
1012                 x++;
1013                 ts->read_z1 = READ_Z1(vref);
1014                 x->tx_buf = &ts->read_z1;
1015                 x->len = 1;
1016                 spi_message_add_tail(x, m);
1017
1018                 x++;
1019                 x->rx_buf = &ts->tc.z1;
1020                 x->len = 2;
1021                 spi_message_add_tail(x, m);
1022
1023                 /* ... maybe discard first sample ... */
1024                 if (pdata->settle_delay_usecs) {
1025                         x->delay_usecs = pdata->settle_delay_usecs;
1026
1027                         x++;
1028                         x->tx_buf = &ts->read_z1;
1029                         x->len = 1;
1030                         spi_message_add_tail(x, m);
1031
1032                         x++;
1033                         x->rx_buf = &ts->tc.z1;
1034                         x->len = 2;
1035                         spi_message_add_tail(x, m);
1036                 }
1037
1038                 m->complete = ads7846_rx_val;
1039                 m->context = ts;
1040
1041                 m++;
1042                 spi_message_init(m);
1043
1044                 x++;
1045                 ts->read_z2 = READ_Z2(vref);
1046                 x->tx_buf = &ts->read_z2;
1047                 x->len = 1;
1048                 spi_message_add_tail(x, m);
1049
1050                 x++;
1051                 x->rx_buf = &ts->tc.z2;
1052                 x->len = 2;
1053                 spi_message_add_tail(x, m);
1054
1055                 /* ... maybe discard first sample ... */
1056                 if (pdata->settle_delay_usecs) {
1057                         x->delay_usecs = pdata->settle_delay_usecs;
1058
1059                         x++;
1060                         x->tx_buf = &ts->read_z2;
1061                         x->len = 1;
1062                         spi_message_add_tail(x, m);
1063
1064                         x++;
1065                         x->rx_buf = &ts->tc.z2;
1066                         x->len = 2;
1067                         spi_message_add_tail(x, m);
1068                 }
1069
1070                 m->complete = ads7846_rx_val;
1071                 m->context = ts;
1072         }
1073
1074         /* power down */
1075         m++;
1076         spi_message_init(m);
1077
1078         x++;
1079         ts->pwrdown = PWRDOWN;
1080         x->tx_buf = &ts->pwrdown;
1081         x->len = 1;
1082         spi_message_add_tail(x, m);
1083
1084         x++;
1085         x->rx_buf = &ts->dummy;
1086         x->len = 2;
1087         CS_CHANGE(*x);
1088         spi_message_add_tail(x, m);
1089
1090         m->complete = ads7846_rx;
1091         m->context = ts;
1092
1093         ts->last_msg = m;
1094
1095         if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
1096                         spi->dev.driver->name, ts)) {
1097                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1098                 err = -EBUSY;
1099                 goto err_cleanup_filter;
1100         }
1101
1102         err = ads784x_hwmon_register(spi, ts);
1103         if (err)
1104                 goto err_free_irq;
1105
1106         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1107
1108         /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1109          * the touchscreen, in case it's not connected.
1110          */
1111         (void) ads7846_read12_ser(&spi->dev,
1112                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1113
1114         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1115         if (err)
1116                 goto err_remove_hwmon;
1117
1118         err = input_register_device(input_dev);
1119         if (err)
1120                 goto err_remove_attr_group;
1121
1122         return 0;
1123
1124  err_remove_attr_group:
1125         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1126  err_remove_hwmon:
1127         ads784x_hwmon_unregister(spi, ts);
1128  err_free_irq:
1129         free_irq(spi->irq, ts);
1130  err_cleanup_filter:
1131         if (ts->filter_cleanup)
1132                 ts->filter_cleanup(ts->filter_data);
1133  err_free_mem:
1134         input_free_device(input_dev);
1135         kfree(ts);
1136         return err;
1137 }
1138
1139 static int __devexit ads7846_remove(struct spi_device *spi)
1140 {
1141         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
1142
1143         ads784x_hwmon_unregister(spi, ts);
1144         input_unregister_device(ts->input);
1145
1146         ads7846_suspend(spi, PMSG_SUSPEND);
1147
1148         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1149
1150         free_irq(ts->spi->irq, ts);
1151         /* suspend left the IRQ disabled */
1152         enable_irq(ts->spi->irq);
1153
1154         if (ts->filter_cleanup)
1155                 ts->filter_cleanup(ts->filter_data);
1156
1157         kfree(ts);
1158
1159         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1160         return 0;
1161 }
1162
1163 static struct spi_driver ads7846_driver = {
1164         .driver = {
1165                 .name   = "ads7846",
1166                 .bus    = &spi_bus_type,
1167                 .owner  = THIS_MODULE,
1168         },
1169         .probe          = ads7846_probe,
1170         .remove         = __devexit_p(ads7846_remove),
1171         .suspend        = ads7846_suspend,
1172         .resume         = ads7846_resume,
1173 };
1174
1175 static int __init ads7846_init(void)
1176 {
1177         /* grr, board-specific init should stay out of drivers!! */
1178
1179 #ifdef  CONFIG_ARCH_OMAP
1180         if (machine_is_omap_osk()) {
1181                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
1182                 omap_request_gpio(4);
1183                 omap_set_gpio_direction(4, 1);
1184                 omap_request_gpio(6);
1185                 omap_set_gpio_direction(6, 1);
1186         }
1187         // also TI 1510 Innovator, bitbanging through FPGA
1188         // also Nokia 770
1189         // also Palm Tungsten T2
1190 #endif
1191
1192         // PXA:
1193         // also Dell Axim X50
1194         // also HP iPaq H191x/H192x/H415x/H435x
1195         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
1196         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
1197
1198         // Atmel at91sam9261-EK uses ads7843
1199
1200         // also various AMD Au1x00 devel boards
1201
1202         return spi_register_driver(&ads7846_driver);
1203 }
1204 module_init(ads7846_init);
1205
1206 static void __exit ads7846_exit(void)
1207 {
1208         spi_unregister_driver(&ads7846_driver);
1209
1210 #ifdef  CONFIG_ARCH_OMAP
1211         if (machine_is_omap_osk()) {
1212                 omap_free_gpio(4);
1213                 omap_free_gpio(6);
1214         }
1215 #endif
1216
1217 }
1218 module_exit(ads7846_exit);
1219
1220 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1221 MODULE_LICENSE("GPL");