Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6
[linux-2.6.git] / 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  * Support for ads7843 tested on Atmel at91sam926x-EK.
43  * Support for ads7845 has only been stubbed in.
44  *
45  * IRQ handling needs a workaround because of a shortcoming in handling
46  * edge triggered IRQs on some platforms like the OMAP1/2. These
47  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
48  * have to maintain our own SW IRQ disabled status. This should be
49  * removed as soon as the affected platform's IRQ handling is fixed.
50  *
51  * app note sbaa036 talks in more detail about accurate sampling...
52  * that ought to help in situations like LCDs inducing noise (which
53  * can also be helped by using synch signals) and more generally.
54  * This driver tries to utilize the measures described in the app
55  * note. The strength of filtering can be set in the board-* specific
56  * files.
57  */
58
59 #define TS_POLL_DELAY   (1 * 1000000)   /* ns delay before the first sample */
60 #define TS_POLL_PERIOD  (5 * 1000000)   /* ns delay between samples */
61
62 /* this driver doesn't aim at the peak continuous sample rate */
63 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
64
65 struct ts_event {
66         /* For portability, we can't read 12 bit values using SPI (which
67          * would make the controller deliver them as native byteorder u16
68          * with msbs zeroed).  Instead, we read them as two 8-bit values,
69          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
70          */
71         u16     x;
72         u16     y;
73         u16     z1, z2;
74         int     ignore;
75 };
76
77 struct ads7846 {
78         struct input_dev        *input;
79         char                    phys[32];
80
81         struct spi_device       *spi;
82
83 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
84         struct attribute_group  *attr_group;
85         struct class_device     *hwmon;
86 #endif
87
88         u16                     model;
89         u16                     vref_delay_usecs;
90         u16                     x_plate_ohms;
91         u16                     pressure_max;
92
93         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
94         u16                     dummy;          /* for the pwrdown read */
95         struct ts_event         tc;
96
97         struct spi_transfer     xfer[10];
98         struct spi_message      msg[5];
99         struct spi_message      *last_msg;
100         int                     msg_idx;
101         int                     read_cnt;
102         int                     read_rep;
103         int                     last_read;
104
105         u16                     debounce_max;
106         u16                     debounce_tol;
107         u16                     debounce_rep;
108
109         spinlock_t              lock;
110         struct hrtimer          timer;
111         unsigned                pendown:1;      /* P: lock */
112         unsigned                pending:1;      /* P: lock */
113 // FIXME remove "irq_disabled"
114         unsigned                irq_disabled:1; /* P: lock */
115         unsigned                disabled:1;
116
117         int                     (*filter)(void *data, int data_idx, int *val);
118         void                    *filter_data;
119         void                    (*filter_cleanup)(void *data);
120         int                     (*get_pendown_state)(void);
121 };
122
123 /* leave chip selected when we're done, for quicker re-select? */
124 #if     0
125 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
126 #else
127 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
128 #endif
129
130 /*--------------------------------------------------------------------------*/
131
132 /* The ADS7846 has touchscreen and other sensors.
133  * Earlier ads784x chips are somewhat compatible.
134  */
135 #define ADS_START               (1 << 7)
136 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
137 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
138 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
139 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
140 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
141 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
142 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
143 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
144 #define ADS_8_BIT               (1 << 3)
145 #define ADS_12_BIT              (0 << 3)
146 #define ADS_SER                 (1 << 2)        /* non-differential */
147 #define ADS_DFR                 (0 << 2)        /* differential */
148 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
149 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
150 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
151 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
152
153 #define MAX_12BIT       ((1<<12)-1)
154
155 /* leave ADC powered up (disables penirq) between differential samples */
156 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
157         | ADS_12_BIT | ADS_DFR | \
158         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
159
160 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
161 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
162 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
163
164 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
165 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
166
167 /* single-ended samples need to first power up reference voltage;
168  * we leave both ADC and VREF powered
169  */
170 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
171         | ADS_12_BIT | ADS_SER)
172
173 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
174 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
175
176 /*--------------------------------------------------------------------------*/
177
178 /*
179  * Non-touchscreen sensors only use single-ended conversions.
180  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
181  * ads7846 lets that pin be unconnected, to use internal vREF.
182  */
183 static unsigned vREF_mV;
184 module_param(vREF_mV, uint, 0);
185 MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts");
186
187 struct ser_req {
188         u8                      ref_on;
189         u8                      command;
190         u8                      ref_off;
191         u16                     scratch;
192         __be16                  sample;
193         struct spi_message      msg;
194         struct spi_transfer     xfer[6];
195 };
196
197 static void ads7846_enable(struct ads7846 *ts);
198 static void ads7846_disable(struct ads7846 *ts);
199
200 static int device_suspended(struct device *dev)
201 {
202         struct ads7846 *ts = dev_get_drvdata(dev);
203         return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
204 }
205
206 static int ads7846_read12_ser(struct device *dev, unsigned command)
207 {
208         struct spi_device       *spi = to_spi_device(dev);
209         struct ads7846          *ts = dev_get_drvdata(dev);
210         struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
211         int                     status;
212         int                     sample;
213         int                     use_internal;
214
215         if (!req)
216                 return -ENOMEM;
217
218         spi_message_init(&req->msg);
219
220         /* FIXME boards with ads7846 might use external vref instead ... */
221         use_internal = (ts->model == 7846);
222
223         /* maybe turn on internal vREF, and let it settle */
224         if (use_internal) {
225                 req->ref_on = REF_ON;
226                 req->xfer[0].tx_buf = &req->ref_on;
227                 req->xfer[0].len = 1;
228                 spi_message_add_tail(&req->xfer[0], &req->msg);
229
230                 req->xfer[1].rx_buf = &req->scratch;
231                 req->xfer[1].len = 2;
232
233                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
234                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
235                 spi_message_add_tail(&req->xfer[1], &req->msg);
236         }
237
238         /* take sample */
239         req->command = (u8) command;
240         req->xfer[2].tx_buf = &req->command;
241         req->xfer[2].len = 1;
242         spi_message_add_tail(&req->xfer[2], &req->msg);
243
244         req->xfer[3].rx_buf = &req->sample;
245         req->xfer[3].len = 2;
246         spi_message_add_tail(&req->xfer[3], &req->msg);
247
248         /* REVISIT:  take a few more samples, and compare ... */
249
250         /* converter in low power mode & enable PENIRQ */
251         req->ref_off = PWRDOWN;
252         req->xfer[4].tx_buf = &req->ref_off;
253         req->xfer[4].len = 1;
254         spi_message_add_tail(&req->xfer[4], &req->msg);
255
256         req->xfer[5].rx_buf = &req->scratch;
257         req->xfer[5].len = 2;
258         CS_CHANGE(req->xfer[5]);
259         spi_message_add_tail(&req->xfer[5], &req->msg);
260
261         ts->irq_disabled = 1;
262         disable_irq(spi->irq);
263         status = spi_sync(spi, &req->msg);
264         ts->irq_disabled = 0;
265         enable_irq(spi->irq);
266
267         if (req->msg.status)
268                 status = req->msg.status;
269
270         /* on-wire is a must-ignore bit, a BE12 value, then padding */
271         sample = be16_to_cpu(req->sample);
272         sample = sample >> 3;
273         sample &= 0x0fff;
274
275         kfree(req);
276         return status ? status : sample;
277 }
278
279 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
280
281 #define SHOW(name, var, adjust) static ssize_t \
282 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
283 { \
284         struct ads7846 *ts = dev_get_drvdata(dev); \
285         ssize_t v = ads7846_read12_ser(dev, \
286                         READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
287         if (v < 0) \
288                 return v; \
289         return sprintf(buf, "%u\n", adjust(ts, v)); \
290 } \
291 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
292
293
294 /* Sysfs conventions report temperatures in millidegrees Celcius.
295  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
296  * accuracy scheme without calibration data.  For now we won't try either;
297  * userspace sees raw sensor values, and must scale/calibrate appropriately.
298  */
299 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
300 {
301         return v;
302 }
303
304 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
305 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
306
307
308 /* sysfs conventions report voltages in millivolts.  We can convert voltages
309  * if we know vREF.  userspace may need to scale vAUX to match the board's
310  * external resistors; we assume that vBATT only uses the internal ones.
311  */
312 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
313 {
314         unsigned retval = v;
315
316         /* external resistors may scale vAUX into 0..vREF */
317         retval *= vREF_mV;
318         retval = retval >> 12;
319         return retval;
320 }
321
322 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
323 {
324         unsigned retval = vaux_adjust(ts, v);
325
326         /* ads7846 has a resistor ladder to scale this signal down */
327         if (ts->model == 7846)
328                 retval *= 4;
329         return retval;
330 }
331
332 SHOW(in0_input, vaux, vaux_adjust)
333 SHOW(in1_input, vbatt, vbatt_adjust)
334
335
336 static struct attribute *ads7846_attributes[] = {
337         &dev_attr_temp0.attr,
338         &dev_attr_temp1.attr,
339         &dev_attr_in0_input.attr,
340         &dev_attr_in1_input.attr,
341         NULL,
342 };
343
344 static struct attribute_group ads7846_attr_group = {
345         .attrs = ads7846_attributes,
346 };
347
348 static struct attribute *ads7843_attributes[] = {
349         &dev_attr_in0_input.attr,
350         &dev_attr_in1_input.attr,
351         NULL,
352 };
353
354 static struct attribute_group ads7843_attr_group = {
355         .attrs = ads7843_attributes,
356 };
357
358 static struct attribute *ads7845_attributes[] = {
359         &dev_attr_in0_input.attr,
360         NULL,
361 };
362
363 static struct attribute_group ads7845_attr_group = {
364         .attrs = ads7845_attributes,
365 };
366
367 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
368 {
369         struct class_device *hwmon;
370         int err;
371
372         /* hwmon sensors need a reference voltage */
373         switch (ts->model) {
374         case 7846:
375                 if (!vREF_mV) {
376                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
377                         vREF_mV = 2500;
378                 }
379                 break;
380         case 7845:
381         case 7843:
382                 if (!vREF_mV) {
383                         dev_warn(&spi->dev,
384                                 "external vREF for ADS%d not specified\n",
385                                 ts->model);
386                         return 0;
387                 }
388                 break;
389         }
390
391         /* different chips have different sensor groups */
392         switch (ts->model) {
393         case 7846:
394                 ts->attr_group = &ads7846_attr_group;
395                 break;
396         case 7845:
397                 ts->attr_group = &ads7845_attr_group;
398                 break;
399         case 7843:
400                 ts->attr_group = &ads7843_attr_group;
401                 break;
402         default:
403                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
404                 return 0;
405         }
406
407         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
408         if (err)
409                 return err;
410
411         hwmon = hwmon_device_register(&spi->dev);
412         if (IS_ERR(hwmon)) {
413                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
414                 return PTR_ERR(hwmon);
415         }
416
417         ts->hwmon = hwmon;
418         return 0;
419 }
420
421 static void ads784x_hwmon_unregister(struct spi_device *spi,
422                                      struct ads7846 *ts)
423 {
424         if (ts->hwmon) {
425                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
426                 hwmon_device_unregister(ts->hwmon);
427         }
428 }
429
430 #else
431 static inline int ads784x_hwmon_register(struct spi_device *spi,
432                                          struct ads7846 *ts)
433 {
434         return 0;
435 }
436
437 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
438                                             struct ads7846 *ts)
439 {
440 }
441 #endif
442
443 static int is_pen_down(struct device *dev)
444 {
445         struct ads7846  *ts = dev_get_drvdata(dev);
446
447         return ts->pendown;
448 }
449
450 static ssize_t ads7846_pen_down_show(struct device *dev,
451                                      struct device_attribute *attr, char *buf)
452 {
453         return sprintf(buf, "%u\n", is_pen_down(dev));
454 }
455
456 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
457
458 static ssize_t ads7846_disable_show(struct device *dev,
459                                      struct device_attribute *attr, char *buf)
460 {
461         struct ads7846  *ts = dev_get_drvdata(dev);
462
463         return sprintf(buf, "%u\n", ts->disabled);
464 }
465
466 static ssize_t ads7846_disable_store(struct device *dev,
467                                      struct device_attribute *attr,
468                                      const char *buf, size_t count)
469 {
470         struct ads7846 *ts = dev_get_drvdata(dev);
471         char *endp;
472         int i;
473
474         i = simple_strtoul(buf, &endp, 10);
475         spin_lock_irq(&ts->lock);
476
477         if (i)
478                 ads7846_disable(ts);
479         else
480                 ads7846_enable(ts);
481
482         spin_unlock_irq(&ts->lock);
483
484         return count;
485 }
486
487 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
488
489 static struct attribute *ads784x_attributes[] = {
490         &dev_attr_pen_down.attr,
491         &dev_attr_disable.attr,
492         NULL,
493 };
494
495 static struct attribute_group ads784x_attr_group = {
496         .attrs = ads784x_attributes,
497 };
498
499 /*--------------------------------------------------------------------------*/
500
501 /*
502  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
503  * to retrieve touchscreen status.
504  *
505  * The SPI transfer completion callback does the real work.  It reports
506  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
507  */
508
509 static void ads7846_rx(void *ads)
510 {
511         struct ads7846          *ts = ads;
512         unsigned                Rt;
513         u16                     x, y, z1, z2;
514
515         /* ads7846_rx_val() did in-place conversion (including byteswap) from
516          * on-the-wire format as part of debouncing to get stable readings.
517          */
518         x = ts->tc.x;
519         y = ts->tc.y;
520         z1 = ts->tc.z1;
521         z2 = ts->tc.z2;
522
523         /* range filtering */
524         if (x == MAX_12BIT)
525                 x = 0;
526
527         if (likely(x && z1)) {
528                 /* compute touch pressure resistance using equation #2 */
529                 Rt = z2;
530                 Rt -= z1;
531                 Rt *= x;
532                 Rt *= ts->x_plate_ohms;
533                 Rt /= z1;
534                 Rt = (Rt + 2047) >> 12;
535         } else
536                 Rt = 0;
537
538         if (ts->model == 7843)
539                 Rt = ts->pressure_max / 2;
540
541         /* Sample found inconsistent by debouncing or pressure is beyond
542          * the maximum. Don't report it to user space, repeat at least
543          * once more the measurement
544          */
545         if (ts->tc.ignore || Rt > ts->pressure_max) {
546 #ifdef VERBOSE
547                 pr_debug("%s: ignored %d pressure %d\n",
548                         ts->spi->dev.bus_id, ts->tc.ignore, Rt);
549 #endif
550                 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
551                               HRTIMER_MODE_REL);
552                 return;
553         }
554
555         /* NOTE: We can't rely on the pressure to determine the pen down
556          * state, even this controller has a pressure sensor.  The pressure
557          * value can fluctuate for quite a while after lifting the pen and
558          * in some cases may not even settle at the expected value.
559          *
560          * The only safe way to check for the pen up condition is in the
561          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
562          */
563         if (Rt) {
564                 struct input_dev *input = ts->input;
565
566                 if (!ts->pendown) {
567                         input_report_key(input, BTN_TOUCH, 1);
568                         ts->pendown = 1;
569 #ifdef VERBOSE
570                         dev_dbg(&ts->spi->dev, "DOWN\n");
571 #endif
572                 }
573                 input_report_abs(input, ABS_X, x);
574                 input_report_abs(input, ABS_Y, y);
575                 input_report_abs(input, ABS_PRESSURE, Rt);
576
577                 input_sync(input);
578 #ifdef VERBOSE
579                 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
580 #endif
581         }
582
583         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
584                         HRTIMER_MODE_REL);
585 }
586
587 static int ads7846_debounce(void *ads, int data_idx, int *val)
588 {
589         struct ads7846          *ts = ads;
590
591         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
592                 /* Start over collecting consistent readings. */
593                 ts->read_rep = 0;
594                 /* Repeat it, if this was the first read or the read
595                  * wasn't consistent enough. */
596                 if (ts->read_cnt < ts->debounce_max) {
597                         ts->last_read = *val;
598                         ts->read_cnt++;
599                         return ADS7846_FILTER_REPEAT;
600                 } else {
601                         /* Maximum number of debouncing reached and still
602                          * not enough number of consistent readings. Abort
603                          * the whole sample, repeat it in the next sampling
604                          * period.
605                          */
606                         ts->read_cnt = 0;
607                         return ADS7846_FILTER_IGNORE;
608                 }
609         } else {
610                 if (++ts->read_rep > ts->debounce_rep) {
611                         /* Got a good reading for this coordinate,
612                          * go for the next one. */
613                         ts->read_cnt = 0;
614                         ts->read_rep = 0;
615                         return ADS7846_FILTER_OK;
616                 } else {
617                         /* Read more values that are consistent. */
618                         ts->read_cnt++;
619                         return ADS7846_FILTER_REPEAT;
620                 }
621         }
622 }
623
624 static int ads7846_no_filter(void *ads, int data_idx, int *val)
625 {
626         return ADS7846_FILTER_OK;
627 }
628
629 static void ads7846_rx_val(void *ads)
630 {
631         struct ads7846 *ts = ads;
632         struct spi_message *m;
633         struct spi_transfer *t;
634         u16 *rx_val;
635         int val;
636         int action;
637         int status;
638
639         m = &ts->msg[ts->msg_idx];
640         t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
641         rx_val = t->rx_buf;
642
643         /* adjust:  on-wire is a must-ignore bit, a BE12 value, then padding;
644          * built from two 8 bit values written msb-first.
645          */
646         val = be16_to_cpu(*rx_val) >> 3;
647
648         action = ts->filter(ts->filter_data, ts->msg_idx, &val);
649         switch (action) {
650         case ADS7846_FILTER_REPEAT:
651                 break;
652         case ADS7846_FILTER_IGNORE:
653                 ts->tc.ignore = 1;
654                 /* Last message will contain ads7846_rx() as the
655                  * completion function.
656                  */
657                 m = ts->last_msg;
658                 break;
659         case ADS7846_FILTER_OK:
660                 *rx_val = val;
661                 ts->tc.ignore = 0;
662                 m = &ts->msg[++ts->msg_idx];
663                 break;
664         default:
665                 BUG();
666         }
667         status = spi_async(ts->spi, m);
668         if (status)
669                 dev_err(&ts->spi->dev, "spi_async --> %d\n",
670                                 status);
671 }
672
673 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
674 {
675         struct ads7846  *ts = container_of(handle, struct ads7846, timer);
676         int             status = 0;
677
678         spin_lock_irq(&ts->lock);
679
680         if (unlikely(!ts->get_pendown_state() ||
681                      device_suspended(&ts->spi->dev))) {
682                 if (ts->pendown) {
683                         struct input_dev *input = ts->input;
684
685                         input_report_key(input, BTN_TOUCH, 0);
686                         input_report_abs(input, ABS_PRESSURE, 0);
687                         input_sync(input);
688
689                         ts->pendown = 0;
690 #ifdef VERBOSE
691                         dev_dbg(&ts->spi->dev, "UP\n");
692 #endif
693                 }
694
695                 /* measurement cycle ended */
696                 if (!device_suspended(&ts->spi->dev)) {
697                         ts->irq_disabled = 0;
698                         enable_irq(ts->spi->irq);
699                 }
700                 ts->pending = 0;
701         } else {
702                 /* pen is still down, continue with the measurement */
703                 ts->msg_idx = 0;
704                 status = spi_async(ts->spi, &ts->msg[0]);
705                 if (status)
706                         dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
707         }
708
709         spin_unlock_irq(&ts->lock);
710         return HRTIMER_NORESTART;
711 }
712
713 static irqreturn_t ads7846_irq(int irq, void *handle)
714 {
715         struct ads7846 *ts = handle;
716         unsigned long flags;
717
718         spin_lock_irqsave(&ts->lock, flags);
719         if (likely(ts->get_pendown_state())) {
720                 if (!ts->irq_disabled) {
721                         /* The ARM do_simple_IRQ() dispatcher doesn't act
722                          * like the other dispatchers:  it will report IRQs
723                          * even after they've been disabled.  We work around
724                          * that here.  (The "generic irq" framework may help...)
725                          */
726                         ts->irq_disabled = 1;
727                         disable_irq(ts->spi->irq);
728                         ts->pending = 1;
729                         hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
730                                         HRTIMER_MODE_REL);
731                 }
732         }
733         spin_unlock_irqrestore(&ts->lock, flags);
734
735         return IRQ_HANDLED;
736 }
737
738 /*--------------------------------------------------------------------------*/
739
740 /* Must be called with ts->lock held */
741 static void ads7846_disable(struct ads7846 *ts)
742 {
743         if (ts->disabled)
744                 return;
745
746         ts->disabled = 1;
747
748         /* are we waiting for IRQ, or polling? */
749         if (!ts->pending) {
750                 ts->irq_disabled = 1;
751                 disable_irq(ts->spi->irq);
752         } else {
753                 /* the timer will run at least once more, and
754                  * leave everything in a clean state, IRQ disabled
755                  */
756                 while (ts->pending) {
757                         spin_unlock_irq(&ts->lock);
758                         msleep(1);
759                         spin_lock_irq(&ts->lock);
760                 }
761         }
762
763         /* we know the chip's in lowpower mode since we always
764          * leave it that way after every request
765          */
766
767 }
768
769 /* Must be called with ts->lock held */
770 static void ads7846_enable(struct ads7846 *ts)
771 {
772         if (!ts->disabled)
773                 return;
774
775         ts->disabled = 0;
776         ts->irq_disabled = 0;
777         enable_irq(ts->spi->irq);
778 }
779
780 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
781 {
782         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
783
784         spin_lock_irq(&ts->lock);
785
786         spi->dev.power.power_state = message;
787         ads7846_disable(ts);
788
789         spin_unlock_irq(&ts->lock);
790
791         return 0;
792
793 }
794
795 static int ads7846_resume(struct spi_device *spi)
796 {
797         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
798
799         spin_lock_irq(&ts->lock);
800
801         spi->dev.power.power_state = PMSG_ON;
802         ads7846_enable(ts);
803
804         spin_unlock_irq(&ts->lock);
805
806         return 0;
807 }
808
809 static int __devinit ads7846_probe(struct spi_device *spi)
810 {
811         struct ads7846                  *ts;
812         struct input_dev                *input_dev;
813         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
814         struct spi_message              *m;
815         struct spi_transfer             *x;
816         int                             vref;
817         int                             err;
818
819         if (!spi->irq) {
820                 dev_dbg(&spi->dev, "no IRQ?\n");
821                 return -ENODEV;
822         }
823
824         if (!pdata) {
825                 dev_dbg(&spi->dev, "no platform data?\n");
826                 return -ENODEV;
827         }
828
829         /* don't exceed max specified sample rate */
830         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
831                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
832                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
833                 return -EINVAL;
834         }
835
836         /* REVISIT when the irq can be triggered active-low, or if for some
837          * reason the touchscreen isn't hooked up, we don't need to access
838          * the pendown state.
839          */
840         if (pdata->get_pendown_state == NULL) {
841                 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
842                 return -EINVAL;
843         }
844
845         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
846          * that even if the hardware can do that, the SPI controller driver
847          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
848          */
849         spi->bits_per_word = 8;
850         spi->mode = SPI_MODE_1;
851         err = spi_setup(spi);
852         if (err < 0)
853                 return err;
854
855         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
856         input_dev = input_allocate_device();
857         if (!ts || !input_dev) {
858                 err = -ENOMEM;
859                 goto err_free_mem;
860         }
861
862         dev_set_drvdata(&spi->dev, ts);
863         spi->dev.power.power_state = PMSG_ON;
864
865         ts->spi = spi;
866         ts->input = input_dev;
867
868         hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
869         ts->timer.function = ads7846_timer;
870
871         spin_lock_init(&ts->lock);
872
873         ts->model = pdata->model ? : 7846;
874         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
875         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
876         ts->pressure_max = pdata->pressure_max ? : ~0;
877
878         if (pdata->filter != NULL) {
879                 if (pdata->filter_init != NULL) {
880                         err = pdata->filter_init(pdata, &ts->filter_data);
881                         if (err < 0)
882                                 goto err_free_mem;
883                 }
884                 ts->filter = pdata->filter;
885                 ts->filter_cleanup = pdata->filter_cleanup;
886         } else if (pdata->debounce_max) {
887                 ts->debounce_max = pdata->debounce_max;
888                 if (ts->debounce_max < 2)
889                         ts->debounce_max = 2;
890                 ts->debounce_tol = pdata->debounce_tol;
891                 ts->debounce_rep = pdata->debounce_rep;
892                 ts->filter = ads7846_debounce;
893                 ts->filter_data = ts;
894         } else
895                 ts->filter = ads7846_no_filter;
896         ts->get_pendown_state = pdata->get_pendown_state;
897
898         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
899
900         input_dev->name = "ADS784x Touchscreen";
901         input_dev->phys = ts->phys;
902         input_dev->dev.parent = &spi->dev;
903
904         input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
905         input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
906         input_set_abs_params(input_dev, ABS_X,
907                         pdata->x_min ? : 0,
908                         pdata->x_max ? : MAX_12BIT,
909                         0, 0);
910         input_set_abs_params(input_dev, ABS_Y,
911                         pdata->y_min ? : 0,
912                         pdata->y_max ? : MAX_12BIT,
913                         0, 0);
914         input_set_abs_params(input_dev, ABS_PRESSURE,
915                         pdata->pressure_min, pdata->pressure_max, 0, 0);
916
917         vref = pdata->keep_vref_on;
918
919         /* set up the transfers to read touchscreen state; this assumes we
920          * use formula #2 for pressure, not #3.
921          */
922         m = &ts->msg[0];
923         x = ts->xfer;
924
925         spi_message_init(m);
926
927         /* y- still on; turn on only y+ (and ADC) */
928         ts->read_y = READ_Y(vref);
929         x->tx_buf = &ts->read_y;
930         x->len = 1;
931         spi_message_add_tail(x, m);
932
933         x++;
934         x->rx_buf = &ts->tc.y;
935         x->len = 2;
936         spi_message_add_tail(x, m);
937
938         m->complete = ads7846_rx_val;
939         m->context = ts;
940
941         m++;
942         spi_message_init(m);
943
944         /* turn y- off, x+ on, then leave in lowpower */
945         x++;
946         ts->read_x = READ_X(vref);
947         x->tx_buf = &ts->read_x;
948         x->len = 1;
949         spi_message_add_tail(x, m);
950
951         x++;
952         x->rx_buf = &ts->tc.x;
953         x->len = 2;
954         spi_message_add_tail(x, m);
955
956         m->complete = ads7846_rx_val;
957         m->context = ts;
958
959         /* turn y+ off, x- on; we'll use formula #2 */
960         if (ts->model == 7846) {
961                 m++;
962                 spi_message_init(m);
963
964                 x++;
965                 ts->read_z1 = READ_Z1(vref);
966                 x->tx_buf = &ts->read_z1;
967                 x->len = 1;
968                 spi_message_add_tail(x, m);
969
970                 x++;
971                 x->rx_buf = &ts->tc.z1;
972                 x->len = 2;
973                 spi_message_add_tail(x, m);
974
975                 m->complete = ads7846_rx_val;
976                 m->context = ts;
977
978                 m++;
979                 spi_message_init(m);
980
981                 x++;
982                 ts->read_z2 = READ_Z2(vref);
983                 x->tx_buf = &ts->read_z2;
984                 x->len = 1;
985                 spi_message_add_tail(x, m);
986
987                 x++;
988                 x->rx_buf = &ts->tc.z2;
989                 x->len = 2;
990                 spi_message_add_tail(x, m);
991
992                 m->complete = ads7846_rx_val;
993                 m->context = ts;
994         }
995
996         /* power down */
997         m++;
998         spi_message_init(m);
999
1000         x++;
1001         ts->pwrdown = PWRDOWN;
1002         x->tx_buf = &ts->pwrdown;
1003         x->len = 1;
1004         spi_message_add_tail(x, m);
1005
1006         x++;
1007         x->rx_buf = &ts->dummy;
1008         x->len = 2;
1009         CS_CHANGE(*x);
1010         spi_message_add_tail(x, m);
1011
1012         m->complete = ads7846_rx;
1013         m->context = ts;
1014
1015         ts->last_msg = m;
1016
1017         if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
1018                         spi->dev.driver->name, ts)) {
1019                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1020                 err = -EBUSY;
1021                 goto err_cleanup_filter;
1022         }
1023
1024         err = ads784x_hwmon_register(spi, ts);
1025         if (err)
1026                 goto err_free_irq;
1027
1028         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1029
1030         /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1031          * the touchscreen, in case it's not connected.
1032          */
1033         (void) ads7846_read12_ser(&spi->dev,
1034                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1035
1036         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1037         if (err)
1038                 goto err_remove_hwmon;
1039
1040         err = input_register_device(input_dev);
1041         if (err)
1042                 goto err_remove_attr_group;
1043
1044         return 0;
1045
1046  err_remove_attr_group:
1047         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1048  err_remove_hwmon:
1049         ads784x_hwmon_unregister(spi, ts);
1050  err_free_irq:
1051         free_irq(spi->irq, ts);
1052  err_cleanup_filter:
1053         if (ts->filter_cleanup)
1054                 ts->filter_cleanup(ts->filter_data);
1055  err_free_mem:
1056         input_free_device(input_dev);
1057         kfree(ts);
1058         return err;
1059 }
1060
1061 static int __devexit ads7846_remove(struct spi_device *spi)
1062 {
1063         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
1064
1065         ads784x_hwmon_unregister(spi, ts);
1066         input_unregister_device(ts->input);
1067
1068         ads7846_suspend(spi, PMSG_SUSPEND);
1069
1070         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1071
1072         free_irq(ts->spi->irq, ts);
1073         /* suspend left the IRQ disabled */
1074         enable_irq(ts->spi->irq);
1075
1076         if (ts->filter_cleanup)
1077                 ts->filter_cleanup(ts->filter_data);
1078
1079         kfree(ts);
1080
1081         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1082         return 0;
1083 }
1084
1085 static struct spi_driver ads7846_driver = {
1086         .driver = {
1087                 .name   = "ads7846",
1088                 .bus    = &spi_bus_type,
1089                 .owner  = THIS_MODULE,
1090         },
1091         .probe          = ads7846_probe,
1092         .remove         = __devexit_p(ads7846_remove),
1093         .suspend        = ads7846_suspend,
1094         .resume         = ads7846_resume,
1095 };
1096
1097 static int __init ads7846_init(void)
1098 {
1099         /* grr, board-specific init should stay out of drivers!! */
1100
1101 #ifdef  CONFIG_ARCH_OMAP
1102         if (machine_is_omap_osk()) {
1103                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
1104                 omap_request_gpio(4);
1105                 omap_set_gpio_direction(4, 1);
1106                 omap_request_gpio(6);
1107                 omap_set_gpio_direction(6, 1);
1108         }
1109         // also TI 1510 Innovator, bitbanging through FPGA
1110         // also Nokia 770
1111         // also Palm Tungsten T2
1112 #endif
1113
1114         // PXA:
1115         // also Dell Axim X50
1116         // also HP iPaq H191x/H192x/H415x/H435x
1117         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
1118         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
1119
1120         // Atmel at91sam9261-EK uses ads7843
1121
1122         // also various AMD Au1x00 devel boards
1123
1124         return spi_register_driver(&ads7846_driver);
1125 }
1126 module_init(ads7846_init);
1127
1128 static void __exit ads7846_exit(void)
1129 {
1130         spi_unregister_driver(&ads7846_driver);
1131
1132 #ifdef  CONFIG_ARCH_OMAP
1133         if (machine_is_omap_osk()) {
1134                 omap_free_gpio(4);
1135                 omap_free_gpio(6);
1136         }
1137 #endif
1138
1139 }
1140 module_exit(ads7846_exit);
1141
1142 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1143 MODULE_LICENSE("GPL");