Merge branch 'next' into for-linus
[sfrench/cifs-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/types.h>
21 #include <linux/hwmon.h>
22 #include <linux/init.h>
23 #include <linux/err.h>
24 #include <linux/sched.h>
25 #include <linux/delay.h>
26 #include <linux/input.h>
27 #include <linux/interrupt.h>
28 #include <linux/slab.h>
29 #include <linux/pm.h>
30 #include <linux/gpio.h>
31 #include <linux/spi/spi.h>
32 #include <linux/spi/ads7846.h>
33 #include <linux/regulator/consumer.h>
34 #include <asm/irq.h>
35
36 /*
37  * This code has been heavily tested on a Nokia 770, and lightly
38  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
39  * TSC2046 is just newer ads7846 silicon.
40  * Support for ads7843 tested on Atmel at91sam926x-EK.
41  * Support for ads7845 has only been stubbed in.
42  * Support for Analog Devices AD7873 and AD7843 tested.
43  *
44  * IRQ handling needs a workaround because of a shortcoming in handling
45  * edge triggered IRQs on some platforms like the OMAP1/2. These
46  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
47  * have to maintain our own SW IRQ disabled status. This should be
48  * removed as soon as the affected platform's IRQ handling is fixed.
49  *
50  * App note sbaa036 talks in more detail about accurate sampling...
51  * that ought to help in situations like LCDs inducing noise (which
52  * can also be helped by using synch signals) and more generally.
53  * This driver tries to utilize the measures described in the app
54  * note. The strength of filtering can be set in the board-* specific
55  * files.
56  */
57
58 #define TS_POLL_DELAY   1       /* ms delay before the first sample */
59 #define TS_POLL_PERIOD  5       /* ms delay between samples */
60
61 /* this driver doesn't aim at the peak continuous sample rate */
62 #define SAMPLE_BITS     (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
63
64 struct ts_event {
65         /*
66          * For portability, we can't read 12 bit values using SPI (which
67          * would make the controller deliver them as native byte order u16
68          * with msbs zeroed).  Instead, we read them as two 8-bit values,
69          * *** WHICH NEED BYTESWAPPING *** and range adjustment.
70          */
71         u16     x;
72         u16     y;
73         u16     z1, z2;
74         bool    ignore;
75         u8      x_buf[3];
76         u8      y_buf[3];
77 };
78
79 /*
80  * We allocate this separately to avoid cache line sharing issues when
81  * driver is used with DMA-based SPI controllers (like atmel_spi) on
82  * systems where main memory is not DMA-coherent (most non-x86 boards).
83  */
84 struct ads7846_packet {
85         u8                      read_x, read_y, read_z1, read_z2, pwrdown;
86         u16                     dummy;          /* for the pwrdown read */
87         struct ts_event         tc;
88         /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
89         u8                      read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
90 };
91
92 struct ads7846 {
93         struct input_dev        *input;
94         char                    phys[32];
95         char                    name[32];
96
97         struct spi_device       *spi;
98         struct regulator        *reg;
99
100 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
101         struct attribute_group  *attr_group;
102         struct device           *hwmon;
103 #endif
104
105         u16                     model;
106         u16                     vref_mv;
107         u16                     vref_delay_usecs;
108         u16                     x_plate_ohms;
109         u16                     pressure_max;
110
111         bool                    swap_xy;
112         bool                    use_internal;
113
114         struct ads7846_packet   *packet;
115
116         struct spi_transfer     xfer[18];
117         struct spi_message      msg[5];
118         int                     msg_count;
119         wait_queue_head_t       wait;
120
121         bool                    pendown;
122
123         int                     read_cnt;
124         int                     read_rep;
125         int                     last_read;
126
127         u16                     debounce_max;
128         u16                     debounce_tol;
129         u16                     debounce_rep;
130
131         u16                     penirq_recheck_delay_usecs;
132
133         struct mutex            lock;
134         bool                    stopped;        /* P: lock */
135         bool                    disabled;       /* P: lock */
136         bool                    suspended;      /* P: lock */
137
138         int                     (*filter)(void *data, int data_idx, int *val);
139         void                    *filter_data;
140         void                    (*filter_cleanup)(void *data);
141         int                     (*get_pendown_state)(void);
142         int                     gpio_pendown;
143
144         void                    (*wait_for_sync)(void);
145 };
146
147 /* leave chip selected when we're done, for quicker re-select? */
148 #if     0
149 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
150 #else
151 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
152 #endif
153
154 /*--------------------------------------------------------------------------*/
155
156 /* The ADS7846 has touchscreen and other sensors.
157  * Earlier ads784x chips are somewhat compatible.
158  */
159 #define ADS_START               (1 << 7)
160 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
161 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
162 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
163 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
164 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
165 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
166 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
167 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
168 #define ADS_8_BIT               (1 << 3)
169 #define ADS_12_BIT              (0 << 3)
170 #define ADS_SER                 (1 << 2)        /* non-differential */
171 #define ADS_DFR                 (0 << 2)        /* differential */
172 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
173 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
174 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
175 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
176
177 #define MAX_12BIT       ((1<<12)-1)
178
179 /* leave ADC powered up (disables penirq) between differential samples */
180 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
181         | ADS_12_BIT | ADS_DFR | \
182         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
183
184 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
185 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
186 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
187
188 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
189 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
190
191 /* single-ended samples need to first power up reference voltage;
192  * we leave both ADC and VREF powered
193  */
194 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
195         | ADS_12_BIT | ADS_SER)
196
197 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
198 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
199
200 /* Must be called with ts->lock held */
201 static void ads7846_stop(struct ads7846 *ts)
202 {
203         if (!ts->disabled && !ts->suspended) {
204                 /* Signal IRQ thread to stop polling and disable the handler. */
205                 ts->stopped = true;
206                 mb();
207                 wake_up(&ts->wait);
208                 disable_irq(ts->spi->irq);
209         }
210 }
211
212 /* Must be called with ts->lock held */
213 static void ads7846_restart(struct ads7846 *ts)
214 {
215         if (!ts->disabled && !ts->suspended) {
216                 /* Tell IRQ thread that it may poll the device. */
217                 ts->stopped = false;
218                 mb();
219                 enable_irq(ts->spi->irq);
220         }
221 }
222
223 /* Must be called with ts->lock held */
224 static void __ads7846_disable(struct ads7846 *ts)
225 {
226         ads7846_stop(ts);
227         regulator_disable(ts->reg);
228
229         /*
230          * We know the chip's in low power mode since we always
231          * leave it that way after every request
232          */
233 }
234
235 /* Must be called with ts->lock held */
236 static void __ads7846_enable(struct ads7846 *ts)
237 {
238         regulator_enable(ts->reg);
239         ads7846_restart(ts);
240 }
241
242 static void ads7846_disable(struct ads7846 *ts)
243 {
244         mutex_lock(&ts->lock);
245
246         if (!ts->disabled) {
247
248                 if  (!ts->suspended)
249                         __ads7846_disable(ts);
250
251                 ts->disabled = true;
252         }
253
254         mutex_unlock(&ts->lock);
255 }
256
257 static void ads7846_enable(struct ads7846 *ts)
258 {
259         mutex_lock(&ts->lock);
260
261         if (ts->disabled) {
262
263                 ts->disabled = false;
264
265                 if (!ts->suspended)
266                         __ads7846_enable(ts);
267         }
268
269         mutex_unlock(&ts->lock);
270 }
271
272 /*--------------------------------------------------------------------------*/
273
274 /*
275  * Non-touchscreen sensors only use single-ended conversions.
276  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
277  * ads7846 lets that pin be unconnected, to use internal vREF.
278  */
279
280 struct ser_req {
281         u8                      ref_on;
282         u8                      command;
283         u8                      ref_off;
284         u16                     scratch;
285         struct spi_message      msg;
286         struct spi_transfer     xfer[6];
287         /*
288          * DMA (thus cache coherency maintenance) requires the
289          * transfer buffers to live in their own cache lines.
290          */
291         __be16 sample ____cacheline_aligned;
292 };
293
294 struct ads7845_ser_req {
295         u8                      command[3];
296         struct spi_message      msg;
297         struct spi_transfer     xfer[2];
298         /*
299          * DMA (thus cache coherency maintenance) requires the
300          * transfer buffers to live in their own cache lines.
301          */
302         u8 sample[3] ____cacheline_aligned;
303 };
304
305 static int ads7846_read12_ser(struct device *dev, unsigned command)
306 {
307         struct spi_device *spi = to_spi_device(dev);
308         struct ads7846 *ts = dev_get_drvdata(dev);
309         struct ser_req *req;
310         int status;
311
312         req = kzalloc(sizeof *req, GFP_KERNEL);
313         if (!req)
314                 return -ENOMEM;
315
316         spi_message_init(&req->msg);
317
318         /* maybe turn on internal vREF, and let it settle */
319         if (ts->use_internal) {
320                 req->ref_on = REF_ON;
321                 req->xfer[0].tx_buf = &req->ref_on;
322                 req->xfer[0].len = 1;
323                 spi_message_add_tail(&req->xfer[0], &req->msg);
324
325                 req->xfer[1].rx_buf = &req->scratch;
326                 req->xfer[1].len = 2;
327
328                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
329                 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
330                 spi_message_add_tail(&req->xfer[1], &req->msg);
331
332                 /* Enable reference voltage */
333                 command |= ADS_PD10_REF_ON;
334         }
335
336         /* Enable ADC in every case */
337         command |= ADS_PD10_ADC_ON;
338
339         /* take sample */
340         req->command = (u8) command;
341         req->xfer[2].tx_buf = &req->command;
342         req->xfer[2].len = 1;
343         spi_message_add_tail(&req->xfer[2], &req->msg);
344
345         req->xfer[3].rx_buf = &req->sample;
346         req->xfer[3].len = 2;
347         spi_message_add_tail(&req->xfer[3], &req->msg);
348
349         /* REVISIT:  take a few more samples, and compare ... */
350
351         /* converter in low power mode & enable PENIRQ */
352         req->ref_off = PWRDOWN;
353         req->xfer[4].tx_buf = &req->ref_off;
354         req->xfer[4].len = 1;
355         spi_message_add_tail(&req->xfer[4], &req->msg);
356
357         req->xfer[5].rx_buf = &req->scratch;
358         req->xfer[5].len = 2;
359         CS_CHANGE(req->xfer[5]);
360         spi_message_add_tail(&req->xfer[5], &req->msg);
361
362         mutex_lock(&ts->lock);
363         ads7846_stop(ts);
364         status = spi_sync(spi, &req->msg);
365         ads7846_restart(ts);
366         mutex_unlock(&ts->lock);
367
368         if (status == 0) {
369                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
370                 status = be16_to_cpu(req->sample);
371                 status = status >> 3;
372                 status &= 0x0fff;
373         }
374
375         kfree(req);
376         return status;
377 }
378
379 static int ads7845_read12_ser(struct device *dev, unsigned command)
380 {
381         struct spi_device *spi = to_spi_device(dev);
382         struct ads7846 *ts = dev_get_drvdata(dev);
383         struct ads7845_ser_req *req;
384         int status;
385
386         req = kzalloc(sizeof *req, GFP_KERNEL);
387         if (!req)
388                 return -ENOMEM;
389
390         spi_message_init(&req->msg);
391
392         req->command[0] = (u8) command;
393         req->xfer[0].tx_buf = req->command;
394         req->xfer[0].rx_buf = req->sample;
395         req->xfer[0].len = 3;
396         spi_message_add_tail(&req->xfer[0], &req->msg);
397
398         mutex_lock(&ts->lock);
399         ads7846_stop(ts);
400         status = spi_sync(spi, &req->msg);
401         ads7846_restart(ts);
402         mutex_unlock(&ts->lock);
403
404         if (status == 0) {
405                 /* BE12 value, then padding */
406                 status = be16_to_cpu(*((u16 *)&req->sample[1]));
407                 status = status >> 3;
408                 status &= 0x0fff;
409         }
410
411         kfree(req);
412         return status;
413 }
414
415 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
416
417 #define SHOW(name, var, adjust) static ssize_t \
418 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
419 { \
420         struct ads7846 *ts = dev_get_drvdata(dev); \
421         ssize_t v = ads7846_read12_ser(dev, \
422                         READ_12BIT_SER(var)); \
423         if (v < 0) \
424                 return v; \
425         return sprintf(buf, "%u\n", adjust(ts, v)); \
426 } \
427 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
428
429
430 /* Sysfs conventions report temperatures in millidegrees Celsius.
431  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
432  * accuracy scheme without calibration data.  For now we won't try either;
433  * userspace sees raw sensor values, and must scale/calibrate appropriately.
434  */
435 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
436 {
437         return v;
438 }
439
440 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
441 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
442
443
444 /* sysfs conventions report voltages in millivolts.  We can convert voltages
445  * if we know vREF.  userspace may need to scale vAUX to match the board's
446  * external resistors; we assume that vBATT only uses the internal ones.
447  */
448 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
449 {
450         unsigned retval = v;
451
452         /* external resistors may scale vAUX into 0..vREF */
453         retval *= ts->vref_mv;
454         retval = retval >> 12;
455
456         return retval;
457 }
458
459 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
460 {
461         unsigned retval = vaux_adjust(ts, v);
462
463         /* ads7846 has a resistor ladder to scale this signal down */
464         if (ts->model == 7846)
465                 retval *= 4;
466
467         return retval;
468 }
469
470 SHOW(in0_input, vaux, vaux_adjust)
471 SHOW(in1_input, vbatt, vbatt_adjust)
472
473 static struct attribute *ads7846_attributes[] = {
474         &dev_attr_temp0.attr,
475         &dev_attr_temp1.attr,
476         &dev_attr_in0_input.attr,
477         &dev_attr_in1_input.attr,
478         NULL,
479 };
480
481 static struct attribute_group ads7846_attr_group = {
482         .attrs = ads7846_attributes,
483 };
484
485 static struct attribute *ads7843_attributes[] = {
486         &dev_attr_in0_input.attr,
487         &dev_attr_in1_input.attr,
488         NULL,
489 };
490
491 static struct attribute_group ads7843_attr_group = {
492         .attrs = ads7843_attributes,
493 };
494
495 static struct attribute *ads7845_attributes[] = {
496         &dev_attr_in0_input.attr,
497         NULL,
498 };
499
500 static struct attribute_group ads7845_attr_group = {
501         .attrs = ads7845_attributes,
502 };
503
504 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
505 {
506         struct device *hwmon;
507         int err;
508
509         /* hwmon sensors need a reference voltage */
510         switch (ts->model) {
511         case 7846:
512                 if (!ts->vref_mv) {
513                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
514                         ts->vref_mv = 2500;
515                         ts->use_internal = true;
516                 }
517                 break;
518         case 7845:
519         case 7843:
520                 if (!ts->vref_mv) {
521                         dev_warn(&spi->dev,
522                                 "external vREF for ADS%d not specified\n",
523                                 ts->model);
524                         return 0;
525                 }
526                 break;
527         }
528
529         /* different chips have different sensor groups */
530         switch (ts->model) {
531         case 7846:
532                 ts->attr_group = &ads7846_attr_group;
533                 break;
534         case 7845:
535                 ts->attr_group = &ads7845_attr_group;
536                 break;
537         case 7843:
538                 ts->attr_group = &ads7843_attr_group;
539                 break;
540         default:
541                 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
542                 return 0;
543         }
544
545         err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
546         if (err)
547                 return err;
548
549         hwmon = hwmon_device_register(&spi->dev);
550         if (IS_ERR(hwmon)) {
551                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
552                 return PTR_ERR(hwmon);
553         }
554
555         ts->hwmon = hwmon;
556         return 0;
557 }
558
559 static void ads784x_hwmon_unregister(struct spi_device *spi,
560                                      struct ads7846 *ts)
561 {
562         if (ts->hwmon) {
563                 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
564                 hwmon_device_unregister(ts->hwmon);
565         }
566 }
567
568 #else
569 static inline int ads784x_hwmon_register(struct spi_device *spi,
570                                          struct ads7846 *ts)
571 {
572         return 0;
573 }
574
575 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
576                                             struct ads7846 *ts)
577 {
578 }
579 #endif
580
581 static ssize_t ads7846_pen_down_show(struct device *dev,
582                                      struct device_attribute *attr, char *buf)
583 {
584         struct ads7846 *ts = dev_get_drvdata(dev);
585
586         return sprintf(buf, "%u\n", ts->pendown);
587 }
588
589 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
590
591 static ssize_t ads7846_disable_show(struct device *dev,
592                                      struct device_attribute *attr, char *buf)
593 {
594         struct ads7846 *ts = dev_get_drvdata(dev);
595
596         return sprintf(buf, "%u\n", ts->disabled);
597 }
598
599 static ssize_t ads7846_disable_store(struct device *dev,
600                                      struct device_attribute *attr,
601                                      const char *buf, size_t count)
602 {
603         struct ads7846 *ts = dev_get_drvdata(dev);
604         unsigned long i;
605
606         if (strict_strtoul(buf, 10, &i))
607                 return -EINVAL;
608
609         if (i)
610                 ads7846_disable(ts);
611         else
612                 ads7846_enable(ts);
613
614         return count;
615 }
616
617 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
618
619 static struct attribute *ads784x_attributes[] = {
620         &dev_attr_pen_down.attr,
621         &dev_attr_disable.attr,
622         NULL,
623 };
624
625 static struct attribute_group ads784x_attr_group = {
626         .attrs = ads784x_attributes,
627 };
628
629 /*--------------------------------------------------------------------------*/
630
631 static int get_pendown_state(struct ads7846 *ts)
632 {
633         if (ts->get_pendown_state)
634                 return ts->get_pendown_state();
635
636         return !gpio_get_value(ts->gpio_pendown);
637 }
638
639 static void null_wait_for_sync(void)
640 {
641 }
642
643 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
644 {
645         struct ads7846 *ts = ads;
646
647         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
648                 /* Start over collecting consistent readings. */
649                 ts->read_rep = 0;
650                 /*
651                  * Repeat it, if this was the first read or the read
652                  * wasn't consistent enough.
653                  */
654                 if (ts->read_cnt < ts->debounce_max) {
655                         ts->last_read = *val;
656                         ts->read_cnt++;
657                         return ADS7846_FILTER_REPEAT;
658                 } else {
659                         /*
660                          * Maximum number of debouncing reached and still
661                          * not enough number of consistent readings. Abort
662                          * the whole sample, repeat it in the next sampling
663                          * period.
664                          */
665                         ts->read_cnt = 0;
666                         return ADS7846_FILTER_IGNORE;
667                 }
668         } else {
669                 if (++ts->read_rep > ts->debounce_rep) {
670                         /*
671                          * Got a good reading for this coordinate,
672                          * go for the next one.
673                          */
674                         ts->read_cnt = 0;
675                         ts->read_rep = 0;
676                         return ADS7846_FILTER_OK;
677                 } else {
678                         /* Read more values that are consistent. */
679                         ts->read_cnt++;
680                         return ADS7846_FILTER_REPEAT;
681                 }
682         }
683 }
684
685 static int ads7846_no_filter(void *ads, int data_idx, int *val)
686 {
687         return ADS7846_FILTER_OK;
688 }
689
690 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
691 {
692         struct spi_transfer *t =
693                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
694
695         if (ts->model == 7845) {
696                 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
697         } else {
698                 /*
699                  * adjust:  on-wire is a must-ignore bit, a BE12 value, then
700                  * padding; built from two 8 bit values written msb-first.
701                  */
702                 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
703         }
704 }
705
706 static void ads7846_update_value(struct spi_message *m, int val)
707 {
708         struct spi_transfer *t =
709                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
710
711         *(u16 *)t->rx_buf = val;
712 }
713
714 static void ads7846_read_state(struct ads7846 *ts)
715 {
716         struct ads7846_packet *packet = ts->packet;
717         struct spi_message *m;
718         int msg_idx = 0;
719         int val;
720         int action;
721         int error;
722
723         while (msg_idx < ts->msg_count) {
724
725                 ts->wait_for_sync();
726
727                 m = &ts->msg[msg_idx];
728                 error = spi_sync(ts->spi, m);
729                 if (error) {
730                         dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
731                         packet->tc.ignore = true;
732                         return;
733                 }
734
735                 /*
736                  * Last message is power down request, no need to convert
737                  * or filter the value.
738                  */
739                 if (msg_idx < ts->msg_count - 1) {
740
741                         val = ads7846_get_value(ts, m);
742
743                         action = ts->filter(ts->filter_data, msg_idx, &val);
744                         switch (action) {
745                         case ADS7846_FILTER_REPEAT:
746                                 continue;
747
748                         case ADS7846_FILTER_IGNORE:
749                                 packet->tc.ignore = true;
750                                 msg_idx = ts->msg_count - 1;
751                                 continue;
752
753                         case ADS7846_FILTER_OK:
754                                 ads7846_update_value(m, val);
755                                 packet->tc.ignore = false;
756                                 msg_idx++;
757                                 break;
758
759                         default:
760                                 BUG();
761                         }
762                 } else {
763                         msg_idx++;
764                 }
765         }
766 }
767
768 static void ads7846_report_state(struct ads7846 *ts)
769 {
770         struct ads7846_packet *packet = ts->packet;
771         unsigned int Rt;
772         u16 x, y, z1, z2;
773
774         /*
775          * ads7846_get_value() does in-place conversion (including byte swap)
776          * from on-the-wire format as part of debouncing to get stable
777          * readings.
778          */
779         if (ts->model == 7845) {
780                 x = *(u16 *)packet->tc.x_buf;
781                 y = *(u16 *)packet->tc.y_buf;
782                 z1 = 0;
783                 z2 = 0;
784         } else {
785                 x = packet->tc.x;
786                 y = packet->tc.y;
787                 z1 = packet->tc.z1;
788                 z2 = packet->tc.z2;
789         }
790
791         /* range filtering */
792         if (x == MAX_12BIT)
793                 x = 0;
794
795         if (ts->model == 7843) {
796                 Rt = ts->pressure_max / 2;
797         } else if (ts->model == 7845) {
798                 if (get_pendown_state(ts))
799                         Rt = ts->pressure_max / 2;
800                 else
801                         Rt = 0;
802                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
803         } else if (likely(x && z1)) {
804                 /* compute touch pressure resistance using equation #2 */
805                 Rt = z2;
806                 Rt -= z1;
807                 Rt *= x;
808                 Rt *= ts->x_plate_ohms;
809                 Rt /= z1;
810                 Rt = (Rt + 2047) >> 12;
811         } else {
812                 Rt = 0;
813         }
814
815         /*
816          * Sample found inconsistent by debouncing or pressure is beyond
817          * the maximum. Don't report it to user space, repeat at least
818          * once more the measurement
819          */
820         if (packet->tc.ignore || Rt > ts->pressure_max) {
821                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
822                          packet->tc.ignore, Rt);
823                 return;
824         }
825
826         /*
827          * Maybe check the pendown state before reporting. This discards
828          * false readings when the pen is lifted.
829          */
830         if (ts->penirq_recheck_delay_usecs) {
831                 udelay(ts->penirq_recheck_delay_usecs);
832                 if (!get_pendown_state(ts))
833                         Rt = 0;
834         }
835
836         /*
837          * NOTE: We can't rely on the pressure to determine the pen down
838          * state, even this controller has a pressure sensor. The pressure
839          * value can fluctuate for quite a while after lifting the pen and
840          * in some cases may not even settle at the expected value.
841          *
842          * The only safe way to check for the pen up condition is in the
843          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
844          */
845         if (Rt) {
846                 struct input_dev *input = ts->input;
847
848                 if (ts->swap_xy)
849                         swap(x, y);
850
851                 if (!ts->pendown) {
852                         input_report_key(input, BTN_TOUCH, 1);
853                         ts->pendown = true;
854                         dev_vdbg(&ts->spi->dev, "DOWN\n");
855                 }
856
857                 input_report_abs(input, ABS_X, x);
858                 input_report_abs(input, ABS_Y, y);
859                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
860
861                 input_sync(input);
862                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
863         }
864 }
865
866 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
867 {
868         struct ads7846 *ts = handle;
869
870         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
871 }
872
873
874 static irqreturn_t ads7846_irq(int irq, void *handle)
875 {
876         struct ads7846 *ts = handle;
877
878         /* Start with a small delay before checking pendown state */
879         msleep(TS_POLL_DELAY);
880
881         while (!ts->stopped && get_pendown_state(ts)) {
882
883                 /* pen is down, continue with the measurement */
884                 ads7846_read_state(ts);
885
886                 if (!ts->stopped)
887                         ads7846_report_state(ts);
888
889                 wait_event_timeout(ts->wait, ts->stopped,
890                                    msecs_to_jiffies(TS_POLL_PERIOD));
891         }
892
893         if (ts->pendown) {
894                 struct input_dev *input = ts->input;
895
896                 input_report_key(input, BTN_TOUCH, 0);
897                 input_report_abs(input, ABS_PRESSURE, 0);
898                 input_sync(input);
899
900                 ts->pendown = false;
901                 dev_vdbg(&ts->spi->dev, "UP\n");
902         }
903
904         return IRQ_HANDLED;
905 }
906
907 #ifdef CONFIG_PM_SLEEP
908 static int ads7846_suspend(struct device *dev)
909 {
910         struct ads7846 *ts = dev_get_drvdata(dev);
911
912         mutex_lock(&ts->lock);
913
914         if (!ts->suspended) {
915
916                 if (!ts->disabled)
917                         __ads7846_disable(ts);
918
919                 if (device_may_wakeup(&ts->spi->dev))
920                         enable_irq_wake(ts->spi->irq);
921
922                 ts->suspended = true;
923         }
924
925         mutex_unlock(&ts->lock);
926
927         return 0;
928 }
929
930 static int ads7846_resume(struct device *dev)
931 {
932         struct ads7846 *ts = dev_get_drvdata(dev);
933
934         mutex_lock(&ts->lock);
935
936         if (ts->suspended) {
937
938                 ts->suspended = false;
939
940                 if (device_may_wakeup(&ts->spi->dev))
941                         disable_irq_wake(ts->spi->irq);
942
943                 if (!ts->disabled)
944                         __ads7846_enable(ts);
945         }
946
947         mutex_unlock(&ts->lock);
948
949         return 0;
950 }
951 #endif
952
953 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
954
955 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
956 {
957         struct ads7846_platform_data *pdata = spi->dev.platform_data;
958         int err;
959
960         /*
961          * REVISIT when the irq can be triggered active-low, or if for some
962          * reason the touchscreen isn't hooked up, we don't need to access
963          * the pendown state.
964          */
965
966         if (pdata->get_pendown_state) {
967                 ts->get_pendown_state = pdata->get_pendown_state;
968         } else if (gpio_is_valid(pdata->gpio_pendown)) {
969
970                 err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
971                 if (err) {
972                         dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
973                                 pdata->gpio_pendown);
974                         return err;
975                 }
976                 err = gpio_direction_input(pdata->gpio_pendown);
977                 if (err) {
978                         dev_err(&spi->dev, "failed to setup pendown GPIO%d\n",
979                                 pdata->gpio_pendown);
980                         gpio_free(pdata->gpio_pendown);
981                         return err;
982                 }
983
984                 ts->gpio_pendown = pdata->gpio_pendown;
985
986         } else {
987                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
988                 return -EINVAL;
989         }
990
991         return 0;
992 }
993
994 /*
995  * Set up the transfers to read touchscreen state; this assumes we
996  * use formula #2 for pressure, not #3.
997  */
998 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
999                                 const struct ads7846_platform_data *pdata)
1000 {
1001         struct spi_message *m = &ts->msg[0];
1002         struct spi_transfer *x = ts->xfer;
1003         struct ads7846_packet *packet = ts->packet;
1004         int vref = pdata->keep_vref_on;
1005
1006         if (ts->model == 7873) {
1007                 /*
1008                  * The AD7873 is almost identical to the ADS7846
1009                  * keep VREF off during differential/ratiometric
1010                  * conversion modes.
1011                  */
1012                 ts->model = 7846;
1013                 vref = 0;
1014         }
1015
1016         ts->msg_count = 1;
1017         spi_message_init(m);
1018         m->context = ts;
1019
1020         if (ts->model == 7845) {
1021                 packet->read_y_cmd[0] = READ_Y(vref);
1022                 packet->read_y_cmd[1] = 0;
1023                 packet->read_y_cmd[2] = 0;
1024                 x->tx_buf = &packet->read_y_cmd[0];
1025                 x->rx_buf = &packet->tc.y_buf[0];
1026                 x->len = 3;
1027                 spi_message_add_tail(x, m);
1028         } else {
1029                 /* y- still on; turn on only y+ (and ADC) */
1030                 packet->read_y = READ_Y(vref);
1031                 x->tx_buf = &packet->read_y;
1032                 x->len = 1;
1033                 spi_message_add_tail(x, m);
1034
1035                 x++;
1036                 x->rx_buf = &packet->tc.y;
1037                 x->len = 2;
1038                 spi_message_add_tail(x, m);
1039         }
1040
1041         /*
1042          * The first sample after switching drivers can be low quality;
1043          * optionally discard it, using a second one after the signals
1044          * have had enough time to stabilize.
1045          */
1046         if (pdata->settle_delay_usecs) {
1047                 x->delay_usecs = pdata->settle_delay_usecs;
1048
1049                 x++;
1050                 x->tx_buf = &packet->read_y;
1051                 x->len = 1;
1052                 spi_message_add_tail(x, m);
1053
1054                 x++;
1055                 x->rx_buf = &packet->tc.y;
1056                 x->len = 2;
1057                 spi_message_add_tail(x, m);
1058         }
1059
1060         ts->msg_count++;
1061         m++;
1062         spi_message_init(m);
1063         m->context = ts;
1064
1065         if (ts->model == 7845) {
1066                 x++;
1067                 packet->read_x_cmd[0] = READ_X(vref);
1068                 packet->read_x_cmd[1] = 0;
1069                 packet->read_x_cmd[2] = 0;
1070                 x->tx_buf = &packet->read_x_cmd[0];
1071                 x->rx_buf = &packet->tc.x_buf[0];
1072                 x->len = 3;
1073                 spi_message_add_tail(x, m);
1074         } else {
1075                 /* turn y- off, x+ on, then leave in lowpower */
1076                 x++;
1077                 packet->read_x = READ_X(vref);
1078                 x->tx_buf = &packet->read_x;
1079                 x->len = 1;
1080                 spi_message_add_tail(x, m);
1081
1082                 x++;
1083                 x->rx_buf = &packet->tc.x;
1084                 x->len = 2;
1085                 spi_message_add_tail(x, m);
1086         }
1087
1088         /* ... maybe discard first sample ... */
1089         if (pdata->settle_delay_usecs) {
1090                 x->delay_usecs = pdata->settle_delay_usecs;
1091
1092                 x++;
1093                 x->tx_buf = &packet->read_x;
1094                 x->len = 1;
1095                 spi_message_add_tail(x, m);
1096
1097                 x++;
1098                 x->rx_buf = &packet->tc.x;
1099                 x->len = 2;
1100                 spi_message_add_tail(x, m);
1101         }
1102
1103         /* turn y+ off, x- on; we'll use formula #2 */
1104         if (ts->model == 7846) {
1105                 ts->msg_count++;
1106                 m++;
1107                 spi_message_init(m);
1108                 m->context = ts;
1109
1110                 x++;
1111                 packet->read_z1 = READ_Z1(vref);
1112                 x->tx_buf = &packet->read_z1;
1113                 x->len = 1;
1114                 spi_message_add_tail(x, m);
1115
1116                 x++;
1117                 x->rx_buf = &packet->tc.z1;
1118                 x->len = 2;
1119                 spi_message_add_tail(x, m);
1120
1121                 /* ... maybe discard first sample ... */
1122                 if (pdata->settle_delay_usecs) {
1123                         x->delay_usecs = pdata->settle_delay_usecs;
1124
1125                         x++;
1126                         x->tx_buf = &packet->read_z1;
1127                         x->len = 1;
1128                         spi_message_add_tail(x, m);
1129
1130                         x++;
1131                         x->rx_buf = &packet->tc.z1;
1132                         x->len = 2;
1133                         spi_message_add_tail(x, m);
1134                 }
1135
1136                 ts->msg_count++;
1137                 m++;
1138                 spi_message_init(m);
1139                 m->context = ts;
1140
1141                 x++;
1142                 packet->read_z2 = READ_Z2(vref);
1143                 x->tx_buf = &packet->read_z2;
1144                 x->len = 1;
1145                 spi_message_add_tail(x, m);
1146
1147                 x++;
1148                 x->rx_buf = &packet->tc.z2;
1149                 x->len = 2;
1150                 spi_message_add_tail(x, m);
1151
1152                 /* ... maybe discard first sample ... */
1153                 if (pdata->settle_delay_usecs) {
1154                         x->delay_usecs = pdata->settle_delay_usecs;
1155
1156                         x++;
1157                         x->tx_buf = &packet->read_z2;
1158                         x->len = 1;
1159                         spi_message_add_tail(x, m);
1160
1161                         x++;
1162                         x->rx_buf = &packet->tc.z2;
1163                         x->len = 2;
1164                         spi_message_add_tail(x, m);
1165                 }
1166         }
1167
1168         /* power down */
1169         ts->msg_count++;
1170         m++;
1171         spi_message_init(m);
1172         m->context = ts;
1173
1174         if (ts->model == 7845) {
1175                 x++;
1176                 packet->pwrdown_cmd[0] = PWRDOWN;
1177                 packet->pwrdown_cmd[1] = 0;
1178                 packet->pwrdown_cmd[2] = 0;
1179                 x->tx_buf = &packet->pwrdown_cmd[0];
1180                 x->len = 3;
1181         } else {
1182                 x++;
1183                 packet->pwrdown = PWRDOWN;
1184                 x->tx_buf = &packet->pwrdown;
1185                 x->len = 1;
1186                 spi_message_add_tail(x, m);
1187
1188                 x++;
1189                 x->rx_buf = &packet->dummy;
1190                 x->len = 2;
1191         }
1192
1193         CS_CHANGE(*x);
1194         spi_message_add_tail(x, m);
1195 }
1196
1197 static int __devinit ads7846_probe(struct spi_device *spi)
1198 {
1199         struct ads7846 *ts;
1200         struct ads7846_packet *packet;
1201         struct input_dev *input_dev;
1202         struct ads7846_platform_data *pdata = spi->dev.platform_data;
1203         unsigned long irq_flags;
1204         int err;
1205
1206         if (!spi->irq) {
1207                 dev_dbg(&spi->dev, "no IRQ?\n");
1208                 return -ENODEV;
1209         }
1210
1211         if (!pdata) {
1212                 dev_dbg(&spi->dev, "no platform data?\n");
1213                 return -ENODEV;
1214         }
1215
1216         /* don't exceed max specified sample rate */
1217         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1218                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1219                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1220                 return -EINVAL;
1221         }
1222
1223         /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1224          * that even if the hardware can do that, the SPI controller driver
1225          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1226          */
1227         spi->bits_per_word = 8;
1228         spi->mode = SPI_MODE_0;
1229         err = spi_setup(spi);
1230         if (err < 0)
1231                 return err;
1232
1233         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1234         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1235         input_dev = input_allocate_device();
1236         if (!ts || !packet || !input_dev) {
1237                 err = -ENOMEM;
1238                 goto err_free_mem;
1239         }
1240
1241         dev_set_drvdata(&spi->dev, ts);
1242
1243         ts->packet = packet;
1244         ts->spi = spi;
1245         ts->input = input_dev;
1246         ts->vref_mv = pdata->vref_mv;
1247         ts->swap_xy = pdata->swap_xy;
1248
1249         mutex_init(&ts->lock);
1250         init_waitqueue_head(&ts->wait);
1251
1252         ts->model = pdata->model ? : 7846;
1253         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1254         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1255         ts->pressure_max = pdata->pressure_max ? : ~0;
1256
1257         if (pdata->filter != NULL) {
1258                 if (pdata->filter_init != NULL) {
1259                         err = pdata->filter_init(pdata, &ts->filter_data);
1260                         if (err < 0)
1261                                 goto err_free_mem;
1262                 }
1263                 ts->filter = pdata->filter;
1264                 ts->filter_cleanup = pdata->filter_cleanup;
1265         } else if (pdata->debounce_max) {
1266                 ts->debounce_max = pdata->debounce_max;
1267                 if (ts->debounce_max < 2)
1268                         ts->debounce_max = 2;
1269                 ts->debounce_tol = pdata->debounce_tol;
1270                 ts->debounce_rep = pdata->debounce_rep;
1271                 ts->filter = ads7846_debounce_filter;
1272                 ts->filter_data = ts;
1273         } else {
1274                 ts->filter = ads7846_no_filter;
1275         }
1276
1277         err = ads7846_setup_pendown(spi, ts);
1278         if (err)
1279                 goto err_cleanup_filter;
1280
1281         if (pdata->penirq_recheck_delay_usecs)
1282                 ts->penirq_recheck_delay_usecs =
1283                                 pdata->penirq_recheck_delay_usecs;
1284
1285         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1286
1287         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1288         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1289
1290         input_dev->name = ts->name;
1291         input_dev->phys = ts->phys;
1292         input_dev->dev.parent = &spi->dev;
1293
1294         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1295         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1296         input_set_abs_params(input_dev, ABS_X,
1297                         pdata->x_min ? : 0,
1298                         pdata->x_max ? : MAX_12BIT,
1299                         0, 0);
1300         input_set_abs_params(input_dev, ABS_Y,
1301                         pdata->y_min ? : 0,
1302                         pdata->y_max ? : MAX_12BIT,
1303                         0, 0);
1304         input_set_abs_params(input_dev, ABS_PRESSURE,
1305                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1306
1307         ads7846_setup_spi_msg(ts, pdata);
1308
1309         ts->reg = regulator_get(&spi->dev, "vcc");
1310         if (IS_ERR(ts->reg)) {
1311                 err = PTR_ERR(ts->reg);
1312                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1313                 goto err_free_gpio;
1314         }
1315
1316         err = regulator_enable(ts->reg);
1317         if (err) {
1318                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1319                 goto err_put_regulator;
1320         }
1321
1322         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1323         irq_flags |= IRQF_ONESHOT;
1324
1325         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1326                                    irq_flags, spi->dev.driver->name, ts);
1327         if (err && !pdata->irq_flags) {
1328                 dev_info(&spi->dev,
1329                         "trying pin change workaround on irq %d\n", spi->irq);
1330                 irq_flags |= IRQF_TRIGGER_RISING;
1331                 err = request_threaded_irq(spi->irq,
1332                                   ads7846_hard_irq, ads7846_irq,
1333                                   irq_flags, spi->dev.driver->name, ts);
1334         }
1335
1336         if (err) {
1337                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1338                 goto err_disable_regulator;
1339         }
1340
1341         err = ads784x_hwmon_register(spi, ts);
1342         if (err)
1343                 goto err_free_irq;
1344
1345         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1346
1347         /*
1348          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1349          * the touchscreen, in case it's not connected.
1350          */
1351         if (ts->model == 7845)
1352                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1353         else
1354                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1355
1356         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1357         if (err)
1358                 goto err_remove_hwmon;
1359
1360         err = input_register_device(input_dev);
1361         if (err)
1362                 goto err_remove_attr_group;
1363
1364         device_init_wakeup(&spi->dev, pdata->wakeup);
1365
1366         return 0;
1367
1368  err_remove_attr_group:
1369         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1370  err_remove_hwmon:
1371         ads784x_hwmon_unregister(spi, ts);
1372  err_free_irq:
1373         free_irq(spi->irq, ts);
1374  err_disable_regulator:
1375         regulator_disable(ts->reg);
1376  err_put_regulator:
1377         regulator_put(ts->reg);
1378  err_free_gpio:
1379         if (!ts->get_pendown_state)
1380                 gpio_free(ts->gpio_pendown);
1381  err_cleanup_filter:
1382         if (ts->filter_cleanup)
1383                 ts->filter_cleanup(ts->filter_data);
1384  err_free_mem:
1385         input_free_device(input_dev);
1386         kfree(packet);
1387         kfree(ts);
1388         return err;
1389 }
1390
1391 static int __devexit ads7846_remove(struct spi_device *spi)
1392 {
1393         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1394
1395         device_init_wakeup(&spi->dev, false);
1396
1397         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1398
1399         ads7846_disable(ts);
1400         free_irq(ts->spi->irq, ts);
1401
1402         input_unregister_device(ts->input);
1403
1404         ads784x_hwmon_unregister(spi, ts);
1405
1406         regulator_disable(ts->reg);
1407         regulator_put(ts->reg);
1408
1409         if (!ts->get_pendown_state) {
1410                 /*
1411                  * If we are not using specialized pendown method we must
1412                  * have been relying on gpio we set up ourselves.
1413                  */
1414                 gpio_free(ts->gpio_pendown);
1415         }
1416
1417         if (ts->filter_cleanup)
1418                 ts->filter_cleanup(ts->filter_data);
1419
1420         kfree(ts->packet);
1421         kfree(ts);
1422
1423         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1424
1425         return 0;
1426 }
1427
1428 static struct spi_driver ads7846_driver = {
1429         .driver = {
1430                 .name   = "ads7846",
1431                 .bus    = &spi_bus_type,
1432                 .owner  = THIS_MODULE,
1433                 .pm     = &ads7846_pm,
1434         },
1435         .probe          = ads7846_probe,
1436         .remove         = __devexit_p(ads7846_remove),
1437 };
1438
1439 static int __init ads7846_init(void)
1440 {
1441         return spi_register_driver(&ads7846_driver);
1442 }
1443 module_init(ads7846_init);
1444
1445 static void __exit ads7846_exit(void)
1446 {
1447         spi_unregister_driver(&ads7846_driver);
1448 }
1449 module_exit(ads7846_exit);
1450
1451 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1452 MODULE_LICENSE("GPL");
1453 MODULE_ALIAS("spi:ads7846");