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