Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/agpgart
[linux-2.6] / drivers / input / touchscreen / ads7846.c
1 /*
2  * ADS7846 based touchscreen and sensor driver
3  *
4  * Copyright (c) 2005 David Brownell
5  *
6  * Using code from:
7  *  - corgi_ts.c
8  *      Copyright (C) 2004-2005 Richard Purdie
9  *  - omap_ts.[hc], ads7846.h, ts_osk.c
10  *      Copyright (C) 2002 MontaVista Software
11  *      Copyright (C) 2004 Texas Instruments
12  *      Copyright (C) 2005 Dirk Behme
13  *
14  *  This program is free software; you can redistribute it and/or modify
15  *  it under the terms of the GNU General Public License version 2 as
16  *  published by the Free Software Foundation.
17  */
18 #include <linux/device.h>
19 #include <linux/init.h>
20 #include <linux/delay.h>
21 #include <linux/input.h>
22 #include <linux/interrupt.h>
23 #include <linux/slab.h>
24 #include <linux/spi/spi.h>
25 #include <linux/spi/ads7846.h>
26
27 #ifdef  CONFIG_ARM
28 #include <asm/mach-types.h>
29 #ifdef  CONFIG_ARCH_OMAP
30 #include <asm/arch/gpio.h>
31 #endif
32 #endif
33
34
35 /*
36  * This code has been lightly tested on an ads7846.
37  * Support for ads7843 and ads7845 has only been stubbed in.
38  *
39  * Not yet done:  investigate the values reported.  Are x/y/pressure
40  * event values sane enough for X11?  How accurate are the temperature
41  * and voltage readings?  (System-specific calibration should support
42  * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
43  *
44  * app note sbaa036 talks in more detail about accurate sampling...
45  * that ought to help in situations like LCDs inducing noise (which
46  * can also be helped by using synch signals) and more generally.
47  */
48
49 #define TS_POLL_PERIOD  msecs_to_jiffies(10)
50
51 struct ts_event {
52         /* For portability, we can't read 12 bit values using SPI (which
53          * would make the controller deliver them as native byteorder u16
54          * with msbs zeroed).  Instead, we read them as two 8-byte values,
55          * which need byteswapping then range adjustment.
56          */
57         __be16 x;
58         __be16 y;
59         __be16 z1, z2;
60 };
61
62 struct ads7846 {
63         struct input_dev        input;
64         char                    phys[32];
65
66         struct spi_device       *spi;
67         u16                     model;
68         u16                     vref_delay_usecs;
69         u16                     x_plate_ohms;
70
71         struct ts_event         tc;
72
73         struct spi_transfer     xfer[8];
74         struct spi_message      msg;
75
76         spinlock_t              lock;
77         struct timer_list       timer;          /* P: lock */
78         unsigned                pendown:1;      /* P: lock */
79         unsigned                pending:1;      /* P: lock */
80 // FIXME remove "irq_disabled"
81         unsigned                irq_disabled:1; /* P: lock */
82 };
83
84 /* leave chip selected when we're done, for quicker re-select? */
85 #if     0
86 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
87 #else
88 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
89 #endif
90
91 /*--------------------------------------------------------------------------*/
92
93 /* The ADS7846 has touchscreen and other sensors.
94  * Earlier ads784x chips are somewhat compatible.
95  */
96 #define ADS_START               (1 << 7)
97 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
98 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
99 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
100 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
101 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
102 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
103 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
104 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
105 #define ADS_8_BIT               (1 << 3)
106 #define ADS_12_BIT              (0 << 3)
107 #define ADS_SER                 (1 << 2)        /* non-differential */
108 #define ADS_DFR                 (0 << 2)        /* differential */
109 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
110 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
111 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
112 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
113
114 #define MAX_12BIT       ((1<<12)-1)
115
116 /* leave ADC powered up (disables penirq) between differential samples */
117 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
118         | ADS_12_BIT | ADS_DFR)
119
120 static const u8 read_y  = READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON;
121 static const u8 read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON;
122 static const u8 read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON;
123 static const u8 read_x  = READ_12BIT_DFR(x)  | ADS_PD10_PDOWN;  /* LAST */
124
125 /* single-ended samples need to first power up reference voltage;
126  * we leave both ADC and VREF powered
127  */
128 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
129         | ADS_12_BIT | ADS_SER)
130
131 static const u8 ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON;
132 static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
133
134 /*--------------------------------------------------------------------------*/
135
136 /*
137  * Non-touchscreen sensors only use single-ended conversions.
138  */
139
140 struct ser_req {
141         u8                      command;
142         u16                     scratch;
143         __be16                  sample;
144         struct spi_message      msg;
145         struct spi_transfer     xfer[6];
146 };
147
148 static int ads7846_read12_ser(struct device *dev, unsigned command)
149 {
150         struct spi_device       *spi = to_spi_device(dev);
151         struct ads7846          *ts = dev_get_drvdata(dev);
152         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
153         int                     status;
154         int                     sample;
155         int                     i;
156
157         if (!req)
158                 return -ENOMEM;
159
160         INIT_LIST_HEAD(&req->msg.transfers);
161
162         /* activate reference, so it has time to settle; */
163         req->xfer[0].tx_buf = &ref_on;
164         req->xfer[0].len = 1;
165         req->xfer[1].rx_buf = &req->scratch;
166         req->xfer[1].len = 2;
167
168         /*
169          * for external VREF, 0 usec (and assume it's always on);
170          * for 1uF, use 800 usec;
171          * no cap, 100 usec.
172          */
173         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
174
175         /* take sample */
176         req->command = (u8) command;
177         req->xfer[2].tx_buf = &req->command;
178         req->xfer[2].len = 1;
179         req->xfer[3].rx_buf = &req->sample;
180         req->xfer[3].len = 2;
181
182         /* REVISIT:  take a few more samples, and compare ... */
183
184         /* turn off reference */
185         req->xfer[4].tx_buf = &ref_off;
186         req->xfer[4].len = 1;
187         req->xfer[5].rx_buf = &req->scratch;
188         req->xfer[5].len = 2;
189
190         CS_CHANGE(req->xfer[5]);
191
192         /* group all the transfers together, so we can't interfere with
193          * reading touchscreen state; disable penirq while sampling
194          */
195         for (i = 0; i < 6; i++)
196                 spi_message_add_tail(&req->xfer[i], &req->msg);
197
198         disable_irq(spi->irq);
199         status = spi_sync(spi, &req->msg);
200         enable_irq(spi->irq);
201
202         if (req->msg.status)
203                 status = req->msg.status;
204         sample = be16_to_cpu(req->sample);
205         sample = sample >> 4;
206         kfree(req);
207
208         return status ? status : sample;
209 }
210
211 #define SHOW(name) static ssize_t \
212 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
213 { \
214         ssize_t v = ads7846_read12_ser(dev, \
215                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
216         if (v < 0) \
217                 return v; \
218         return sprintf(buf, "%u\n", (unsigned) v); \
219 } \
220 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
221
222 SHOW(temp0)
223 SHOW(temp1)
224 SHOW(vaux)
225 SHOW(vbatt)
226
227 /*--------------------------------------------------------------------------*/
228
229 /*
230  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
231  * to retrieve touchscreen status.
232  *
233  * The SPI transfer completion callback does the real work.  It reports
234  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
235  */
236
237 static void ads7846_rx(void *ads)
238 {
239         struct ads7846  *ts = ads;
240         unsigned        Rt;
241         unsigned        sync = 0;
242         u16             x, y, z1, z2;
243         unsigned long   flags;
244
245         /* adjust:  12 bit samples (left aligned), built from
246          * two 8 bit values writen msb-first.
247          */
248         x = be16_to_cpu(ts->tc.x) >> 4;
249         y = be16_to_cpu(ts->tc.y) >> 4;
250         z1 = be16_to_cpu(ts->tc.z1) >> 4;
251         z2 = be16_to_cpu(ts->tc.z2) >> 4;
252
253         /* range filtering */
254         if (x == MAX_12BIT)
255                 x = 0;
256
257         if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
258                 /* compute touch pressure resistance using equation #2 */
259                 Rt = z2;
260                 Rt -= z1;
261                 Rt *= x;
262                 Rt *= ts->x_plate_ohms;
263                 Rt /= z1;
264                 Rt = (Rt + 2047) >> 12;
265         } else
266                 Rt = 0;
267
268         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
269          * being able to check nPENIRQ status, or "friendly" trigger modes
270          * (both-edges is much better than just-falling or low-level).
271          *
272          * REVISIT:  some boards may require reading nPENIRQ; it's
273          * needed on 7843.  and 7845 reads pressure differently...
274          *
275          * REVISIT:  the touchscreen might not be connected; this code
276          * won't notice that, even if nPENIRQ never fires ...
277          */
278         if (!ts->pendown && Rt != 0) {
279                 input_report_key(&ts->input, BTN_TOUCH, 1);
280                 sync = 1;
281         } else if (ts->pendown && Rt == 0) {
282                 input_report_key(&ts->input, BTN_TOUCH, 0);
283                 sync = 1;
284         }
285
286         if (Rt) {
287                 input_report_abs(&ts->input, ABS_X, x);
288                 input_report_abs(&ts->input, ABS_Y, y);
289                 input_report_abs(&ts->input, ABS_PRESSURE, Rt);
290                 sync = 1;
291         }
292         if (sync)
293                 input_sync(&ts->input);
294
295 #ifdef  VERBOSE
296         if (Rt || ts->pendown)
297                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
298                         x, y, Rt, Rt ? "" : " UP");
299 #endif
300
301         /* don't retrigger while we're suspended */
302         spin_lock_irqsave(&ts->lock, flags);
303
304         ts->pendown = (Rt != 0);
305         ts->pending = 0;
306
307         if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
308                 if (ts->pendown)
309                         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
310                 else if (ts->irq_disabled) {
311                         ts->irq_disabled = 0;
312                         enable_irq(ts->spi->irq);
313                 }
314         }
315
316         spin_unlock_irqrestore(&ts->lock, flags);
317 }
318
319 static void ads7846_timer(unsigned long handle)
320 {
321         struct ads7846  *ts = (void *)handle;
322         int             status = 0;
323         unsigned long   flags;
324
325         spin_lock_irqsave(&ts->lock, flags);
326         if (!ts->pending) {
327                 ts->pending = 1;
328                 if (!ts->irq_disabled) {
329                         ts->irq_disabled = 1;
330                         disable_irq(ts->spi->irq);
331                 }
332                 status = spi_async(ts->spi, &ts->msg);
333                 if (status)
334                         dev_err(&ts->spi->dev, "spi_async --> %d\n",
335                                         status);
336         }
337         spin_unlock_irqrestore(&ts->lock, flags);
338 }
339
340 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
341 {
342         ads7846_timer((unsigned long) handle);
343         return IRQ_HANDLED;
344 }
345
346 /*--------------------------------------------------------------------------*/
347
348 static int
349 ads7846_suspend(struct spi_device *spi, pm_message_t message)
350 {
351         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
352         unsigned long   flags;
353
354         spin_lock_irqsave(&ts->lock, flags);
355
356         spi->dev.power.power_state = message;
357
358         /* are we waiting for IRQ, or polling? */
359         if (!ts->pendown) {
360                 if (!ts->irq_disabled) {
361                         ts->irq_disabled = 1;
362                         disable_irq(ts->spi->irq);
363                 }
364         } else {
365                 /* polling; force a final SPI completion;
366                  * that will clean things up neatly
367                  */
368                 if (!ts->pending)
369                         mod_timer(&ts->timer, jiffies);
370
371                 while (ts->pendown || ts->pending) {
372                         spin_unlock_irqrestore(&ts->lock, flags);
373                         udelay(10);
374                         spin_lock_irqsave(&ts->lock, flags);
375                 }
376         }
377
378         /* we know the chip's in lowpower mode since we always
379          * leave it that way after every request
380          */
381
382         spin_unlock_irqrestore(&ts->lock, flags);
383         return 0;
384 }
385
386 static int ads7846_resume(struct spi_device *spi)
387 {
388         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
389
390         ts->irq_disabled = 0;
391         enable_irq(ts->spi->irq);
392         spi->dev.power.power_state = PMSG_ON;
393         return 0;
394 }
395
396 static int __devinit ads7846_probe(struct spi_device *spi)
397 {
398         struct ads7846                  *ts;
399         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
400         struct spi_transfer             *x;
401         int                             i;
402
403         if (!spi->irq) {
404                 dev_dbg(&spi->dev, "no IRQ?\n");
405                 return -ENODEV;
406         }
407
408         if (!pdata) {
409                 dev_dbg(&spi->dev, "no platform data?\n");
410                 return -ENODEV;
411         }
412
413         /* don't exceed max specified sample rate */
414         if (spi->max_speed_hz > (125000 * 16)) {
415                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
416                                 (spi->max_speed_hz/16)/1000);
417                 return -EINVAL;
418         }
419
420         /* We'd set the wordsize to 12 bits ... except that some controllers
421          * will then treat the 8 bit command words as 12 bits (and drop the
422          * four MSBs of the 12 bit result).  Result: inputs must be shifted
423          * to discard the four garbage LSBs.
424          */
425
426         if (!(ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL)))
427                 return -ENOMEM;
428
429         dev_set_drvdata(&spi->dev, ts);
430
431         ts->spi = spi;
432         spi->dev.power.power_state = PMSG_ON;
433
434         init_timer(&ts->timer);
435         ts->timer.data = (unsigned long) ts;
436         ts->timer.function = ads7846_timer;
437
438         ts->model = pdata->model ? : 7846;
439         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
440         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
441
442         init_input_dev(&ts->input);
443
444         ts->input.dev = &spi->dev;
445         ts->input.name = "ADS784x Touchscreen";
446         snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id);
447         ts->input.phys = ts->phys;
448
449         ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
450         ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
451         input_set_abs_params(&ts->input, ABS_X,
452                         pdata->x_min ? : 0,
453                         pdata->x_max ? : MAX_12BIT,
454                         0, 0);
455         input_set_abs_params(&ts->input, ABS_Y,
456                         pdata->y_min ? : 0,
457                         pdata->y_max ? : MAX_12BIT,
458                         0, 0);
459         input_set_abs_params(&ts->input, ABS_PRESSURE,
460                         pdata->pressure_min, pdata->pressure_max, 0, 0);
461
462         input_register_device(&ts->input);
463
464         /* set up the transfers to read touchscreen state; this assumes we
465          * use formula #2 for pressure, not #3.
466          */
467         x = ts->xfer;
468
469         /* y- still on; turn on only y+ (and ADC) */
470         x->tx_buf = &read_y;
471         x->len = 1;
472         x++;
473         x->rx_buf = &ts->tc.y;
474         x->len = 2;
475         x++;
476
477         /* turn y+ off, x- on; we'll use formula #2 */
478         if (ts->model == 7846) {
479                 x->tx_buf = &read_z1;
480                 x->len = 1;
481                 x++;
482                 x->rx_buf = &ts->tc.z1;
483                 x->len = 2;
484                 x++;
485
486                 x->tx_buf = &read_z2;
487                 x->len = 1;
488                 x++;
489                 x->rx_buf = &ts->tc.z2;
490                 x->len = 2;
491                 x++;
492         }
493
494         /* turn y- off, x+ on, then leave in lowpower */
495         x->tx_buf = &read_x;
496         x->len = 1;
497         x++;
498         x->rx_buf = &ts->tc.x;
499         x->len = 2;
500         x++;
501
502         CS_CHANGE(x[-1]);
503
504         for (i = 0; i < x - ts->xfer; i++)
505                 spi_message_add_tail(&ts->xfer[i], &ts->msg);
506         ts->msg.complete = ads7846_rx;
507         ts->msg.context = ts;
508
509         if (request_irq(spi->irq, ads7846_irq,
510                         SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
511                         spi->dev.bus_id, ts)) {
512                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
513                 input_unregister_device(&ts->input);
514                 kfree(ts);
515                 return -EBUSY;
516         }
517
518         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
519
520         /* take a first sample, leaving nPENIRQ active; avoid
521          * the touchscreen, in case it's not connected.
522          */
523         (void) ads7846_read12_ser(&spi->dev,
524                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
525
526         /* ads7843/7845 don't have temperature sensors, and
527          * use the other sensors a bit differently too
528          */
529         if (ts->model == 7846) {
530                 device_create_file(&spi->dev, &dev_attr_temp0);
531                 device_create_file(&spi->dev, &dev_attr_temp1);
532         }
533         if (ts->model != 7845)
534                 device_create_file(&spi->dev, &dev_attr_vbatt);
535         device_create_file(&spi->dev, &dev_attr_vaux);
536
537         return 0;
538 }
539
540 static int __devexit ads7846_remove(struct spi_device *spi)
541 {
542         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
543
544         ads7846_suspend(spi, PMSG_SUSPEND);
545         free_irq(ts->spi->irq, ts);
546         if (ts->irq_disabled)
547                 enable_irq(ts->spi->irq);
548
549         if (ts->model == 7846) {
550                 device_remove_file(&spi->dev, &dev_attr_temp0);
551                 device_remove_file(&spi->dev, &dev_attr_temp1);
552         }
553         if (ts->model != 7845)
554                 device_remove_file(&spi->dev, &dev_attr_vbatt);
555         device_remove_file(&spi->dev, &dev_attr_vaux);
556
557         input_unregister_device(&ts->input);
558         kfree(ts);
559
560         dev_dbg(&spi->dev, "unregistered touchscreen\n");
561         return 0;
562 }
563
564 static struct spi_driver ads7846_driver = {
565         .driver = {
566                 .name   = "ads7846",
567                 .bus    = &spi_bus_type,
568                 .owner  = THIS_MODULE,
569         },
570         .probe          = ads7846_probe,
571         .remove         = __devexit_p(ads7846_remove),
572         .suspend        = ads7846_suspend,
573         .resume         = ads7846_resume,
574 };
575
576 static int __init ads7846_init(void)
577 {
578         /* grr, board-specific init should stay out of drivers!! */
579
580 #ifdef  CONFIG_ARCH_OMAP
581         if (machine_is_omap_osk()) {
582                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
583                 omap_request_gpio(4);
584                 omap_set_gpio_direction(4, 1);
585                 omap_request_gpio(6);
586                 omap_set_gpio_direction(6, 1);
587         }
588         // also TI 1510 Innovator, bitbanging through FPGA
589         // also Nokia 770
590         // also Palm Tungsten T2
591 #endif
592
593         // PXA:
594         // also Dell Axim X50
595         // also HP iPaq H191x/H192x/H415x/H435x
596         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
597         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
598
599         // Atmel at91sam9261-EK uses ads7843
600
601         // also various AMD Au1x00 devel boards
602
603         return spi_register_driver(&ads7846_driver);
604 }
605 module_init(ads7846_init);
606
607 static void __exit ads7846_exit(void)
608 {
609         spi_unregister_driver(&ads7846_driver);
610
611 #ifdef  CONFIG_ARCH_OMAP
612         if (machine_is_omap_osk()) {
613                 omap_free_gpio(4);
614                 omap_free_gpio(6);
615         }
616 #endif
617
618 }
619 module_exit(ads7846_exit);
620
621 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
622 MODULE_LICENSE("GPL");