[PATCH] sh: consolidate hp620/hp680/hp690 targets into hp6xx
[linux-2.6.git] / drivers / input / touchscreen / ads7846.c
1 /*
2  * ADS7846 based touchscreen and sensor driver
3  *
4  * Copyright (c) 2005 David Brownell
5  *
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
33 #else
34 #define set_irq_type(irq,type)  do{}while(0)
35 #endif
36
37
38 /*
39  * This code has been lightly tested on an ads7846.
40  * Support for ads7843 and ads7845 has only been stubbed in.
41  *
42  * Not yet done:  investigate the values reported.  Are x/y/pressure
43  * event values sane enough for X11?  How accurate are the temperature
44  * and voltage readings?  (System-specific calibration should support
45  * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
46  *
47  * app note sbaa036 talks in more detail about accurate sampling...
48  * that ought to help in situations like LCDs inducing noise (which
49  * can also be helped by using synch signals) and more generally.
50  */
51
52 #define TS_POLL_PERIOD  msecs_to_jiffies(10)
53
54 struct ts_event {
55         /* For portability, we can't read 12 bit values using SPI (which
56          * would make the controller deliver them as native byteorder u16
57          * with msbs zeroed).  Instead, we read them as two 8-byte values,
58          * which need byteswapping then range adjustment.
59          */
60         __be16 x;
61         __be16 y;
62         __be16 z1, z2;
63 };
64
65 struct ads7846 {
66         struct input_dev        input;
67         char                    phys[32];
68
69         struct spi_device       *spi;
70         u16                     model;
71         u16                     vref_delay_usecs;
72         u16                     x_plate_ohms;
73
74         struct ts_event         tc;
75
76         struct spi_transfer     xfer[8];
77         struct spi_message      msg;
78
79         spinlock_t              lock;
80         struct timer_list       timer;          /* P: lock */
81         unsigned                pendown:1;      /* P: lock */
82         unsigned                pending:1;      /* P: lock */
83 // FIXME remove "irq_disabled"
84         unsigned                irq_disabled:1; /* P: lock */
85 };
86
87 /* leave chip selected when we're done, for quicker re-select? */
88 #if     0
89 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
90 #else
91 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
92 #endif
93
94 /*--------------------------------------------------------------------------*/
95
96 /* The ADS7846 has touchscreen and other sensors.
97  * Earlier ads784x chips are somewhat compatible.
98  */
99 #define ADS_START               (1 << 7)
100 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
101 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
102 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
103 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
104 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
105 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
106 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
107 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
108 #define ADS_8_BIT               (1 << 3)
109 #define ADS_12_BIT              (0 << 3)
110 #define ADS_SER                 (1 << 2)        /* non-differential */
111 #define ADS_DFR                 (0 << 2)        /* differential */
112 #define ADS_PD10_PDOWN          (0 << 0)        /* lowpower mode + penirq */
113 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
114 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
115 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
116
117 #define MAX_12BIT       ((1<<12)-1)
118
119 /* leave ADC powered up (disables penirq) between differential samples */
120 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
121         | ADS_12_BIT | ADS_DFR)
122
123 static const u8 read_y  = READ_12BIT_DFR(y)  | ADS_PD10_ADC_ON;
124 static const u8 read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON;
125 static const u8 read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON;
126 static const u8 read_x  = READ_12BIT_DFR(x)  | ADS_PD10_PDOWN;  /* LAST */
127
128 /* single-ended samples need to first power up reference voltage;
129  * we leave both ADC and VREF powered
130  */
131 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
132         | ADS_12_BIT | ADS_SER)
133
134 static const u8 ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON;
135 static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
136
137 /*--------------------------------------------------------------------------*/
138
139 /*
140  * Non-touchscreen sensors only use single-ended conversions.
141  */
142
143 struct ser_req {
144         u8                      command;
145         u16                     scratch;
146         __be16                  sample;
147         struct spi_message      msg;
148         struct spi_transfer     xfer[6];
149 };
150
151 static int ads7846_read12_ser(struct device *dev, unsigned command)
152 {
153         struct spi_device       *spi = to_spi_device(dev);
154         struct ads7846          *ts = dev_get_drvdata(dev);
155         struct ser_req          *req = kzalloc(sizeof *req, SLAB_KERNEL);
156         int                     status;
157         int                     sample;
158         int                     i;
159
160         if (!req)
161                 return -ENOMEM;
162
163         INIT_LIST_HEAD(&req->msg.transfers);
164
165         /* activate reference, so it has time to settle; */
166         req->xfer[0].tx_buf = &ref_on;
167         req->xfer[0].len = 1;
168         req->xfer[1].rx_buf = &req->scratch;
169         req->xfer[1].len = 2;
170
171         /*
172          * for external VREF, 0 usec (and assume it's always on);
173          * for 1uF, use 800 usec;
174          * no cap, 100 usec.
175          */
176         req->xfer[1].delay_usecs = ts->vref_delay_usecs;
177
178         /* take sample */
179         req->command = (u8) command;
180         req->xfer[2].tx_buf = &req->command;
181         req->xfer[2].len = 1;
182         req->xfer[3].rx_buf = &req->sample;
183         req->xfer[3].len = 2;
184
185         /* REVISIT:  take a few more samples, and compare ... */
186
187         /* turn off reference */
188         req->xfer[4].tx_buf = &ref_off;
189         req->xfer[4].len = 1;
190         req->xfer[5].rx_buf = &req->scratch;
191         req->xfer[5].len = 2;
192
193         CS_CHANGE(req->xfer[5]);
194
195         /* group all the transfers together, so we can't interfere with
196          * reading touchscreen state; disable penirq while sampling
197          */
198         for (i = 0; i < 6; i++)
199                 spi_message_add_tail(&req->xfer[i], &req->msg);
200
201         disable_irq(spi->irq);
202         status = spi_sync(spi, &req->msg);
203         enable_irq(spi->irq);
204
205         if (req->msg.status)
206                 status = req->msg.status;
207         sample = be16_to_cpu(req->sample);
208         sample = sample >> 4;
209         kfree(req);
210
211         return status ? status : sample;
212 }
213
214 #define SHOW(name) static ssize_t \
215 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
216 { \
217         ssize_t v = ads7846_read12_ser(dev, \
218                         READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
219         if (v < 0) \
220                 return v; \
221         return sprintf(buf, "%u\n", (unsigned) v); \
222 } \
223 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
224
225 SHOW(temp0)
226 SHOW(temp1)
227 SHOW(vaux)
228 SHOW(vbatt)
229
230 /*--------------------------------------------------------------------------*/
231
232 /*
233  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
234  * to retrieve touchscreen status.
235  *
236  * The SPI transfer completion callback does the real work.  It reports
237  * touchscreen events and reactivates the timer (or IRQ) as appropriate.
238  */
239
240 static void ads7846_rx(void *ads)
241 {
242         struct ads7846  *ts = ads;
243         unsigned        Rt;
244         unsigned        sync = 0;
245         u16             x, y, z1, z2;
246         unsigned long   flags;
247
248         /* adjust:  12 bit samples (left aligned), built from
249          * two 8 bit values writen msb-first.
250          */
251         x = be16_to_cpu(ts->tc.x) >> 4;
252         y = be16_to_cpu(ts->tc.y) >> 4;
253         z1 = be16_to_cpu(ts->tc.z1) >> 4;
254         z2 = be16_to_cpu(ts->tc.z2) >> 4;
255
256         /* range filtering */
257         if (x == MAX_12BIT)
258                 x = 0;
259
260         if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
261                 /* compute touch pressure resistance using equation #2 */
262                 Rt = z2;
263                 Rt -= z1;
264                 Rt *= x;
265                 Rt *= ts->x_plate_ohms;
266                 Rt /= z1;
267                 Rt = (Rt + 2047) >> 12;
268         } else
269                 Rt = 0;
270
271         /* NOTE:  "pendown" is inferred from pressure; we don't rely on
272          * being able to check nPENIRQ status, or "friendly" trigger modes
273          * (both-edges is much better than just-falling or low-level).
274          *
275          * REVISIT:  some boards may require reading nPENIRQ; it's
276          * needed on 7843.  and 7845 reads pressure differently...
277          *
278          * REVISIT:  the touchscreen might not be connected; this code
279          * won't notice that, even if nPENIRQ never fires ...
280          */
281         if (!ts->pendown && Rt != 0) {
282                 input_report_key(&ts->input, BTN_TOUCH, 1);
283                 sync = 1;
284         } else if (ts->pendown && Rt == 0) {
285                 input_report_key(&ts->input, BTN_TOUCH, 0);
286                 sync = 1;
287         }
288
289         if (Rt) {
290                 input_report_abs(&ts->input, ABS_X, x);
291                 input_report_abs(&ts->input, ABS_Y, y);
292                 input_report_abs(&ts->input, ABS_PRESSURE, Rt);
293                 sync = 1;
294         }
295         if (sync)
296                 input_sync(&ts->input);
297
298 #ifdef  VERBOSE
299         if (Rt || ts->pendown)
300                 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
301                         x, y, Rt, Rt ? "" : " UP");
302 #endif
303
304         /* don't retrigger while we're suspended */
305         spin_lock_irqsave(&ts->lock, flags);
306
307         ts->pendown = (Rt != 0);
308         ts->pending = 0;
309
310         if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
311                 if (ts->pendown)
312                         mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
313                 else if (ts->irq_disabled) {
314                         ts->irq_disabled = 0;
315                         enable_irq(ts->spi->irq);
316                 }
317         }
318
319         spin_unlock_irqrestore(&ts->lock, flags);
320 }
321
322 static void ads7846_timer(unsigned long handle)
323 {
324         struct ads7846  *ts = (void *)handle;
325         int             status = 0;
326         unsigned long   flags;
327
328         spin_lock_irqsave(&ts->lock, flags);
329         if (!ts->pending) {
330                 ts->pending = 1;
331                 if (!ts->irq_disabled) {
332                         ts->irq_disabled = 1;
333                         disable_irq(ts->spi->irq);
334                 }
335                 status = spi_async(ts->spi, &ts->msg);
336                 if (status)
337                         dev_err(&ts->spi->dev, "spi_async --> %d\n",
338                                         status);
339         }
340         spin_unlock_irqrestore(&ts->lock, flags);
341 }
342
343 static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
344 {
345         ads7846_timer((unsigned long) handle);
346         return IRQ_HANDLED;
347 }
348
349 /*--------------------------------------------------------------------------*/
350
351 static int
352 ads7846_suspend(struct spi_device *spi, pm_message_t message)
353 {
354         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
355         unsigned long   flags;
356
357         spin_lock_irqsave(&ts->lock, flags);
358
359         spi->dev.power.power_state = message;
360
361         /* are we waiting for IRQ, or polling? */
362         if (!ts->pendown) {
363                 if (!ts->irq_disabled) {
364                         ts->irq_disabled = 1;
365                         disable_irq(ts->spi->irq);
366                 }
367         } else {
368                 /* polling; force a final SPI completion;
369                  * that will clean things up neatly
370                  */
371                 if (!ts->pending)
372                         mod_timer(&ts->timer, jiffies);
373
374                 while (ts->pendown || ts->pending) {
375                         spin_unlock_irqrestore(&ts->lock, flags);
376                         udelay(10);
377                         spin_lock_irqsave(&ts->lock, flags);
378                 }
379         }
380
381         /* we know the chip's in lowpower mode since we always
382          * leave it that way after every request
383          */
384
385         spin_unlock_irqrestore(&ts->lock, flags);
386         return 0;
387 }
388
389 static int ads7846_resume(struct spi_device *spi)
390 {
391         struct ads7846 *ts = dev_get_drvdata(&spi->dev);
392
393         ts->irq_disabled = 0;
394         enable_irq(ts->spi->irq);
395         spi->dev.power.power_state = PMSG_ON;
396         return 0;
397 }
398
399 static int __devinit ads7846_probe(struct spi_device *spi)
400 {
401         struct ads7846                  *ts;
402         struct ads7846_platform_data    *pdata = spi->dev.platform_data;
403         struct spi_transfer             *x;
404         int                             i;
405
406         if (!spi->irq) {
407                 dev_dbg(&spi->dev, "no IRQ?\n");
408                 return -ENODEV;
409         }
410
411         if (!pdata) {
412                 dev_dbg(&spi->dev, "no platform data?\n");
413                 return -ENODEV;
414         }
415
416         /* don't exceed max specified sample rate */
417         if (spi->max_speed_hz > (125000 * 16)) {
418                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
419                                 (spi->max_speed_hz/16)/1000);
420                 return -EINVAL;
421         }
422
423         /* We'd set the wordsize to 12 bits ... except that some controllers
424          * will then treat the 8 bit command words as 12 bits (and drop the
425          * four MSBs of the 12 bit result).  Result: inputs must be shifted
426          * to discard the four garbage LSBs.
427          */
428
429         if (!(ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL)))
430                 return -ENOMEM;
431
432         dev_set_drvdata(&spi->dev, ts);
433
434         ts->spi = spi;
435         spi->dev.power.power_state = PMSG_ON;
436
437         init_timer(&ts->timer);
438         ts->timer.data = (unsigned long) ts;
439         ts->timer.function = ads7846_timer;
440
441         ts->model = pdata->model ? : 7846;
442         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
443         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
444
445         init_input_dev(&ts->input);
446
447         ts->input.dev = &spi->dev;
448         ts->input.name = "ADS784x Touchscreen";
449         snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id);
450         ts->input.phys = ts->phys;
451
452         ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
453         ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
454         input_set_abs_params(&ts->input, ABS_X,
455                         pdata->x_min ? : 0,
456                         pdata->x_max ? : MAX_12BIT,
457                         0, 0);
458         input_set_abs_params(&ts->input, ABS_Y,
459                         pdata->y_min ? : 0,
460                         pdata->y_max ? : MAX_12BIT,
461                         0, 0);
462         input_set_abs_params(&ts->input, ABS_PRESSURE,
463                         pdata->pressure_min, pdata->pressure_max, 0, 0);
464
465         input_register_device(&ts->input);
466
467         /* set up the transfers to read touchscreen state; this assumes we
468          * use formula #2 for pressure, not #3.
469          */
470         x = ts->xfer;
471
472         /* y- still on; turn on only y+ (and ADC) */
473         x->tx_buf = &read_y;
474         x->len = 1;
475         x++;
476         x->rx_buf = &ts->tc.y;
477         x->len = 2;
478         x++;
479
480         /* turn y+ off, x- on; we'll use formula #2 */
481         if (ts->model == 7846) {
482                 x->tx_buf = &read_z1;
483                 x->len = 1;
484                 x++;
485                 x->rx_buf = &ts->tc.z1;
486                 x->len = 2;
487                 x++;
488
489                 x->tx_buf = &read_z2;
490                 x->len = 1;
491                 x++;
492                 x->rx_buf = &ts->tc.z2;
493                 x->len = 2;
494                 x++;
495         }
496
497         /* turn y- off, x+ on, then leave in lowpower */
498         x->tx_buf = &read_x;
499         x->len = 1;
500         x++;
501         x->rx_buf = &ts->tc.x;
502         x->len = 2;
503         x++;
504
505         CS_CHANGE(x[-1]);
506
507         for (i = 0; i < x - ts->xfer; i++)
508                 spi_message_add_tail(&ts->xfer[i], &ts->msg);
509         ts->msg.complete = ads7846_rx;
510         ts->msg.context = ts;
511
512         if (request_irq(spi->irq, ads7846_irq, SA_SAMPLE_RANDOM,
513                                 spi->dev.bus_id, ts)) {
514                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
515                 input_unregister_device(&ts->input);
516                 kfree(ts);
517                 return -EBUSY;
518         }
519         set_irq_type(spi->irq, IRQT_FALLING);
520
521         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
522
523         /* take a first sample, leaving nPENIRQ active; avoid
524          * the touchscreen, in case it's not connected.
525          */
526         (void) ads7846_read12_ser(&spi->dev,
527                           READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
528
529         /* ads7843/7845 don't have temperature sensors, and
530          * use the other sensors a bit differently too
531          */
532         if (ts->model == 7846) {
533                 device_create_file(&spi->dev, &dev_attr_temp0);
534                 device_create_file(&spi->dev, &dev_attr_temp1);
535         }
536         if (ts->model != 7845)
537                 device_create_file(&spi->dev, &dev_attr_vbatt);
538         device_create_file(&spi->dev, &dev_attr_vaux);
539
540         return 0;
541 }
542
543 static int __devexit ads7846_remove(struct spi_device *spi)
544 {
545         struct ads7846          *ts = dev_get_drvdata(&spi->dev);
546
547         ads7846_suspend(spi, PMSG_SUSPEND);
548         free_irq(ts->spi->irq, ts);
549         if (ts->irq_disabled)
550                 enable_irq(ts->spi->irq);
551
552         if (ts->model == 7846) {
553                 device_remove_file(&spi->dev, &dev_attr_temp0);
554                 device_remove_file(&spi->dev, &dev_attr_temp1);
555         }
556         if (ts->model != 7845)
557                 device_remove_file(&spi->dev, &dev_attr_vbatt);
558         device_remove_file(&spi->dev, &dev_attr_vaux);
559
560         input_unregister_device(&ts->input);
561         kfree(ts);
562
563         dev_dbg(&spi->dev, "unregistered touchscreen\n");
564         return 0;
565 }
566
567 static struct spi_driver ads7846_driver = {
568         .driver = {
569                 .name   = "ads7846",
570                 .bus    = &spi_bus_type,
571                 .owner  = THIS_MODULE,
572         },
573         .probe          = ads7846_probe,
574         .remove         = __devexit_p(ads7846_remove),
575         .suspend        = ads7846_suspend,
576         .resume         = ads7846_resume,
577 };
578
579 static int __init ads7846_init(void)
580 {
581         /* grr, board-specific init should stay out of drivers!! */
582
583 #ifdef  CONFIG_ARCH_OMAP
584         if (machine_is_omap_osk()) {
585                 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
586                 omap_request_gpio(4);
587                 omap_set_gpio_direction(4, 1);
588                 omap_request_gpio(6);
589                 omap_set_gpio_direction(6, 1);
590         }
591         // also TI 1510 Innovator, bitbanging through FPGA
592         // also Nokia 770
593         // also Palm Tungsten T2
594 #endif
595
596         // PXA:
597         // also Dell Axim X50
598         // also HP iPaq H191x/H192x/H415x/H435x
599         // also Intel Lubbock (additional to UCB1400; as temperature sensor)
600         // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
601
602         // Atmel at91sam9261-EK uses ads7843
603
604         // also various AMD Au1x00 devel boards
605
606         return spi_register_driver(&ads7846_driver);
607 }
608 module_init(ads7846_init);
609
610 static void __exit ads7846_exit(void)
611 {
612         spi_unregister_driver(&ads7846_driver);
613
614 #ifdef  CONFIG_ARCH_OMAP
615         if (machine_is_omap_osk()) {
616                 omap_free_gpio(4);
617                 omap_free_gpio(6);
618         }
619 #endif
620
621 }
622 module_exit(ads7846_exit);
623
624 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
625 MODULE_LICENSE("GPL");