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1/*
2 * Intel MID Resistive Touch Screen Driver
3 *
4 * Copyright (C) 2008 Intel Corp
5 *
6 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; version 2 of the License.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20 *
21 * Questions/Comments/Bug fixes to Sreedhara (sreedhara.ds@intel.com)
22 * Ramesh Agarwal (ramesh.agarwal@intel.com)
23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24 *
25 * TODO:
26 * review conversion of r/m/w sequences
27 */
28
29#include <linux/module.h>
30#include <linux/input.h>
31#include <linux/interrupt.h>
32#include <linux/err.h>
33#include <linux/param.h>
34#include <linux/slab.h>
35#include <linux/platform_device.h>
36#include <linux/irq.h>
37#include <linux/delay.h>
38#include <asm/intel_scu_ipc.h>
39
40/* PMIC Interrupt registers */
41#define PMIC_REG_ID1 0x00 /* PMIC ID1 register */
42
43/* PMIC Interrupt registers */
44#define PMIC_REG_INT 0x04 /* PMIC interrupt register */
45#define PMIC_REG_MINT 0x05 /* PMIC interrupt mask register */
46
47/* ADC Interrupt registers */
48#define PMIC_REG_ADCINT 0x5F /* ADC interrupt register */
49#define PMIC_REG_MADCINT 0x60 /* ADC interrupt mask register */
50
51/* ADC Control registers */
52#define PMIC_REG_ADCCNTL1 0x61 /* ADC control register */
53
54/* ADC Channel Selection registers */
55#define PMICADDR0 0xA4
56#define END_OF_CHANNEL 0x1F
57
58/* ADC Result register */
59#define PMIC_REG_ADCSNS0H 0x64
60
61/* ADC channels for touch screen */
62#define MRST_TS_CHAN10 0xA /* Touch screen X+ connection */
63#define MRST_TS_CHAN11 0xB /* Touch screen X- connection */
64#define MRST_TS_CHAN12 0xC /* Touch screen Y+ connection */
65#define MRST_TS_CHAN13 0xD /* Touch screen Y- connection */
66
67/* Touch screen channel BIAS constants */
68#define MRST_XBIAS 0x20
69#define MRST_YBIAS 0x40
70#define MRST_ZBIAS 0x80
71
72/* Touch screen coordinates */
73#define MRST_X_MIN 10
74#define MRST_X_MAX 1024
75#define MRST_X_FUZZ 5
76#define MRST_Y_MIN 10
77#define MRST_Y_MAX 1024
78#define MRST_Y_FUZZ 5
79#define MRST_PRESSURE_MIN 0
80#define MRST_PRESSURE_NOMINAL 50
81#define MRST_PRESSURE_MAX 100
82
83#define WAIT_ADC_COMPLETION 10 /* msec */
84
85/* PMIC ADC round robin delays */
86#define ADC_LOOP_DELAY0 0x0 /* Continuous loop */
87#define ADC_LOOP_DELAY1 0x1 /* 4.5 ms approximate */
88
89/* PMIC Vendor Identifiers */
90#define PMIC_VENDOR_FS 0 /* PMIC vendor FreeScale */
91#define PMIC_VENDOR_MAXIM 1 /* PMIC vendor MAXIM */
92#define PMIC_VENDOR_NEC 2 /* PMIC vendor NEC */
93#define MRSTOUCH_MAX_CHANNELS 32 /* Maximum ADC channels */
94
95/* Touch screen device structure */
96struct mrstouch_dev {
97 struct device *dev; /* device associated with touch screen */
98 struct input_dev *input;
99 char phys[32];
100 u16 asr; /* Address selection register */
101 int irq;
102 unsigned int vendor; /* PMIC vendor */
103 unsigned int rev; /* PMIC revision */
104
105 int (*read_prepare)(struct mrstouch_dev *tsdev);
106 int (*read)(struct mrstouch_dev *tsdev, u16 *x, u16 *y, u16 *z);
107 int (*read_finish)(struct mrstouch_dev *tsdev);
108};
109
110
111/*************************** NEC and Maxim Interface ************************/
112
113static int mrstouch_nec_adc_read_prepare(struct mrstouch_dev *tsdev)
114{
115 return intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0, 0x20);
116}
117
118/*
119 * Enables PENDET interrupt.
120 */
121static int mrstouch_nec_adc_read_finish(struct mrstouch_dev *tsdev)
122{
123 int err;
124
125 err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x20, 0x20);
126 if (!err)
127 err = intel_scu_ipc_update_register(PMIC_REG_ADCCNTL1, 0, 0x05);
128
129 return err;
130}
131
132/*
133 * Reads PMIC ADC touch screen result
134 * Reads ADC storage registers for higher 7 and lower 3 bits and
135 * converts the two readings into a single value and turns off gain bit
136 */
137static int mrstouch_ts_chan_read(u16 offset, u16 chan, u16 *vp, u16 *vm)
138{
139 int err;
140 u16 result;
141 u32 res;
142
143 result = PMIC_REG_ADCSNS0H + offset;
144
145 if (chan == MRST_TS_CHAN12)
146 result += 4;
147
148 err = intel_scu_ipc_ioread32(result, &res);
149 if (err)
150 return err;
151
152 /* Mash the bits up */
153
154 *vp = (res & 0xFF) << 3; /* Highest 7 bits */
155 *vp |= (res >> 8) & 0x07; /* Lower 3 bits */
156 *vp &= 0x3FF;
157
158 res >>= 16;
159
160 *vm = (res & 0xFF) << 3; /* Highest 7 bits */
161 *vm |= (res >> 8) & 0x07; /* Lower 3 bits */
162 *vm &= 0x3FF;
163
164 return 0;
165}
166
167/*
168 * Enables X, Y and Z bias values
169 * Enables YPYM for X channels and XPXM for Y channels
170 */
171static int mrstouch_ts_bias_set(uint offset, uint bias)
172{
173 int count;
174 u16 chan, start;
175 u16 reg[4];
176 u8 data[4];
177
178 chan = PMICADDR0 + offset;
179 start = MRST_TS_CHAN10;
180
181 for (count = 0; count <= 3; count++) {
182 reg[count] = chan++;
183 data[count] = bias | (start + count);
184 }
185
186 return intel_scu_ipc_writev(reg, data, 4);
187}
188
189/* To read touch screen channel values */
190static int mrstouch_nec_adc_read(struct mrstouch_dev *tsdev,
191 u16 *x, u16 *y, u16 *z)
192{
193 int err;
194 u16 xm, ym, zm;
195
196 /* configure Y bias for X channels */
197 err = mrstouch_ts_bias_set(tsdev->asr, MRST_YBIAS);
198 if (err)
199 goto ipc_error;
200
201 msleep(WAIT_ADC_COMPLETION);
202
203 /* read x+ and x- channels */
204 err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN10, x, &xm);
205 if (err)
206 goto ipc_error;
207
208 /* configure x bias for y channels */
209 err = mrstouch_ts_bias_set(tsdev->asr, MRST_XBIAS);
210 if (err)
211 goto ipc_error;
212
213 msleep(WAIT_ADC_COMPLETION);
214
215 /* read y+ and y- channels */
216 err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN12, y, &ym);
217 if (err)
218 goto ipc_error;
219
220 /* configure z bias for x and y channels */
221 err = mrstouch_ts_bias_set(tsdev->asr, MRST_ZBIAS);
222 if (err)
223 goto ipc_error;
224
225 msleep(WAIT_ADC_COMPLETION);
226
227 /* read z+ and z- channels */
228 err = mrstouch_ts_chan_read(tsdev->asr, MRST_TS_CHAN10, z, &zm);
229 if (err)
230 goto ipc_error;
231
232 return 0;
233
234ipc_error:
235 dev_err(tsdev->dev, "ipc error during adc read\n");
236 return err;
237}
238
239
240/*************************** Freescale Interface ************************/
241
242static int mrstouch_fs_adc_read_prepare(struct mrstouch_dev *tsdev)
243{
244 int err, count;
245 u16 chan;
246 u16 reg[5];
247 u8 data[5];
248
249 /* Stop the ADC */
250 err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x00, 0x02);
251 if (err)
252 goto ipc_error;
253
254 chan = PMICADDR0 + tsdev->asr;
255
256 /* Set X BIAS */
257 for (count = 0; count <= 3; count++) {
258 reg[count] = chan++;
259 data[count] = 0x2A;
260 }
261 reg[count] = chan++; /* Dummy */
262 data[count] = 0;
263
264 err = intel_scu_ipc_writev(reg, data, 5);
265 if (err)
266 goto ipc_error;
267
268 msleep(WAIT_ADC_COMPLETION);
269
270 /* Set Y BIAS */
271 for (count = 0; count <= 3; count++) {
272 reg[count] = chan++;
273 data[count] = 0x4A;
274 }
275 reg[count] = chan++; /* Dummy */
276 data[count] = 0;
277
278 err = intel_scu_ipc_writev(reg, data, 5);
279 if (err)
280 goto ipc_error;
281
282 msleep(WAIT_ADC_COMPLETION);
283
284 /* Set Z BIAS */
285 err = intel_scu_ipc_iowrite32(chan + 2, 0x8A8A8A8A);
286 if (err)
287 goto ipc_error;
288
289 msleep(WAIT_ADC_COMPLETION);
290
291 return 0;
292
293ipc_error:
294 dev_err(tsdev->dev, "ipc error during %s\n", __func__);
295 return err;
296}
297
298static int mrstouch_fs_adc_read(struct mrstouch_dev *tsdev,
299 u16 *x, u16 *y, u16 *z)
300{
301 int err;
302 u16 result;
303 u16 reg[4];
304 u8 data[4];
305
306 result = PMIC_REG_ADCSNS0H + tsdev->asr;
307
308 reg[0] = result + 4;
309 reg[1] = result + 5;
310 reg[2] = result + 16;
311 reg[3] = result + 17;
312
313 err = intel_scu_ipc_readv(reg, data, 4);
314 if (err)
315 goto ipc_error;
316
317 *x = data[0] << 3; /* Higher 7 bits */
318 *x |= data[1] & 0x7; /* Lower 3 bits */
319 *x &= 0x3FF;
320
321 *y = data[2] << 3; /* Higher 7 bits */
322 *y |= data[3] & 0x7; /* Lower 3 bits */
323 *y &= 0x3FF;
324
325 /* Read Z value */
326 reg[0] = result + 28;
327 reg[1] = result + 29;
328
329 err = intel_scu_ipc_readv(reg, data, 4);
330 if (err)
331 goto ipc_error;
332
333 *z = data[0] << 3; /* Higher 7 bits */
334 *z |= data[1] & 0x7; /* Lower 3 bits */
335 *z &= 0x3FF;
336
337 return 0;
338
339ipc_error:
340 dev_err(tsdev->dev, "ipc error during %s\n", __func__);
341 return err;
342}
343
344static int mrstouch_fs_adc_read_finish(struct mrstouch_dev *tsdev)
345{
346 int err, count;
347 u16 chan;
348 u16 reg[5];
349 u8 data[5];
350
351 /* Clear all TS channels */
352 chan = PMICADDR0 + tsdev->asr;
353 for (count = 0; count <= 4; count++) {
354 reg[count] = chan++;
355 data[count] = 0;
356 }
357 err = intel_scu_ipc_writev(reg, data, 5);
358 if (err)
359 goto ipc_error;
360
361 for (count = 0; count <= 4; count++) {
362 reg[count] = chan++;
363 data[count] = 0;
364 }
365 err = intel_scu_ipc_writev(reg, data, 5);
366 if (err)
367 goto ipc_error;
368
369 err = intel_scu_ipc_iowrite32(chan + 2, 0x00000000);
370 if (err)
371 goto ipc_error;
372
373 /* Start ADC */
374 err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, 0x02, 0x02);
375 if (err)
376 goto ipc_error;
377
378 return 0;
379
380ipc_error:
381 dev_err(tsdev->dev, "ipc error during %s\n", __func__);
382 return err;
383}
384
385static void mrstouch_report_event(struct input_dev *input,
386 unsigned int x, unsigned int y, unsigned int z)
387{
388 if (z > MRST_PRESSURE_NOMINAL) {
389 /* Pen touched, report button touch and coordinates */
390 input_report_key(input, BTN_TOUCH, 1);
391 input_report_abs(input, ABS_X, x);
392 input_report_abs(input, ABS_Y, y);
393 } else {
394 input_report_key(input, BTN_TOUCH, 0);
395 }
396
397 input_report_abs(input, ABS_PRESSURE, z);
398 input_sync(input);
399}
400
401/* PENDET interrupt handler */
402static irqreturn_t mrstouch_pendet_irq(int irq, void *dev_id)
403{
404 struct mrstouch_dev *tsdev = dev_id;
405 u16 x, y, z;
406
407 /*
408 * Should we lower thread priority? Probably not, since we are
409 * not spinning but sleeping...
410 */
411
412 if (tsdev->read_prepare(tsdev))
413 goto out;
414
415 do {
416 if (tsdev->read(tsdev, &x, &y, &z))
417 break;
418
419 mrstouch_report_event(tsdev->input, x, y, z);
420 } while (z > MRST_PRESSURE_NOMINAL);
421
422 tsdev->read_finish(tsdev);
423
424out:
425 return IRQ_HANDLED;
426}
427
428/* Utility to read PMIC ID */
429static int mrstouch_read_pmic_id(uint *vendor, uint *rev)
430{
431 int err;
432 u8 r;
433
434 err = intel_scu_ipc_ioread8(PMIC_REG_ID1, &r);
435 if (err)
436 return err;
437
438 *vendor = r & 0x7;
439 *rev = (r >> 3) & 0x7;
440
441 return 0;
442}
443
444/*
445 * Parse ADC channels to find end of the channel configured by other ADC user
446 * NEC and MAXIM requires 4 channels and FreeScale needs 18 channels
447 */
448static int mrstouch_chan_parse(struct mrstouch_dev *tsdev)
449{
450 int found = 0;
451 int err, i;
452 u8 r8;
453
454 for (i = 0; i < MRSTOUCH_MAX_CHANNELS; i++) {
455 err = intel_scu_ipc_ioread8(PMICADDR0 + i, &r8);
456 if (err)
457 return err;
458
459 if (r8 == END_OF_CHANNEL) {
460 found = i;
461 break;
462 }
463 }
464
465 if (tsdev->vendor == PMIC_VENDOR_FS) {
466 if (found > MRSTOUCH_MAX_CHANNELS - 18)
467 return -ENOSPC;
468 } else {
469 if (found > MRSTOUCH_MAX_CHANNELS - 4)
470 return -ENOSPC;
471 }
472
473 return found;
474}
475
476
477/*
478 * Writes touch screen channels to ADC address selection registers
479 */
480static int mrstouch_ts_chan_set(uint offset)
481{
482 u16 chan;
483
484 int ret, count;
485
486 chan = PMICADDR0 + offset;
487 for (count = 0; count <= 3; count++) {
488 ret = intel_scu_ipc_iowrite8(chan++, MRST_TS_CHAN10 + count);
489 if (ret)
490 return ret;
491 }
492 return intel_scu_ipc_iowrite8(chan++, END_OF_CHANNEL);
493}
494
495/* Initialize ADC */
496static int mrstouch_adc_init(struct mrstouch_dev *tsdev)
497{
498 int err, start;
499 u8 ra, rm;
500
501 err = mrstouch_read_pmic_id(&tsdev->vendor, &tsdev->rev);
502 if (err) {
503 dev_err(tsdev->dev, "Unable to read PMIC id\n");
504 return err;
505 }
506
507 switch (tsdev->vendor) {
508 case PMIC_VENDOR_NEC:
509 case PMIC_VENDOR_MAXIM:
510 tsdev->read_prepare = mrstouch_nec_adc_read_prepare;
511 tsdev->read = mrstouch_nec_adc_read;
512 tsdev->read_finish = mrstouch_nec_adc_read_finish;
513 break;
514
515 case PMIC_VENDOR_FS:
516 tsdev->read_prepare = mrstouch_fs_adc_read_prepare;
517 tsdev->read = mrstouch_fs_adc_read;
518 tsdev->read_finish = mrstouch_fs_adc_read_finish;
519 break;
520
521 default:
522 dev_err(tsdev->dev,
523 "Unsupported touchscreen: %d\n", tsdev->vendor);
524 return -ENXIO;
525 }
526
527 start = mrstouch_chan_parse(tsdev);
528 if (start < 0) {
529 dev_err(tsdev->dev, "Unable to parse channels\n");
530 return start;
531 }
532
533 tsdev->asr = start;
534
535 /*
536 * ADC power on, start, enable PENDET and set loop delay
537 * ADC loop delay is set to 4.5 ms approximately
538 * Loop delay more than this results in jitter in adc readings
539 * Setting loop delay to 0 (continuous loop) in MAXIM stops PENDET
540 * interrupt generation sometimes.
541 */
542
543 if (tsdev->vendor == PMIC_VENDOR_FS) {
544 ra = 0xE0 | ADC_LOOP_DELAY0;
545 rm = 0x5;
546 } else {
547 /* NEC and MAXIm not consistent with loop delay 0 */
548 ra = 0xE0 | ADC_LOOP_DELAY1;
549 rm = 0x0;
550
551 /* configure touch screen channels */
552 err = mrstouch_ts_chan_set(tsdev->asr);
553 if (err)
554 return err;
555 }
556
557 err = intel_scu_ipc_update_register(PMIC_REG_ADCCNTL1, ra, 0xE7);
558 if (err)
559 return err;
560
561 err = intel_scu_ipc_update_register(PMIC_REG_MADCINT, rm, 0x03);
562 if (err)
563 return err;
564
565 return 0;
566}
567
568
569/* Probe function for touch screen driver */
570static int mrstouch_probe(struct platform_device *pdev)
571{
572 struct mrstouch_dev *tsdev;
573 struct input_dev *input;
574 int err;
575 int irq;
576
577 irq = platform_get_irq(pdev, 0);
578 if (irq < 0) {
579 dev_err(&pdev->dev, "no interrupt assigned\n");
580 return -EINVAL;
581 }
582
583 tsdev = kzalloc(sizeof(struct mrstouch_dev), GFP_KERNEL);
584 input = input_allocate_device();
585 if (!tsdev || !input) {
586 dev_err(&pdev->dev, "unable to allocate memory\n");
587 err = -ENOMEM;
588 goto err_free_mem;
589 }
590
591 tsdev->dev = &pdev->dev;
592 tsdev->input = input;
593 tsdev->irq = irq;
594
595 snprintf(tsdev->phys, sizeof(tsdev->phys),
596 "%s/input0", dev_name(tsdev->dev));
597
598 err = mrstouch_adc_init(tsdev);
599 if (err) {
600 dev_err(&pdev->dev, "ADC initialization failed\n");
601 goto err_free_mem;
602 }
603
604 input->name = "mrst_touchscreen";
605 input->phys = tsdev->phys;
606 input->dev.parent = tsdev->dev;
607
608 input->id.vendor = tsdev->vendor;
609 input->id.version = tsdev->rev;
610
611 input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
612 input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
613
614 input_set_abs_params(tsdev->input, ABS_X,
615 MRST_X_MIN, MRST_X_MAX, MRST_X_FUZZ, 0);
616 input_set_abs_params(tsdev->input, ABS_Y,
617 MRST_Y_MIN, MRST_Y_MAX, MRST_Y_FUZZ, 0);
618 input_set_abs_params(tsdev->input, ABS_PRESSURE,
619 MRST_PRESSURE_MIN, MRST_PRESSURE_MAX, 0, 0);
620
621 err = request_threaded_irq(tsdev->irq, NULL, mrstouch_pendet_irq,
622 IRQF_ONESHOT, "mrstouch", tsdev);
623 if (err) {
624 dev_err(tsdev->dev, "unable to allocate irq\n");
625 goto err_free_mem;
626 }
627
628 err = input_register_device(tsdev->input);
629 if (err) {
630 dev_err(tsdev->dev, "unable to register input device\n");
631 goto err_free_irq;
632 }
633
634 platform_set_drvdata(pdev, tsdev);
635 return 0;
636
637err_free_irq:
638 free_irq(tsdev->irq, tsdev);
639err_free_mem:
640 input_free_device(input);
641 kfree(tsdev);
642 return err;
643}
644
645static int mrstouch_remove(struct platform_device *pdev)
646{
647 struct mrstouch_dev *tsdev = platform_get_drvdata(pdev);
648
649 free_irq(tsdev->irq, tsdev);
650 input_unregister_device(tsdev->input);
651 kfree(tsdev);
652
653 return 0;
654}
655
656static struct platform_driver mrstouch_driver = {
657 .driver = {
658 .name = "pmic_touch",
659 .owner = THIS_MODULE,
660 },
661 .probe = mrstouch_probe,
662 .remove = mrstouch_remove,
663};
664module_platform_driver(mrstouch_driver);
665
666MODULE_AUTHOR("Sreedhara Murthy. D.S, sreedhara.ds@intel.com");
667MODULE_DESCRIPTION("Intel Moorestown Resistive Touch Screen Driver");
668MODULE_LICENSE("GPL");