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authorImre Deak <imre.deak@nokia.com>2006-04-11 23:42:03 -0400
committerDmitry Torokhov <dtor_core@ameritech.net>2006-04-11 23:42:03 -0400
commit0b7018aae7e1798f55f736b9a77c201708aa0e33 (patch)
treeb561dbcdb07540ffc76616894dddfa8f787f9202 /drivers/input/touchscreen/ads7846.c
parent53a0ef89e95c725f3faab98573770aeb7429c1a3 (diff)
Input: ads7846 - debouncing and rudimentary sample filtering
Some touchscreens seem to oscillate heavily for a while after touching the screen.  Implement support for sampling the screen until we get two consecutive values that are close enough. Signed-off-by: Imre Deak <imre.deak@nokia.com> Signed-off-by: Juha Yrjola <juha.yrjola@nokia.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
-rw-r--r--drivers/input/touchscreen/ads7846.c156
1 files changed, 118 insertions, 38 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 54d433477860..8670cd13bd5d 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -77,7 +77,13 @@ struct ads7846 {
77 struct ts_event tc; 77 struct ts_event tc;
78 78
79 struct spi_transfer xfer[10]; 79 struct spi_transfer xfer[10];
80 struct spi_message msg; 80 struct spi_message msg[5];
81 int msg_idx;
82 int read_cnt;
83 int last_read;
84
85 u16 debounce_max;
86 u16 debounce_tol;
81 87
82 spinlock_t lock; 88 spinlock_t lock;
83 struct timer_list timer; /* P: lock */ 89 struct timer_list timer; /* P: lock */
@@ -167,7 +173,7 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
167 if (!req) 173 if (!req)
168 return -ENOMEM; 174 return -ENOMEM;
169 175
170 INIT_LIST_HEAD(&req->msg.transfers); 176 spi_message_init(&req->msg);
171 177
172 /* activate reference, so it has time to settle; */ 178 /* activate reference, so it has time to settle; */
173 req->ref_on = REF_ON; 179 req->ref_on = REF_ON;
@@ -344,31 +350,76 @@ static void ads7846_rx(void *ads)
344 spin_unlock_irqrestore(&ts->lock, flags); 350 spin_unlock_irqrestore(&ts->lock, flags);
345} 351}
346 352
353static void ads7846_debounce(void *ads)
354{
355 struct ads7846 *ts = ads;
356 struct spi_message *m;
357 struct spi_transfer *t;
358 u16 val;
359 int status;
360
361 m = &ts->msg[ts->msg_idx];
362 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
363 val = (*(u16 *)t->rx_buf) >> 3;
364
365 if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol
366 && ts->read_cnt < ts->debounce_max)) {
367 /* Repeat it, if this was the first read or the read wasn't
368 * consistent enough
369 */
370 ts->read_cnt++;
371 ts->last_read = val;
372 } else {
373 /* Go for the next read */
374 ts->msg_idx++;
375 ts->read_cnt = 0;
376 m++;
377 }
378 status = spi_async(ts->spi, m);
379 if (status)
380 dev_err(&ts->spi->dev, "spi_async --> %d\n",
381 status);
382}
383
347static void ads7846_timer(unsigned long handle) 384static void ads7846_timer(unsigned long handle)
348{ 385{
349 struct ads7846 *ts = (void *)handle; 386 struct ads7846 *ts = (void *)handle;
350 int status = 0; 387 int status = 0;
351 unsigned long flags; 388
389 ts->msg_idx = 0;
390 status = spi_async(ts->spi, &ts->msg[0]);
391 if (status)
392 dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
393}
394
395static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
396{
397 struct ads7846 *ts = handle;
398 unsigned long flags;
399 int r = IRQ_HANDLED;
352 400
353 spin_lock_irqsave(&ts->lock, flags); 401 spin_lock_irqsave(&ts->lock, flags);
354 if (!ts->pending) { 402 if (ts->irq_disabled)
355 ts->pending = 1; 403 r = IRQ_HANDLED;
404 else {
356 if (!ts->irq_disabled) { 405 if (!ts->irq_disabled) {
406 /* REVISIT irq logic for many ARM chips has cloned a
407 * bug wherein disabling an irq in its handler won't
408 * work;(it's disabled lazily, and too late to work.
409 * until all their irq logic is fixed, we must shadow
410 * that state here.
411 */
357 ts->irq_disabled = 1; 412 ts->irq_disabled = 1;
413
358 disable_irq(ts->spi->irq); 414 disable_irq(ts->spi->irq);
359 } 415 }
360 status = spi_async(ts->spi, &ts->msg); 416 if (!ts->pending) {
361 if (status) 417 ts->pending = 1;
362 dev_err(&ts->spi->dev, "spi_async --> %d\n", 418 mod_timer(&ts->timer, jiffies);
363 status); 419 }
364 } 420 }
365 spin_unlock_irqrestore(&ts->lock, flags); 421 spin_unlock_irqrestore(&ts->lock, flags);
366} 422 return r;
367
368static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
369{
370 ads7846_timer((unsigned long) handle);
371 return IRQ_HANDLED;
372} 423}
373 424
374/*--------------------------------------------------------------------------*/ 425/*--------------------------------------------------------------------------*/
@@ -426,6 +477,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
426 struct ads7846 *ts; 477 struct ads7846 *ts;
427 struct input_dev *input_dev; 478 struct input_dev *input_dev;
428 struct ads7846_platform_data *pdata = spi->dev.platform_data; 479 struct ads7846_platform_data *pdata = spi->dev.platform_data;
480 struct spi_message *m;
429 struct spi_transfer *x; 481 struct spi_transfer *x;
430 int err; 482 int err;
431 483
@@ -472,6 +524,8 @@ static int __devinit ads7846_probe(struct spi_device *spi)
472 ts->model = pdata->model ? : 7846; 524 ts->model = pdata->model ? : 7846;
473 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 525 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
474 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 526 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
527 ts->debounce_max = pdata->debounce_max ? : 1;
528 ts->debounce_tol = pdata->debounce_tol ? : 10;
475 529
476 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); 530 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
477 531
@@ -495,72 +549,98 @@ static int __devinit ads7846_probe(struct spi_device *spi)
495 /* set up the transfers to read touchscreen state; this assumes we 549 /* set up the transfers to read touchscreen state; this assumes we
496 * use formula #2 for pressure, not #3. 550 * use formula #2 for pressure, not #3.
497 */ 551 */
498 INIT_LIST_HEAD(&ts->msg.transfers); 552 m = &ts->msg[0];
499 x = ts->xfer; 553 x = ts->xfer;
500 554
555 spi_message_init(m);
556
501 /* y- still on; turn on only y+ (and ADC) */ 557 /* y- still on; turn on only y+ (and ADC) */
502 ts->read_y = READ_Y; 558 ts->read_y = READ_Y;
503 x->tx_buf = &ts->read_y; 559 x->tx_buf = &ts->read_y;
504 x->len = 1; 560 x->len = 1;
505 spi_message_add_tail(x, &ts->msg); 561 spi_message_add_tail(x, m);
506 562
507 x++; 563 x++;
508 x->rx_buf = &ts->tc.y; 564 x->rx_buf = &ts->tc.y;
509 x->len = 2; 565 x->len = 2;
510 spi_message_add_tail(x, &ts->msg); 566 spi_message_add_tail(x, m);
567
568 m->complete = ads7846_debounce;
569 m->context = ts;
570
571 m++;
572 spi_message_init(m);
573
574 /* turn y- off, x+ on, then leave in lowpower */
575 x++;
576 ts->read_x = READ_X;
577 x->tx_buf = &ts->read_x;
578 x->len = 1;
579 spi_message_add_tail(x, m);
580
581 x++;
582 x->rx_buf = &ts->tc.x;
583 x->len = 2;
584 spi_message_add_tail(x, m);
585
586 m->complete = ads7846_debounce;
587 m->context = ts;
511 588
512 /* turn y+ off, x- on; we'll use formula #2 */ 589 /* turn y+ off, x- on; we'll use formula #2 */
513 if (ts->model == 7846) { 590 if (ts->model == 7846) {
591 m++;
592 spi_message_init(m);
593
514 x++; 594 x++;
515 ts->read_z1 = READ_Z1; 595 ts->read_z1 = READ_Z1;
516 x->tx_buf = &ts->read_z1; 596 x->tx_buf = &ts->read_z1;
517 x->len = 1; 597 x->len = 1;
518 spi_message_add_tail(x, &ts->msg); 598 spi_message_add_tail(x, m);
519 599
520 x++; 600 x++;
521 x->rx_buf = &ts->tc.z1; 601 x->rx_buf = &ts->tc.z1;
522 x->len = 2; 602 x->len = 2;
523 spi_message_add_tail(x, &ts->msg); 603 spi_message_add_tail(x, m);
604
605 m->complete = ads7846_debounce;
606 m->context = ts;
607
608 m++;
609 spi_message_init(m);
524 610
525 x++; 611 x++;
526 ts->read_z2 = READ_Z2; 612 ts->read_z2 = READ_Z2;
527 x->tx_buf = &ts->read_z2; 613 x->tx_buf = &ts->read_z2;
528 x->len = 1; 614 x->len = 1;
529 spi_message_add_tail(x, &ts->msg); 615 spi_message_add_tail(x, m);
530 616
531 x++; 617 x++;
532 x->rx_buf = &ts->tc.z2; 618 x->rx_buf = &ts->tc.z2;
533 x->len = 2; 619 x->len = 2;
534 spi_message_add_tail(x, &ts->msg); 620 spi_message_add_tail(x, m);
535 }
536 621
537 /* turn y- off, x+ on, then leave in lowpower */ 622 m->complete = ads7846_debounce;
538 x++; 623 m->context = ts;
539 ts->read_x = READ_X; 624 }
540 x->tx_buf = &ts->read_x;
541 x->len = 1;
542 spi_message_add_tail(x, &ts->msg);
543
544 x++;
545 x->rx_buf = &ts->tc.x;
546 x->len = 2;
547 spi_message_add_tail(x, &ts->msg);
548 625
549 /* power down */ 626 /* power down */
627 m++;
628 spi_message_init(m);
629
550 x++; 630 x++;
551 ts->pwrdown = PWRDOWN; 631 ts->pwrdown = PWRDOWN;
552 x->tx_buf = &ts->pwrdown; 632 x->tx_buf = &ts->pwrdown;
553 x->len = 1; 633 x->len = 1;
554 spi_message_add_tail(x, &ts->msg); 634 spi_message_add_tail(x, m);
555 635
556 x++; 636 x++;
557 x->rx_buf = &ts->dummy; 637 x->rx_buf = &ts->dummy;
558 x->len = 2; 638 x->len = 2;
559 CS_CHANGE(*x); 639 CS_CHANGE(*x);
560 spi_message_add_tail(x, &ts->msg); 640 spi_message_add_tail(x, m);
561 641
562 ts->msg.complete = ads7846_rx; 642 m->complete = ads7846_rx;
563 ts->msg.context = ts; 643 m->context = ts;
564 644
565 if (request_irq(spi->irq, ads7846_irq, 645 if (request_irq(spi->irq, ads7846_irq,
566 SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING, 646 SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,