2 * ADS7846 based touchscreen and sensor driver
4 * Copyright (c) 2005 David Brownell
5 * Copyright (c) 2006 Nokia Corporation
6 * Various changes: Imre Deak <imre.deak@nokia.com>
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
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.
20 #include <linux/hwmon.h>
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/delay.h>
24 #include <linux/input.h>
25 #include <linux/interrupt.h>
26 #include <linux/slab.h>
27 #include <linux/gpio.h>
28 #include <linux/spi/spi.h>
29 #include <linux/spi/ads7846.h>
33 * This code has been heavily tested on a Nokia 770, and lightly
34 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
35 * TSC2046 is just newer ads7846 silicon.
36 * Support for ads7843 tested on Atmel at91sam926x-EK.
37 * Support for ads7845 has only been stubbed in.
39 * IRQ handling needs a workaround because of a shortcoming in handling
40 * edge triggered IRQs on some platforms like the OMAP1/2. These
41 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
42 * have to maintain our own SW IRQ disabled status. This should be
43 * removed as soon as the affected platform's IRQ handling is fixed.
45 * App note sbaa036 talks in more detail about accurate sampling...
46 * that ought to help in situations like LCDs inducing noise (which
47 * can also be helped by using synch signals) and more generally.
48 * This driver tries to utilize the measures described in the app
49 * note. The strength of filtering can be set in the board-* specific
53 #define TS_POLL_DELAY (1 * 1000000) /* ns delay before the first sample */
54 #define TS_POLL_PERIOD (5 * 1000000) /* ns delay between samples */
56 /* this driver doesn't aim at the peak continuous sample rate */
57 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
60 /* For portability, we can't read 12 bit values using SPI (which
61 * would make the controller deliver them as native byteorder u16
62 * with msbs zeroed). Instead, we read them as two 8-bit values,
63 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
72 * We allocate this separately to avoid cache line sharing issues when
73 * driver is used with DMA-based SPI controllers (like atmel_spi) on
74 * systems where main memory is not DMA-coherent (most non-x86 boards).
76 struct ads7846_packet {
77 u8 read_x, read_y, read_z1, read_z2, pwrdown;
78 u16 dummy; /* for the pwrdown read */
83 struct input_dev *input;
87 struct spi_device *spi;
89 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
90 struct attribute_group *attr_group;
102 struct ads7846_packet *packet;
104 struct spi_transfer xfer[18];
105 struct spi_message msg[5];
106 struct spi_message *last_msg;
116 u16 penirq_recheck_delay_usecs;
119 struct hrtimer timer;
120 unsigned pendown:1; /* P: lock */
121 unsigned pending:1; /* P: lock */
122 // FIXME remove "irq_disabled"
123 unsigned irq_disabled:1; /* P: lock */
125 unsigned is_suspended:1;
127 int (*filter)(void *data, int data_idx, int *val);
129 void (*filter_cleanup)(void *data);
130 int (*get_pendown_state)(void);
133 void (*wait_for_sync)(void);
136 /* leave chip selected when we're done, for quicker re-select? */
138 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
140 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
143 /*--------------------------------------------------------------------------*/
145 /* The ADS7846 has touchscreen and other sensors.
146 * Earlier ads784x chips are somewhat compatible.
148 #define ADS_START (1 << 7)
149 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
150 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
151 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
152 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
153 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
154 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
155 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
156 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
157 #define ADS_8_BIT (1 << 3)
158 #define ADS_12_BIT (0 << 3)
159 #define ADS_SER (1 << 2) /* non-differential */
160 #define ADS_DFR (0 << 2) /* differential */
161 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */
162 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
163 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
164 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
166 #define MAX_12BIT ((1<<12)-1)
168 /* leave ADC powered up (disables penirq) between differential samples */
169 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
170 | ADS_12_BIT | ADS_DFR | \
171 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
173 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
174 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
175 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
177 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
178 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
180 /* single-ended samples need to first power up reference voltage;
181 * we leave both ADC and VREF powered
183 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
184 | ADS_12_BIT | ADS_SER)
186 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
187 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
189 /*--------------------------------------------------------------------------*/
192 * Non-touchscreen sensors only use single-ended conversions.
193 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
194 * ads7846 lets that pin be unconnected, to use internal vREF.
203 struct spi_message msg;
204 struct spi_transfer xfer[6];
207 static void ads7846_enable(struct ads7846 *ts);
208 static void ads7846_disable(struct ads7846 *ts);
210 static int device_suspended(struct device *dev)
212 struct ads7846 *ts = dev_get_drvdata(dev);
213 return ts->is_suspended || ts->disabled;
216 static int ads7846_read12_ser(struct device *dev, unsigned command)
218 struct spi_device *spi = to_spi_device(dev);
219 struct ads7846 *ts = dev_get_drvdata(dev);
220 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL);
227 spi_message_init(&req->msg);
229 /* FIXME boards with ads7846 might use external vref instead ... */
230 use_internal = (ts->model == 7846);
232 /* maybe turn on internal vREF, and let it settle */
234 req->ref_on = REF_ON;
235 req->xfer[0].tx_buf = &req->ref_on;
236 req->xfer[0].len = 1;
237 spi_message_add_tail(&req->xfer[0], &req->msg);
239 req->xfer[1].rx_buf = &req->scratch;
240 req->xfer[1].len = 2;
242 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
243 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
244 spi_message_add_tail(&req->xfer[1], &req->msg);
248 req->command = (u8) command;
249 req->xfer[2].tx_buf = &req->command;
250 req->xfer[2].len = 1;
251 spi_message_add_tail(&req->xfer[2], &req->msg);
253 req->xfer[3].rx_buf = &req->sample;
254 req->xfer[3].len = 2;
255 spi_message_add_tail(&req->xfer[3], &req->msg);
257 /* REVISIT: take a few more samples, and compare ... */
259 /* converter in low power mode & enable PENIRQ */
260 req->ref_off = PWRDOWN;
261 req->xfer[4].tx_buf = &req->ref_off;
262 req->xfer[4].len = 1;
263 spi_message_add_tail(&req->xfer[4], &req->msg);
265 req->xfer[5].rx_buf = &req->scratch;
266 req->xfer[5].len = 2;
267 CS_CHANGE(req->xfer[5]);
268 spi_message_add_tail(&req->xfer[5], &req->msg);
270 ts->irq_disabled = 1;
271 disable_irq(spi->irq);
272 status = spi_sync(spi, &req->msg);
273 ts->irq_disabled = 0;
274 enable_irq(spi->irq);
277 /* on-wire is a must-ignore bit, a BE12 value, then padding */
278 status = be16_to_cpu(req->sample);
279 status = status >> 3;
287 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
289 #define SHOW(name, var, adjust) static ssize_t \
290 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
292 struct ads7846 *ts = dev_get_drvdata(dev); \
293 ssize_t v = ads7846_read12_ser(dev, \
294 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
297 return sprintf(buf, "%u\n", adjust(ts, v)); \
299 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
302 /* Sysfs conventions report temperatures in millidegrees Celsius.
303 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
304 * accuracy scheme without calibration data. For now we won't try either;
305 * userspace sees raw sensor values, and must scale/calibrate appropriately.
307 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
312 SHOW(temp0, temp0, null_adjust) /* temp1_input */
313 SHOW(temp1, temp1, null_adjust) /* temp2_input */
316 /* sysfs conventions report voltages in millivolts. We can convert voltages
317 * if we know vREF. userspace may need to scale vAUX to match the board's
318 * external resistors; we assume that vBATT only uses the internal ones.
320 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
324 /* external resistors may scale vAUX into 0..vREF */
325 retval *= ts->vref_mv;
326 retval = retval >> 12;
330 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
332 unsigned retval = vaux_adjust(ts, v);
334 /* ads7846 has a resistor ladder to scale this signal down */
335 if (ts->model == 7846)
340 SHOW(in0_input, vaux, vaux_adjust)
341 SHOW(in1_input, vbatt, vbatt_adjust)
344 static struct attribute *ads7846_attributes[] = {
345 &dev_attr_temp0.attr,
346 &dev_attr_temp1.attr,
347 &dev_attr_in0_input.attr,
348 &dev_attr_in1_input.attr,
352 static struct attribute_group ads7846_attr_group = {
353 .attrs = ads7846_attributes,
356 static struct attribute *ads7843_attributes[] = {
357 &dev_attr_in0_input.attr,
358 &dev_attr_in1_input.attr,
362 static struct attribute_group ads7843_attr_group = {
363 .attrs = ads7843_attributes,
366 static struct attribute *ads7845_attributes[] = {
367 &dev_attr_in0_input.attr,
371 static struct attribute_group ads7845_attr_group = {
372 .attrs = ads7845_attributes,
375 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
377 struct device *hwmon;
380 /* hwmon sensors need a reference voltage */
384 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
392 "external vREF for ADS%d not specified\n",
399 /* different chips have different sensor groups */
402 ts->attr_group = &ads7846_attr_group;
405 ts->attr_group = &ads7845_attr_group;
408 ts->attr_group = &ads7843_attr_group;
411 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
415 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
419 hwmon = hwmon_device_register(&spi->dev);
421 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
422 return PTR_ERR(hwmon);
429 static void ads784x_hwmon_unregister(struct spi_device *spi,
433 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
434 hwmon_device_unregister(ts->hwmon);
439 static inline int ads784x_hwmon_register(struct spi_device *spi,
445 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
451 static int is_pen_down(struct device *dev)
453 struct ads7846 *ts = dev_get_drvdata(dev);
458 static ssize_t ads7846_pen_down_show(struct device *dev,
459 struct device_attribute *attr, char *buf)
461 return sprintf(buf, "%u\n", is_pen_down(dev));
464 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
466 static ssize_t ads7846_disable_show(struct device *dev,
467 struct device_attribute *attr, char *buf)
469 struct ads7846 *ts = dev_get_drvdata(dev);
471 return sprintf(buf, "%u\n", ts->disabled);
474 static ssize_t ads7846_disable_store(struct device *dev,
475 struct device_attribute *attr,
476 const char *buf, size_t count)
478 struct ads7846 *ts = dev_get_drvdata(dev);
481 if (strict_strtoul(buf, 10, &i))
484 spin_lock_irq(&ts->lock);
491 spin_unlock_irq(&ts->lock);
496 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
498 static struct attribute *ads784x_attributes[] = {
499 &dev_attr_pen_down.attr,
500 &dev_attr_disable.attr,
504 static struct attribute_group ads784x_attr_group = {
505 .attrs = ads784x_attributes,
508 /*--------------------------------------------------------------------------*/
510 static int get_pendown_state(struct ads7846 *ts)
512 if (ts->get_pendown_state)
513 return ts->get_pendown_state();
515 return !gpio_get_value(ts->gpio_pendown);
518 static void null_wait_for_sync(void)
523 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer,
524 * to retrieve touchscreen status.
526 * The SPI transfer completion callback does the real work. It reports
527 * touchscreen events and reactivates the timer (or IRQ) as appropriate.
530 static void ads7846_rx(void *ads)
532 struct ads7846 *ts = ads;
533 struct ads7846_packet *packet = ts->packet;
537 /* ads7846_rx_val() did in-place conversion (including byteswap) from
538 * on-the-wire format as part of debouncing to get stable readings.
545 /* range filtering */
549 if (ts->model == 7843) {
550 Rt = ts->pressure_max / 2;
551 } else if (likely(x && z1)) {
552 /* compute touch pressure resistance using equation #2 */
556 Rt *= ts->x_plate_ohms;
558 Rt = (Rt + 2047) >> 12;
563 /* Sample found inconsistent by debouncing or pressure is beyond
564 * the maximum. Don't report it to user space, repeat at least
565 * once more the measurement
567 if (packet->tc.ignore || Rt > ts->pressure_max) {
568 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
569 packet->tc.ignore, Rt);
570 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
575 /* Maybe check the pendown state before reporting. This discards
576 * false readings when the pen is lifted.
578 if (ts->penirq_recheck_delay_usecs) {
579 udelay(ts->penirq_recheck_delay_usecs);
580 if (!get_pendown_state(ts))
584 /* NOTE: We can't rely on the pressure to determine the pen down
585 * state, even this controller has a pressure sensor. The pressure
586 * value can fluctuate for quite a while after lifting the pen and
587 * in some cases may not even settle at the expected value.
589 * The only safe way to check for the pen up condition is in the
590 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
593 struct input_dev *input = ts->input;
596 input_report_key(input, BTN_TOUCH, 1);
598 dev_vdbg(&ts->spi->dev, "DOWN\n");
604 input_report_abs(input, ABS_X, x);
605 input_report_abs(input, ABS_Y, y);
606 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
609 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
612 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
616 static int ads7846_debounce(void *ads, int data_idx, int *val)
618 struct ads7846 *ts = ads;
620 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
621 /* Start over collecting consistent readings. */
623 /* Repeat it, if this was the first read or the read
624 * wasn't consistent enough. */
625 if (ts->read_cnt < ts->debounce_max) {
626 ts->last_read = *val;
628 return ADS7846_FILTER_REPEAT;
630 /* Maximum number of debouncing reached and still
631 * not enough number of consistent readings. Abort
632 * the whole sample, repeat it in the next sampling
636 return ADS7846_FILTER_IGNORE;
639 if (++ts->read_rep > ts->debounce_rep) {
640 /* Got a good reading for this coordinate,
641 * go for the next one. */
644 return ADS7846_FILTER_OK;
646 /* Read more values that are consistent. */
648 return ADS7846_FILTER_REPEAT;
653 static int ads7846_no_filter(void *ads, int data_idx, int *val)
655 return ADS7846_FILTER_OK;
658 static void ads7846_rx_val(void *ads)
660 struct ads7846 *ts = ads;
661 struct ads7846_packet *packet = ts->packet;
662 struct spi_message *m;
663 struct spi_transfer *t;
668 m = &ts->msg[ts->msg_idx];
669 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
671 /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding;
672 * built from two 8 bit values written msb-first.
674 val = be16_to_cpup((__be16 *)t->rx_buf) >> 3;
676 action = ts->filter(ts->filter_data, ts->msg_idx, &val);
678 case ADS7846_FILTER_REPEAT:
680 case ADS7846_FILTER_IGNORE:
681 packet->tc.ignore = 1;
682 /* Last message will contain ads7846_rx() as the
683 * completion function.
687 case ADS7846_FILTER_OK:
688 *(u16 *)t->rx_buf = val;
689 packet->tc.ignore = 0;
690 m = &ts->msg[++ts->msg_idx];
696 status = spi_async(ts->spi, m);
698 dev_err(&ts->spi->dev, "spi_async --> %d\n",
702 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
704 struct ads7846 *ts = container_of(handle, struct ads7846, timer);
707 spin_lock(&ts->lock);
709 if (unlikely(!get_pendown_state(ts) ||
710 device_suspended(&ts->spi->dev))) {
712 struct input_dev *input = ts->input;
714 input_report_key(input, BTN_TOUCH, 0);
715 input_report_abs(input, ABS_PRESSURE, 0);
719 dev_vdbg(&ts->spi->dev, "UP\n");
722 /* measurement cycle ended */
723 if (!device_suspended(&ts->spi->dev)) {
724 ts->irq_disabled = 0;
725 enable_irq(ts->spi->irq);
729 /* pen is still down, continue with the measurement */
732 status = spi_async(ts->spi, &ts->msg[0]);
734 dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
737 spin_unlock(&ts->lock);
738 return HRTIMER_NORESTART;
741 static irqreturn_t ads7846_irq(int irq, void *handle)
743 struct ads7846 *ts = handle;
746 spin_lock_irqsave(&ts->lock, flags);
747 if (likely(get_pendown_state(ts))) {
748 if (!ts->irq_disabled) {
749 /* The ARM do_simple_IRQ() dispatcher doesn't act
750 * like the other dispatchers: it will report IRQs
751 * even after they've been disabled. We work around
752 * that here. (The "generic irq" framework may help...)
754 ts->irq_disabled = 1;
755 disable_irq_nosync(ts->spi->irq);
757 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
761 spin_unlock_irqrestore(&ts->lock, flags);
766 /*--------------------------------------------------------------------------*/
768 /* Must be called with ts->lock held */
769 static void ads7846_disable(struct ads7846 *ts)
776 /* are we waiting for IRQ, or polling? */
778 ts->irq_disabled = 1;
779 disable_irq(ts->spi->irq);
781 /* the timer will run at least once more, and
782 * leave everything in a clean state, IRQ disabled
784 while (ts->pending) {
785 spin_unlock_irq(&ts->lock);
787 spin_lock_irq(&ts->lock);
791 /* we know the chip's in lowpower mode since we always
792 * leave it that way after every request
796 /* Must be called with ts->lock held */
797 static void ads7846_enable(struct ads7846 *ts)
803 ts->irq_disabled = 0;
804 enable_irq(ts->spi->irq);
807 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
809 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
811 spin_lock_irq(&ts->lock);
813 ts->is_suspended = 1;
816 spin_unlock_irq(&ts->lock);
822 static int ads7846_resume(struct spi_device *spi)
824 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
826 spin_lock_irq(&ts->lock);
828 ts->is_suspended = 0;
831 spin_unlock_irq(&ts->lock);
836 static int __devinit setup_pendown(struct spi_device *spi, struct ads7846 *ts)
838 struct ads7846_platform_data *pdata = spi->dev.platform_data;
841 /* REVISIT when the irq can be triggered active-low, or if for some
842 * reason the touchscreen isn't hooked up, we don't need to access
845 if (!pdata->get_pendown_state && !gpio_is_valid(pdata->gpio_pendown)) {
846 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
850 if (pdata->get_pendown_state) {
851 ts->get_pendown_state = pdata->get_pendown_state;
855 err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
857 dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
858 pdata->gpio_pendown);
862 ts->gpio_pendown = pdata->gpio_pendown;
866 static int __devinit ads7846_probe(struct spi_device *spi)
869 struct ads7846_packet *packet;
870 struct input_dev *input_dev;
871 struct ads7846_platform_data *pdata = spi->dev.platform_data;
872 struct spi_message *m;
873 struct spi_transfer *x;
878 dev_dbg(&spi->dev, "no IRQ?\n");
883 dev_dbg(&spi->dev, "no platform data?\n");
887 /* don't exceed max specified sample rate */
888 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
889 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
890 (spi->max_speed_hz/SAMPLE_BITS)/1000);
894 /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
895 * that even if the hardware can do that, the SPI controller driver
896 * may not. So we stick to very-portable 8 bit words, both RX and TX.
898 spi->bits_per_word = 8;
899 spi->mode = SPI_MODE_0;
900 err = spi_setup(spi);
904 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
905 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
906 input_dev = input_allocate_device();
907 if (!ts || !packet || !input_dev) {
912 dev_set_drvdata(&spi->dev, ts);
916 ts->input = input_dev;
917 ts->vref_mv = pdata->vref_mv;
918 ts->swap_xy = pdata->swap_xy;
920 hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
921 ts->timer.function = ads7846_timer;
923 spin_lock_init(&ts->lock);
925 ts->model = pdata->model ? : 7846;
926 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
927 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
928 ts->pressure_max = pdata->pressure_max ? : ~0;
930 if (pdata->filter != NULL) {
931 if (pdata->filter_init != NULL) {
932 err = pdata->filter_init(pdata, &ts->filter_data);
936 ts->filter = pdata->filter;
937 ts->filter_cleanup = pdata->filter_cleanup;
938 } else if (pdata->debounce_max) {
939 ts->debounce_max = pdata->debounce_max;
940 if (ts->debounce_max < 2)
941 ts->debounce_max = 2;
942 ts->debounce_tol = pdata->debounce_tol;
943 ts->debounce_rep = pdata->debounce_rep;
944 ts->filter = ads7846_debounce;
945 ts->filter_data = ts;
947 ts->filter = ads7846_no_filter;
949 err = setup_pendown(spi, ts);
951 goto err_cleanup_filter;
953 if (pdata->penirq_recheck_delay_usecs)
954 ts->penirq_recheck_delay_usecs =
955 pdata->penirq_recheck_delay_usecs;
957 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
959 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
960 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
962 input_dev->name = ts->name;
963 input_dev->phys = ts->phys;
964 input_dev->dev.parent = &spi->dev;
966 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
967 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
968 input_set_abs_params(input_dev, ABS_X,
970 pdata->x_max ? : MAX_12BIT,
972 input_set_abs_params(input_dev, ABS_Y,
974 pdata->y_max ? : MAX_12BIT,
976 input_set_abs_params(input_dev, ABS_PRESSURE,
977 pdata->pressure_min, pdata->pressure_max, 0, 0);
979 vref = pdata->keep_vref_on;
981 /* set up the transfers to read touchscreen state; this assumes we
982 * use formula #2 for pressure, not #3.
989 /* y- still on; turn on only y+ (and ADC) */
990 packet->read_y = READ_Y(vref);
991 x->tx_buf = &packet->read_y;
993 spi_message_add_tail(x, m);
996 x->rx_buf = &packet->tc.y;
998 spi_message_add_tail(x, m);
1000 /* the first sample after switching drivers can be low quality;
1001 * optionally discard it, using a second one after the signals
1002 * have had enough time to stabilize.
1004 if (pdata->settle_delay_usecs) {
1005 x->delay_usecs = pdata->settle_delay_usecs;
1008 x->tx_buf = &packet->read_y;
1010 spi_message_add_tail(x, m);
1013 x->rx_buf = &packet->tc.y;
1015 spi_message_add_tail(x, m);
1018 m->complete = ads7846_rx_val;
1022 spi_message_init(m);
1024 /* turn y- off, x+ on, then leave in lowpower */
1026 packet->read_x = READ_X(vref);
1027 x->tx_buf = &packet->read_x;
1029 spi_message_add_tail(x, m);
1032 x->rx_buf = &packet->tc.x;
1034 spi_message_add_tail(x, m);
1036 /* ... maybe discard first sample ... */
1037 if (pdata->settle_delay_usecs) {
1038 x->delay_usecs = pdata->settle_delay_usecs;
1041 x->tx_buf = &packet->read_x;
1043 spi_message_add_tail(x, m);
1046 x->rx_buf = &packet->tc.x;
1048 spi_message_add_tail(x, m);
1051 m->complete = ads7846_rx_val;
1054 /* turn y+ off, x- on; we'll use formula #2 */
1055 if (ts->model == 7846) {
1057 spi_message_init(m);
1060 packet->read_z1 = READ_Z1(vref);
1061 x->tx_buf = &packet->read_z1;
1063 spi_message_add_tail(x, m);
1066 x->rx_buf = &packet->tc.z1;
1068 spi_message_add_tail(x, m);
1070 /* ... maybe discard first sample ... */
1071 if (pdata->settle_delay_usecs) {
1072 x->delay_usecs = pdata->settle_delay_usecs;
1075 x->tx_buf = &packet->read_z1;
1077 spi_message_add_tail(x, m);
1080 x->rx_buf = &packet->tc.z1;
1082 spi_message_add_tail(x, m);
1085 m->complete = ads7846_rx_val;
1089 spi_message_init(m);
1092 packet->read_z2 = READ_Z2(vref);
1093 x->tx_buf = &packet->read_z2;
1095 spi_message_add_tail(x, m);
1098 x->rx_buf = &packet->tc.z2;
1100 spi_message_add_tail(x, m);
1102 /* ... maybe discard first sample ... */
1103 if (pdata->settle_delay_usecs) {
1104 x->delay_usecs = pdata->settle_delay_usecs;
1107 x->tx_buf = &packet->read_z2;
1109 spi_message_add_tail(x, m);
1112 x->rx_buf = &packet->tc.z2;
1114 spi_message_add_tail(x, m);
1117 m->complete = ads7846_rx_val;
1123 spi_message_init(m);
1126 packet->pwrdown = PWRDOWN;
1127 x->tx_buf = &packet->pwrdown;
1129 spi_message_add_tail(x, m);
1132 x->rx_buf = &packet->dummy;
1135 spi_message_add_tail(x, m);
1137 m->complete = ads7846_rx;
1142 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
1143 spi->dev.driver->name, ts)) {
1145 "trying pin change workaround on irq %d\n", spi->irq);
1146 err = request_irq(spi->irq, ads7846_irq,
1147 IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
1148 spi->dev.driver->name, ts);
1150 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1155 err = ads784x_hwmon_register(spi, ts);
1159 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1161 /* take a first sample, leaving nPENIRQ active and vREF off; avoid
1162 * the touchscreen, in case it's not connected.
1164 (void) ads7846_read12_ser(&spi->dev,
1165 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1167 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1169 goto err_remove_hwmon;
1171 err = input_register_device(input_dev);
1173 goto err_remove_attr_group;
1177 err_remove_attr_group:
1178 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1180 ads784x_hwmon_unregister(spi, ts);
1182 free_irq(spi->irq, ts);
1184 if (ts->gpio_pendown != -1)
1185 gpio_free(ts->gpio_pendown);
1187 if (ts->filter_cleanup)
1188 ts->filter_cleanup(ts->filter_data);
1190 input_free_device(input_dev);
1196 static int __devexit ads7846_remove(struct spi_device *spi)
1198 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1200 ads784x_hwmon_unregister(spi, ts);
1201 input_unregister_device(ts->input);
1203 ads7846_suspend(spi, PMSG_SUSPEND);
1205 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1207 free_irq(ts->spi->irq, ts);
1208 /* suspend left the IRQ disabled */
1209 enable_irq(ts->spi->irq);
1211 if (ts->gpio_pendown != -1)
1212 gpio_free(ts->gpio_pendown);
1214 if (ts->filter_cleanup)
1215 ts->filter_cleanup(ts->filter_data);
1220 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1224 static struct spi_driver ads7846_driver = {
1227 .bus = &spi_bus_type,
1228 .owner = THIS_MODULE,
1230 .probe = ads7846_probe,
1231 .remove = __devexit_p(ads7846_remove),
1232 .suspend = ads7846_suspend,
1233 .resume = ads7846_resume,
1236 static int __init ads7846_init(void)
1238 return spi_register_driver(&ads7846_driver);
1240 module_init(ads7846_init);
1242 static void __exit ads7846_exit(void)
1244 spi_unregister_driver(&ads7846_driver);
1246 module_exit(ads7846_exit);
1248 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1249 MODULE_LICENSE("GPL");
1250 MODULE_ALIAS("spi:ads7846");