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/types.h>
21 #include <linux/hwmon.h>
22 #include <linux/init.h>
23 #include <linux/err.h>
24 #include <linux/sched.h>
25 #include <linux/delay.h>
26 #include <linux/input.h>
27 #include <linux/interrupt.h>
28 #include <linux/slab.h>
30 #include <linux/gpio.h>
31 #include <linux/spi/spi.h>
32 #include <linux/spi/ads7846.h>
33 #include <linux/regulator/consumer.h>
34 #include <linux/module.h>
38 * This code has been heavily tested on a Nokia 770, and lightly
39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
40 * TSC2046 is just newer ads7846 silicon.
41 * Support for ads7843 tested on Atmel at91sam926x-EK.
42 * Support for ads7845 has only been stubbed in.
43 * Support for Analog Devices AD7873 and AD7843 tested.
45 * IRQ handling needs a workaround because of a shortcoming in handling
46 * edge triggered IRQs on some platforms like the OMAP1/2. These
47 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
48 * have to maintain our own SW IRQ disabled status. This should be
49 * removed as soon as the affected platform's IRQ handling is fixed.
51 * App note sbaa036 talks in more detail about accurate sampling...
52 * that ought to help in situations like LCDs inducing noise (which
53 * can also be helped by using synch signals) and more generally.
54 * This driver tries to utilize the measures described in the app
55 * note. The strength of filtering can be set in the board-* specific
59 #define TS_POLL_DELAY 1 /* ms delay before the first sample */
60 #define TS_POLL_PERIOD 5 /* ms delay between samples */
62 /* this driver doesn't aim at the peak continuous sample rate */
63 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
67 * For portability, we can't read 12 bit values using SPI (which
68 * would make the controller deliver them as native byte order u16
69 * with msbs zeroed). Instead, we read them as two 8-bit values,
70 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
81 * We allocate this separately to avoid cache line sharing issues when
82 * driver is used with DMA-based SPI controllers (like atmel_spi) on
83 * systems where main memory is not DMA-coherent (most non-x86 boards).
85 struct ads7846_packet {
86 u8 read_x, read_y, read_z1, read_z2, pwrdown;
87 u16 dummy; /* for the pwrdown read */
89 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
90 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
94 struct input_dev *input;
98 struct spi_device *spi;
99 struct regulator *reg;
101 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
102 struct attribute_group *attr_group;
103 struct device *hwmon;
108 u16 vref_delay_usecs;
115 struct ads7846_packet *packet;
117 struct spi_transfer xfer[18];
118 struct spi_message msg[5];
120 wait_queue_head_t wait;
132 u16 penirq_recheck_delay_usecs;
135 bool stopped; /* P: lock */
136 bool disabled; /* P: lock */
137 bool suspended; /* P: lock */
139 int (*filter)(void *data, int data_idx, int *val);
141 void (*filter_cleanup)(void *data);
142 int (*get_pendown_state)(void);
145 void (*wait_for_sync)(void);
148 /* leave chip selected when we're done, for quicker re-select? */
150 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
152 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
155 /*--------------------------------------------------------------------------*/
157 /* The ADS7846 has touchscreen and other sensors.
158 * Earlier ads784x chips are somewhat compatible.
160 #define ADS_START (1 << 7)
161 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
162 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
163 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
164 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
165 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
166 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
167 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
168 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
169 #define ADS_8_BIT (1 << 3)
170 #define ADS_12_BIT (0 << 3)
171 #define ADS_SER (1 << 2) /* non-differential */
172 #define ADS_DFR (0 << 2) /* differential */
173 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
174 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
175 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
176 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
178 #define MAX_12BIT ((1<<12)-1)
180 /* leave ADC powered up (disables penirq) between differential samples */
181 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
182 | ADS_12_BIT | ADS_DFR | \
183 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
185 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
186 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
187 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
189 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
190 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
192 /* single-ended samples need to first power up reference voltage;
193 * we leave both ADC and VREF powered
195 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
196 | ADS_12_BIT | ADS_SER)
198 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
199 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
201 /* Must be called with ts->lock held */
202 static void ads7846_stop(struct ads7846 *ts)
204 if (!ts->disabled && !ts->suspended) {
205 /* Signal IRQ thread to stop polling and disable the handler. */
209 disable_irq(ts->spi->irq);
213 /* Must be called with ts->lock held */
214 static void ads7846_restart(struct ads7846 *ts)
216 if (!ts->disabled && !ts->suspended) {
217 /* Tell IRQ thread that it may poll the device. */
220 enable_irq(ts->spi->irq);
224 /* Must be called with ts->lock held */
225 static void __ads7846_disable(struct ads7846 *ts)
228 regulator_disable(ts->reg);
231 * We know the chip's in low power mode since we always
232 * leave it that way after every request
236 /* Must be called with ts->lock held */
237 static void __ads7846_enable(struct ads7846 *ts)
241 error = regulator_enable(ts->reg);
243 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
248 static void ads7846_disable(struct ads7846 *ts)
250 mutex_lock(&ts->lock);
255 __ads7846_disable(ts);
260 mutex_unlock(&ts->lock);
263 static void ads7846_enable(struct ads7846 *ts)
265 mutex_lock(&ts->lock);
269 ts->disabled = false;
272 __ads7846_enable(ts);
275 mutex_unlock(&ts->lock);
278 /*--------------------------------------------------------------------------*/
281 * Non-touchscreen sensors only use single-ended conversions.
282 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
283 * ads7846 lets that pin be unconnected, to use internal vREF.
291 struct spi_message msg;
292 struct spi_transfer xfer[6];
294 * DMA (thus cache coherency maintenance) requires the
295 * transfer buffers to live in their own cache lines.
297 __be16 sample ____cacheline_aligned;
300 struct ads7845_ser_req {
302 struct spi_message msg;
303 struct spi_transfer xfer[2];
305 * DMA (thus cache coherency maintenance) requires the
306 * transfer buffers to live in their own cache lines.
308 u8 sample[3] ____cacheline_aligned;
311 static int ads7846_read12_ser(struct device *dev, unsigned command)
313 struct spi_device *spi = to_spi_device(dev);
314 struct ads7846 *ts = dev_get_drvdata(dev);
318 req = kzalloc(sizeof *req, GFP_KERNEL);
322 spi_message_init(&req->msg);
324 /* maybe turn on internal vREF, and let it settle */
325 if (ts->use_internal) {
326 req->ref_on = REF_ON;
327 req->xfer[0].tx_buf = &req->ref_on;
328 req->xfer[0].len = 1;
329 spi_message_add_tail(&req->xfer[0], &req->msg);
331 req->xfer[1].rx_buf = &req->scratch;
332 req->xfer[1].len = 2;
334 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
335 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
336 spi_message_add_tail(&req->xfer[1], &req->msg);
338 /* Enable reference voltage */
339 command |= ADS_PD10_REF_ON;
342 /* Enable ADC in every case */
343 command |= ADS_PD10_ADC_ON;
346 req->command = (u8) command;
347 req->xfer[2].tx_buf = &req->command;
348 req->xfer[2].len = 1;
349 spi_message_add_tail(&req->xfer[2], &req->msg);
351 req->xfer[3].rx_buf = &req->sample;
352 req->xfer[3].len = 2;
353 spi_message_add_tail(&req->xfer[3], &req->msg);
355 /* REVISIT: take a few more samples, and compare ... */
357 /* converter in low power mode & enable PENIRQ */
358 req->ref_off = PWRDOWN;
359 req->xfer[4].tx_buf = &req->ref_off;
360 req->xfer[4].len = 1;
361 spi_message_add_tail(&req->xfer[4], &req->msg);
363 req->xfer[5].rx_buf = &req->scratch;
364 req->xfer[5].len = 2;
365 CS_CHANGE(req->xfer[5]);
366 spi_message_add_tail(&req->xfer[5], &req->msg);
368 mutex_lock(&ts->lock);
370 status = spi_sync(spi, &req->msg);
372 mutex_unlock(&ts->lock);
375 /* on-wire is a must-ignore bit, a BE12 value, then padding */
376 status = be16_to_cpu(req->sample);
377 status = status >> 3;
385 static int ads7845_read12_ser(struct device *dev, unsigned command)
387 struct spi_device *spi = to_spi_device(dev);
388 struct ads7846 *ts = dev_get_drvdata(dev);
389 struct ads7845_ser_req *req;
392 req = kzalloc(sizeof *req, GFP_KERNEL);
396 spi_message_init(&req->msg);
398 req->command[0] = (u8) command;
399 req->xfer[0].tx_buf = req->command;
400 req->xfer[0].rx_buf = req->sample;
401 req->xfer[0].len = 3;
402 spi_message_add_tail(&req->xfer[0], &req->msg);
404 mutex_lock(&ts->lock);
406 status = spi_sync(spi, &req->msg);
408 mutex_unlock(&ts->lock);
411 /* BE12 value, then padding */
412 status = be16_to_cpu(*((u16 *)&req->sample[1]));
413 status = status >> 3;
421 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
423 #define SHOW(name, var, adjust) static ssize_t \
424 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
426 struct ads7846 *ts = dev_get_drvdata(dev); \
427 ssize_t v = ads7846_read12_ser(dev, \
428 READ_12BIT_SER(var)); \
431 return sprintf(buf, "%u\n", adjust(ts, v)); \
433 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
436 /* Sysfs conventions report temperatures in millidegrees Celsius.
437 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
438 * accuracy scheme without calibration data. For now we won't try either;
439 * userspace sees raw sensor values, and must scale/calibrate appropriately.
441 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
446 SHOW(temp0, temp0, null_adjust) /* temp1_input */
447 SHOW(temp1, temp1, null_adjust) /* temp2_input */
450 /* sysfs conventions report voltages in millivolts. We can convert voltages
451 * if we know vREF. userspace may need to scale vAUX to match the board's
452 * external resistors; we assume that vBATT only uses the internal ones.
454 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
458 /* external resistors may scale vAUX into 0..vREF */
459 retval *= ts->vref_mv;
460 retval = retval >> 12;
465 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
467 unsigned retval = vaux_adjust(ts, v);
469 /* ads7846 has a resistor ladder to scale this signal down */
470 if (ts->model == 7846)
476 SHOW(in0_input, vaux, vaux_adjust)
477 SHOW(in1_input, vbatt, vbatt_adjust)
479 static struct attribute *ads7846_attributes[] = {
480 &dev_attr_temp0.attr,
481 &dev_attr_temp1.attr,
482 &dev_attr_in0_input.attr,
483 &dev_attr_in1_input.attr,
487 static struct attribute_group ads7846_attr_group = {
488 .attrs = ads7846_attributes,
491 static struct attribute *ads7843_attributes[] = {
492 &dev_attr_in0_input.attr,
493 &dev_attr_in1_input.attr,
497 static struct attribute_group ads7843_attr_group = {
498 .attrs = ads7843_attributes,
501 static struct attribute *ads7845_attributes[] = {
502 &dev_attr_in0_input.attr,
506 static struct attribute_group ads7845_attr_group = {
507 .attrs = ads7845_attributes,
510 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
512 struct device *hwmon;
515 /* hwmon sensors need a reference voltage */
519 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
521 ts->use_internal = true;
528 "external vREF for ADS%d not specified\n",
535 /* different chips have different sensor groups */
538 ts->attr_group = &ads7846_attr_group;
541 ts->attr_group = &ads7845_attr_group;
544 ts->attr_group = &ads7843_attr_group;
547 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
551 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
555 hwmon = hwmon_device_register(&spi->dev);
557 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
558 return PTR_ERR(hwmon);
565 static void ads784x_hwmon_unregister(struct spi_device *spi,
569 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
570 hwmon_device_unregister(ts->hwmon);
575 static inline int ads784x_hwmon_register(struct spi_device *spi,
581 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
587 static ssize_t ads7846_pen_down_show(struct device *dev,
588 struct device_attribute *attr, char *buf)
590 struct ads7846 *ts = dev_get_drvdata(dev);
592 return sprintf(buf, "%u\n", ts->pendown);
595 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
597 static ssize_t ads7846_disable_show(struct device *dev,
598 struct device_attribute *attr, char *buf)
600 struct ads7846 *ts = dev_get_drvdata(dev);
602 return sprintf(buf, "%u\n", ts->disabled);
605 static ssize_t ads7846_disable_store(struct device *dev,
606 struct device_attribute *attr,
607 const char *buf, size_t count)
609 struct ads7846 *ts = dev_get_drvdata(dev);
613 err = kstrtouint(buf, 10, &i);
625 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
627 static struct attribute *ads784x_attributes[] = {
628 &dev_attr_pen_down.attr,
629 &dev_attr_disable.attr,
633 static struct attribute_group ads784x_attr_group = {
634 .attrs = ads784x_attributes,
637 /*--------------------------------------------------------------------------*/
639 static int get_pendown_state(struct ads7846 *ts)
641 if (ts->get_pendown_state)
642 return ts->get_pendown_state();
644 return !gpio_get_value(ts->gpio_pendown);
647 static void null_wait_for_sync(void)
651 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
653 struct ads7846 *ts = ads;
655 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
656 /* Start over collecting consistent readings. */
659 * Repeat it, if this was the first read or the read
660 * wasn't consistent enough.
662 if (ts->read_cnt < ts->debounce_max) {
663 ts->last_read = *val;
665 return ADS7846_FILTER_REPEAT;
668 * Maximum number of debouncing reached and still
669 * not enough number of consistent readings. Abort
670 * the whole sample, repeat it in the next sampling
674 return ADS7846_FILTER_IGNORE;
677 if (++ts->read_rep > ts->debounce_rep) {
679 * Got a good reading for this coordinate,
680 * go for the next one.
684 return ADS7846_FILTER_OK;
686 /* Read more values that are consistent. */
688 return ADS7846_FILTER_REPEAT;
693 static int ads7846_no_filter(void *ads, int data_idx, int *val)
695 return ADS7846_FILTER_OK;
698 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
700 struct spi_transfer *t =
701 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
703 if (ts->model == 7845) {
704 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
707 * adjust: on-wire is a must-ignore bit, a BE12 value, then
708 * padding; built from two 8 bit values written msb-first.
710 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
714 static void ads7846_update_value(struct spi_message *m, int val)
716 struct spi_transfer *t =
717 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
719 *(u16 *)t->rx_buf = val;
722 static void ads7846_read_state(struct ads7846 *ts)
724 struct ads7846_packet *packet = ts->packet;
725 struct spi_message *m;
731 while (msg_idx < ts->msg_count) {
735 m = &ts->msg[msg_idx];
736 error = spi_sync(ts->spi, m);
738 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
739 packet->tc.ignore = true;
744 * Last message is power down request, no need to convert
745 * or filter the value.
747 if (msg_idx < ts->msg_count - 1) {
749 val = ads7846_get_value(ts, m);
751 action = ts->filter(ts->filter_data, msg_idx, &val);
753 case ADS7846_FILTER_REPEAT:
756 case ADS7846_FILTER_IGNORE:
757 packet->tc.ignore = true;
758 msg_idx = ts->msg_count - 1;
761 case ADS7846_FILTER_OK:
762 ads7846_update_value(m, val);
763 packet->tc.ignore = false;
776 static void ads7846_report_state(struct ads7846 *ts)
778 struct ads7846_packet *packet = ts->packet;
783 * ads7846_get_value() does in-place conversion (including byte swap)
784 * from on-the-wire format as part of debouncing to get stable
787 if (ts->model == 7845) {
788 x = *(u16 *)packet->tc.x_buf;
789 y = *(u16 *)packet->tc.y_buf;
799 /* range filtering */
803 if (ts->model == 7843) {
804 Rt = ts->pressure_max / 2;
805 } else if (ts->model == 7845) {
806 if (get_pendown_state(ts))
807 Rt = ts->pressure_max / 2;
810 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
811 } else if (likely(x && z1)) {
812 /* compute touch pressure resistance using equation #2 */
816 Rt *= ts->x_plate_ohms;
818 Rt = (Rt + 2047) >> 12;
824 * Sample found inconsistent by debouncing or pressure is beyond
825 * the maximum. Don't report it to user space, repeat at least
826 * once more the measurement
828 if (packet->tc.ignore || Rt > ts->pressure_max) {
829 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
830 packet->tc.ignore, Rt);
835 * Maybe check the pendown state before reporting. This discards
836 * false readings when the pen is lifted.
838 if (ts->penirq_recheck_delay_usecs) {
839 udelay(ts->penirq_recheck_delay_usecs);
840 if (!get_pendown_state(ts))
845 * NOTE: We can't rely on the pressure to determine the pen down
846 * state, even this controller has a pressure sensor. The pressure
847 * value can fluctuate for quite a while after lifting the pen and
848 * in some cases may not even settle at the expected value.
850 * The only safe way to check for the pen up condition is in the
851 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
854 struct input_dev *input = ts->input;
860 input_report_key(input, BTN_TOUCH, 1);
862 dev_vdbg(&ts->spi->dev, "DOWN\n");
865 input_report_abs(input, ABS_X, x);
866 input_report_abs(input, ABS_Y, y);
867 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
870 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
874 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
876 struct ads7846 *ts = handle;
878 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
882 static irqreturn_t ads7846_irq(int irq, void *handle)
884 struct ads7846 *ts = handle;
886 /* Start with a small delay before checking pendown state */
887 msleep(TS_POLL_DELAY);
889 while (!ts->stopped && get_pendown_state(ts)) {
891 /* pen is down, continue with the measurement */
892 ads7846_read_state(ts);
895 ads7846_report_state(ts);
897 wait_event_timeout(ts->wait, ts->stopped,
898 msecs_to_jiffies(TS_POLL_PERIOD));
902 struct input_dev *input = ts->input;
904 input_report_key(input, BTN_TOUCH, 0);
905 input_report_abs(input, ABS_PRESSURE, 0);
909 dev_vdbg(&ts->spi->dev, "UP\n");
915 #ifdef CONFIG_PM_SLEEP
916 static int ads7846_suspend(struct device *dev)
918 struct ads7846 *ts = dev_get_drvdata(dev);
920 mutex_lock(&ts->lock);
922 if (!ts->suspended) {
925 __ads7846_disable(ts);
927 if (device_may_wakeup(&ts->spi->dev))
928 enable_irq_wake(ts->spi->irq);
930 ts->suspended = true;
933 mutex_unlock(&ts->lock);
938 static int ads7846_resume(struct device *dev)
940 struct ads7846 *ts = dev_get_drvdata(dev);
942 mutex_lock(&ts->lock);
946 ts->suspended = false;
948 if (device_may_wakeup(&ts->spi->dev))
949 disable_irq_wake(ts->spi->irq);
952 __ads7846_enable(ts);
955 mutex_unlock(&ts->lock);
961 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
963 static int ads7846_setup_pendown(struct spi_device *spi,
966 struct ads7846_platform_data *pdata = spi->dev.platform_data;
970 * REVISIT when the irq can be triggered active-low, or if for some
971 * reason the touchscreen isn't hooked up, we don't need to access
975 if (pdata->get_pendown_state) {
976 ts->get_pendown_state = pdata->get_pendown_state;
977 } else if (gpio_is_valid(pdata->gpio_pendown)) {
979 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
983 "failed to request/setup pendown GPIO%d: %d\n",
984 pdata->gpio_pendown, err);
988 ts->gpio_pendown = pdata->gpio_pendown;
990 if (pdata->gpio_pendown_debounce)
991 gpio_set_debounce(pdata->gpio_pendown,
992 pdata->gpio_pendown_debounce);
994 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
1002 * Set up the transfers to read touchscreen state; this assumes we
1003 * use formula #2 for pressure, not #3.
1005 static void ads7846_setup_spi_msg(struct ads7846 *ts,
1006 const struct ads7846_platform_data *pdata)
1008 struct spi_message *m = &ts->msg[0];
1009 struct spi_transfer *x = ts->xfer;
1010 struct ads7846_packet *packet = ts->packet;
1011 int vref = pdata->keep_vref_on;
1013 if (ts->model == 7873) {
1015 * The AD7873 is almost identical to the ADS7846
1016 * keep VREF off during differential/ratiometric
1024 spi_message_init(m);
1027 if (ts->model == 7845) {
1028 packet->read_y_cmd[0] = READ_Y(vref);
1029 packet->read_y_cmd[1] = 0;
1030 packet->read_y_cmd[2] = 0;
1031 x->tx_buf = &packet->read_y_cmd[0];
1032 x->rx_buf = &packet->tc.y_buf[0];
1034 spi_message_add_tail(x, m);
1036 /* y- still on; turn on only y+ (and ADC) */
1037 packet->read_y = READ_Y(vref);
1038 x->tx_buf = &packet->read_y;
1040 spi_message_add_tail(x, m);
1043 x->rx_buf = &packet->tc.y;
1045 spi_message_add_tail(x, m);
1049 * The first sample after switching drivers can be low quality;
1050 * optionally discard it, using a second one after the signals
1051 * have had enough time to stabilize.
1053 if (pdata->settle_delay_usecs) {
1054 x->delay_usecs = pdata->settle_delay_usecs;
1057 x->tx_buf = &packet->read_y;
1059 spi_message_add_tail(x, m);
1062 x->rx_buf = &packet->tc.y;
1064 spi_message_add_tail(x, m);
1069 spi_message_init(m);
1072 if (ts->model == 7845) {
1074 packet->read_x_cmd[0] = READ_X(vref);
1075 packet->read_x_cmd[1] = 0;
1076 packet->read_x_cmd[2] = 0;
1077 x->tx_buf = &packet->read_x_cmd[0];
1078 x->rx_buf = &packet->tc.x_buf[0];
1080 spi_message_add_tail(x, m);
1082 /* turn y- off, x+ on, then leave in lowpower */
1084 packet->read_x = READ_X(vref);
1085 x->tx_buf = &packet->read_x;
1087 spi_message_add_tail(x, m);
1090 x->rx_buf = &packet->tc.x;
1092 spi_message_add_tail(x, m);
1095 /* ... maybe discard first sample ... */
1096 if (pdata->settle_delay_usecs) {
1097 x->delay_usecs = pdata->settle_delay_usecs;
1100 x->tx_buf = &packet->read_x;
1102 spi_message_add_tail(x, m);
1105 x->rx_buf = &packet->tc.x;
1107 spi_message_add_tail(x, m);
1110 /* turn y+ off, x- on; we'll use formula #2 */
1111 if (ts->model == 7846) {
1114 spi_message_init(m);
1118 packet->read_z1 = READ_Z1(vref);
1119 x->tx_buf = &packet->read_z1;
1121 spi_message_add_tail(x, m);
1124 x->rx_buf = &packet->tc.z1;
1126 spi_message_add_tail(x, m);
1128 /* ... maybe discard first sample ... */
1129 if (pdata->settle_delay_usecs) {
1130 x->delay_usecs = pdata->settle_delay_usecs;
1133 x->tx_buf = &packet->read_z1;
1135 spi_message_add_tail(x, m);
1138 x->rx_buf = &packet->tc.z1;
1140 spi_message_add_tail(x, m);
1145 spi_message_init(m);
1149 packet->read_z2 = READ_Z2(vref);
1150 x->tx_buf = &packet->read_z2;
1152 spi_message_add_tail(x, m);
1155 x->rx_buf = &packet->tc.z2;
1157 spi_message_add_tail(x, m);
1159 /* ... maybe discard first sample ... */
1160 if (pdata->settle_delay_usecs) {
1161 x->delay_usecs = pdata->settle_delay_usecs;
1164 x->tx_buf = &packet->read_z2;
1166 spi_message_add_tail(x, m);
1169 x->rx_buf = &packet->tc.z2;
1171 spi_message_add_tail(x, m);
1178 spi_message_init(m);
1181 if (ts->model == 7845) {
1183 packet->pwrdown_cmd[0] = PWRDOWN;
1184 packet->pwrdown_cmd[1] = 0;
1185 packet->pwrdown_cmd[2] = 0;
1186 x->tx_buf = &packet->pwrdown_cmd[0];
1190 packet->pwrdown = PWRDOWN;
1191 x->tx_buf = &packet->pwrdown;
1193 spi_message_add_tail(x, m);
1196 x->rx_buf = &packet->dummy;
1201 spi_message_add_tail(x, m);
1204 static int ads7846_probe(struct spi_device *spi)
1207 struct ads7846_packet *packet;
1208 struct input_dev *input_dev;
1209 struct ads7846_platform_data *pdata = spi->dev.platform_data;
1210 unsigned long irq_flags;
1214 dev_dbg(&spi->dev, "no IRQ?\n");
1219 dev_dbg(&spi->dev, "no platform data?\n");
1223 /* don't exceed max specified sample rate */
1224 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1225 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1226 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1230 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1231 * that even if the hardware can do that, the SPI controller driver
1232 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1234 spi->bits_per_word = 8;
1235 spi->mode = SPI_MODE_0;
1236 err = spi_setup(spi);
1240 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1241 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1242 input_dev = input_allocate_device();
1243 if (!ts || !packet || !input_dev) {
1248 dev_set_drvdata(&spi->dev, ts);
1250 ts->packet = packet;
1252 ts->input = input_dev;
1253 ts->vref_mv = pdata->vref_mv;
1254 ts->swap_xy = pdata->swap_xy;
1256 mutex_init(&ts->lock);
1257 init_waitqueue_head(&ts->wait);
1259 ts->model = pdata->model ? : 7846;
1260 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1261 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1262 ts->pressure_max = pdata->pressure_max ? : ~0;
1264 if (pdata->filter != NULL) {
1265 if (pdata->filter_init != NULL) {
1266 err = pdata->filter_init(pdata, &ts->filter_data);
1270 ts->filter = pdata->filter;
1271 ts->filter_cleanup = pdata->filter_cleanup;
1272 } else if (pdata->debounce_max) {
1273 ts->debounce_max = pdata->debounce_max;
1274 if (ts->debounce_max < 2)
1275 ts->debounce_max = 2;
1276 ts->debounce_tol = pdata->debounce_tol;
1277 ts->debounce_rep = pdata->debounce_rep;
1278 ts->filter = ads7846_debounce_filter;
1279 ts->filter_data = ts;
1281 ts->filter = ads7846_no_filter;
1284 err = ads7846_setup_pendown(spi, ts);
1286 goto err_cleanup_filter;
1288 if (pdata->penirq_recheck_delay_usecs)
1289 ts->penirq_recheck_delay_usecs =
1290 pdata->penirq_recheck_delay_usecs;
1292 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1294 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1295 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1297 input_dev->name = ts->name;
1298 input_dev->phys = ts->phys;
1299 input_dev->dev.parent = &spi->dev;
1301 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1302 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1303 input_set_abs_params(input_dev, ABS_X,
1305 pdata->x_max ? : MAX_12BIT,
1307 input_set_abs_params(input_dev, ABS_Y,
1309 pdata->y_max ? : MAX_12BIT,
1311 input_set_abs_params(input_dev, ABS_PRESSURE,
1312 pdata->pressure_min, pdata->pressure_max, 0, 0);
1314 ads7846_setup_spi_msg(ts, pdata);
1316 ts->reg = regulator_get(&spi->dev, "vcc");
1317 if (IS_ERR(ts->reg)) {
1318 err = PTR_ERR(ts->reg);
1319 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1323 err = regulator_enable(ts->reg);
1325 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1326 goto err_put_regulator;
1329 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1330 irq_flags |= IRQF_ONESHOT;
1332 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1333 irq_flags, spi->dev.driver->name, ts);
1334 if (err && !pdata->irq_flags) {
1336 "trying pin change workaround on irq %d\n", spi->irq);
1337 irq_flags |= IRQF_TRIGGER_RISING;
1338 err = request_threaded_irq(spi->irq,
1339 ads7846_hard_irq, ads7846_irq,
1340 irq_flags, spi->dev.driver->name, ts);
1344 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1345 goto err_disable_regulator;
1348 err = ads784x_hwmon_register(spi, ts);
1352 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1355 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1356 * the touchscreen, in case it's not connected.
1358 if (ts->model == 7845)
1359 ads7845_read12_ser(&spi->dev, PWRDOWN);
1361 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1363 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1365 goto err_remove_hwmon;
1367 err = input_register_device(input_dev);
1369 goto err_remove_attr_group;
1371 device_init_wakeup(&spi->dev, pdata->wakeup);
1375 err_remove_attr_group:
1376 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1378 ads784x_hwmon_unregister(spi, ts);
1380 free_irq(spi->irq, ts);
1381 err_disable_regulator:
1382 regulator_disable(ts->reg);
1384 regulator_put(ts->reg);
1386 if (!ts->get_pendown_state)
1387 gpio_free(ts->gpio_pendown);
1389 if (ts->filter_cleanup)
1390 ts->filter_cleanup(ts->filter_data);
1392 input_free_device(input_dev);
1398 static int ads7846_remove(struct spi_device *spi)
1400 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1402 device_init_wakeup(&spi->dev, false);
1404 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1406 ads7846_disable(ts);
1407 free_irq(ts->spi->irq, ts);
1409 input_unregister_device(ts->input);
1411 ads784x_hwmon_unregister(spi, ts);
1413 regulator_disable(ts->reg);
1414 regulator_put(ts->reg);
1416 if (!ts->get_pendown_state) {
1418 * If we are not using specialized pendown method we must
1419 * have been relying on gpio we set up ourselves.
1421 gpio_free(ts->gpio_pendown);
1424 if (ts->filter_cleanup)
1425 ts->filter_cleanup(ts->filter_data);
1430 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1435 static struct spi_driver ads7846_driver = {
1438 .owner = THIS_MODULE,
1441 .probe = ads7846_probe,
1442 .remove = ads7846_remove,
1445 module_spi_driver(ads7846_driver);
1447 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1448 MODULE_LICENSE("GPL");
1449 MODULE_ALIAS("spi:ads7846");