1 // SPDX-License-Identifier: GPL-2.0-only
3 * ADS7846 based touchscreen and sensor driver
5 * Copyright (c) 2005 David Brownell
6 * Copyright (c) 2006 Nokia Corporation
7 * Various changes: Imre Deak <imre.deak@nokia.com>
11 * Copyright (C) 2004-2005 Richard Purdie
12 * - omap_ts.[hc], ads7846.h, ts_osk.c
13 * Copyright (C) 2002 MontaVista Software
14 * Copyright (C) 2004 Texas Instruments
15 * Copyright (C) 2005 Dirk Behme
17 #include <linux/types.h>
18 #include <linux/hwmon.h>
19 #include <linux/err.h>
20 #include <linux/sched.h>
21 #include <linux/delay.h>
22 #include <linux/input.h>
23 #include <linux/interrupt.h>
24 #include <linux/slab.h>
27 #include <linux/of_gpio.h>
28 #include <linux/of_device.h>
29 #include <linux/gpio.h>
30 #include <linux/spi/spi.h>
31 #include <linux/spi/ads7846.h>
32 #include <linux/regulator/consumer.h>
33 #include <linux/module.h>
37 * This code has been heavily tested on a Nokia 770, and lightly
38 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
39 * TSC2046 is just newer ads7846 silicon.
40 * Support for ads7843 tested on Atmel at91sam926x-EK.
41 * Support for ads7845 has only been stubbed in.
42 * Support for Analog Devices AD7873 and AD7843 tested.
44 * IRQ handling needs a workaround because of a shortcoming in handling
45 * edge triggered IRQs on some platforms like the OMAP1/2. These
46 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
47 * have to maintain our own SW IRQ disabled status. This should be
48 * removed as soon as the affected platform's IRQ handling is fixed.
50 * App note sbaa036 talks in more detail about accurate sampling...
51 * that ought to help in situations like LCDs inducing noise (which
52 * can also be helped by using synch signals) and more generally.
53 * This driver tries to utilize the measures described in the app
54 * note. The strength of filtering can be set in the board-* specific
58 #define TS_POLL_DELAY 1 /* ms delay before the first sample */
59 #define TS_POLL_PERIOD 5 /* ms delay between samples */
61 /* this driver doesn't aim at the peak continuous sample rate */
62 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
66 * For portability, we can't read 12 bit values using SPI (which
67 * would make the controller deliver them as native byte order u16
68 * with msbs zeroed). Instead, we read them as two 8-bit values,
69 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
80 * We allocate this separately to avoid cache line sharing issues when
81 * driver is used with DMA-based SPI controllers (like atmel_spi) on
82 * systems where main memory is not DMA-coherent (most non-x86 boards).
84 struct ads7846_packet {
85 u8 read_x, read_y, read_z1, read_z2, pwrdown;
86 u16 dummy; /* for the pwrdown read */
88 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
89 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
93 struct input_dev *input;
97 struct spi_device *spi;
98 struct regulator *reg;
100 #if IS_ENABLED(CONFIG_HWMON)
101 struct device *hwmon;
106 u16 vref_delay_usecs;
113 struct ads7846_packet *packet;
115 struct spi_transfer xfer[18];
116 struct spi_message msg[5];
118 wait_queue_head_t wait;
130 u16 penirq_recheck_delay_usecs;
133 bool stopped; /* P: lock */
134 bool disabled; /* P: lock */
135 bool suspended; /* P: lock */
137 int (*filter)(void *data, int data_idx, int *val);
139 void (*filter_cleanup)(void *data);
140 int (*get_pendown_state)(void);
143 void (*wait_for_sync)(void);
146 /* leave chip selected when we're done, for quicker re-select? */
148 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
150 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
153 /*--------------------------------------------------------------------------*/
155 /* The ADS7846 has touchscreen and other sensors.
156 * Earlier ads784x chips are somewhat compatible.
158 #define ADS_START (1 << 7)
159 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
160 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
161 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
162 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
163 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
164 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
165 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
166 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
167 #define ADS_8_BIT (1 << 3)
168 #define ADS_12_BIT (0 << 3)
169 #define ADS_SER (1 << 2) /* non-differential */
170 #define ADS_DFR (0 << 2) /* differential */
171 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
172 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
173 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
174 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
176 #define MAX_12BIT ((1<<12)-1)
178 /* leave ADC powered up (disables penirq) between differential samples */
179 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
180 | ADS_12_BIT | ADS_DFR | \
181 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
183 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
184 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
185 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
187 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
188 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
190 /* single-ended samples need to first power up reference voltage;
191 * we leave both ADC and VREF powered
193 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
194 | ADS_12_BIT | ADS_SER)
196 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
197 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
199 /* Must be called with ts->lock held */
200 static void ads7846_stop(struct ads7846 *ts)
202 if (!ts->disabled && !ts->suspended) {
203 /* Signal IRQ thread to stop polling and disable the handler. */
207 disable_irq(ts->spi->irq);
211 /* Must be called with ts->lock held */
212 static void ads7846_restart(struct ads7846 *ts)
214 if (!ts->disabled && !ts->suspended) {
215 /* Tell IRQ thread that it may poll the device. */
218 enable_irq(ts->spi->irq);
222 /* Must be called with ts->lock held */
223 static void __ads7846_disable(struct ads7846 *ts)
226 regulator_disable(ts->reg);
229 * We know the chip's in low power mode since we always
230 * leave it that way after every request
234 /* Must be called with ts->lock held */
235 static void __ads7846_enable(struct ads7846 *ts)
239 error = regulator_enable(ts->reg);
241 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
246 static void ads7846_disable(struct ads7846 *ts)
248 mutex_lock(&ts->lock);
253 __ads7846_disable(ts);
258 mutex_unlock(&ts->lock);
261 static void ads7846_enable(struct ads7846 *ts)
263 mutex_lock(&ts->lock);
267 ts->disabled = false;
270 __ads7846_enable(ts);
273 mutex_unlock(&ts->lock);
276 /*--------------------------------------------------------------------------*/
279 * Non-touchscreen sensors only use single-ended conversions.
280 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
281 * ads7846 lets that pin be unconnected, to use internal vREF.
289 struct spi_message msg;
290 struct spi_transfer xfer[6];
292 * DMA (thus cache coherency maintenance) requires the
293 * transfer buffers to live in their own cache lines.
295 __be16 sample ____cacheline_aligned;
298 struct ads7845_ser_req {
300 struct spi_message msg;
301 struct spi_transfer xfer[2];
303 * DMA (thus cache coherency maintenance) requires the
304 * transfer buffers to live in their own cache lines.
306 u8 sample[3] ____cacheline_aligned;
309 static int ads7846_read12_ser(struct device *dev, unsigned command)
311 struct spi_device *spi = to_spi_device(dev);
312 struct ads7846 *ts = dev_get_drvdata(dev);
316 req = kzalloc(sizeof *req, GFP_KERNEL);
320 spi_message_init(&req->msg);
322 /* maybe turn on internal vREF, and let it settle */
323 if (ts->use_internal) {
324 req->ref_on = REF_ON;
325 req->xfer[0].tx_buf = &req->ref_on;
326 req->xfer[0].len = 1;
327 spi_message_add_tail(&req->xfer[0], &req->msg);
329 req->xfer[1].rx_buf = &req->scratch;
330 req->xfer[1].len = 2;
332 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
333 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
334 spi_message_add_tail(&req->xfer[1], &req->msg);
336 /* Enable reference voltage */
337 command |= ADS_PD10_REF_ON;
340 /* Enable ADC in every case */
341 command |= ADS_PD10_ADC_ON;
344 req->command = (u8) command;
345 req->xfer[2].tx_buf = &req->command;
346 req->xfer[2].len = 1;
347 spi_message_add_tail(&req->xfer[2], &req->msg);
349 req->xfer[3].rx_buf = &req->sample;
350 req->xfer[3].len = 2;
351 spi_message_add_tail(&req->xfer[3], &req->msg);
353 /* REVISIT: take a few more samples, and compare ... */
355 /* converter in low power mode & enable PENIRQ */
356 req->ref_off = PWRDOWN;
357 req->xfer[4].tx_buf = &req->ref_off;
358 req->xfer[4].len = 1;
359 spi_message_add_tail(&req->xfer[4], &req->msg);
361 req->xfer[5].rx_buf = &req->scratch;
362 req->xfer[5].len = 2;
363 CS_CHANGE(req->xfer[5]);
364 spi_message_add_tail(&req->xfer[5], &req->msg);
366 mutex_lock(&ts->lock);
368 status = spi_sync(spi, &req->msg);
370 mutex_unlock(&ts->lock);
373 /* on-wire is a must-ignore bit, a BE12 value, then padding */
374 status = be16_to_cpu(req->sample);
375 status = status >> 3;
383 static int ads7845_read12_ser(struct device *dev, unsigned command)
385 struct spi_device *spi = to_spi_device(dev);
386 struct ads7846 *ts = dev_get_drvdata(dev);
387 struct ads7845_ser_req *req;
390 req = kzalloc(sizeof *req, GFP_KERNEL);
394 spi_message_init(&req->msg);
396 req->command[0] = (u8) command;
397 req->xfer[0].tx_buf = req->command;
398 req->xfer[0].rx_buf = req->sample;
399 req->xfer[0].len = 3;
400 spi_message_add_tail(&req->xfer[0], &req->msg);
402 mutex_lock(&ts->lock);
404 status = spi_sync(spi, &req->msg);
406 mutex_unlock(&ts->lock);
409 /* BE12 value, then padding */
410 status = be16_to_cpu(*((u16 *)&req->sample[1]));
411 status = status >> 3;
419 #if IS_ENABLED(CONFIG_HWMON)
421 #define SHOW(name, var, adjust) static ssize_t \
422 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
424 struct ads7846 *ts = dev_get_drvdata(dev); \
425 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
426 READ_12BIT_SER(var)); \
429 return sprintf(buf, "%u\n", adjust(ts, v)); \
431 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
434 /* Sysfs conventions report temperatures in millidegrees Celsius.
435 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
436 * accuracy scheme without calibration data. For now we won't try either;
437 * userspace sees raw sensor values, and must scale/calibrate appropriately.
439 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
444 SHOW(temp0, temp0, null_adjust) /* temp1_input */
445 SHOW(temp1, temp1, null_adjust) /* temp2_input */
448 /* sysfs conventions report voltages in millivolts. We can convert voltages
449 * if we know vREF. userspace may need to scale vAUX to match the board's
450 * external resistors; we assume that vBATT only uses the internal ones.
452 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
456 /* external resistors may scale vAUX into 0..vREF */
457 retval *= ts->vref_mv;
458 retval = retval >> 12;
463 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
465 unsigned retval = vaux_adjust(ts, v);
467 /* ads7846 has a resistor ladder to scale this signal down */
468 if (ts->model == 7846)
474 SHOW(in0_input, vaux, vaux_adjust)
475 SHOW(in1_input, vbatt, vbatt_adjust)
477 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
480 struct device *dev = container_of(kobj, struct device, kobj);
481 struct ads7846 *ts = dev_get_drvdata(dev);
483 if (ts->model == 7843 && index < 2) /* in0, in1 */
485 if (ts->model == 7845 && index != 2) /* in0 */
491 static struct attribute *ads7846_attributes[] = {
492 &dev_attr_temp0.attr, /* 0 */
493 &dev_attr_temp1.attr, /* 1 */
494 &dev_attr_in0_input.attr, /* 2 */
495 &dev_attr_in1_input.attr, /* 3 */
499 static const struct attribute_group ads7846_attr_group = {
500 .attrs = ads7846_attributes,
501 .is_visible = ads7846_is_visible,
503 __ATTRIBUTE_GROUPS(ads7846_attr);
505 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
507 /* hwmon sensors need a reference voltage */
511 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
513 ts->use_internal = true;
520 "external vREF for ADS%d not specified\n",
527 ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
528 ts, ads7846_attr_groups);
530 return PTR_ERR_OR_ZERO(ts->hwmon);
533 static void ads784x_hwmon_unregister(struct spi_device *spi,
537 hwmon_device_unregister(ts->hwmon);
541 static inline int ads784x_hwmon_register(struct spi_device *spi,
547 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
553 static ssize_t ads7846_pen_down_show(struct device *dev,
554 struct device_attribute *attr, char *buf)
556 struct ads7846 *ts = dev_get_drvdata(dev);
558 return sprintf(buf, "%u\n", ts->pendown);
561 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
563 static ssize_t ads7846_disable_show(struct device *dev,
564 struct device_attribute *attr, char *buf)
566 struct ads7846 *ts = dev_get_drvdata(dev);
568 return sprintf(buf, "%u\n", ts->disabled);
571 static ssize_t ads7846_disable_store(struct device *dev,
572 struct device_attribute *attr,
573 const char *buf, size_t count)
575 struct ads7846 *ts = dev_get_drvdata(dev);
579 err = kstrtouint(buf, 10, &i);
591 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
593 static struct attribute *ads784x_attributes[] = {
594 &dev_attr_pen_down.attr,
595 &dev_attr_disable.attr,
599 static const struct attribute_group ads784x_attr_group = {
600 .attrs = ads784x_attributes,
603 /*--------------------------------------------------------------------------*/
605 static int get_pendown_state(struct ads7846 *ts)
607 if (ts->get_pendown_state)
608 return ts->get_pendown_state();
610 return !gpio_get_value(ts->gpio_pendown);
613 static void null_wait_for_sync(void)
617 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
619 struct ads7846 *ts = ads;
621 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
622 /* Start over collecting consistent readings. */
625 * Repeat it, if this was the first read or the read
626 * wasn't consistent enough.
628 if (ts->read_cnt < ts->debounce_max) {
629 ts->last_read = *val;
631 return ADS7846_FILTER_REPEAT;
634 * Maximum number of debouncing reached and still
635 * not enough number of consistent readings. Abort
636 * the whole sample, repeat it in the next sampling
640 return ADS7846_FILTER_IGNORE;
643 if (++ts->read_rep > ts->debounce_rep) {
645 * Got a good reading for this coordinate,
646 * go for the next one.
650 return ADS7846_FILTER_OK;
652 /* Read more values that are consistent. */
654 return ADS7846_FILTER_REPEAT;
659 static int ads7846_no_filter(void *ads, int data_idx, int *val)
661 return ADS7846_FILTER_OK;
664 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
667 struct spi_transfer *t =
668 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
670 if (ts->model == 7845) {
671 value = be16_to_cpup((__be16 *)&(((char *)t->rx_buf)[1]));
674 * adjust: on-wire is a must-ignore bit, a BE12 value, then
675 * padding; built from two 8 bit values written msb-first.
677 value = be16_to_cpup((__be16 *)t->rx_buf);
680 /* enforce ADC output is 12 bits width */
681 return (value >> 3) & 0xfff;
684 static void ads7846_update_value(struct spi_message *m, int val)
686 struct spi_transfer *t =
687 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
689 *(u16 *)t->rx_buf = val;
692 static void ads7846_read_state(struct ads7846 *ts)
694 struct ads7846_packet *packet = ts->packet;
695 struct spi_message *m;
701 while (msg_idx < ts->msg_count) {
705 m = &ts->msg[msg_idx];
706 error = spi_sync(ts->spi, m);
708 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
709 packet->tc.ignore = true;
714 * Last message is power down request, no need to convert
715 * or filter the value.
717 if (msg_idx < ts->msg_count - 1) {
719 val = ads7846_get_value(ts, m);
721 action = ts->filter(ts->filter_data, msg_idx, &val);
723 case ADS7846_FILTER_REPEAT:
726 case ADS7846_FILTER_IGNORE:
727 packet->tc.ignore = true;
728 msg_idx = ts->msg_count - 1;
731 case ADS7846_FILTER_OK:
732 ads7846_update_value(m, val);
733 packet->tc.ignore = false;
746 static void ads7846_report_state(struct ads7846 *ts)
748 struct ads7846_packet *packet = ts->packet;
753 * ads7846_get_value() does in-place conversion (including byte swap)
754 * from on-the-wire format as part of debouncing to get stable
757 if (ts->model == 7845) {
758 x = *(u16 *)packet->tc.x_buf;
759 y = *(u16 *)packet->tc.y_buf;
769 /* range filtering */
773 if (ts->model == 7843) {
774 Rt = ts->pressure_max / 2;
775 } else if (ts->model == 7845) {
776 if (get_pendown_state(ts))
777 Rt = ts->pressure_max / 2;
780 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
781 } else if (likely(x && z1)) {
782 /* compute touch pressure resistance using equation #2 */
786 Rt *= ts->x_plate_ohms;
788 Rt = (Rt + 2047) >> 12;
794 * Sample found inconsistent by debouncing or pressure is beyond
795 * the maximum. Don't report it to user space, repeat at least
796 * once more the measurement
798 if (packet->tc.ignore || Rt > ts->pressure_max) {
799 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
800 packet->tc.ignore, Rt);
805 * Maybe check the pendown state before reporting. This discards
806 * false readings when the pen is lifted.
808 if (ts->penirq_recheck_delay_usecs) {
809 udelay(ts->penirq_recheck_delay_usecs);
810 if (!get_pendown_state(ts))
815 * NOTE: We can't rely on the pressure to determine the pen down
816 * state, even this controller has a pressure sensor. The pressure
817 * value can fluctuate for quite a while after lifting the pen and
818 * in some cases may not even settle at the expected value.
820 * The only safe way to check for the pen up condition is in the
821 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
824 struct input_dev *input = ts->input;
830 input_report_key(input, BTN_TOUCH, 1);
832 dev_vdbg(&ts->spi->dev, "DOWN\n");
835 input_report_abs(input, ABS_X, x);
836 input_report_abs(input, ABS_Y, y);
837 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
840 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
844 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
846 struct ads7846 *ts = handle;
848 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
852 static irqreturn_t ads7846_irq(int irq, void *handle)
854 struct ads7846 *ts = handle;
856 /* Start with a small delay before checking pendown state */
857 msleep(TS_POLL_DELAY);
859 while (!ts->stopped && get_pendown_state(ts)) {
861 /* pen is down, continue with the measurement */
862 ads7846_read_state(ts);
865 ads7846_report_state(ts);
867 wait_event_timeout(ts->wait, ts->stopped,
868 msecs_to_jiffies(TS_POLL_PERIOD));
871 if (ts->pendown && !ts->stopped) {
872 struct input_dev *input = ts->input;
874 input_report_key(input, BTN_TOUCH, 0);
875 input_report_abs(input, ABS_PRESSURE, 0);
879 dev_vdbg(&ts->spi->dev, "UP\n");
885 static int __maybe_unused ads7846_suspend(struct device *dev)
887 struct ads7846 *ts = dev_get_drvdata(dev);
889 mutex_lock(&ts->lock);
891 if (!ts->suspended) {
894 __ads7846_disable(ts);
896 if (device_may_wakeup(&ts->spi->dev))
897 enable_irq_wake(ts->spi->irq);
899 ts->suspended = true;
902 mutex_unlock(&ts->lock);
907 static int __maybe_unused ads7846_resume(struct device *dev)
909 struct ads7846 *ts = dev_get_drvdata(dev);
911 mutex_lock(&ts->lock);
915 ts->suspended = false;
917 if (device_may_wakeup(&ts->spi->dev))
918 disable_irq_wake(ts->spi->irq);
921 __ads7846_enable(ts);
924 mutex_unlock(&ts->lock);
929 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
931 static int ads7846_setup_pendown(struct spi_device *spi,
933 const struct ads7846_platform_data *pdata)
938 * REVISIT when the irq can be triggered active-low, or if for some
939 * reason the touchscreen isn't hooked up, we don't need to access
943 if (pdata->get_pendown_state) {
944 ts->get_pendown_state = pdata->get_pendown_state;
945 } else if (gpio_is_valid(pdata->gpio_pendown)) {
947 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
951 "failed to request/setup pendown GPIO%d: %d\n",
952 pdata->gpio_pendown, err);
956 ts->gpio_pendown = pdata->gpio_pendown;
958 if (pdata->gpio_pendown_debounce)
959 gpio_set_debounce(pdata->gpio_pendown,
960 pdata->gpio_pendown_debounce);
962 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
970 * Set up the transfers to read touchscreen state; this assumes we
971 * use formula #2 for pressure, not #3.
973 static void ads7846_setup_spi_msg(struct ads7846 *ts,
974 const struct ads7846_platform_data *pdata)
976 struct spi_message *m = &ts->msg[0];
977 struct spi_transfer *x = ts->xfer;
978 struct ads7846_packet *packet = ts->packet;
979 int vref = pdata->keep_vref_on;
981 if (ts->model == 7873) {
983 * The AD7873 is almost identical to the ADS7846
984 * keep VREF off during differential/ratiometric
995 if (ts->model == 7845) {
996 packet->read_y_cmd[0] = READ_Y(vref);
997 packet->read_y_cmd[1] = 0;
998 packet->read_y_cmd[2] = 0;
999 x->tx_buf = &packet->read_y_cmd[0];
1000 x->rx_buf = &packet->tc.y_buf[0];
1002 spi_message_add_tail(x, m);
1004 /* y- still on; turn on only y+ (and ADC) */
1005 packet->read_y = READ_Y(vref);
1006 x->tx_buf = &packet->read_y;
1008 spi_message_add_tail(x, m);
1011 x->rx_buf = &packet->tc.y;
1013 spi_message_add_tail(x, m);
1017 * The first sample after switching drivers can be low quality;
1018 * optionally discard it, using a second one after the signals
1019 * have had enough time to stabilize.
1021 if (pdata->settle_delay_usecs) {
1022 x->delay_usecs = pdata->settle_delay_usecs;
1025 x->tx_buf = &packet->read_y;
1027 spi_message_add_tail(x, m);
1030 x->rx_buf = &packet->tc.y;
1032 spi_message_add_tail(x, m);
1037 spi_message_init(m);
1040 if (ts->model == 7845) {
1042 packet->read_x_cmd[0] = READ_X(vref);
1043 packet->read_x_cmd[1] = 0;
1044 packet->read_x_cmd[2] = 0;
1045 x->tx_buf = &packet->read_x_cmd[0];
1046 x->rx_buf = &packet->tc.x_buf[0];
1048 spi_message_add_tail(x, m);
1050 /* turn y- off, x+ on, then leave in lowpower */
1052 packet->read_x = READ_X(vref);
1053 x->tx_buf = &packet->read_x;
1055 spi_message_add_tail(x, m);
1058 x->rx_buf = &packet->tc.x;
1060 spi_message_add_tail(x, m);
1063 /* ... maybe discard first sample ... */
1064 if (pdata->settle_delay_usecs) {
1065 x->delay_usecs = pdata->settle_delay_usecs;
1068 x->tx_buf = &packet->read_x;
1070 spi_message_add_tail(x, m);
1073 x->rx_buf = &packet->tc.x;
1075 spi_message_add_tail(x, m);
1078 /* turn y+ off, x- on; we'll use formula #2 */
1079 if (ts->model == 7846) {
1082 spi_message_init(m);
1086 packet->read_z1 = READ_Z1(vref);
1087 x->tx_buf = &packet->read_z1;
1089 spi_message_add_tail(x, m);
1092 x->rx_buf = &packet->tc.z1;
1094 spi_message_add_tail(x, m);
1096 /* ... maybe discard first sample ... */
1097 if (pdata->settle_delay_usecs) {
1098 x->delay_usecs = pdata->settle_delay_usecs;
1101 x->tx_buf = &packet->read_z1;
1103 spi_message_add_tail(x, m);
1106 x->rx_buf = &packet->tc.z1;
1108 spi_message_add_tail(x, m);
1113 spi_message_init(m);
1117 packet->read_z2 = READ_Z2(vref);
1118 x->tx_buf = &packet->read_z2;
1120 spi_message_add_tail(x, m);
1123 x->rx_buf = &packet->tc.z2;
1125 spi_message_add_tail(x, m);
1127 /* ... maybe discard first sample ... */
1128 if (pdata->settle_delay_usecs) {
1129 x->delay_usecs = pdata->settle_delay_usecs;
1132 x->tx_buf = &packet->read_z2;
1134 spi_message_add_tail(x, m);
1137 x->rx_buf = &packet->tc.z2;
1139 spi_message_add_tail(x, m);
1146 spi_message_init(m);
1149 if (ts->model == 7845) {
1151 packet->pwrdown_cmd[0] = PWRDOWN;
1152 packet->pwrdown_cmd[1] = 0;
1153 packet->pwrdown_cmd[2] = 0;
1154 x->tx_buf = &packet->pwrdown_cmd[0];
1158 packet->pwrdown = PWRDOWN;
1159 x->tx_buf = &packet->pwrdown;
1161 spi_message_add_tail(x, m);
1164 x->rx_buf = &packet->dummy;
1169 spi_message_add_tail(x, m);
1173 static const struct of_device_id ads7846_dt_ids[] = {
1174 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1175 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1176 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1177 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1178 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1181 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1183 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1185 struct ads7846_platform_data *pdata;
1186 struct device_node *node = dev->of_node;
1187 const struct of_device_id *match;
1190 dev_err(dev, "Device does not have associated DT data\n");
1191 return ERR_PTR(-EINVAL);
1194 match = of_match_device(ads7846_dt_ids, dev);
1196 dev_err(dev, "Unknown device model\n");
1197 return ERR_PTR(-EINVAL);
1200 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1202 return ERR_PTR(-ENOMEM);
1204 pdata->model = (unsigned long)match->data;
1206 of_property_read_u16(node, "ti,vref-delay-usecs",
1207 &pdata->vref_delay_usecs);
1208 of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1209 pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1211 pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1213 of_property_read_u16(node, "ti,settle-delay-usec",
1214 &pdata->settle_delay_usecs);
1215 of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1216 &pdata->penirq_recheck_delay_usecs);
1218 of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1219 of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1221 of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1222 of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1223 of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1224 of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1226 of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1227 of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1229 of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1230 of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1231 of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1233 of_property_read_u32(node, "ti,pendown-gpio-debounce",
1234 &pdata->gpio_pendown_debounce);
1236 pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1237 of_property_read_bool(node, "linux,wakeup");
1239 pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1244 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1246 dev_err(dev, "no platform data defined\n");
1247 return ERR_PTR(-EINVAL);
1251 static int ads7846_probe(struct spi_device *spi)
1253 const struct ads7846_platform_data *pdata;
1255 struct ads7846_packet *packet;
1256 struct input_dev *input_dev;
1257 unsigned long irq_flags;
1261 dev_dbg(&spi->dev, "no IRQ?\n");
1265 /* don't exceed max specified sample rate */
1266 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1267 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1268 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1273 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1274 * that even if the hardware can do that, the SPI controller driver
1275 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1277 spi->bits_per_word = 8;
1278 spi->mode = SPI_MODE_0;
1279 err = spi_setup(spi);
1283 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1284 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1285 input_dev = input_allocate_device();
1286 if (!ts || !packet || !input_dev) {
1291 spi_set_drvdata(spi, ts);
1293 ts->packet = packet;
1295 ts->input = input_dev;
1297 mutex_init(&ts->lock);
1298 init_waitqueue_head(&ts->wait);
1300 pdata = dev_get_platdata(&spi->dev);
1302 pdata = ads7846_probe_dt(&spi->dev);
1303 if (IS_ERR(pdata)) {
1304 err = PTR_ERR(pdata);
1309 ts->model = pdata->model ? : 7846;
1310 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1311 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1312 ts->pressure_max = pdata->pressure_max ? : ~0;
1314 ts->vref_mv = pdata->vref_mv;
1315 ts->swap_xy = pdata->swap_xy;
1317 if (pdata->filter != NULL) {
1318 if (pdata->filter_init != NULL) {
1319 err = pdata->filter_init(pdata, &ts->filter_data);
1323 ts->filter = pdata->filter;
1324 ts->filter_cleanup = pdata->filter_cleanup;
1325 } else if (pdata->debounce_max) {
1326 ts->debounce_max = pdata->debounce_max;
1327 if (ts->debounce_max < 2)
1328 ts->debounce_max = 2;
1329 ts->debounce_tol = pdata->debounce_tol;
1330 ts->debounce_rep = pdata->debounce_rep;
1331 ts->filter = ads7846_debounce_filter;
1332 ts->filter_data = ts;
1334 ts->filter = ads7846_no_filter;
1337 err = ads7846_setup_pendown(spi, ts, pdata);
1339 goto err_cleanup_filter;
1341 if (pdata->penirq_recheck_delay_usecs)
1342 ts->penirq_recheck_delay_usecs =
1343 pdata->penirq_recheck_delay_usecs;
1345 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1347 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1348 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1350 input_dev->name = ts->name;
1351 input_dev->phys = ts->phys;
1352 input_dev->dev.parent = &spi->dev;
1354 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1355 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1356 input_set_abs_params(input_dev, ABS_X,
1358 pdata->x_max ? : MAX_12BIT,
1360 input_set_abs_params(input_dev, ABS_Y,
1362 pdata->y_max ? : MAX_12BIT,
1364 input_set_abs_params(input_dev, ABS_PRESSURE,
1365 pdata->pressure_min, pdata->pressure_max, 0, 0);
1367 ads7846_setup_spi_msg(ts, pdata);
1369 ts->reg = regulator_get(&spi->dev, "vcc");
1370 if (IS_ERR(ts->reg)) {
1371 err = PTR_ERR(ts->reg);
1372 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1376 err = regulator_enable(ts->reg);
1378 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1379 goto err_put_regulator;
1382 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1383 irq_flags |= IRQF_ONESHOT;
1385 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1386 irq_flags, spi->dev.driver->name, ts);
1387 if (err && !pdata->irq_flags) {
1389 "trying pin change workaround on irq %d\n", spi->irq);
1390 irq_flags |= IRQF_TRIGGER_RISING;
1391 err = request_threaded_irq(spi->irq,
1392 ads7846_hard_irq, ads7846_irq,
1393 irq_flags, spi->dev.driver->name, ts);
1397 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1398 goto err_disable_regulator;
1401 err = ads784x_hwmon_register(spi, ts);
1405 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1408 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1409 * the touchscreen, in case it's not connected.
1411 if (ts->model == 7845)
1412 ads7845_read12_ser(&spi->dev, PWRDOWN);
1414 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1416 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1418 goto err_remove_hwmon;
1420 err = input_register_device(input_dev);
1422 goto err_remove_attr_group;
1424 device_init_wakeup(&spi->dev, pdata->wakeup);
1427 * If device does not carry platform data we must have allocated it
1428 * when parsing DT data.
1430 if (!dev_get_platdata(&spi->dev))
1431 devm_kfree(&spi->dev, (void *)pdata);
1435 err_remove_attr_group:
1436 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1438 ads784x_hwmon_unregister(spi, ts);
1440 free_irq(spi->irq, ts);
1441 err_disable_regulator:
1442 regulator_disable(ts->reg);
1444 regulator_put(ts->reg);
1446 if (!ts->get_pendown_state)
1447 gpio_free(ts->gpio_pendown);
1449 if (ts->filter_cleanup)
1450 ts->filter_cleanup(ts->filter_data);
1452 input_free_device(input_dev);
1458 static int ads7846_remove(struct spi_device *spi)
1460 struct ads7846 *ts = spi_get_drvdata(spi);
1462 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1464 ads7846_disable(ts);
1465 free_irq(ts->spi->irq, ts);
1467 input_unregister_device(ts->input);
1469 ads784x_hwmon_unregister(spi, ts);
1471 regulator_put(ts->reg);
1473 if (!ts->get_pendown_state) {
1475 * If we are not using specialized pendown method we must
1476 * have been relying on gpio we set up ourselves.
1478 gpio_free(ts->gpio_pendown);
1481 if (ts->filter_cleanup)
1482 ts->filter_cleanup(ts->filter_data);
1487 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1492 static struct spi_driver ads7846_driver = {
1496 .of_match_table = of_match_ptr(ads7846_dt_ids),
1498 .probe = ads7846_probe,
1499 .remove = ads7846_remove,
1502 module_spi_driver(ads7846_driver);
1504 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1505 MODULE_LICENSE("GPL");
1506 MODULE_ALIAS("spi:ads7846");