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/err.h>
23 #include <linux/sched.h>
24 #include <linux/delay.h>
25 #include <linux/input.h>
26 #include <linux/interrupt.h>
27 #include <linux/slab.h>
30 #include <linux/of_gpio.h>
31 #include <linux/of_device.h>
32 #include <linux/gpio.h>
33 #include <linux/spi/spi.h>
34 #include <linux/spi/ads7846.h>
35 #include <linux/regulator/consumer.h>
36 #include <linux/module.h>
38 #include <asm/unaligned.h>
41 * This code has been heavily tested on a Nokia 770, and lightly
42 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
43 * TSC2046 is just newer ads7846 silicon.
44 * Support for ads7843 tested on Atmel at91sam926x-EK.
45 * Support for ads7845 has only been stubbed in.
46 * Support for Analog Devices AD7873 and AD7843 tested.
48 * IRQ handling needs a workaround because of a shortcoming in handling
49 * edge triggered IRQs on some platforms like the OMAP1/2. These
50 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
51 * have to maintain our own SW IRQ disabled status. This should be
52 * removed as soon as the affected platform's IRQ handling is fixed.
54 * App note sbaa036 talks in more detail about accurate sampling...
55 * that ought to help in situations like LCDs inducing noise (which
56 * can also be helped by using synch signals) and more generally.
57 * This driver tries to utilize the measures described in the app
58 * note. The strength of filtering can be set in the board-* specific
62 #define TS_POLL_DELAY 1 /* ms delay before the first sample */
63 #define TS_POLL_PERIOD 5 /* ms delay between samples */
65 /* this driver doesn't aim at the peak continuous sample rate */
66 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
70 * For portability, we can't read 12 bit values using SPI (which
71 * would make the controller deliver them as native byte order u16
72 * with msbs zeroed). Instead, we read them as two 8-bit values,
73 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
84 * We allocate this separately to avoid cache line sharing issues when
85 * driver is used with DMA-based SPI controllers (like atmel_spi) on
86 * systems where main memory is not DMA-coherent (most non-x86 boards).
88 struct ads7846_packet {
89 u8 read_x, read_y, read_z1, read_z2, pwrdown;
90 u16 dummy; /* for the pwrdown read */
92 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
93 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
97 struct input_dev *input;
101 struct spi_device *spi;
102 struct regulator *reg;
104 #if IS_ENABLED(CONFIG_HWMON)
105 struct device *hwmon;
110 u16 vref_delay_usecs;
117 struct ads7846_packet *packet;
119 struct spi_transfer xfer[18];
120 struct spi_message msg[5];
122 wait_queue_head_t wait;
134 u16 penirq_recheck_delay_usecs;
137 bool stopped; /* P: lock */
138 bool disabled; /* P: lock */
139 bool suspended; /* P: lock */
141 int (*filter)(void *data, int data_idx, int *val);
143 void (*filter_cleanup)(void *data);
144 int (*get_pendown_state)(void);
147 void (*wait_for_sync)(void);
150 /* leave chip selected when we're done, for quicker re-select? */
152 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
154 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
157 /*--------------------------------------------------------------------------*/
159 /* The ADS7846 has touchscreen and other sensors.
160 * Earlier ads784x chips are somewhat compatible.
162 #define ADS_START (1 << 7)
163 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
164 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
165 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
166 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
167 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
168 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
169 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
170 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
171 #define ADS_8_BIT (1 << 3)
172 #define ADS_12_BIT (0 << 3)
173 #define ADS_SER (1 << 2) /* non-differential */
174 #define ADS_DFR (0 << 2) /* differential */
175 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
176 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
177 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
178 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
180 #define MAX_12BIT ((1<<12)-1)
182 /* leave ADC powered up (disables penirq) between differential samples */
183 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
184 | ADS_12_BIT | ADS_DFR | \
185 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
187 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
188 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
189 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
191 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
192 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
194 /* single-ended samples need to first power up reference voltage;
195 * we leave both ADC and VREF powered
197 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
198 | ADS_12_BIT | ADS_SER)
200 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
201 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
203 static int get_pendown_state(struct ads7846 *ts)
205 if (ts->get_pendown_state)
206 return ts->get_pendown_state();
208 return !gpio_get_value(ts->gpio_pendown);
211 static void ads7846_report_pen_up(struct ads7846 *ts)
213 struct input_dev *input = ts->input;
215 input_report_key(input, BTN_TOUCH, 0);
216 input_report_abs(input, ABS_PRESSURE, 0);
220 dev_vdbg(&ts->spi->dev, "UP\n");
223 /* Must be called with ts->lock held */
224 static void ads7846_stop(struct ads7846 *ts)
226 if (!ts->disabled && !ts->suspended) {
227 /* Signal IRQ thread to stop polling and disable the handler. */
231 disable_irq(ts->spi->irq);
235 /* Must be called with ts->lock held */
236 static void ads7846_restart(struct ads7846 *ts)
238 if (!ts->disabled && !ts->suspended) {
239 /* Check if pen was released since last stop */
240 if (ts->pendown && !get_pendown_state(ts))
241 ads7846_report_pen_up(ts);
243 /* Tell IRQ thread that it may poll the device. */
246 enable_irq(ts->spi->irq);
250 /* Must be called with ts->lock held */
251 static void __ads7846_disable(struct ads7846 *ts)
254 regulator_disable(ts->reg);
257 * We know the chip's in low power mode since we always
258 * leave it that way after every request
262 /* Must be called with ts->lock held */
263 static void __ads7846_enable(struct ads7846 *ts)
267 error = regulator_enable(ts->reg);
269 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
274 static void ads7846_disable(struct ads7846 *ts)
276 mutex_lock(&ts->lock);
281 __ads7846_disable(ts);
286 mutex_unlock(&ts->lock);
289 static void ads7846_enable(struct ads7846 *ts)
291 mutex_lock(&ts->lock);
295 ts->disabled = false;
298 __ads7846_enable(ts);
301 mutex_unlock(&ts->lock);
304 /*--------------------------------------------------------------------------*/
307 * Non-touchscreen sensors only use single-ended conversions.
308 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
309 * ads7846 lets that pin be unconnected, to use internal vREF.
317 struct spi_message msg;
318 struct spi_transfer xfer[6];
320 * DMA (thus cache coherency maintenance) requires the
321 * transfer buffers to live in their own cache lines.
323 __be16 sample ____cacheline_aligned;
326 struct ads7845_ser_req {
328 struct spi_message msg;
329 struct spi_transfer xfer[2];
331 * DMA (thus cache coherency maintenance) requires the
332 * transfer buffers to live in their own cache lines.
334 u8 sample[3] ____cacheline_aligned;
337 static int ads7846_read12_ser(struct device *dev, unsigned command)
339 struct spi_device *spi = to_spi_device(dev);
340 struct ads7846 *ts = dev_get_drvdata(dev);
344 req = kzalloc(sizeof *req, GFP_KERNEL);
348 spi_message_init(&req->msg);
350 /* maybe turn on internal vREF, and let it settle */
351 if (ts->use_internal) {
352 req->ref_on = REF_ON;
353 req->xfer[0].tx_buf = &req->ref_on;
354 req->xfer[0].len = 1;
355 spi_message_add_tail(&req->xfer[0], &req->msg);
357 req->xfer[1].rx_buf = &req->scratch;
358 req->xfer[1].len = 2;
360 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
361 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
362 spi_message_add_tail(&req->xfer[1], &req->msg);
364 /* Enable reference voltage */
365 command |= ADS_PD10_REF_ON;
368 /* Enable ADC in every case */
369 command |= ADS_PD10_ADC_ON;
372 req->command = (u8) command;
373 req->xfer[2].tx_buf = &req->command;
374 req->xfer[2].len = 1;
375 spi_message_add_tail(&req->xfer[2], &req->msg);
377 req->xfer[3].rx_buf = &req->sample;
378 req->xfer[3].len = 2;
379 spi_message_add_tail(&req->xfer[3], &req->msg);
381 /* REVISIT: take a few more samples, and compare ... */
383 /* converter in low power mode & enable PENIRQ */
384 req->ref_off = PWRDOWN;
385 req->xfer[4].tx_buf = &req->ref_off;
386 req->xfer[4].len = 1;
387 spi_message_add_tail(&req->xfer[4], &req->msg);
389 req->xfer[5].rx_buf = &req->scratch;
390 req->xfer[5].len = 2;
391 CS_CHANGE(req->xfer[5]);
392 spi_message_add_tail(&req->xfer[5], &req->msg);
394 mutex_lock(&ts->lock);
396 status = spi_sync(spi, &req->msg);
398 mutex_unlock(&ts->lock);
401 /* on-wire is a must-ignore bit, a BE12 value, then padding */
402 status = be16_to_cpu(req->sample);
403 status = status >> 3;
411 static int ads7845_read12_ser(struct device *dev, unsigned command)
413 struct spi_device *spi = to_spi_device(dev);
414 struct ads7846 *ts = dev_get_drvdata(dev);
415 struct ads7845_ser_req *req;
418 req = kzalloc(sizeof *req, GFP_KERNEL);
422 spi_message_init(&req->msg);
424 req->command[0] = (u8) command;
425 req->xfer[0].tx_buf = req->command;
426 req->xfer[0].rx_buf = req->sample;
427 req->xfer[0].len = 3;
428 spi_message_add_tail(&req->xfer[0], &req->msg);
430 mutex_lock(&ts->lock);
432 status = spi_sync(spi, &req->msg);
434 mutex_unlock(&ts->lock);
437 /* BE12 value, then padding */
438 status = get_unaligned_be16(&req->sample[1]);
439 status = status >> 3;
447 #if IS_ENABLED(CONFIG_HWMON)
449 #define SHOW(name, var, adjust) static ssize_t \
450 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
452 struct ads7846 *ts = dev_get_drvdata(dev); \
453 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
454 READ_12BIT_SER(var)); \
457 return sprintf(buf, "%u\n", adjust(ts, v)); \
459 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
462 /* Sysfs conventions report temperatures in millidegrees Celsius.
463 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
464 * accuracy scheme without calibration data. For now we won't try either;
465 * userspace sees raw sensor values, and must scale/calibrate appropriately.
467 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
472 SHOW(temp0, temp0, null_adjust) /* temp1_input */
473 SHOW(temp1, temp1, null_adjust) /* temp2_input */
476 /* sysfs conventions report voltages in millivolts. We can convert voltages
477 * if we know vREF. userspace may need to scale vAUX to match the board's
478 * external resistors; we assume that vBATT only uses the internal ones.
480 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
484 /* external resistors may scale vAUX into 0..vREF */
485 retval *= ts->vref_mv;
486 retval = retval >> 12;
491 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
493 unsigned retval = vaux_adjust(ts, v);
495 /* ads7846 has a resistor ladder to scale this signal down */
496 if (ts->model == 7846)
502 SHOW(in0_input, vaux, vaux_adjust)
503 SHOW(in1_input, vbatt, vbatt_adjust)
505 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
508 struct device *dev = container_of(kobj, struct device, kobj);
509 struct ads7846 *ts = dev_get_drvdata(dev);
511 if (ts->model == 7843 && index < 2) /* in0, in1 */
513 if (ts->model == 7845 && index != 2) /* in0 */
519 static struct attribute *ads7846_attributes[] = {
520 &dev_attr_temp0.attr, /* 0 */
521 &dev_attr_temp1.attr, /* 1 */
522 &dev_attr_in0_input.attr, /* 2 */
523 &dev_attr_in1_input.attr, /* 3 */
527 static const struct attribute_group ads7846_attr_group = {
528 .attrs = ads7846_attributes,
529 .is_visible = ads7846_is_visible,
531 __ATTRIBUTE_GROUPS(ads7846_attr);
533 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
535 /* hwmon sensors need a reference voltage */
539 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
541 ts->use_internal = true;
548 "external vREF for ADS%d not specified\n",
555 ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
556 ts, ads7846_attr_groups);
558 return PTR_ERR_OR_ZERO(ts->hwmon);
561 static void ads784x_hwmon_unregister(struct spi_device *spi,
565 hwmon_device_unregister(ts->hwmon);
569 static inline int ads784x_hwmon_register(struct spi_device *spi,
575 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
581 static ssize_t ads7846_pen_down_show(struct device *dev,
582 struct device_attribute *attr, char *buf)
584 struct ads7846 *ts = dev_get_drvdata(dev);
586 return sprintf(buf, "%u\n", ts->pendown);
589 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
591 static ssize_t ads7846_disable_show(struct device *dev,
592 struct device_attribute *attr, char *buf)
594 struct ads7846 *ts = dev_get_drvdata(dev);
596 return sprintf(buf, "%u\n", ts->disabled);
599 static ssize_t ads7846_disable_store(struct device *dev,
600 struct device_attribute *attr,
601 const char *buf, size_t count)
603 struct ads7846 *ts = dev_get_drvdata(dev);
607 err = kstrtouint(buf, 10, &i);
619 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
621 static struct attribute *ads784x_attributes[] = {
622 &dev_attr_pen_down.attr,
623 &dev_attr_disable.attr,
627 static const struct attribute_group ads784x_attr_group = {
628 .attrs = ads784x_attributes,
631 /*--------------------------------------------------------------------------*/
633 static void null_wait_for_sync(void)
637 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
639 struct ads7846 *ts = ads;
641 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
642 /* Start over collecting consistent readings. */
645 * Repeat it, if this was the first read or the read
646 * wasn't consistent enough.
648 if (ts->read_cnt < ts->debounce_max) {
649 ts->last_read = *val;
651 return ADS7846_FILTER_REPEAT;
654 * Maximum number of debouncing reached and still
655 * not enough number of consistent readings. Abort
656 * the whole sample, repeat it in the next sampling
660 return ADS7846_FILTER_IGNORE;
663 if (++ts->read_rep > ts->debounce_rep) {
665 * Got a good reading for this coordinate,
666 * go for the next one.
670 return ADS7846_FILTER_OK;
672 /* Read more values that are consistent. */
674 return ADS7846_FILTER_REPEAT;
679 static int ads7846_no_filter(void *ads, int data_idx, int *val)
681 return ADS7846_FILTER_OK;
684 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
687 struct spi_transfer *t =
688 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
690 if (ts->model == 7845) {
691 value = be16_to_cpup((__be16 *)&(((char *)t->rx_buf)[1]));
694 * adjust: on-wire is a must-ignore bit, a BE12 value, then
695 * padding; built from two 8 bit values written msb-first.
697 value = be16_to_cpup((__be16 *)t->rx_buf);
700 /* enforce ADC output is 12 bits width */
701 return (value >> 3) & 0xfff;
704 static void ads7846_update_value(struct spi_message *m, int val)
706 struct spi_transfer *t =
707 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
709 *(u16 *)t->rx_buf = val;
712 static void ads7846_read_state(struct ads7846 *ts)
714 struct ads7846_packet *packet = ts->packet;
715 struct spi_message *m;
721 while (msg_idx < ts->msg_count) {
725 m = &ts->msg[msg_idx];
726 error = spi_sync(ts->spi, m);
728 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
729 packet->tc.ignore = true;
734 * Last message is power down request, no need to convert
735 * or filter the value.
737 if (msg_idx < ts->msg_count - 1) {
739 val = ads7846_get_value(ts, m);
741 action = ts->filter(ts->filter_data, msg_idx, &val);
743 case ADS7846_FILTER_REPEAT:
746 case ADS7846_FILTER_IGNORE:
747 packet->tc.ignore = true;
748 msg_idx = ts->msg_count - 1;
751 case ADS7846_FILTER_OK:
752 ads7846_update_value(m, val);
753 packet->tc.ignore = false;
766 static void ads7846_report_state(struct ads7846 *ts)
768 struct ads7846_packet *packet = ts->packet;
773 * ads7846_get_value() does in-place conversion (including byte swap)
774 * from on-the-wire format as part of debouncing to get stable
777 if (ts->model == 7845) {
778 x = *(u16 *)packet->tc.x_buf;
779 y = *(u16 *)packet->tc.y_buf;
789 /* range filtering */
793 if (ts->model == 7843 || ts->model == 7845) {
794 Rt = ts->pressure_max / 2;
795 } else if (likely(x && z1)) {
796 /* compute touch pressure resistance using equation #2 */
799 Rt *= ts->x_plate_ohms;
800 Rt = DIV_ROUND_CLOSEST(Rt, 16);
803 Rt = DIV_ROUND_CLOSEST(Rt, 256);
809 * Sample found inconsistent by debouncing or pressure is beyond
810 * the maximum. Don't report it to user space, repeat at least
811 * once more the measurement
813 if (packet->tc.ignore || Rt > ts->pressure_max) {
814 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
815 packet->tc.ignore, Rt);
820 * Maybe check the pendown state before reporting. This discards
821 * false readings when the pen is lifted.
823 if (ts->penirq_recheck_delay_usecs) {
824 udelay(ts->penirq_recheck_delay_usecs);
825 if (!get_pendown_state(ts))
830 * NOTE: We can't rely on the pressure to determine the pen down
831 * state, even this controller has a pressure sensor. The pressure
832 * value can fluctuate for quite a while after lifting the pen and
833 * in some cases may not even settle at the expected value.
835 * The only safe way to check for the pen up condition is in the
836 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
839 struct input_dev *input = ts->input;
845 input_report_key(input, BTN_TOUCH, 1);
847 dev_vdbg(&ts->spi->dev, "DOWN\n");
850 input_report_abs(input, ABS_X, x);
851 input_report_abs(input, ABS_Y, y);
852 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
855 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
859 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
861 struct ads7846 *ts = handle;
863 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
867 static irqreturn_t ads7846_irq(int irq, void *handle)
869 struct ads7846 *ts = handle;
871 /* Start with a small delay before checking pendown state */
872 msleep(TS_POLL_DELAY);
874 while (!ts->stopped && get_pendown_state(ts)) {
876 /* pen is down, continue with the measurement */
877 ads7846_read_state(ts);
880 ads7846_report_state(ts);
882 wait_event_timeout(ts->wait, ts->stopped,
883 msecs_to_jiffies(TS_POLL_PERIOD));
886 if (ts->pendown && !ts->stopped)
887 ads7846_report_pen_up(ts);
892 static int __maybe_unused ads7846_suspend(struct device *dev)
894 struct ads7846 *ts = dev_get_drvdata(dev);
896 mutex_lock(&ts->lock);
898 if (!ts->suspended) {
901 __ads7846_disable(ts);
903 if (device_may_wakeup(&ts->spi->dev))
904 enable_irq_wake(ts->spi->irq);
906 ts->suspended = true;
909 mutex_unlock(&ts->lock);
914 static int __maybe_unused ads7846_resume(struct device *dev)
916 struct ads7846 *ts = dev_get_drvdata(dev);
918 mutex_lock(&ts->lock);
922 ts->suspended = false;
924 if (device_may_wakeup(&ts->spi->dev))
925 disable_irq_wake(ts->spi->irq);
928 __ads7846_enable(ts);
931 mutex_unlock(&ts->lock);
936 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
938 static int ads7846_setup_pendown(struct spi_device *spi,
940 const struct ads7846_platform_data *pdata)
945 * REVISIT when the irq can be triggered active-low, or if for some
946 * reason the touchscreen isn't hooked up, we don't need to access
950 if (pdata->get_pendown_state) {
951 ts->get_pendown_state = pdata->get_pendown_state;
952 } else if (gpio_is_valid(pdata->gpio_pendown)) {
954 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
958 "failed to request/setup pendown GPIO%d: %d\n",
959 pdata->gpio_pendown, err);
963 ts->gpio_pendown = pdata->gpio_pendown;
965 if (pdata->gpio_pendown_debounce)
966 gpio_set_debounce(pdata->gpio_pendown,
967 pdata->gpio_pendown_debounce);
969 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
977 * Set up the transfers to read touchscreen state; this assumes we
978 * use formula #2 for pressure, not #3.
980 static void ads7846_setup_spi_msg(struct ads7846 *ts,
981 const struct ads7846_platform_data *pdata)
983 struct spi_message *m = &ts->msg[0];
984 struct spi_transfer *x = ts->xfer;
985 struct ads7846_packet *packet = ts->packet;
986 int vref = pdata->keep_vref_on;
988 if (ts->model == 7873) {
990 * The AD7873 is almost identical to the ADS7846
991 * keep VREF off during differential/ratiometric
1002 if (ts->model == 7845) {
1003 packet->read_y_cmd[0] = READ_Y(vref);
1004 packet->read_y_cmd[1] = 0;
1005 packet->read_y_cmd[2] = 0;
1006 x->tx_buf = &packet->read_y_cmd[0];
1007 x->rx_buf = &packet->tc.y_buf[0];
1009 spi_message_add_tail(x, m);
1011 /* y- still on; turn on only y+ (and ADC) */
1012 packet->read_y = READ_Y(vref);
1013 x->tx_buf = &packet->read_y;
1015 spi_message_add_tail(x, m);
1018 x->rx_buf = &packet->tc.y;
1020 spi_message_add_tail(x, m);
1024 * The first sample after switching drivers can be low quality;
1025 * optionally discard it, using a second one after the signals
1026 * have had enough time to stabilize.
1028 if (pdata->settle_delay_usecs) {
1029 x->delay_usecs = pdata->settle_delay_usecs;
1032 x->tx_buf = &packet->read_y;
1034 spi_message_add_tail(x, m);
1037 x->rx_buf = &packet->tc.y;
1039 spi_message_add_tail(x, m);
1044 spi_message_init(m);
1047 if (ts->model == 7845) {
1049 packet->read_x_cmd[0] = READ_X(vref);
1050 packet->read_x_cmd[1] = 0;
1051 packet->read_x_cmd[2] = 0;
1052 x->tx_buf = &packet->read_x_cmd[0];
1053 x->rx_buf = &packet->tc.x_buf[0];
1055 spi_message_add_tail(x, m);
1057 /* turn y- off, x+ on, then leave in lowpower */
1059 packet->read_x = READ_X(vref);
1060 x->tx_buf = &packet->read_x;
1062 spi_message_add_tail(x, m);
1065 x->rx_buf = &packet->tc.x;
1067 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_x;
1077 spi_message_add_tail(x, m);
1080 x->rx_buf = &packet->tc.x;
1082 spi_message_add_tail(x, m);
1085 /* turn y+ off, x- on; we'll use formula #2 */
1086 if (ts->model == 7846) {
1089 spi_message_init(m);
1093 packet->read_z1 = READ_Z1(vref);
1094 x->tx_buf = &packet->read_z1;
1096 spi_message_add_tail(x, m);
1099 x->rx_buf = &packet->tc.z1;
1101 spi_message_add_tail(x, m);
1103 /* ... maybe discard first sample ... */
1104 if (pdata->settle_delay_usecs) {
1105 x->delay_usecs = pdata->settle_delay_usecs;
1108 x->tx_buf = &packet->read_z1;
1110 spi_message_add_tail(x, m);
1113 x->rx_buf = &packet->tc.z1;
1115 spi_message_add_tail(x, m);
1120 spi_message_init(m);
1124 packet->read_z2 = READ_Z2(vref);
1125 x->tx_buf = &packet->read_z2;
1127 spi_message_add_tail(x, m);
1130 x->rx_buf = &packet->tc.z2;
1132 spi_message_add_tail(x, m);
1134 /* ... maybe discard first sample ... */
1135 if (pdata->settle_delay_usecs) {
1136 x->delay_usecs = pdata->settle_delay_usecs;
1139 x->tx_buf = &packet->read_z2;
1141 spi_message_add_tail(x, m);
1144 x->rx_buf = &packet->tc.z2;
1146 spi_message_add_tail(x, m);
1153 spi_message_init(m);
1156 if (ts->model == 7845) {
1158 packet->pwrdown_cmd[0] = PWRDOWN;
1159 packet->pwrdown_cmd[1] = 0;
1160 packet->pwrdown_cmd[2] = 0;
1161 x->tx_buf = &packet->pwrdown_cmd[0];
1165 packet->pwrdown = PWRDOWN;
1166 x->tx_buf = &packet->pwrdown;
1168 spi_message_add_tail(x, m);
1171 x->rx_buf = &packet->dummy;
1176 spi_message_add_tail(x, m);
1180 static const struct of_device_id ads7846_dt_ids[] = {
1181 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1182 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1183 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1184 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1185 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1188 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1190 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1192 struct ads7846_platform_data *pdata;
1193 struct device_node *node = dev->of_node;
1194 const struct of_device_id *match;
1197 dev_err(dev, "Device does not have associated DT data\n");
1198 return ERR_PTR(-EINVAL);
1201 match = of_match_device(ads7846_dt_ids, dev);
1203 dev_err(dev, "Unknown device model\n");
1204 return ERR_PTR(-EINVAL);
1207 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1209 return ERR_PTR(-ENOMEM);
1211 pdata->model = (unsigned long)match->data;
1213 of_property_read_u16(node, "ti,vref-delay-usecs",
1214 &pdata->vref_delay_usecs);
1215 of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1216 pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1218 pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1220 of_property_read_u16(node, "ti,settle-delay-usec",
1221 &pdata->settle_delay_usecs);
1222 of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1223 &pdata->penirq_recheck_delay_usecs);
1225 of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1226 of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1228 of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1229 of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1230 of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1231 of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1233 of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1234 of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1236 of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1237 of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1238 of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1240 of_property_read_u32(node, "ti,pendown-gpio-debounce",
1241 &pdata->gpio_pendown_debounce);
1243 pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1244 of_property_read_bool(node, "linux,wakeup");
1246 pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1251 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1253 dev_err(dev, "no platform data defined\n");
1254 return ERR_PTR(-EINVAL);
1258 static int ads7846_probe(struct spi_device *spi)
1260 const struct ads7846_platform_data *pdata;
1262 struct ads7846_packet *packet;
1263 struct input_dev *input_dev;
1264 unsigned long irq_flags;
1268 dev_dbg(&spi->dev, "no IRQ?\n");
1272 /* don't exceed max specified sample rate */
1273 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1274 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1275 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1280 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1281 * that even if the hardware can do that, the SPI controller driver
1282 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1284 spi->bits_per_word = 8;
1285 spi->mode = SPI_MODE_0;
1286 err = spi_setup(spi);
1290 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1291 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1292 input_dev = input_allocate_device();
1293 if (!ts || !packet || !input_dev) {
1298 spi_set_drvdata(spi, ts);
1300 ts->packet = packet;
1302 ts->input = input_dev;
1304 mutex_init(&ts->lock);
1305 init_waitqueue_head(&ts->wait);
1307 pdata = dev_get_platdata(&spi->dev);
1309 pdata = ads7846_probe_dt(&spi->dev);
1310 if (IS_ERR(pdata)) {
1311 err = PTR_ERR(pdata);
1316 ts->model = pdata->model ? : 7846;
1317 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1318 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1319 ts->pressure_max = pdata->pressure_max ? : ~0;
1321 ts->vref_mv = pdata->vref_mv;
1322 ts->swap_xy = pdata->swap_xy;
1324 if (pdata->filter != NULL) {
1325 if (pdata->filter_init != NULL) {
1326 err = pdata->filter_init(pdata, &ts->filter_data);
1330 ts->filter = pdata->filter;
1331 ts->filter_cleanup = pdata->filter_cleanup;
1332 } else if (pdata->debounce_max) {
1333 ts->debounce_max = pdata->debounce_max;
1334 if (ts->debounce_max < 2)
1335 ts->debounce_max = 2;
1336 ts->debounce_tol = pdata->debounce_tol;
1337 ts->debounce_rep = pdata->debounce_rep;
1338 ts->filter = ads7846_debounce_filter;
1339 ts->filter_data = ts;
1341 ts->filter = ads7846_no_filter;
1344 err = ads7846_setup_pendown(spi, ts, pdata);
1346 goto err_cleanup_filter;
1348 if (pdata->penirq_recheck_delay_usecs)
1349 ts->penirq_recheck_delay_usecs =
1350 pdata->penirq_recheck_delay_usecs;
1352 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1354 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1355 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1357 input_dev->name = ts->name;
1358 input_dev->phys = ts->phys;
1359 input_dev->dev.parent = &spi->dev;
1361 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1362 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1363 input_set_abs_params(input_dev, ABS_X,
1365 pdata->x_max ? : MAX_12BIT,
1367 input_set_abs_params(input_dev, ABS_Y,
1369 pdata->y_max ? : MAX_12BIT,
1371 if (ts->model != 7845)
1372 input_set_abs_params(input_dev, ABS_PRESSURE,
1373 pdata->pressure_min, pdata->pressure_max, 0, 0);
1375 ads7846_setup_spi_msg(ts, pdata);
1377 ts->reg = regulator_get(&spi->dev, "vcc");
1378 if (IS_ERR(ts->reg)) {
1379 err = PTR_ERR(ts->reg);
1380 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1384 err = regulator_enable(ts->reg);
1386 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1387 goto err_put_regulator;
1390 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1391 irq_flags |= IRQF_ONESHOT;
1393 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1394 irq_flags, spi->dev.driver->name, ts);
1395 if (err && !pdata->irq_flags) {
1397 "trying pin change workaround on irq %d\n", spi->irq);
1398 irq_flags |= IRQF_TRIGGER_RISING;
1399 err = request_threaded_irq(spi->irq,
1400 ads7846_hard_irq, ads7846_irq,
1401 irq_flags, spi->dev.driver->name, ts);
1405 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1406 goto err_disable_regulator;
1409 err = ads784x_hwmon_register(spi, ts);
1413 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1416 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1417 * the touchscreen, in case it's not connected.
1419 if (ts->model == 7845)
1420 ads7845_read12_ser(&spi->dev, PWRDOWN);
1422 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1424 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1426 goto err_remove_hwmon;
1428 err = input_register_device(input_dev);
1430 goto err_remove_attr_group;
1432 device_init_wakeup(&spi->dev, pdata->wakeup);
1435 * If device does not carry platform data we must have allocated it
1436 * when parsing DT data.
1438 if (!dev_get_platdata(&spi->dev))
1439 devm_kfree(&spi->dev, (void *)pdata);
1443 err_remove_attr_group:
1444 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1446 ads784x_hwmon_unregister(spi, ts);
1448 free_irq(spi->irq, ts);
1449 err_disable_regulator:
1450 regulator_disable(ts->reg);
1452 regulator_put(ts->reg);
1454 if (!ts->get_pendown_state)
1455 gpio_free(ts->gpio_pendown);
1457 if (ts->filter_cleanup)
1458 ts->filter_cleanup(ts->filter_data);
1460 input_free_device(input_dev);
1466 static int ads7846_remove(struct spi_device *spi)
1468 struct ads7846 *ts = spi_get_drvdata(spi);
1470 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1472 ads7846_disable(ts);
1473 free_irq(ts->spi->irq, ts);
1475 input_unregister_device(ts->input);
1477 ads784x_hwmon_unregister(spi, ts);
1479 regulator_put(ts->reg);
1481 if (!ts->get_pendown_state) {
1483 * If we are not using specialized pendown method we must
1484 * have been relying on gpio we set up ourselves.
1486 gpio_free(ts->gpio_pendown);
1489 if (ts->filter_cleanup)
1490 ts->filter_cleanup(ts->filter_data);
1495 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1500 static struct spi_driver ads7846_driver = {
1504 .of_match_table = of_match_ptr(ads7846_dt_ids),
1506 .probe = ads7846_probe,
1507 .remove = ads7846_remove,
1510 module_spi_driver(ads7846_driver);
1512 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1513 MODULE_LICENSE("GPL");
1514 MODULE_ALIAS("spi:ads7846");