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/input/touchscreen.h>
24 #include <linux/interrupt.h>
25 #include <linux/slab.h>
28 #include <linux/of_gpio.h>
29 #include <linux/of_device.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>
35 #include <asm/unaligned.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 */)
70 struct ads7846_buf_layout {
77 * We allocate this separately to avoid cache line sharing issues when
78 * driver is used with DMA-based SPI controllers (like atmel_spi) on
79 * systems where main memory is not DMA-coherent (most non-x86 boards).
81 struct ads7846_packet {
83 unsigned int count_skip;
85 unsigned int last_cmd_idx;
86 struct ads7846_buf_layout l[5];
87 struct ads7846_buf *rx;
88 struct ads7846_buf *tx;
90 struct ads7846_buf pwrdown_cmd;
97 struct input_dev *input;
101 struct spi_device *spi;
102 struct regulator *reg;
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;
132 struct touchscreen_properties core_prop;
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 int (*get_pendown_state)(void);
144 void (*wait_for_sync)(void);
147 enum ads7846_filter {
149 ADS7846_FILTER_REPEAT,
150 ADS7846_FILTER_IGNORE,
153 /* leave chip selected when we're done, for quicker re-select? */
155 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
157 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
160 /*--------------------------------------------------------------------------*/
162 /* The ADS7846 has touchscreen and other sensors.
163 * Earlier ads784x chips are somewhat compatible.
165 #define ADS_START (1 << 7)
166 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
167 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
168 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
169 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
170 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
171 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
172 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
173 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
174 #define ADS_8_BIT (1 << 3)
175 #define ADS_12_BIT (0 << 3)
176 #define ADS_SER (1 << 2) /* non-differential */
177 #define ADS_DFR (0 << 2) /* differential */
178 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
179 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
180 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
181 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
183 #define MAX_12BIT ((1<<12)-1)
185 /* leave ADC powered up (disables penirq) between differential samples */
186 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
187 | ADS_12_BIT | ADS_DFR | \
188 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
190 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
191 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
192 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
193 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
194 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
196 /* single-ended samples need to first power up reference voltage;
197 * we leave both ADC and VREF powered
199 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
200 | ADS_12_BIT | ADS_SER)
202 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
203 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
205 /* Order commands in the most optimal way to reduce Vref switching and
207 * Measure: X; Vref: X+, X-; IN: Y+
208 * Measure: Y; Vref: Y+, Y-; IN: X+
209 * Measure: Z1; Vref: Y+, X-; IN: X+
210 * Measure: Z2; Vref: Y+, X-; IN: Y-
220 static int get_pendown_state(struct ads7846 *ts)
222 if (ts->get_pendown_state)
223 return ts->get_pendown_state();
225 return !gpio_get_value(ts->gpio_pendown);
228 static void ads7846_report_pen_up(struct ads7846 *ts)
230 struct input_dev *input = ts->input;
232 input_report_key(input, BTN_TOUCH, 0);
233 input_report_abs(input, ABS_PRESSURE, 0);
237 dev_vdbg(&ts->spi->dev, "UP\n");
240 /* Must be called with ts->lock held */
241 static void ads7846_stop(struct ads7846 *ts)
243 if (!ts->disabled && !ts->suspended) {
244 /* Signal IRQ thread to stop polling and disable the handler. */
248 disable_irq(ts->spi->irq);
252 /* Must be called with ts->lock held */
253 static void ads7846_restart(struct ads7846 *ts)
255 if (!ts->disabled && !ts->suspended) {
256 /* Check if pen was released since last stop */
257 if (ts->pendown && !get_pendown_state(ts))
258 ads7846_report_pen_up(ts);
260 /* Tell IRQ thread that it may poll the device. */
263 enable_irq(ts->spi->irq);
267 /* Must be called with ts->lock held */
268 static void __ads7846_disable(struct ads7846 *ts)
271 regulator_disable(ts->reg);
274 * We know the chip's in low power mode since we always
275 * leave it that way after every request
279 /* Must be called with ts->lock held */
280 static void __ads7846_enable(struct ads7846 *ts)
284 error = regulator_enable(ts->reg);
286 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
291 static void ads7846_disable(struct ads7846 *ts)
293 mutex_lock(&ts->lock);
298 __ads7846_disable(ts);
303 mutex_unlock(&ts->lock);
306 static void ads7846_enable(struct ads7846 *ts)
308 mutex_lock(&ts->lock);
312 ts->disabled = false;
315 __ads7846_enable(ts);
318 mutex_unlock(&ts->lock);
321 /*--------------------------------------------------------------------------*/
324 * Non-touchscreen sensors only use single-ended conversions.
325 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
326 * ads7846 lets that pin be unconnected, to use internal vREF.
334 struct spi_message msg;
335 struct spi_transfer xfer[6];
337 * DMA (thus cache coherency maintenance) requires the
338 * transfer buffers to live in their own cache lines.
340 __be16 sample ____cacheline_aligned;
343 struct ads7845_ser_req {
345 struct spi_message msg;
346 struct spi_transfer xfer[2];
348 * DMA (thus cache coherency maintenance) requires the
349 * transfer buffers to live in their own cache lines.
351 u8 sample[3] ____cacheline_aligned;
354 static int ads7846_read12_ser(struct device *dev, unsigned command)
356 struct spi_device *spi = to_spi_device(dev);
357 struct ads7846 *ts = dev_get_drvdata(dev);
361 req = kzalloc(sizeof *req, GFP_KERNEL);
365 spi_message_init(&req->msg);
367 /* maybe turn on internal vREF, and let it settle */
368 if (ts->use_internal) {
369 req->ref_on = REF_ON;
370 req->xfer[0].tx_buf = &req->ref_on;
371 req->xfer[0].len = 1;
372 spi_message_add_tail(&req->xfer[0], &req->msg);
374 req->xfer[1].rx_buf = &req->scratch;
375 req->xfer[1].len = 2;
377 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
378 req->xfer[1].delay.value = ts->vref_delay_usecs;
379 req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
380 spi_message_add_tail(&req->xfer[1], &req->msg);
382 /* Enable reference voltage */
383 command |= ADS_PD10_REF_ON;
386 /* Enable ADC in every case */
387 command |= ADS_PD10_ADC_ON;
390 req->command = (u8) command;
391 req->xfer[2].tx_buf = &req->command;
392 req->xfer[2].len = 1;
393 spi_message_add_tail(&req->xfer[2], &req->msg);
395 req->xfer[3].rx_buf = &req->sample;
396 req->xfer[3].len = 2;
397 spi_message_add_tail(&req->xfer[3], &req->msg);
399 /* REVISIT: take a few more samples, and compare ... */
401 /* converter in low power mode & enable PENIRQ */
402 req->ref_off = PWRDOWN;
403 req->xfer[4].tx_buf = &req->ref_off;
404 req->xfer[4].len = 1;
405 spi_message_add_tail(&req->xfer[4], &req->msg);
407 req->xfer[5].rx_buf = &req->scratch;
408 req->xfer[5].len = 2;
409 CS_CHANGE(req->xfer[5]);
410 spi_message_add_tail(&req->xfer[5], &req->msg);
412 mutex_lock(&ts->lock);
414 status = spi_sync(spi, &req->msg);
416 mutex_unlock(&ts->lock);
419 /* on-wire is a must-ignore bit, a BE12 value, then padding */
420 status = be16_to_cpu(req->sample);
421 status = status >> 3;
429 static int ads7845_read12_ser(struct device *dev, unsigned command)
431 struct spi_device *spi = to_spi_device(dev);
432 struct ads7846 *ts = dev_get_drvdata(dev);
433 struct ads7845_ser_req *req;
436 req = kzalloc(sizeof *req, GFP_KERNEL);
440 spi_message_init(&req->msg);
442 req->command[0] = (u8) command;
443 req->xfer[0].tx_buf = req->command;
444 req->xfer[0].rx_buf = req->sample;
445 req->xfer[0].len = 3;
446 spi_message_add_tail(&req->xfer[0], &req->msg);
448 mutex_lock(&ts->lock);
450 status = spi_sync(spi, &req->msg);
452 mutex_unlock(&ts->lock);
455 /* BE12 value, then padding */
456 status = get_unaligned_be16(&req->sample[1]);
457 status = status >> 3;
465 #if IS_ENABLED(CONFIG_HWMON)
467 #define SHOW(name, var, adjust) static ssize_t \
468 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
470 struct ads7846 *ts = dev_get_drvdata(dev); \
471 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
472 READ_12BIT_SER(var)); \
475 return sprintf(buf, "%u\n", adjust(ts, v)); \
477 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
480 /* Sysfs conventions report temperatures in millidegrees Celsius.
481 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
482 * accuracy scheme without calibration data. For now we won't try either;
483 * userspace sees raw sensor values, and must scale/calibrate appropriately.
485 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
490 SHOW(temp0, temp0, null_adjust) /* temp1_input */
491 SHOW(temp1, temp1, null_adjust) /* temp2_input */
494 /* sysfs conventions report voltages in millivolts. We can convert voltages
495 * if we know vREF. userspace may need to scale vAUX to match the board's
496 * external resistors; we assume that vBATT only uses the internal ones.
498 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
502 /* external resistors may scale vAUX into 0..vREF */
503 retval *= ts->vref_mv;
504 retval = retval >> 12;
509 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
511 unsigned retval = vaux_adjust(ts, v);
513 /* ads7846 has a resistor ladder to scale this signal down */
514 if (ts->model == 7846)
520 SHOW(in0_input, vaux, vaux_adjust)
521 SHOW(in1_input, vbatt, vbatt_adjust)
523 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
526 struct device *dev = kobj_to_dev(kobj);
527 struct ads7846 *ts = dev_get_drvdata(dev);
529 if (ts->model == 7843 && index < 2) /* in0, in1 */
531 if (ts->model == 7845 && index != 2) /* in0 */
537 static struct attribute *ads7846_attributes[] = {
538 &dev_attr_temp0.attr, /* 0 */
539 &dev_attr_temp1.attr, /* 1 */
540 &dev_attr_in0_input.attr, /* 2 */
541 &dev_attr_in1_input.attr, /* 3 */
545 static const struct attribute_group ads7846_attr_group = {
546 .attrs = ads7846_attributes,
547 .is_visible = ads7846_is_visible,
549 __ATTRIBUTE_GROUPS(ads7846_attr);
551 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
553 struct device *hwmon;
555 /* hwmon sensors need a reference voltage */
559 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
561 ts->use_internal = true;
568 "external vREF for ADS%d not specified\n",
575 hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
577 ads7846_attr_groups);
579 return PTR_ERR_OR_ZERO(hwmon);
583 static inline int ads784x_hwmon_register(struct spi_device *spi,
590 static ssize_t ads7846_pen_down_show(struct device *dev,
591 struct device_attribute *attr, char *buf)
593 struct ads7846 *ts = dev_get_drvdata(dev);
595 return sprintf(buf, "%u\n", ts->pendown);
598 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
600 static ssize_t ads7846_disable_show(struct device *dev,
601 struct device_attribute *attr, char *buf)
603 struct ads7846 *ts = dev_get_drvdata(dev);
605 return sprintf(buf, "%u\n", ts->disabled);
608 static ssize_t ads7846_disable_store(struct device *dev,
609 struct device_attribute *attr,
610 const char *buf, size_t count)
612 struct ads7846 *ts = dev_get_drvdata(dev);
616 err = kstrtouint(buf, 10, &i);
628 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
630 static struct attribute *ads784x_attributes[] = {
631 &dev_attr_pen_down.attr,
632 &dev_attr_disable.attr,
636 static const struct attribute_group ads784x_attr_group = {
637 .attrs = ads784x_attributes,
640 /*--------------------------------------------------------------------------*/
642 static void null_wait_for_sync(void)
646 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
648 struct ads7846 *ts = ads;
650 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
651 /* Start over collecting consistent readings. */
654 * Repeat it, if this was the first read or the read
655 * wasn't consistent enough.
657 if (ts->read_cnt < ts->debounce_max) {
658 ts->last_read = *val;
660 return ADS7846_FILTER_REPEAT;
663 * Maximum number of debouncing reached and still
664 * not enough number of consistent readings. Abort
665 * the whole sample, repeat it in the next sampling
669 return ADS7846_FILTER_IGNORE;
672 if (++ts->read_rep > ts->debounce_rep) {
674 * Got a good reading for this coordinate,
675 * go for the next one.
679 return ADS7846_FILTER_OK;
681 /* Read more values that are consistent. */
683 return ADS7846_FILTER_REPEAT;
688 static int ads7846_no_filter(void *ads, int data_idx, int *val)
690 return ADS7846_FILTER_OK;
693 static int ads7846_get_value(struct ads7846_buf *buf)
697 value = be16_to_cpup(&buf->data);
699 /* enforce ADC output is 12 bits width */
700 return (value >> 3) & 0xfff;
703 static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
706 struct ads7846_packet *packet = ts->packet;
726 static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
734 /* 7846 specific commands */
736 return READ_Z1(vref);
738 return READ_Z2(vref);
748 static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
765 static int ads7846_filter(struct ads7846 *ts)
767 struct ads7846_packet *packet = ts->packet;
770 unsigned int cmd_idx, b;
772 packet->ignore = false;
773 for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
774 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
776 packet->last_cmd_idx = cmd_idx;
778 for (b = l->skip; b < l->count; b++) {
779 val = ads7846_get_value(&packet->rx[l->offset + b]);
781 action = ts->filter(ts->filter_data, cmd_idx, &val);
782 if (action == ADS7846_FILTER_REPEAT) {
783 if (b == l->count - 1)
785 } else if (action == ADS7846_FILTER_OK) {
786 ads7846_set_cmd_val(ts, cmd_idx, val);
789 packet->ignore = true;
798 static void ads7846_read_state(struct ads7846 *ts)
800 struct ads7846_packet *packet = ts->packet;
801 struct spi_message *m;
805 packet->last_cmd_idx = 0;
810 m = &ts->msg[msg_idx];
811 error = spi_sync(ts->spi, m);
813 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
814 packet->ignore = true;
818 error = ads7846_filter(ts);
826 static void ads7846_report_state(struct ads7846 *ts)
828 struct ads7846_packet *packet = ts->packet;
834 if (ts->model == 7845) {
842 /* range filtering */
846 if (ts->model == 7843) {
847 Rt = ts->pressure_max / 2;
848 } else if (ts->model == 7845) {
849 if (get_pendown_state(ts))
850 Rt = ts->pressure_max / 2;
853 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
854 } else if (likely(x && z1)) {
855 /* compute touch pressure resistance using equation #2 */
858 Rt *= ts->x_plate_ohms;
859 Rt = DIV_ROUND_CLOSEST(Rt, 16);
862 Rt = DIV_ROUND_CLOSEST(Rt, 256);
868 * Sample found inconsistent by debouncing or pressure is beyond
869 * the maximum. Don't report it to user space, repeat at least
870 * once more the measurement
872 if (packet->ignore || Rt > ts->pressure_max) {
873 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
879 * Maybe check the pendown state before reporting. This discards
880 * false readings when the pen is lifted.
882 if (ts->penirq_recheck_delay_usecs) {
883 udelay(ts->penirq_recheck_delay_usecs);
884 if (!get_pendown_state(ts))
889 * NOTE: We can't rely on the pressure to determine the pen down
890 * state, even this controller has a pressure sensor. The pressure
891 * value can fluctuate for quite a while after lifting the pen and
892 * in some cases may not even settle at the expected value.
894 * The only safe way to check for the pen up condition is in the
895 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
898 struct input_dev *input = ts->input;
901 input_report_key(input, BTN_TOUCH, 1);
903 dev_vdbg(&ts->spi->dev, "DOWN\n");
906 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
907 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
910 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
914 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
916 struct ads7846 *ts = handle;
918 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
922 static irqreturn_t ads7846_irq(int irq, void *handle)
924 struct ads7846 *ts = handle;
926 /* Start with a small delay before checking pendown state */
927 msleep(TS_POLL_DELAY);
929 while (!ts->stopped && get_pendown_state(ts)) {
931 /* pen is down, continue with the measurement */
932 ads7846_read_state(ts);
935 ads7846_report_state(ts);
937 wait_event_timeout(ts->wait, ts->stopped,
938 msecs_to_jiffies(TS_POLL_PERIOD));
941 if (ts->pendown && !ts->stopped)
942 ads7846_report_pen_up(ts);
947 static int __maybe_unused ads7846_suspend(struct device *dev)
949 struct ads7846 *ts = dev_get_drvdata(dev);
951 mutex_lock(&ts->lock);
953 if (!ts->suspended) {
956 __ads7846_disable(ts);
958 if (device_may_wakeup(&ts->spi->dev))
959 enable_irq_wake(ts->spi->irq);
961 ts->suspended = true;
964 mutex_unlock(&ts->lock);
969 static int __maybe_unused ads7846_resume(struct device *dev)
971 struct ads7846 *ts = dev_get_drvdata(dev);
973 mutex_lock(&ts->lock);
977 ts->suspended = false;
979 if (device_may_wakeup(&ts->spi->dev))
980 disable_irq_wake(ts->spi->irq);
983 __ads7846_enable(ts);
986 mutex_unlock(&ts->lock);
991 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
993 static int ads7846_setup_pendown(struct spi_device *spi,
995 const struct ads7846_platform_data *pdata)
1000 * REVISIT when the irq can be triggered active-low, or if for some
1001 * reason the touchscreen isn't hooked up, we don't need to access
1002 * the pendown state.
1005 if (pdata->get_pendown_state) {
1006 ts->get_pendown_state = pdata->get_pendown_state;
1007 } else if (gpio_is_valid(pdata->gpio_pendown)) {
1009 err = devm_gpio_request_one(&spi->dev, pdata->gpio_pendown,
1010 GPIOF_IN, "ads7846_pendown");
1013 "failed to request/setup pendown GPIO%d: %d\n",
1014 pdata->gpio_pendown, err);
1018 ts->gpio_pendown = pdata->gpio_pendown;
1020 if (pdata->gpio_pendown_debounce)
1021 gpio_set_debounce(pdata->gpio_pendown,
1022 pdata->gpio_pendown_debounce);
1024 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
1032 * Set up the transfers to read touchscreen state; this assumes we
1033 * use formula #2 for pressure, not #3.
1035 static int ads7846_setup_spi_msg(struct ads7846 *ts,
1036 const struct ads7846_platform_data *pdata)
1038 struct spi_message *m = &ts->msg[0];
1039 struct spi_transfer *x = ts->xfer;
1040 struct ads7846_packet *packet = ts->packet;
1041 int vref = pdata->keep_vref_on;
1042 unsigned int count, offset = 0;
1043 unsigned int cmd_idx, b;
1048 time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1050 count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1051 packet->count_skip = DIV_ROUND_UP(count, 24);
1053 if (ts->debounce_max && ts->debounce_rep)
1054 /* ads7846_debounce_filter() is making ts->debounce_rep + 2
1055 * reads. So we need to get all samples for normal case. */
1056 packet->count = ts->debounce_rep + 2;
1060 if (ts->model == 7846)
1061 packet->cmds = 5; /* x, y, z1, z2, pwdown */
1063 packet->cmds = 3; /* x, y, pwdown */
1065 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1066 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1067 unsigned int max_count;
1069 if (ads7846_cmd_need_settle(cmd_idx))
1070 max_count = packet->count + packet->count_skip;
1072 max_count = packet->count;
1075 offset += max_count;
1076 l->count = max_count;
1077 l->skip = packet->count_skip;
1078 size += sizeof(*packet->tx) * max_count;
1081 packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1085 packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1089 if (ts->model == 7873) {
1091 * The AD7873 is almost identical to the ADS7846
1092 * keep VREF off during differential/ratiometric
1100 spi_message_init(m);
1103 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1104 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1105 u8 cmd = ads7846_get_cmd(cmd_idx, vref);
1107 for (b = 0; b < l->count; b++)
1108 packet->tx[l->offset + b].cmd = cmd;
1111 x->tx_buf = packet->tx;
1112 x->rx_buf = packet->rx;
1114 spi_message_add_tail(x, m);
1120 static const struct of_device_id ads7846_dt_ids[] = {
1121 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1122 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1123 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1124 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1125 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1128 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1130 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1132 struct ads7846_platform_data *pdata;
1133 struct device_node *node = dev->of_node;
1134 const struct of_device_id *match;
1138 dev_err(dev, "Device does not have associated DT data\n");
1139 return ERR_PTR(-EINVAL);
1142 match = of_match_device(ads7846_dt_ids, dev);
1144 dev_err(dev, "Unknown device model\n");
1145 return ERR_PTR(-EINVAL);
1148 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1150 return ERR_PTR(-ENOMEM);
1152 pdata->model = (unsigned long)match->data;
1154 of_property_read_u16(node, "ti,vref-delay-usecs",
1155 &pdata->vref_delay_usecs);
1156 of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1157 pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1159 pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1161 of_property_read_u16(node, "ti,settle-delay-usec",
1162 &pdata->settle_delay_usecs);
1163 of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1164 &pdata->penirq_recheck_delay_usecs);
1166 of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1167 of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1169 of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1170 of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1171 of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1172 of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1175 * touchscreen-max-pressure gets parsed during
1176 * touchscreen_parse_properties()
1178 of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1179 if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
1180 pdata->pressure_min = (u16) value;
1181 of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1183 of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1184 if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
1185 pdata->debounce_max = (u16) value;
1186 of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1187 of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1189 of_property_read_u32(node, "ti,pendown-gpio-debounce",
1190 &pdata->gpio_pendown_debounce);
1192 pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1193 of_property_read_bool(node, "linux,wakeup");
1195 pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1200 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1202 dev_err(dev, "no platform data defined\n");
1203 return ERR_PTR(-EINVAL);
1207 static void ads7846_regulator_disable(void *regulator)
1209 regulator_disable(regulator);
1212 static int ads7846_probe(struct spi_device *spi)
1214 const struct ads7846_platform_data *pdata;
1216 struct device *dev = &spi->dev;
1217 struct ads7846_packet *packet;
1218 struct input_dev *input_dev;
1219 unsigned long irq_flags;
1223 dev_dbg(dev, "no IRQ?\n");
1227 /* don't exceed max specified sample rate */
1228 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1229 dev_err(dev, "f(sample) %d KHz?\n",
1230 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1235 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1236 * that even if the hardware can do that, the SPI controller driver
1237 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1239 spi->bits_per_word = 8;
1240 spi->mode &= ~SPI_MODE_X_MASK;
1241 spi->mode |= SPI_MODE_0;
1242 err = spi_setup(spi);
1246 ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1250 packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1254 input_dev = devm_input_allocate_device(dev);
1258 spi_set_drvdata(spi, ts);
1260 ts->packet = packet;
1262 ts->input = input_dev;
1264 mutex_init(&ts->lock);
1265 init_waitqueue_head(&ts->wait);
1267 pdata = dev_get_platdata(dev);
1269 pdata = ads7846_probe_dt(dev);
1271 return PTR_ERR(pdata);
1274 ts->model = pdata->model ? : 7846;
1275 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1276 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1277 ts->vref_mv = pdata->vref_mv;
1279 if (pdata->debounce_max) {
1280 ts->debounce_max = pdata->debounce_max;
1281 if (ts->debounce_max < 2)
1282 ts->debounce_max = 2;
1283 ts->debounce_tol = pdata->debounce_tol;
1284 ts->debounce_rep = pdata->debounce_rep;
1285 ts->filter = ads7846_debounce_filter;
1286 ts->filter_data = ts;
1288 ts->filter = ads7846_no_filter;
1291 err = ads7846_setup_pendown(spi, ts, pdata);
1295 if (pdata->penirq_recheck_delay_usecs)
1296 ts->penirq_recheck_delay_usecs =
1297 pdata->penirq_recheck_delay_usecs;
1299 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1301 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1302 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1304 input_dev->name = ts->name;
1305 input_dev->phys = ts->phys;
1307 input_dev->id.bustype = BUS_SPI;
1308 input_dev->id.product = pdata->model;
1310 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1311 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1312 input_set_abs_params(input_dev, ABS_X,
1314 pdata->x_max ? : MAX_12BIT,
1316 input_set_abs_params(input_dev, ABS_Y,
1318 pdata->y_max ? : MAX_12BIT,
1320 input_set_abs_params(input_dev, ABS_PRESSURE,
1321 pdata->pressure_min, pdata->pressure_max, 0, 0);
1324 * Parse common framework properties. Must be done here to ensure the
1325 * correct behaviour in case of using the legacy vendor bindings. The
1326 * general binding value overrides the vendor specific one.
1328 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1329 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1332 * Check if legacy ti,swap-xy binding is used instead of
1333 * touchscreen-swapped-x-y
1335 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1336 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1337 ts->core_prop.swap_x_y = true;
1340 ads7846_setup_spi_msg(ts, pdata);
1342 ts->reg = devm_regulator_get(dev, "vcc");
1343 if (IS_ERR(ts->reg)) {
1344 err = PTR_ERR(ts->reg);
1345 dev_err(dev, "unable to get regulator: %d\n", err);
1349 err = regulator_enable(ts->reg);
1351 dev_err(dev, "unable to enable regulator: %d\n", err);
1355 err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1359 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1360 irq_flags |= IRQF_ONESHOT;
1362 err = devm_request_threaded_irq(dev, spi->irq,
1363 ads7846_hard_irq, ads7846_irq,
1364 irq_flags, dev->driver->name, ts);
1365 if (err && !pdata->irq_flags) {
1367 "trying pin change workaround on irq %d\n", spi->irq);
1368 irq_flags |= IRQF_TRIGGER_RISING;
1369 err = devm_request_threaded_irq(dev, spi->irq,
1370 ads7846_hard_irq, ads7846_irq,
1371 irq_flags, dev->driver->name,
1376 dev_dbg(dev, "irq %d busy?\n", spi->irq);
1380 err = ads784x_hwmon_register(spi, ts);
1384 dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1387 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1388 * the touchscreen, in case it's not connected.
1390 if (ts->model == 7845)
1391 ads7845_read12_ser(dev, PWRDOWN);
1393 (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1395 err = devm_device_add_group(dev, &ads784x_attr_group);
1399 err = input_register_device(input_dev);
1403 device_init_wakeup(dev, pdata->wakeup);
1406 * If device does not carry platform data we must have allocated it
1407 * when parsing DT data.
1409 if (!dev_get_platdata(dev))
1410 devm_kfree(dev, (void *)pdata);
1415 static int ads7846_remove(struct spi_device *spi)
1417 struct ads7846 *ts = spi_get_drvdata(spi);
1424 static struct spi_driver ads7846_driver = {
1428 .of_match_table = of_match_ptr(ads7846_dt_ids),
1430 .probe = ads7846_probe,
1431 .remove = ads7846_remove,
1434 module_spi_driver(ads7846_driver);
1436 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1437 MODULE_LICENSE("GPL");
1438 MODULE_ALIAS("spi:ads7846");