2 * ADS7846 based touchscreen and sensor driver
4 * Copyright (c) 2005 David Brownell
5 * Copyright (c) 2006 Nokia Corporation
6 * Various changes: Imre Deak <imre.deak@nokia.com>
10 * Copyright (C) 2004-2005 Richard Purdie
11 * - omap_ts.[hc], ads7846.h, ts_osk.c
12 * Copyright (C) 2002 MontaVista Software
13 * Copyright (C) 2004 Texas Instruments
14 * Copyright (C) 2005 Dirk Behme
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License version 2 as
18 * published by the Free Software Foundation.
20 #include <linux/types.h>
21 #include <linux/hwmon.h>
22 #include <linux/init.h>
23 #include <linux/err.h>
24 #include <linux/sched.h>
25 #include <linux/delay.h>
26 #include <linux/input.h>
27 #include <linux/interrupt.h>
28 #include <linux/slab.h>
30 #include <linux/gpio.h>
31 #include <linux/spi/spi.h>
32 #include <linux/spi/ads7846.h>
33 #include <linux/regulator/consumer.h>
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 defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
101 struct attribute_group *attr_group;
102 struct device *hwmon;
107 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)
237 regulator_enable(ts->reg);
241 static void ads7846_disable(struct ads7846 *ts)
243 mutex_lock(&ts->lock);
248 __ads7846_disable(ts);
253 mutex_unlock(&ts->lock);
256 static void ads7846_enable(struct ads7846 *ts)
258 mutex_lock(&ts->lock);
262 ts->disabled = false;
265 __ads7846_enable(ts);
268 mutex_unlock(&ts->lock);
271 /*--------------------------------------------------------------------------*/
274 * Non-touchscreen sensors only use single-ended conversions.
275 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
276 * ads7846 lets that pin be unconnected, to use internal vREF.
284 struct spi_message msg;
285 struct spi_transfer xfer[6];
287 * DMA (thus cache coherency maintenance) requires the
288 * transfer buffers to live in their own cache lines.
290 __be16 sample ____cacheline_aligned;
293 struct ads7845_ser_req {
295 struct spi_message msg;
296 struct spi_transfer xfer[2];
298 * DMA (thus cache coherency maintenance) requires the
299 * transfer buffers to live in their own cache lines.
301 u8 sample[3] ____cacheline_aligned;
304 static int ads7846_read12_ser(struct device *dev, unsigned command)
306 struct spi_device *spi = to_spi_device(dev);
307 struct ads7846 *ts = dev_get_drvdata(dev);
312 req = kzalloc(sizeof *req, GFP_KERNEL);
316 spi_message_init(&req->msg);
318 /* FIXME boards with ads7846 might use external vref instead ... */
319 use_internal = (ts->model == 7846);
321 /* maybe turn on internal vREF, and let it settle */
323 req->ref_on = REF_ON;
324 req->xfer[0].tx_buf = &req->ref_on;
325 req->xfer[0].len = 1;
326 spi_message_add_tail(&req->xfer[0], &req->msg);
328 req->xfer[1].rx_buf = &req->scratch;
329 req->xfer[1].len = 2;
331 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
332 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
333 spi_message_add_tail(&req->xfer[1], &req->msg);
337 req->command = (u8) command;
338 req->xfer[2].tx_buf = &req->command;
339 req->xfer[2].len = 1;
340 spi_message_add_tail(&req->xfer[2], &req->msg);
342 req->xfer[3].rx_buf = &req->sample;
343 req->xfer[3].len = 2;
344 spi_message_add_tail(&req->xfer[3], &req->msg);
346 /* REVISIT: take a few more samples, and compare ... */
348 /* converter in low power mode & enable PENIRQ */
349 req->ref_off = PWRDOWN;
350 req->xfer[4].tx_buf = &req->ref_off;
351 req->xfer[4].len = 1;
352 spi_message_add_tail(&req->xfer[4], &req->msg);
354 req->xfer[5].rx_buf = &req->scratch;
355 req->xfer[5].len = 2;
356 CS_CHANGE(req->xfer[5]);
357 spi_message_add_tail(&req->xfer[5], &req->msg);
359 mutex_lock(&ts->lock);
361 status = spi_sync(spi, &req->msg);
363 mutex_unlock(&ts->lock);
366 /* on-wire is a must-ignore bit, a BE12 value, then padding */
367 status = be16_to_cpu(req->sample);
368 status = status >> 3;
376 static int ads7845_read12_ser(struct device *dev, unsigned command)
378 struct spi_device *spi = to_spi_device(dev);
379 struct ads7846 *ts = dev_get_drvdata(dev);
380 struct ads7845_ser_req *req;
383 req = kzalloc(sizeof *req, GFP_KERNEL);
387 spi_message_init(&req->msg);
389 req->command[0] = (u8) command;
390 req->xfer[0].tx_buf = req->command;
391 req->xfer[0].rx_buf = req->sample;
392 req->xfer[0].len = 3;
393 spi_message_add_tail(&req->xfer[0], &req->msg);
395 mutex_lock(&ts->lock);
397 status = spi_sync(spi, &req->msg);
399 mutex_unlock(&ts->lock);
402 /* BE12 value, then padding */
403 status = be16_to_cpu(*((u16 *)&req->sample[1]));
404 status = status >> 3;
412 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
414 #define SHOW(name, var, adjust) static ssize_t \
415 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
417 struct ads7846 *ts = dev_get_drvdata(dev); \
418 ssize_t v = ads7846_read12_ser(dev, \
419 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
422 return sprintf(buf, "%u\n", adjust(ts, v)); \
424 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
427 /* Sysfs conventions report temperatures in millidegrees Celsius.
428 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
429 * accuracy scheme without calibration data. For now we won't try either;
430 * userspace sees raw sensor values, and must scale/calibrate appropriately.
432 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
437 SHOW(temp0, temp0, null_adjust) /* temp1_input */
438 SHOW(temp1, temp1, null_adjust) /* temp2_input */
441 /* sysfs conventions report voltages in millivolts. We can convert voltages
442 * if we know vREF. userspace may need to scale vAUX to match the board's
443 * external resistors; we assume that vBATT only uses the internal ones.
445 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
449 /* external resistors may scale vAUX into 0..vREF */
450 retval *= ts->vref_mv;
451 retval = retval >> 12;
456 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
458 unsigned retval = vaux_adjust(ts, v);
460 /* ads7846 has a resistor ladder to scale this signal down */
461 if (ts->model == 7846)
467 SHOW(in0_input, vaux, vaux_adjust)
468 SHOW(in1_input, vbatt, vbatt_adjust)
470 static struct attribute *ads7846_attributes[] = {
471 &dev_attr_temp0.attr,
472 &dev_attr_temp1.attr,
473 &dev_attr_in0_input.attr,
474 &dev_attr_in1_input.attr,
478 static struct attribute_group ads7846_attr_group = {
479 .attrs = ads7846_attributes,
482 static struct attribute *ads7843_attributes[] = {
483 &dev_attr_in0_input.attr,
484 &dev_attr_in1_input.attr,
488 static struct attribute_group ads7843_attr_group = {
489 .attrs = ads7843_attributes,
492 static struct attribute *ads7845_attributes[] = {
493 &dev_attr_in0_input.attr,
497 static struct attribute_group ads7845_attr_group = {
498 .attrs = ads7845_attributes,
501 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
503 struct device *hwmon;
506 /* hwmon sensors need a reference voltage */
510 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
518 "external vREF for ADS%d not specified\n",
525 /* different chips have different sensor groups */
528 ts->attr_group = &ads7846_attr_group;
531 ts->attr_group = &ads7845_attr_group;
534 ts->attr_group = &ads7843_attr_group;
537 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
541 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
545 hwmon = hwmon_device_register(&spi->dev);
547 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
548 return PTR_ERR(hwmon);
555 static void ads784x_hwmon_unregister(struct spi_device *spi,
559 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
560 hwmon_device_unregister(ts->hwmon);
565 static inline int ads784x_hwmon_register(struct spi_device *spi,
571 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
577 static ssize_t ads7846_pen_down_show(struct device *dev,
578 struct device_attribute *attr, char *buf)
580 struct ads7846 *ts = dev_get_drvdata(dev);
582 return sprintf(buf, "%u\n", ts->pendown);
585 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
587 static ssize_t ads7846_disable_show(struct device *dev,
588 struct device_attribute *attr, char *buf)
590 struct ads7846 *ts = dev_get_drvdata(dev);
592 return sprintf(buf, "%u\n", ts->disabled);
595 static ssize_t ads7846_disable_store(struct device *dev,
596 struct device_attribute *attr,
597 const char *buf, size_t count)
599 struct ads7846 *ts = dev_get_drvdata(dev);
602 if (strict_strtoul(buf, 10, &i))
613 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
615 static struct attribute *ads784x_attributes[] = {
616 &dev_attr_pen_down.attr,
617 &dev_attr_disable.attr,
621 static struct attribute_group ads784x_attr_group = {
622 .attrs = ads784x_attributes,
625 /*--------------------------------------------------------------------------*/
627 static int get_pendown_state(struct ads7846 *ts)
629 if (ts->get_pendown_state)
630 return ts->get_pendown_state();
632 return !gpio_get_value(ts->gpio_pendown);
635 static void null_wait_for_sync(void)
639 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
641 struct ads7846 *ts = ads;
643 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
644 /* Start over collecting consistent readings. */
647 * Repeat it, if this was the first read or the read
648 * wasn't consistent enough.
650 if (ts->read_cnt < ts->debounce_max) {
651 ts->last_read = *val;
653 return ADS7846_FILTER_REPEAT;
656 * Maximum number of debouncing reached and still
657 * not enough number of consistent readings. Abort
658 * the whole sample, repeat it in the next sampling
662 return ADS7846_FILTER_IGNORE;
665 if (++ts->read_rep > ts->debounce_rep) {
667 * Got a good reading for this coordinate,
668 * go for the next one.
672 return ADS7846_FILTER_OK;
674 /* Read more values that are consistent. */
676 return ADS7846_FILTER_REPEAT;
681 static int ads7846_no_filter(void *ads, int data_idx, int *val)
683 return ADS7846_FILTER_OK;
686 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
688 struct spi_transfer *t =
689 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
691 if (ts->model == 7845) {
692 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
695 * adjust: on-wire is a must-ignore bit, a BE12 value, then
696 * padding; built from two 8 bit values written msb-first.
698 return be16_to_cpup((__be16 *)t->rx_buf) >> 3;
702 static void ads7846_update_value(struct spi_message *m, int val)
704 struct spi_transfer *t =
705 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
707 *(u16 *)t->rx_buf = val;
710 static void ads7846_read_state(struct ads7846 *ts)
712 struct ads7846_packet *packet = ts->packet;
713 struct spi_message *m;
719 while (msg_idx < ts->msg_count) {
723 m = &ts->msg[msg_idx];
724 error = spi_sync(ts->spi, m);
726 dev_err(&ts->spi->dev, "spi_async --> %d\n", error);
727 packet->tc.ignore = true;
732 * Last message is power down request, no need to convert
733 * or filter the value.
735 if (msg_idx < ts->msg_count - 1) {
737 val = ads7846_get_value(ts, m);
739 action = ts->filter(ts->filter_data, msg_idx, &val);
741 case ADS7846_FILTER_REPEAT:
744 case ADS7846_FILTER_IGNORE:
745 packet->tc.ignore = true;
746 msg_idx = ts->msg_count - 1;
749 case ADS7846_FILTER_OK:
750 ads7846_update_value(m, val);
751 packet->tc.ignore = false;
764 static void ads7846_report_state(struct ads7846 *ts)
766 struct ads7846_packet *packet = ts->packet;
771 * ads7846_get_value() does in-place conversion (including byte swap)
772 * from on-the-wire format as part of debouncing to get stable
775 if (ts->model == 7845) {
776 x = *(u16 *)packet->tc.x_buf;
777 y = *(u16 *)packet->tc.y_buf;
787 /* range filtering */
791 if (ts->model == 7843) {
792 Rt = ts->pressure_max / 2;
793 } else if (ts->model == 7845) {
794 if (get_pendown_state(ts))
795 Rt = ts->pressure_max / 2;
798 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
799 } else if (likely(x && z1)) {
800 /* compute touch pressure resistance using equation #2 */
804 Rt *= ts->x_plate_ohms;
806 Rt = (Rt + 2047) >> 12;
812 * Sample found inconsistent by debouncing or pressure is beyond
813 * the maximum. Don't report it to user space, repeat at least
814 * once more the measurement
816 if (packet->tc.ignore || Rt > ts->pressure_max) {
817 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
818 packet->tc.ignore, Rt);
823 * Maybe check the pendown state before reporting. This discards
824 * false readings when the pen is lifted.
826 if (ts->penirq_recheck_delay_usecs) {
827 udelay(ts->penirq_recheck_delay_usecs);
828 if (!get_pendown_state(ts))
833 * NOTE: We can't rely on the pressure to determine the pen down
834 * state, even this controller has a pressure sensor. The pressure
835 * value can fluctuate for quite a while after lifting the pen and
836 * in some cases may not even settle at the expected value.
838 * The only safe way to check for the pen up condition is in the
839 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
842 struct input_dev *input = ts->input;
848 input_report_key(input, BTN_TOUCH, 1);
850 dev_vdbg(&ts->spi->dev, "DOWN\n");
853 input_report_abs(input, ABS_X, x);
854 input_report_abs(input, ABS_Y, y);
855 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
858 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
862 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
864 struct ads7846 *ts = handle;
866 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
870 static irqreturn_t ads7846_irq(int irq, void *handle)
872 struct ads7846 *ts = handle;
874 /* Start with a small delay before checking pendown state */
875 msleep(TS_POLL_DELAY);
877 while (!ts->stopped && get_pendown_state(ts)) {
879 /* pen is down, continue with the measurement */
880 ads7846_read_state(ts);
883 ads7846_report_state(ts);
885 wait_event_timeout(ts->wait, ts->stopped,
886 msecs_to_jiffies(TS_POLL_PERIOD));
890 struct input_dev *input = ts->input;
892 input_report_key(input, BTN_TOUCH, 0);
893 input_report_abs(input, ABS_PRESSURE, 0);
897 dev_vdbg(&ts->spi->dev, "UP\n");
903 #ifdef CONFIG_PM_SLEEP
904 static int ads7846_suspend(struct device *dev)
906 struct ads7846 *ts = dev_get_drvdata(dev);
908 mutex_lock(&ts->lock);
910 if (!ts->suspended) {
913 __ads7846_disable(ts);
915 if (device_may_wakeup(&ts->spi->dev))
916 enable_irq_wake(ts->spi->irq);
918 ts->suspended = true;
921 mutex_unlock(&ts->lock);
926 static int ads7846_resume(struct device *dev)
928 struct ads7846 *ts = dev_get_drvdata(dev);
930 mutex_lock(&ts->lock);
934 ts->suspended = false;
936 if (device_may_wakeup(&ts->spi->dev))
937 disable_irq_wake(ts->spi->irq);
940 __ads7846_enable(ts);
943 mutex_unlock(&ts->lock);
949 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
951 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts)
953 struct ads7846_platform_data *pdata = spi->dev.platform_data;
957 * REVISIT when the irq can be triggered active-low, or if for some
958 * reason the touchscreen isn't hooked up, we don't need to access
962 if (pdata->get_pendown_state) {
963 ts->get_pendown_state = pdata->get_pendown_state;
964 } else if (gpio_is_valid(pdata->gpio_pendown)) {
966 err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
968 dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
969 pdata->gpio_pendown);
973 ts->gpio_pendown = pdata->gpio_pendown;
976 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
984 * Set up the transfers to read touchscreen state; this assumes we
985 * use formula #2 for pressure, not #3.
987 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts,
988 const struct ads7846_platform_data *pdata)
990 struct spi_message *m = &ts->msg[0];
991 struct spi_transfer *x = ts->xfer;
992 struct ads7846_packet *packet = ts->packet;
993 int vref = pdata->keep_vref_on;
995 if (ts->model == 7873) {
997 * The AD7873 is almost identical to the ADS7846
998 * keep VREF off during differential/ratiometric
1006 spi_message_init(m);
1009 if (ts->model == 7845) {
1010 packet->read_y_cmd[0] = READ_Y(vref);
1011 packet->read_y_cmd[1] = 0;
1012 packet->read_y_cmd[2] = 0;
1013 x->tx_buf = &packet->read_y_cmd[0];
1014 x->rx_buf = &packet->tc.y_buf[0];
1016 spi_message_add_tail(x, m);
1018 /* y- still on; turn on only y+ (and ADC) */
1019 packet->read_y = READ_Y(vref);
1020 x->tx_buf = &packet->read_y;
1022 spi_message_add_tail(x, m);
1025 x->rx_buf = &packet->tc.y;
1027 spi_message_add_tail(x, m);
1031 * The first sample after switching drivers can be low quality;
1032 * optionally discard it, using a second one after the signals
1033 * have had enough time to stabilize.
1035 if (pdata->settle_delay_usecs) {
1036 x->delay_usecs = pdata->settle_delay_usecs;
1039 x->tx_buf = &packet->read_y;
1041 spi_message_add_tail(x, m);
1044 x->rx_buf = &packet->tc.y;
1046 spi_message_add_tail(x, m);
1051 spi_message_init(m);
1054 if (ts->model == 7845) {
1056 packet->read_x_cmd[0] = READ_X(vref);
1057 packet->read_x_cmd[1] = 0;
1058 packet->read_x_cmd[2] = 0;
1059 x->tx_buf = &packet->read_x_cmd[0];
1060 x->rx_buf = &packet->tc.x_buf[0];
1062 spi_message_add_tail(x, m);
1064 /* turn y- off, x+ on, then leave in lowpower */
1066 packet->read_x = READ_X(vref);
1067 x->tx_buf = &packet->read_x;
1069 spi_message_add_tail(x, m);
1072 x->rx_buf = &packet->tc.x;
1074 spi_message_add_tail(x, m);
1077 /* ... maybe discard first sample ... */
1078 if (pdata->settle_delay_usecs) {
1079 x->delay_usecs = pdata->settle_delay_usecs;
1082 x->tx_buf = &packet->read_x;
1084 spi_message_add_tail(x, m);
1087 x->rx_buf = &packet->tc.x;
1089 spi_message_add_tail(x, m);
1092 /* turn y+ off, x- on; we'll use formula #2 */
1093 if (ts->model == 7846) {
1096 spi_message_init(m);
1100 packet->read_z1 = READ_Z1(vref);
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);
1110 /* ... maybe discard first sample ... */
1111 if (pdata->settle_delay_usecs) {
1112 x->delay_usecs = pdata->settle_delay_usecs;
1115 x->tx_buf = &packet->read_z1;
1117 spi_message_add_tail(x, m);
1120 x->rx_buf = &packet->tc.z1;
1122 spi_message_add_tail(x, m);
1127 spi_message_init(m);
1131 packet->read_z2 = READ_Z2(vref);
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);
1141 /* ... maybe discard first sample ... */
1142 if (pdata->settle_delay_usecs) {
1143 x->delay_usecs = pdata->settle_delay_usecs;
1146 x->tx_buf = &packet->read_z2;
1148 spi_message_add_tail(x, m);
1151 x->rx_buf = &packet->tc.z2;
1153 spi_message_add_tail(x, m);
1160 spi_message_init(m);
1163 if (ts->model == 7845) {
1165 packet->pwrdown_cmd[0] = PWRDOWN;
1166 packet->pwrdown_cmd[1] = 0;
1167 packet->pwrdown_cmd[2] = 0;
1168 x->tx_buf = &packet->pwrdown_cmd[0];
1172 packet->pwrdown = PWRDOWN;
1173 x->tx_buf = &packet->pwrdown;
1175 spi_message_add_tail(x, m);
1178 x->rx_buf = &packet->dummy;
1183 spi_message_add_tail(x, m);
1186 static int __devinit ads7846_probe(struct spi_device *spi)
1189 struct ads7846_packet *packet;
1190 struct input_dev *input_dev;
1191 struct ads7846_platform_data *pdata = spi->dev.platform_data;
1192 unsigned long irq_flags;
1196 dev_dbg(&spi->dev, "no IRQ?\n");
1201 dev_dbg(&spi->dev, "no platform data?\n");
1205 /* don't exceed max specified sample rate */
1206 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1207 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
1208 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1212 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
1213 * that even if the hardware can do that, the SPI controller driver
1214 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1216 spi->bits_per_word = 8;
1217 spi->mode = SPI_MODE_0;
1218 err = spi_setup(spi);
1222 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1223 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1224 input_dev = input_allocate_device();
1225 if (!ts || !packet || !input_dev) {
1230 dev_set_drvdata(&spi->dev, ts);
1232 ts->packet = packet;
1234 ts->input = input_dev;
1235 ts->vref_mv = pdata->vref_mv;
1236 ts->swap_xy = pdata->swap_xy;
1238 mutex_init(&ts->lock);
1239 init_waitqueue_head(&ts->wait);
1241 ts->model = pdata->model ? : 7846;
1242 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1243 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1244 ts->pressure_max = pdata->pressure_max ? : ~0;
1246 if (pdata->filter != NULL) {
1247 if (pdata->filter_init != NULL) {
1248 err = pdata->filter_init(pdata, &ts->filter_data);
1252 ts->filter = pdata->filter;
1253 ts->filter_cleanup = pdata->filter_cleanup;
1254 } else if (pdata->debounce_max) {
1255 ts->debounce_max = pdata->debounce_max;
1256 if (ts->debounce_max < 2)
1257 ts->debounce_max = 2;
1258 ts->debounce_tol = pdata->debounce_tol;
1259 ts->debounce_rep = pdata->debounce_rep;
1260 ts->filter = ads7846_debounce_filter;
1261 ts->filter_data = ts;
1263 ts->filter = ads7846_no_filter;
1266 err = ads7846_setup_pendown(spi, ts);
1268 goto err_cleanup_filter;
1270 if (pdata->penirq_recheck_delay_usecs)
1271 ts->penirq_recheck_delay_usecs =
1272 pdata->penirq_recheck_delay_usecs;
1274 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1276 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1277 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1279 input_dev->name = ts->name;
1280 input_dev->phys = ts->phys;
1281 input_dev->dev.parent = &spi->dev;
1283 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1284 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1285 input_set_abs_params(input_dev, ABS_X,
1287 pdata->x_max ? : MAX_12BIT,
1289 input_set_abs_params(input_dev, ABS_Y,
1291 pdata->y_max ? : MAX_12BIT,
1293 input_set_abs_params(input_dev, ABS_PRESSURE,
1294 pdata->pressure_min, pdata->pressure_max, 0, 0);
1296 ads7846_setup_spi_msg(ts, pdata);
1298 ts->reg = regulator_get(&spi->dev, "vcc");
1299 if (IS_ERR(ts->reg)) {
1300 err = PTR_ERR(ts->reg);
1301 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1305 err = regulator_enable(ts->reg);
1307 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1308 goto err_put_regulator;
1311 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1312 irq_flags |= IRQF_ONESHOT;
1314 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1315 irq_flags, spi->dev.driver->name, ts);
1316 if (err && !pdata->irq_flags) {
1318 "trying pin change workaround on irq %d\n", spi->irq);
1319 irq_flags |= IRQF_TRIGGER_RISING;
1320 err = request_threaded_irq(spi->irq,
1321 ads7846_hard_irq, ads7846_irq,
1322 irq_flags, spi->dev.driver->name, ts);
1326 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1327 goto err_disable_regulator;
1330 err = ads784x_hwmon_register(spi, ts);
1334 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1337 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1338 * the touchscreen, in case it's not connected.
1340 if (ts->model == 7845)
1341 ads7845_read12_ser(&spi->dev, PWRDOWN);
1343 (void) ads7846_read12_ser(&spi->dev,
1344 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
1346 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1348 goto err_remove_hwmon;
1350 err = input_register_device(input_dev);
1352 goto err_remove_attr_group;
1354 device_init_wakeup(&spi->dev, pdata->wakeup);
1358 err_remove_attr_group:
1359 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1361 ads784x_hwmon_unregister(spi, ts);
1363 free_irq(spi->irq, ts);
1364 err_disable_regulator:
1365 regulator_disable(ts->reg);
1367 regulator_put(ts->reg);
1369 if (!ts->get_pendown_state)
1370 gpio_free(ts->gpio_pendown);
1372 if (ts->filter_cleanup)
1373 ts->filter_cleanup(ts->filter_data);
1375 input_free_device(input_dev);
1381 static int __devexit ads7846_remove(struct spi_device *spi)
1383 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
1385 device_init_wakeup(&spi->dev, false);
1387 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1389 ads7846_disable(ts);
1390 free_irq(ts->spi->irq, ts);
1392 input_unregister_device(ts->input);
1394 ads784x_hwmon_unregister(spi, ts);
1396 regulator_disable(ts->reg);
1397 regulator_put(ts->reg);
1399 if (!ts->get_pendown_state) {
1401 * If we are not using specialized pendown method we must
1402 * have been relying on gpio we set up ourselves.
1404 gpio_free(ts->gpio_pendown);
1407 if (ts->filter_cleanup)
1408 ts->filter_cleanup(ts->filter_data);
1413 dev_dbg(&spi->dev, "unregistered touchscreen\n");
1418 static struct spi_driver ads7846_driver = {
1421 .bus = &spi_bus_type,
1422 .owner = THIS_MODULE,
1425 .probe = ads7846_probe,
1426 .remove = __devexit_p(ads7846_remove),
1429 static int __init ads7846_init(void)
1431 return spi_register_driver(&ads7846_driver);
1433 module_init(ads7846_init);
1435 static void __exit ads7846_exit(void)
1437 spi_unregister_driver(&ads7846_driver);
1439 module_exit(ads7846_exit);
1441 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1442 MODULE_LICENSE("GPL");
1443 MODULE_ALIAS("spi:ads7846");