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>
40 * This code has been heavily tested on a Nokia 770, and lightly
41 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
42 * TSC2046 is just newer ads7846 silicon.
43 * Support for ads7843 tested on Atmel at91sam926x-EK.
44 * Support for ads7845 has only been stubbed in.
45 * Support for Analog Devices AD7873 and AD7843 tested.
47 * IRQ handling needs a workaround because of a shortcoming in handling
48 * edge triggered IRQs on some platforms like the OMAP1/2. These
49 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
50 * have to maintain our own SW IRQ disabled status. This should be
51 * removed as soon as the affected platform's IRQ handling is fixed.
53 * App note sbaa036 talks in more detail about accurate sampling...
54 * that ought to help in situations like LCDs inducing noise (which
55 * can also be helped by using synch signals) and more generally.
56 * This driver tries to utilize the measures described in the app
57 * note. The strength of filtering can be set in the board-* specific
61 #define TS_POLL_DELAY 1 /* ms delay before the first sample */
62 #define TS_POLL_PERIOD 5 /* ms delay between samples */
64 /* this driver doesn't aim at the peak continuous sample rate */
65 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
69 * For portability, we can't read 12 bit values using SPI (which
70 * would make the controller deliver them as native byte order u16
71 * with msbs zeroed). Instead, we read them as two 8-bit values,
72 * *** WHICH NEED BYTESWAPPING *** and range adjustment.
83 * We allocate this separately to avoid cache line sharing issues when
84 * driver is used with DMA-based SPI controllers (like atmel_spi) on
85 * systems where main memory is not DMA-coherent (most non-x86 boards).
87 struct ads7846_packet
{
88 u8 read_x
, read_y
, read_z1
, read_z2
, pwrdown
;
89 u16 dummy
; /* for the pwrdown read */
91 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
92 u8 read_x_cmd
[3], read_y_cmd
[3], pwrdown_cmd
[3];
96 struct input_dev
*input
;
100 struct spi_device
*spi
;
101 struct regulator
*reg
;
103 #if IS_ENABLED(CONFIG_HWMON)
104 struct device
*hwmon
;
109 u16 vref_delay_usecs
;
116 struct ads7846_packet
*packet
;
118 struct spi_transfer xfer
[18];
119 struct spi_message msg
[5];
121 wait_queue_head_t wait
;
133 u16 penirq_recheck_delay_usecs
;
136 bool stopped
; /* P: lock */
137 bool disabled
; /* P: lock */
138 bool suspended
; /* P: lock */
140 int (*filter
)(void *data
, int data_idx
, int *val
);
142 void (*filter_cleanup
)(void *data
);
143 int (*get_pendown_state
)(void);
146 void (*wait_for_sync
)(void);
149 /* leave chip selected when we're done, for quicker re-select? */
151 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
153 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
156 /*--------------------------------------------------------------------------*/
158 /* The ADS7846 has touchscreen and other sensors.
159 * Earlier ads784x chips are somewhat compatible.
161 #define ADS_START (1 << 7)
162 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
163 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
164 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
165 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
166 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
167 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
168 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
169 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
170 #define ADS_8_BIT (1 << 3)
171 #define ADS_12_BIT (0 << 3)
172 #define ADS_SER (1 << 2) /* non-differential */
173 #define ADS_DFR (0 << 2) /* differential */
174 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
175 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
176 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
177 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
179 #define MAX_12BIT ((1<<12)-1)
181 /* leave ADC powered up (disables penirq) between differential samples */
182 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
183 | ADS_12_BIT | ADS_DFR | \
184 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
186 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
187 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
188 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
190 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
191 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
193 /* single-ended samples need to first power up reference voltage;
194 * we leave both ADC and VREF powered
196 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
197 | ADS_12_BIT | ADS_SER)
199 #define REF_ON (READ_12BIT_DFR(x, 1, 1))
200 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
202 /* Must be called with ts->lock held */
203 static void ads7846_stop(struct ads7846
*ts
)
205 if (!ts
->disabled
&& !ts
->suspended
) {
206 /* Signal IRQ thread to stop polling and disable the handler. */
210 disable_irq(ts
->spi
->irq
);
214 /* Must be called with ts->lock held */
215 static void ads7846_restart(struct ads7846
*ts
)
217 if (!ts
->disabled
&& !ts
->suspended
) {
218 /* Tell IRQ thread that it may poll the device. */
221 enable_irq(ts
->spi
->irq
);
225 /* Must be called with ts->lock held */
226 static void __ads7846_disable(struct ads7846
*ts
)
229 regulator_disable(ts
->reg
);
232 * We know the chip's in low power mode since we always
233 * leave it that way after every request
237 /* Must be called with ts->lock held */
238 static void __ads7846_enable(struct ads7846
*ts
)
242 error
= regulator_enable(ts
->reg
);
244 dev_err(&ts
->spi
->dev
, "Failed to enable supply: %d\n", error
);
249 static void ads7846_disable(struct ads7846
*ts
)
251 mutex_lock(&ts
->lock
);
256 __ads7846_disable(ts
);
261 mutex_unlock(&ts
->lock
);
264 static void ads7846_enable(struct ads7846
*ts
)
266 mutex_lock(&ts
->lock
);
270 ts
->disabled
= false;
273 __ads7846_enable(ts
);
276 mutex_unlock(&ts
->lock
);
279 /*--------------------------------------------------------------------------*/
282 * Non-touchscreen sensors only use single-ended conversions.
283 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
284 * ads7846 lets that pin be unconnected, to use internal vREF.
292 struct spi_message msg
;
293 struct spi_transfer xfer
[6];
295 * DMA (thus cache coherency maintenance) requires the
296 * transfer buffers to live in their own cache lines.
298 __be16 sample ____cacheline_aligned
;
301 struct ads7845_ser_req
{
303 struct spi_message msg
;
304 struct spi_transfer xfer
[2];
306 * DMA (thus cache coherency maintenance) requires the
307 * transfer buffers to live in their own cache lines.
309 u8 sample
[3] ____cacheline_aligned
;
312 static int ads7846_read12_ser(struct device
*dev
, unsigned command
)
314 struct spi_device
*spi
= to_spi_device(dev
);
315 struct ads7846
*ts
= dev_get_drvdata(dev
);
319 req
= kzalloc(sizeof *req
, GFP_KERNEL
);
323 spi_message_init(&req
->msg
);
325 /* maybe turn on internal vREF, and let it settle */
326 if (ts
->use_internal
) {
327 req
->ref_on
= REF_ON
;
328 req
->xfer
[0].tx_buf
= &req
->ref_on
;
329 req
->xfer
[0].len
= 1;
330 spi_message_add_tail(&req
->xfer
[0], &req
->msg
);
332 req
->xfer
[1].rx_buf
= &req
->scratch
;
333 req
->xfer
[1].len
= 2;
335 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
336 req
->xfer
[1].delay_usecs
= ts
->vref_delay_usecs
;
337 spi_message_add_tail(&req
->xfer
[1], &req
->msg
);
339 /* Enable reference voltage */
340 command
|= ADS_PD10_REF_ON
;
343 /* Enable ADC in every case */
344 command
|= ADS_PD10_ADC_ON
;
347 req
->command
= (u8
) command
;
348 req
->xfer
[2].tx_buf
= &req
->command
;
349 req
->xfer
[2].len
= 1;
350 spi_message_add_tail(&req
->xfer
[2], &req
->msg
);
352 req
->xfer
[3].rx_buf
= &req
->sample
;
353 req
->xfer
[3].len
= 2;
354 spi_message_add_tail(&req
->xfer
[3], &req
->msg
);
356 /* REVISIT: take a few more samples, and compare ... */
358 /* converter in low power mode & enable PENIRQ */
359 req
->ref_off
= PWRDOWN
;
360 req
->xfer
[4].tx_buf
= &req
->ref_off
;
361 req
->xfer
[4].len
= 1;
362 spi_message_add_tail(&req
->xfer
[4], &req
->msg
);
364 req
->xfer
[5].rx_buf
= &req
->scratch
;
365 req
->xfer
[5].len
= 2;
366 CS_CHANGE(req
->xfer
[5]);
367 spi_message_add_tail(&req
->xfer
[5], &req
->msg
);
369 mutex_lock(&ts
->lock
);
371 status
= spi_sync(spi
, &req
->msg
);
373 mutex_unlock(&ts
->lock
);
376 /* on-wire is a must-ignore bit, a BE12 value, then padding */
377 status
= be16_to_cpu(req
->sample
);
378 status
= status
>> 3;
386 static int ads7845_read12_ser(struct device
*dev
, unsigned command
)
388 struct spi_device
*spi
= to_spi_device(dev
);
389 struct ads7846
*ts
= dev_get_drvdata(dev
);
390 struct ads7845_ser_req
*req
;
393 req
= kzalloc(sizeof *req
, GFP_KERNEL
);
397 spi_message_init(&req
->msg
);
399 req
->command
[0] = (u8
) command
;
400 req
->xfer
[0].tx_buf
= req
->command
;
401 req
->xfer
[0].rx_buf
= req
->sample
;
402 req
->xfer
[0].len
= 3;
403 spi_message_add_tail(&req
->xfer
[0], &req
->msg
);
405 mutex_lock(&ts
->lock
);
407 status
= spi_sync(spi
, &req
->msg
);
409 mutex_unlock(&ts
->lock
);
412 /* BE12 value, then padding */
413 status
= be16_to_cpu(*((u16
*)&req
->sample
[1]));
414 status
= status
>> 3;
422 #if IS_ENABLED(CONFIG_HWMON)
424 #define SHOW(name, var, adjust) static ssize_t \
425 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
427 struct ads7846 *ts = dev_get_drvdata(dev); \
428 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
429 READ_12BIT_SER(var)); \
432 return sprintf(buf, "%u\n", adjust(ts, v)); \
434 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
437 /* Sysfs conventions report temperatures in millidegrees Celsius.
438 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
439 * accuracy scheme without calibration data. For now we won't try either;
440 * userspace sees raw sensor values, and must scale/calibrate appropriately.
442 static inline unsigned null_adjust(struct ads7846
*ts
, ssize_t v
)
447 SHOW(temp0
, temp0
, null_adjust
) /* temp1_input */
448 SHOW(temp1
, temp1
, null_adjust
) /* temp2_input */
451 /* sysfs conventions report voltages in millivolts. We can convert voltages
452 * if we know vREF. userspace may need to scale vAUX to match the board's
453 * external resistors; we assume that vBATT only uses the internal ones.
455 static inline unsigned vaux_adjust(struct ads7846
*ts
, ssize_t v
)
459 /* external resistors may scale vAUX into 0..vREF */
460 retval
*= ts
->vref_mv
;
461 retval
= retval
>> 12;
466 static inline unsigned vbatt_adjust(struct ads7846
*ts
, ssize_t v
)
468 unsigned retval
= vaux_adjust(ts
, v
);
470 /* ads7846 has a resistor ladder to scale this signal down */
471 if (ts
->model
== 7846)
477 SHOW(in0_input
, vaux
, vaux_adjust
)
478 SHOW(in1_input
, vbatt
, vbatt_adjust
)
480 static umode_t
ads7846_is_visible(struct kobject
*kobj
, struct attribute
*attr
,
483 struct device
*dev
= container_of(kobj
, struct device
, kobj
);
484 struct ads7846
*ts
= dev_get_drvdata(dev
);
486 if (ts
->model
== 7843 && index
< 2) /* in0, in1 */
488 if (ts
->model
== 7845 && index
!= 2) /* in0 */
494 static struct attribute
*ads7846_attributes
[] = {
495 &dev_attr_temp0
.attr
, /* 0 */
496 &dev_attr_temp1
.attr
, /* 1 */
497 &dev_attr_in0_input
.attr
, /* 2 */
498 &dev_attr_in1_input
.attr
, /* 3 */
502 static struct attribute_group ads7846_attr_group
= {
503 .attrs
= ads7846_attributes
,
504 .is_visible
= ads7846_is_visible
,
506 __ATTRIBUTE_GROUPS(ads7846_attr
);
508 static int ads784x_hwmon_register(struct spi_device
*spi
, struct ads7846
*ts
)
510 /* hwmon sensors need a reference voltage */
514 dev_dbg(&spi
->dev
, "assuming 2.5V internal vREF\n");
516 ts
->use_internal
= true;
523 "external vREF for ADS%d not specified\n",
530 ts
->hwmon
= hwmon_device_register_with_groups(&spi
->dev
, spi
->modalias
,
531 ts
, ads7846_attr_groups
);
532 if (IS_ERR(ts
->hwmon
))
533 return PTR_ERR(ts
->hwmon
);
538 static void ads784x_hwmon_unregister(struct spi_device
*spi
,
542 hwmon_device_unregister(ts
->hwmon
);
546 static inline int ads784x_hwmon_register(struct spi_device
*spi
,
552 static inline void ads784x_hwmon_unregister(struct spi_device
*spi
,
558 static ssize_t
ads7846_pen_down_show(struct device
*dev
,
559 struct device_attribute
*attr
, char *buf
)
561 struct ads7846
*ts
= dev_get_drvdata(dev
);
563 return sprintf(buf
, "%u\n", ts
->pendown
);
566 static DEVICE_ATTR(pen_down
, S_IRUGO
, ads7846_pen_down_show
, NULL
);
568 static ssize_t
ads7846_disable_show(struct device
*dev
,
569 struct device_attribute
*attr
, char *buf
)
571 struct ads7846
*ts
= dev_get_drvdata(dev
);
573 return sprintf(buf
, "%u\n", ts
->disabled
);
576 static ssize_t
ads7846_disable_store(struct device
*dev
,
577 struct device_attribute
*attr
,
578 const char *buf
, size_t count
)
580 struct ads7846
*ts
= dev_get_drvdata(dev
);
584 err
= kstrtouint(buf
, 10, &i
);
596 static DEVICE_ATTR(disable
, 0664, ads7846_disable_show
, ads7846_disable_store
);
598 static struct attribute
*ads784x_attributes
[] = {
599 &dev_attr_pen_down
.attr
,
600 &dev_attr_disable
.attr
,
604 static struct attribute_group ads784x_attr_group
= {
605 .attrs
= ads784x_attributes
,
608 /*--------------------------------------------------------------------------*/
610 static int get_pendown_state(struct ads7846
*ts
)
612 if (ts
->get_pendown_state
)
613 return ts
->get_pendown_state();
615 return !gpio_get_value(ts
->gpio_pendown
);
618 static void null_wait_for_sync(void)
622 static int ads7846_debounce_filter(void *ads
, int data_idx
, int *val
)
624 struct ads7846
*ts
= ads
;
626 if (!ts
->read_cnt
|| (abs(ts
->last_read
- *val
) > ts
->debounce_tol
)) {
627 /* Start over collecting consistent readings. */
630 * Repeat it, if this was the first read or the read
631 * wasn't consistent enough.
633 if (ts
->read_cnt
< ts
->debounce_max
) {
634 ts
->last_read
= *val
;
636 return ADS7846_FILTER_REPEAT
;
639 * Maximum number of debouncing reached and still
640 * not enough number of consistent readings. Abort
641 * the whole sample, repeat it in the next sampling
645 return ADS7846_FILTER_IGNORE
;
648 if (++ts
->read_rep
> ts
->debounce_rep
) {
650 * Got a good reading for this coordinate,
651 * go for the next one.
655 return ADS7846_FILTER_OK
;
657 /* Read more values that are consistent. */
659 return ADS7846_FILTER_REPEAT
;
664 static int ads7846_no_filter(void *ads
, int data_idx
, int *val
)
666 return ADS7846_FILTER_OK
;
669 static int ads7846_get_value(struct ads7846
*ts
, struct spi_message
*m
)
671 struct spi_transfer
*t
=
672 list_entry(m
->transfers
.prev
, struct spi_transfer
, transfer_list
);
674 if (ts
->model
== 7845) {
675 return be16_to_cpup((__be16
*)&(((char*)t
->rx_buf
)[1])) >> 3;
678 * adjust: on-wire is a must-ignore bit, a BE12 value, then
679 * padding; built from two 8 bit values written msb-first.
681 return be16_to_cpup((__be16
*)t
->rx_buf
) >> 3;
685 static void ads7846_update_value(struct spi_message
*m
, int val
)
687 struct spi_transfer
*t
=
688 list_entry(m
->transfers
.prev
, struct spi_transfer
, transfer_list
);
690 *(u16
*)t
->rx_buf
= val
;
693 static void ads7846_read_state(struct ads7846
*ts
)
695 struct ads7846_packet
*packet
= ts
->packet
;
696 struct spi_message
*m
;
702 while (msg_idx
< ts
->msg_count
) {
706 m
= &ts
->msg
[msg_idx
];
707 error
= spi_sync(ts
->spi
, m
);
709 dev_err(&ts
->spi
->dev
, "spi_sync --> %d\n", error
);
710 packet
->tc
.ignore
= true;
715 * Last message is power down request, no need to convert
716 * or filter the value.
718 if (msg_idx
< ts
->msg_count
- 1) {
720 val
= ads7846_get_value(ts
, m
);
722 action
= ts
->filter(ts
->filter_data
, msg_idx
, &val
);
724 case ADS7846_FILTER_REPEAT
:
727 case ADS7846_FILTER_IGNORE
:
728 packet
->tc
.ignore
= true;
729 msg_idx
= ts
->msg_count
- 1;
732 case ADS7846_FILTER_OK
:
733 ads7846_update_value(m
, val
);
734 packet
->tc
.ignore
= false;
747 static void ads7846_report_state(struct ads7846
*ts
)
749 struct ads7846_packet
*packet
= ts
->packet
;
754 * ads7846_get_value() does in-place conversion (including byte swap)
755 * from on-the-wire format as part of debouncing to get stable
758 if (ts
->model
== 7845) {
759 x
= *(u16
*)packet
->tc
.x_buf
;
760 y
= *(u16
*)packet
->tc
.y_buf
;
770 /* range filtering */
774 if (ts
->model
== 7843) {
775 Rt
= ts
->pressure_max
/ 2;
776 } else if (ts
->model
== 7845) {
777 if (get_pendown_state(ts
))
778 Rt
= ts
->pressure_max
/ 2;
781 dev_vdbg(&ts
->spi
->dev
, "x/y: %d/%d, PD %d\n", x
, y
, Rt
);
782 } else if (likely(x
&& z1
)) {
783 /* compute touch pressure resistance using equation #2 */
787 Rt
*= ts
->x_plate_ohms
;
789 Rt
= (Rt
+ 2047) >> 12;
795 * Sample found inconsistent by debouncing or pressure is beyond
796 * the maximum. Don't report it to user space, repeat at least
797 * once more the measurement
799 if (packet
->tc
.ignore
|| Rt
> ts
->pressure_max
) {
800 dev_vdbg(&ts
->spi
->dev
, "ignored %d pressure %d\n",
801 packet
->tc
.ignore
, Rt
);
806 * Maybe check the pendown state before reporting. This discards
807 * false readings when the pen is lifted.
809 if (ts
->penirq_recheck_delay_usecs
) {
810 udelay(ts
->penirq_recheck_delay_usecs
);
811 if (!get_pendown_state(ts
))
816 * NOTE: We can't rely on the pressure to determine the pen down
817 * state, even this controller has a pressure sensor. The pressure
818 * value can fluctuate for quite a while after lifting the pen and
819 * in some cases may not even settle at the expected value.
821 * The only safe way to check for the pen up condition is in the
822 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
825 struct input_dev
*input
= ts
->input
;
831 input_report_key(input
, BTN_TOUCH
, 1);
833 dev_vdbg(&ts
->spi
->dev
, "DOWN\n");
836 input_report_abs(input
, ABS_X
, x
);
837 input_report_abs(input
, ABS_Y
, y
);
838 input_report_abs(input
, ABS_PRESSURE
, ts
->pressure_max
- Rt
);
841 dev_vdbg(&ts
->spi
->dev
, "%4d/%4d/%4d\n", x
, y
, Rt
);
845 static irqreturn_t
ads7846_hard_irq(int irq
, void *handle
)
847 struct ads7846
*ts
= handle
;
849 return get_pendown_state(ts
) ? IRQ_WAKE_THREAD
: IRQ_HANDLED
;
853 static irqreturn_t
ads7846_irq(int irq
, void *handle
)
855 struct ads7846
*ts
= handle
;
857 /* Start with a small delay before checking pendown state */
858 msleep(TS_POLL_DELAY
);
860 while (!ts
->stopped
&& get_pendown_state(ts
)) {
862 /* pen is down, continue with the measurement */
863 ads7846_read_state(ts
);
866 ads7846_report_state(ts
);
868 wait_event_timeout(ts
->wait
, ts
->stopped
,
869 msecs_to_jiffies(TS_POLL_PERIOD
));
873 struct input_dev
*input
= ts
->input
;
875 input_report_key(input
, BTN_TOUCH
, 0);
876 input_report_abs(input
, ABS_PRESSURE
, 0);
880 dev_vdbg(&ts
->spi
->dev
, "UP\n");
886 #ifdef CONFIG_PM_SLEEP
887 static int ads7846_suspend(struct device
*dev
)
889 struct ads7846
*ts
= dev_get_drvdata(dev
);
891 mutex_lock(&ts
->lock
);
893 if (!ts
->suspended
) {
896 __ads7846_disable(ts
);
898 if (device_may_wakeup(&ts
->spi
->dev
))
899 enable_irq_wake(ts
->spi
->irq
);
901 ts
->suspended
= true;
904 mutex_unlock(&ts
->lock
);
909 static int ads7846_resume(struct device
*dev
)
911 struct ads7846
*ts
= dev_get_drvdata(dev
);
913 mutex_lock(&ts
->lock
);
917 ts
->suspended
= false;
919 if (device_may_wakeup(&ts
->spi
->dev
))
920 disable_irq_wake(ts
->spi
->irq
);
923 __ads7846_enable(ts
);
926 mutex_unlock(&ts
->lock
);
932 static SIMPLE_DEV_PM_OPS(ads7846_pm
, ads7846_suspend
, ads7846_resume
);
934 static int ads7846_setup_pendown(struct spi_device
*spi
,
936 const struct ads7846_platform_data
*pdata
)
941 * REVISIT when the irq can be triggered active-low, or if for some
942 * reason the touchscreen isn't hooked up, we don't need to access
946 if (pdata
->get_pendown_state
) {
947 ts
->get_pendown_state
= pdata
->get_pendown_state
;
948 } else if (gpio_is_valid(pdata
->gpio_pendown
)) {
950 err
= gpio_request_one(pdata
->gpio_pendown
, GPIOF_IN
,
954 "failed to request/setup pendown GPIO%d: %d\n",
955 pdata
->gpio_pendown
, err
);
959 ts
->gpio_pendown
= pdata
->gpio_pendown
;
961 if (pdata
->gpio_pendown_debounce
)
962 gpio_set_debounce(pdata
->gpio_pendown
,
963 pdata
->gpio_pendown_debounce
);
965 dev_err(&spi
->dev
, "no get_pendown_state nor gpio_pendown?\n");
973 * Set up the transfers to read touchscreen state; this assumes we
974 * use formula #2 for pressure, not #3.
976 static void ads7846_setup_spi_msg(struct ads7846
*ts
,
977 const struct ads7846_platform_data
*pdata
)
979 struct spi_message
*m
= &ts
->msg
[0];
980 struct spi_transfer
*x
= ts
->xfer
;
981 struct ads7846_packet
*packet
= ts
->packet
;
982 int vref
= pdata
->keep_vref_on
;
984 if (ts
->model
== 7873) {
986 * The AD7873 is almost identical to the ADS7846
987 * keep VREF off during differential/ratiometric
998 if (ts
->model
== 7845) {
999 packet
->read_y_cmd
[0] = READ_Y(vref
);
1000 packet
->read_y_cmd
[1] = 0;
1001 packet
->read_y_cmd
[2] = 0;
1002 x
->tx_buf
= &packet
->read_y_cmd
[0];
1003 x
->rx_buf
= &packet
->tc
.y_buf
[0];
1005 spi_message_add_tail(x
, m
);
1007 /* y- still on; turn on only y+ (and ADC) */
1008 packet
->read_y
= READ_Y(vref
);
1009 x
->tx_buf
= &packet
->read_y
;
1011 spi_message_add_tail(x
, m
);
1014 x
->rx_buf
= &packet
->tc
.y
;
1016 spi_message_add_tail(x
, m
);
1020 * The first sample after switching drivers can be low quality;
1021 * optionally discard it, using a second one after the signals
1022 * have had enough time to stabilize.
1024 if (pdata
->settle_delay_usecs
) {
1025 x
->delay_usecs
= pdata
->settle_delay_usecs
;
1028 x
->tx_buf
= &packet
->read_y
;
1030 spi_message_add_tail(x
, m
);
1033 x
->rx_buf
= &packet
->tc
.y
;
1035 spi_message_add_tail(x
, m
);
1040 spi_message_init(m
);
1043 if (ts
->model
== 7845) {
1045 packet
->read_x_cmd
[0] = READ_X(vref
);
1046 packet
->read_x_cmd
[1] = 0;
1047 packet
->read_x_cmd
[2] = 0;
1048 x
->tx_buf
= &packet
->read_x_cmd
[0];
1049 x
->rx_buf
= &packet
->tc
.x_buf
[0];
1051 spi_message_add_tail(x
, m
);
1053 /* turn y- off, x+ on, then leave in lowpower */
1055 packet
->read_x
= READ_X(vref
);
1056 x
->tx_buf
= &packet
->read_x
;
1058 spi_message_add_tail(x
, m
);
1061 x
->rx_buf
= &packet
->tc
.x
;
1063 spi_message_add_tail(x
, m
);
1066 /* ... maybe discard first sample ... */
1067 if (pdata
->settle_delay_usecs
) {
1068 x
->delay_usecs
= pdata
->settle_delay_usecs
;
1071 x
->tx_buf
= &packet
->read_x
;
1073 spi_message_add_tail(x
, m
);
1076 x
->rx_buf
= &packet
->tc
.x
;
1078 spi_message_add_tail(x
, m
);
1081 /* turn y+ off, x- on; we'll use formula #2 */
1082 if (ts
->model
== 7846) {
1085 spi_message_init(m
);
1089 packet
->read_z1
= READ_Z1(vref
);
1090 x
->tx_buf
= &packet
->read_z1
;
1092 spi_message_add_tail(x
, m
);
1095 x
->rx_buf
= &packet
->tc
.z1
;
1097 spi_message_add_tail(x
, m
);
1099 /* ... maybe discard first sample ... */
1100 if (pdata
->settle_delay_usecs
) {
1101 x
->delay_usecs
= pdata
->settle_delay_usecs
;
1104 x
->tx_buf
= &packet
->read_z1
;
1106 spi_message_add_tail(x
, m
);
1109 x
->rx_buf
= &packet
->tc
.z1
;
1111 spi_message_add_tail(x
, m
);
1116 spi_message_init(m
);
1120 packet
->read_z2
= READ_Z2(vref
);
1121 x
->tx_buf
= &packet
->read_z2
;
1123 spi_message_add_tail(x
, m
);
1126 x
->rx_buf
= &packet
->tc
.z2
;
1128 spi_message_add_tail(x
, m
);
1130 /* ... maybe discard first sample ... */
1131 if (pdata
->settle_delay_usecs
) {
1132 x
->delay_usecs
= pdata
->settle_delay_usecs
;
1135 x
->tx_buf
= &packet
->read_z2
;
1137 spi_message_add_tail(x
, m
);
1140 x
->rx_buf
= &packet
->tc
.z2
;
1142 spi_message_add_tail(x
, m
);
1149 spi_message_init(m
);
1152 if (ts
->model
== 7845) {
1154 packet
->pwrdown_cmd
[0] = PWRDOWN
;
1155 packet
->pwrdown_cmd
[1] = 0;
1156 packet
->pwrdown_cmd
[2] = 0;
1157 x
->tx_buf
= &packet
->pwrdown_cmd
[0];
1161 packet
->pwrdown
= PWRDOWN
;
1162 x
->tx_buf
= &packet
->pwrdown
;
1164 spi_message_add_tail(x
, m
);
1167 x
->rx_buf
= &packet
->dummy
;
1172 spi_message_add_tail(x
, m
);
1176 static const struct of_device_id ads7846_dt_ids
[] = {
1177 { .compatible
= "ti,tsc2046", .data
= (void *) 7846 },
1178 { .compatible
= "ti,ads7843", .data
= (void *) 7843 },
1179 { .compatible
= "ti,ads7845", .data
= (void *) 7845 },
1180 { .compatible
= "ti,ads7846", .data
= (void *) 7846 },
1181 { .compatible
= "ti,ads7873", .data
= (void *) 7873 },
1184 MODULE_DEVICE_TABLE(of
, ads7846_dt_ids
);
1186 static const struct ads7846_platform_data
*ads7846_probe_dt(struct device
*dev
)
1188 struct ads7846_platform_data
*pdata
;
1189 struct device_node
*node
= dev
->of_node
;
1190 const struct of_device_id
*match
;
1193 dev_err(dev
, "Device does not have associated DT data\n");
1194 return ERR_PTR(-EINVAL
);
1197 match
= of_match_device(ads7846_dt_ids
, dev
);
1199 dev_err(dev
, "Unknown device model\n");
1200 return ERR_PTR(-EINVAL
);
1203 pdata
= devm_kzalloc(dev
, sizeof(*pdata
), GFP_KERNEL
);
1205 return ERR_PTR(-ENOMEM
);
1207 pdata
->model
= (unsigned long)match
->data
;
1209 of_property_read_u16(node
, "ti,vref-delay-usecs",
1210 &pdata
->vref_delay_usecs
);
1211 of_property_read_u16(node
, "ti,vref-mv", &pdata
->vref_mv
);
1212 pdata
->keep_vref_on
= of_property_read_bool(node
, "ti,keep-vref-on");
1214 pdata
->swap_xy
= of_property_read_bool(node
, "ti,swap-xy");
1216 of_property_read_u16(node
, "ti,settle-delay-usec",
1217 &pdata
->settle_delay_usecs
);
1218 of_property_read_u16(node
, "ti,penirq-recheck-delay-usecs",
1219 &pdata
->penirq_recheck_delay_usecs
);
1221 of_property_read_u16(node
, "ti,x-plate-ohms", &pdata
->x_plate_ohms
);
1222 of_property_read_u16(node
, "ti,y-plate-ohms", &pdata
->y_plate_ohms
);
1224 of_property_read_u16(node
, "ti,x-min", &pdata
->x_min
);
1225 of_property_read_u16(node
, "ti,y-min", &pdata
->y_min
);
1226 of_property_read_u16(node
, "ti,x-max", &pdata
->x_max
);
1227 of_property_read_u16(node
, "ti,y-max", &pdata
->y_max
);
1229 of_property_read_u16(node
, "ti,pressure-min", &pdata
->pressure_min
);
1230 of_property_read_u16(node
, "ti,pressure-max", &pdata
->pressure_max
);
1232 of_property_read_u16(node
, "ti,debounce-max", &pdata
->debounce_max
);
1233 of_property_read_u16(node
, "ti,debounce-tol", &pdata
->debounce_tol
);
1234 of_property_read_u16(node
, "ti,debounce-rep", &pdata
->debounce_rep
);
1236 of_property_read_u32(node
, "ti,pendown-gpio-debounce",
1237 &pdata
->gpio_pendown_debounce
);
1239 pdata
->wakeup
= of_property_read_bool(node
, "linux,wakeup");
1241 pdata
->gpio_pendown
= of_get_named_gpio(dev
->of_node
, "pendown-gpio", 0);
1246 static const struct ads7846_platform_data
*ads7846_probe_dt(struct device
*dev
)
1248 dev_err(dev
, "no platform data defined\n");
1249 return ERR_PTR(-EINVAL
);
1253 static int ads7846_probe(struct spi_device
*spi
)
1255 const struct ads7846_platform_data
*pdata
;
1257 struct ads7846_packet
*packet
;
1258 struct input_dev
*input_dev
;
1259 unsigned long irq_flags
;
1263 dev_dbg(&spi
->dev
, "no IRQ?\n");
1267 /* don't exceed max specified sample rate */
1268 if (spi
->max_speed_hz
> (125000 * SAMPLE_BITS
)) {
1269 dev_err(&spi
->dev
, "f(sample) %d KHz?\n",
1270 (spi
->max_speed_hz
/SAMPLE_BITS
)/1000);
1275 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1276 * that even if the hardware can do that, the SPI controller driver
1277 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1279 spi
->bits_per_word
= 8;
1280 spi
->mode
= SPI_MODE_0
;
1281 err
= spi_setup(spi
);
1285 ts
= kzalloc(sizeof(struct ads7846
), GFP_KERNEL
);
1286 packet
= kzalloc(sizeof(struct ads7846_packet
), GFP_KERNEL
);
1287 input_dev
= input_allocate_device();
1288 if (!ts
|| !packet
|| !input_dev
) {
1293 spi_set_drvdata(spi
, ts
);
1295 ts
->packet
= packet
;
1297 ts
->input
= input_dev
;
1299 mutex_init(&ts
->lock
);
1300 init_waitqueue_head(&ts
->wait
);
1302 pdata
= dev_get_platdata(&spi
->dev
);
1304 pdata
= ads7846_probe_dt(&spi
->dev
);
1306 return PTR_ERR(pdata
);
1309 ts
->model
= pdata
->model
? : 7846;
1310 ts
->vref_delay_usecs
= pdata
->vref_delay_usecs
? : 100;
1311 ts
->x_plate_ohms
= pdata
->x_plate_ohms
? : 400;
1312 ts
->pressure_max
= pdata
->pressure_max
? : ~0;
1314 ts
->vref_mv
= pdata
->vref_mv
;
1315 ts
->swap_xy
= pdata
->swap_xy
;
1317 if (pdata
->filter
!= NULL
) {
1318 if (pdata
->filter_init
!= NULL
) {
1319 err
= pdata
->filter_init(pdata
, &ts
->filter_data
);
1323 ts
->filter
= pdata
->filter
;
1324 ts
->filter_cleanup
= pdata
->filter_cleanup
;
1325 } else if (pdata
->debounce_max
) {
1326 ts
->debounce_max
= pdata
->debounce_max
;
1327 if (ts
->debounce_max
< 2)
1328 ts
->debounce_max
= 2;
1329 ts
->debounce_tol
= pdata
->debounce_tol
;
1330 ts
->debounce_rep
= pdata
->debounce_rep
;
1331 ts
->filter
= ads7846_debounce_filter
;
1332 ts
->filter_data
= ts
;
1334 ts
->filter
= ads7846_no_filter
;
1337 err
= ads7846_setup_pendown(spi
, ts
, pdata
);
1339 goto err_cleanup_filter
;
1341 if (pdata
->penirq_recheck_delay_usecs
)
1342 ts
->penirq_recheck_delay_usecs
=
1343 pdata
->penirq_recheck_delay_usecs
;
1345 ts
->wait_for_sync
= pdata
->wait_for_sync
? : null_wait_for_sync
;
1347 snprintf(ts
->phys
, sizeof(ts
->phys
), "%s/input0", dev_name(&spi
->dev
));
1348 snprintf(ts
->name
, sizeof(ts
->name
), "ADS%d Touchscreen", ts
->model
);
1350 input_dev
->name
= ts
->name
;
1351 input_dev
->phys
= ts
->phys
;
1352 input_dev
->dev
.parent
= &spi
->dev
;
1354 input_dev
->evbit
[0] = BIT_MASK(EV_KEY
) | BIT_MASK(EV_ABS
);
1355 input_dev
->keybit
[BIT_WORD(BTN_TOUCH
)] = BIT_MASK(BTN_TOUCH
);
1356 input_set_abs_params(input_dev
, ABS_X
,
1358 pdata
->x_max
? : MAX_12BIT
,
1360 input_set_abs_params(input_dev
, ABS_Y
,
1362 pdata
->y_max
? : MAX_12BIT
,
1364 input_set_abs_params(input_dev
, ABS_PRESSURE
,
1365 pdata
->pressure_min
, pdata
->pressure_max
, 0, 0);
1367 ads7846_setup_spi_msg(ts
, pdata
);
1369 ts
->reg
= regulator_get(&spi
->dev
, "vcc");
1370 if (IS_ERR(ts
->reg
)) {
1371 err
= PTR_ERR(ts
->reg
);
1372 dev_err(&spi
->dev
, "unable to get regulator: %d\n", err
);
1376 err
= regulator_enable(ts
->reg
);
1378 dev_err(&spi
->dev
, "unable to enable regulator: %d\n", err
);
1379 goto err_put_regulator
;
1382 irq_flags
= pdata
->irq_flags
? : IRQF_TRIGGER_FALLING
;
1383 irq_flags
|= IRQF_ONESHOT
;
1385 err
= request_threaded_irq(spi
->irq
, ads7846_hard_irq
, ads7846_irq
,
1386 irq_flags
, spi
->dev
.driver
->name
, ts
);
1387 if (err
&& !pdata
->irq_flags
) {
1389 "trying pin change workaround on irq %d\n", spi
->irq
);
1390 irq_flags
|= IRQF_TRIGGER_RISING
;
1391 err
= request_threaded_irq(spi
->irq
,
1392 ads7846_hard_irq
, ads7846_irq
,
1393 irq_flags
, spi
->dev
.driver
->name
, ts
);
1397 dev_dbg(&spi
->dev
, "irq %d busy?\n", spi
->irq
);
1398 goto err_disable_regulator
;
1401 err
= ads784x_hwmon_register(spi
, ts
);
1405 dev_info(&spi
->dev
, "touchscreen, irq %d\n", spi
->irq
);
1408 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1409 * the touchscreen, in case it's not connected.
1411 if (ts
->model
== 7845)
1412 ads7845_read12_ser(&spi
->dev
, PWRDOWN
);
1414 (void) ads7846_read12_ser(&spi
->dev
, READ_12BIT_SER(vaux
));
1416 err
= sysfs_create_group(&spi
->dev
.kobj
, &ads784x_attr_group
);
1418 goto err_remove_hwmon
;
1420 err
= input_register_device(input_dev
);
1422 goto err_remove_attr_group
;
1424 device_init_wakeup(&spi
->dev
, pdata
->wakeup
);
1427 * If device does not carry platform data we must have allocated it
1428 * when parsing DT data.
1430 if (!dev_get_platdata(&spi
->dev
))
1431 devm_kfree(&spi
->dev
, (void *)pdata
);
1435 err_remove_attr_group
:
1436 sysfs_remove_group(&spi
->dev
.kobj
, &ads784x_attr_group
);
1438 ads784x_hwmon_unregister(spi
, ts
);
1440 free_irq(spi
->irq
, ts
);
1441 err_disable_regulator
:
1442 regulator_disable(ts
->reg
);
1444 regulator_put(ts
->reg
);
1446 if (!ts
->get_pendown_state
)
1447 gpio_free(ts
->gpio_pendown
);
1449 if (ts
->filter_cleanup
)
1450 ts
->filter_cleanup(ts
->filter_data
);
1452 input_free_device(input_dev
);
1458 static int ads7846_remove(struct spi_device
*spi
)
1460 struct ads7846
*ts
= spi_get_drvdata(spi
);
1462 device_init_wakeup(&spi
->dev
, false);
1464 sysfs_remove_group(&spi
->dev
.kobj
, &ads784x_attr_group
);
1466 ads7846_disable(ts
);
1467 free_irq(ts
->spi
->irq
, ts
);
1469 input_unregister_device(ts
->input
);
1471 ads784x_hwmon_unregister(spi
, ts
);
1473 regulator_disable(ts
->reg
);
1474 regulator_put(ts
->reg
);
1476 if (!ts
->get_pendown_state
) {
1478 * If we are not using specialized pendown method we must
1479 * have been relying on gpio we set up ourselves.
1481 gpio_free(ts
->gpio_pendown
);
1484 if (ts
->filter_cleanup
)
1485 ts
->filter_cleanup(ts
->filter_data
);
1490 dev_dbg(&spi
->dev
, "unregistered touchscreen\n");
1495 static struct spi_driver ads7846_driver
= {
1498 .owner
= THIS_MODULE
,
1500 .of_match_table
= of_match_ptr(ads7846_dt_ids
),
1502 .probe
= ads7846_probe
,
1503 .remove
= ads7846_remove
,
1506 module_spi_driver(ads7846_driver
);
1508 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1509 MODULE_LICENSE("GPL");
1510 MODULE_ALIAS("spi:ads7846");