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/device.h>
21 #include <linux/init.h>
22 #include <linux/delay.h>
23 #include <linux/input.h>
24 #include <linux/interrupt.h>
25 #include <linux/slab.h>
26 #include <linux/spi/spi.h>
27 #include <linux/spi/ads7846.h>
31 #include <asm/mach-types.h>
32 #ifdef CONFIG_ARCH_OMAP
33 #include <asm/arch/gpio.h>
39 * This code has been heavily tested on a Nokia 770, and lightly
40 * tested on other ads7846 devices (OSK/Mistral, Lubbock).
41 * Support for ads7843 and ads7845 has only been stubbed in.
43 * IRQ handling needs a workaround because of a shortcoming in handling
44 * edge triggered IRQs on some platforms like the OMAP1/2. These
45 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
46 * have to maintain our own SW IRQ disabled status. This should be
47 * removed as soon as the affected platform's IRQ handling is fixed.
49 * app note sbaa036 talks in more detail about accurate sampling...
50 * that ought to help in situations like LCDs inducing noise (which
51 * can also be helped by using synch signals) and more generally.
52 * This driver tries to utilize the measures described in the app
53 * note. The strength of filtering can be set in the board-* specific
57 #define TS_POLL_PERIOD msecs_to_jiffies(10)
59 /* this driver doesn't aim at the peak continuous sample rate */
60 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
63 /* For portability, we can't read 12 bit values using SPI (which
64 * would make the controller deliver them as native byteorder u16
65 * with msbs zeroed). Instead, we read them as two 8-bit values,
66 * which need byteswapping then range adjustment.
75 struct input_dev *input;
78 struct spi_device *spi;
79 struct attribute_group *attr_group;
85 u8 read_x, read_y, read_z1, read_z2, pwrdown;
86 u16 dummy; /* for the pwrdown read */
89 struct spi_transfer xfer[10];
90 struct spi_message msg[5];
91 struct spi_message *last_msg;
102 struct timer_list timer; /* P: lock */
103 unsigned pendown:1; /* P: lock */
104 unsigned pending:1; /* P: lock */
105 // FIXME remove "irq_disabled"
106 unsigned irq_disabled:1; /* P: lock */
109 int (*get_pendown_state)(void);
112 /* leave chip selected when we're done, for quicker re-select? */
114 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
116 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
119 /*--------------------------------------------------------------------------*/
121 /* The ADS7846 has touchscreen and other sensors.
122 * Earlier ads784x chips are somewhat compatible.
124 #define ADS_START (1 << 7)
125 #define ADS_A2A1A0_d_y (1 << 4) /* differential */
126 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
127 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
128 #define ADS_A2A1A0_d_x (5 << 4) /* differential */
129 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
130 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
131 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
132 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
133 #define ADS_8_BIT (1 << 3)
134 #define ADS_12_BIT (0 << 3)
135 #define ADS_SER (1 << 2) /* non-differential */
136 #define ADS_DFR (0 << 2) /* differential */
137 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */
138 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
139 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
140 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
142 #define MAX_12BIT ((1<<12)-1)
144 /* leave ADC powered up (disables penirq) between differential samples */
145 #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
146 | ADS_12_BIT | ADS_DFR)
148 #define READ_Y (READ_12BIT_DFR(y) | ADS_PD10_ADC_ON)
149 #define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
150 #define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
152 #define READ_X (READ_12BIT_DFR(x) | ADS_PD10_ADC_ON)
153 #define PWRDOWN (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) /* LAST */
155 /* single-ended samples need to first power up reference voltage;
156 * we leave both ADC and VREF powered
158 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
159 | ADS_12_BIT | ADS_SER)
161 #define REF_ON (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
162 #define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
164 /*--------------------------------------------------------------------------*/
167 * Non-touchscreen sensors only use single-ended conversions.
176 struct spi_message msg;
177 struct spi_transfer xfer[6];
180 static void ads7846_enable(struct ads7846 *ts);
181 static void ads7846_disable(struct ads7846 *ts);
183 static int device_suspended(struct device *dev)
185 struct ads7846 *ts = dev_get_drvdata(dev);
186 return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
189 static int ads7846_read12_ser(struct device *dev, unsigned command)
191 struct spi_device *spi = to_spi_device(dev);
192 struct ads7846 *ts = dev_get_drvdata(dev);
193 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL);
201 spi_message_init(&req->msg);
203 /* activate reference, so it has time to settle; */
204 req->ref_on = REF_ON;
205 req->xfer[0].tx_buf = &req->ref_on;
206 req->xfer[0].len = 1;
207 req->xfer[1].rx_buf = &req->scratch;
208 req->xfer[1].len = 2;
211 * for external VREF, 0 usec (and assume it's always on);
212 * for 1uF, use 800 usec;
215 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
218 req->command = (u8) command;
219 req->xfer[2].tx_buf = &req->command;
220 req->xfer[2].len = 1;
221 req->xfer[3].rx_buf = &req->sample;
222 req->xfer[3].len = 2;
224 /* REVISIT: take a few more samples, and compare ... */
226 /* turn off reference */
227 req->ref_off = REF_OFF;
228 req->xfer[4].tx_buf = &req->ref_off;
229 req->xfer[4].len = 1;
230 req->xfer[5].rx_buf = &req->scratch;
231 req->xfer[5].len = 2;
233 CS_CHANGE(req->xfer[5]);
235 /* group all the transfers together, so we can't interfere with
236 * reading touchscreen state; disable penirq while sampling
238 for (i = 0; i < 6; i++)
239 spi_message_add_tail(&req->xfer[i], &req->msg);
241 ts->irq_disabled = 1;
242 disable_irq(spi->irq);
243 status = spi_sync(spi, &req->msg);
244 ts->irq_disabled = 0;
245 enable_irq(spi->irq);
248 status = req->msg.status;
250 /* on-wire is a must-ignore bit, a BE12 value, then padding */
251 sample = be16_to_cpu(req->sample);
252 sample = sample >> 3;
256 return status ? status : sample;
259 #define SHOW(name) static ssize_t \
260 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
262 ssize_t v = ads7846_read12_ser(dev, \
263 READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
266 return sprintf(buf, "%u\n", (unsigned) v); \
268 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
275 static int is_pen_down(struct device *dev)
277 struct ads7846 *ts = dev_get_drvdata(dev);
282 static ssize_t ads7846_pen_down_show(struct device *dev,
283 struct device_attribute *attr, char *buf)
285 return sprintf(buf, "%u\n", is_pen_down(dev));
288 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
290 static ssize_t ads7846_disable_show(struct device *dev,
291 struct device_attribute *attr, char *buf)
293 struct ads7846 *ts = dev_get_drvdata(dev);
295 return sprintf(buf, "%u\n", ts->disabled);
298 static ssize_t ads7846_disable_store(struct device *dev,
299 struct device_attribute *attr,
300 const char *buf, size_t count)
302 struct ads7846 *ts = dev_get_drvdata(dev);
306 i = simple_strtoul(buf, &endp, 10);
307 spin_lock_irq(&ts->lock);
314 spin_unlock_irq(&ts->lock);
319 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
321 static struct attribute *ads7846_attributes[] = {
322 &dev_attr_temp0.attr,
323 &dev_attr_temp1.attr,
324 &dev_attr_vbatt.attr,
326 &dev_attr_pen_down.attr,
327 &dev_attr_disable.attr,
331 static struct attribute_group ads7846_attr_group = {
332 .attrs = ads7846_attributes,
336 * ads7843/7845 don't have temperature sensors, and
337 * use the other sensors a bit differently too
340 static struct attribute *ads7843_attributes[] = {
341 &dev_attr_vbatt.attr,
343 &dev_attr_pen_down.attr,
344 &dev_attr_disable.attr,
348 static struct attribute_group ads7843_attr_group = {
349 .attrs = ads7843_attributes,
352 static struct attribute *ads7845_attributes[] = {
354 &dev_attr_pen_down.attr,
355 &dev_attr_disable.attr,
359 static struct attribute_group ads7845_attr_group = {
360 .attrs = ads7845_attributes,
363 /*--------------------------------------------------------------------------*/
366 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer,
367 * to retrieve touchscreen status.
369 * The SPI transfer completion callback does the real work. It reports
370 * touchscreen events and reactivates the timer (or IRQ) as appropriate.
373 static void ads7846_rx(void *ads)
375 struct ads7846 *ts = ads;
376 struct input_dev *input_dev = ts->input;
382 /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding;
383 * built from two 8 bit values written msb-first.
385 x = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff;
386 y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff;
387 z1 = (be16_to_cpu(ts->tc.z1) >> 3) & 0x0fff;
388 z2 = (be16_to_cpu(ts->tc.z2) >> 3) & 0x0fff;
390 /* range filtering */
394 if (likely(x && z1 && !device_suspended(&ts->spi->dev))) {
395 /* compute touch pressure resistance using equation #2 */
399 Rt *= ts->x_plate_ohms;
401 Rt = (Rt + 2047) >> 12;
405 /* Sample found inconsistent by debouncing or pressure is beyond
406 * the maximum. Don't report it to user space, repeat at least
407 * once more the measurement */
408 if (ts->tc.ignore || Rt > ts->pressure_max) {
409 mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
413 /* NOTE: "pendown" is inferred from pressure; we don't rely on
414 * being able to check nPENIRQ status, or "friendly" trigger modes
415 * (both-edges is much better than just-falling or low-level).
417 * REVISIT: some boards may require reading nPENIRQ; it's
418 * needed on 7843. and 7845 reads pressure differently...
420 * REVISIT: the touchscreen might not be connected; this code
421 * won't notice that, even if nPENIRQ never fires ...
423 if (!ts->pendown && Rt != 0) {
424 input_report_key(input_dev, BTN_TOUCH, 1);
426 } else if (ts->pendown && Rt == 0) {
427 input_report_key(input_dev, BTN_TOUCH, 0);
432 input_report_abs(input_dev, ABS_X, x);
433 input_report_abs(input_dev, ABS_Y, y);
438 input_report_abs(input_dev, ABS_PRESSURE, Rt);
439 input_sync(input_dev);
443 if (Rt || ts->pendown)
444 pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
445 x, y, Rt, Rt ? "" : " UP");
448 spin_lock_irqsave(&ts->lock, flags);
450 ts->pendown = (Rt != 0);
451 mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
453 spin_unlock_irqrestore(&ts->lock, flags);
456 static void ads7846_debounce(void *ads)
458 struct ads7846 *ts = ads;
459 struct spi_message *m;
460 struct spi_transfer *t;
464 m = &ts->msg[ts->msg_idx];
465 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
466 val = (be16_to_cpu(*(__be16 *)t->rx_buf) >> 3) & 0x0fff;
467 if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) {
468 /* Repeat it, if this was the first read or the read
469 * wasn't consistent enough. */
470 if (ts->read_cnt < ts->debounce_max) {
474 /* Maximum number of debouncing reached and still
475 * not enough number of consistent readings. Abort
476 * the whole sample, repeat it in the next sampling
481 /* Last message will contain ads7846_rx() as the
482 * completion function.
486 /* Start over collecting consistent readings. */
489 if (++ts->read_rep > ts->debounce_rep) {
490 /* Got a good reading for this coordinate,
491 * go for the next one. */
498 /* Read more values that are consistent. */
501 status = spi_async(ts->spi, m);
503 dev_err(&ts->spi->dev, "spi_async --> %d\n",
507 static void ads7846_timer(unsigned long handle)
509 struct ads7846 *ts = (void *)handle;
512 spin_lock_irq(&ts->lock);
514 if (unlikely(ts->msg_idx && !ts->pendown)) {
515 /* measurement cycle ended */
516 if (!device_suspended(&ts->spi->dev)) {
517 ts->irq_disabled = 0;
518 enable_irq(ts->spi->irq);
523 /* pen is still down, continue with the measurement */
525 status = spi_async(ts->spi, &ts->msg[0]);
527 dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
530 spin_unlock_irq(&ts->lock);
533 static irqreturn_t ads7846_irq(int irq, void *handle)
535 struct ads7846 *ts = handle;
538 spin_lock_irqsave(&ts->lock, flags);
539 if (likely(ts->get_pendown_state())) {
540 if (!ts->irq_disabled) {
541 /* The ARM do_simple_IRQ() dispatcher doesn't act
542 * like the other dispatchers: it will report IRQs
543 * even after they've been disabled. We work around
544 * that here. (The "generic irq" framework may help...)
546 ts->irq_disabled = 1;
547 disable_irq(ts->spi->irq);
549 mod_timer(&ts->timer, jiffies);
552 spin_unlock_irqrestore(&ts->lock, flags);
557 /*--------------------------------------------------------------------------*/
559 /* Must be called with ts->lock held */
560 static void ads7846_disable(struct ads7846 *ts)
567 /* are we waiting for IRQ, or polling? */
569 ts->irq_disabled = 1;
570 disable_irq(ts->spi->irq);
572 /* the timer will run at least once more, and
573 * leave everything in a clean state, IRQ disabled
575 while (ts->pending) {
576 spin_unlock_irq(&ts->lock);
578 spin_lock_irq(&ts->lock);
582 /* we know the chip's in lowpower mode since we always
583 * leave it that way after every request
588 /* Must be called with ts->lock held */
589 static void ads7846_enable(struct ads7846 *ts)
595 ts->irq_disabled = 0;
596 enable_irq(ts->spi->irq);
599 static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
601 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
603 spin_lock_irq(&ts->lock);
605 spi->dev.power.power_state = message;
608 spin_unlock_irq(&ts->lock);
614 static int ads7846_resume(struct spi_device *spi)
616 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
618 spin_lock_irq(&ts->lock);
620 spi->dev.power.power_state = PMSG_ON;
623 spin_unlock_irq(&ts->lock);
628 static int __devinit ads7846_probe(struct spi_device *spi)
631 struct input_dev *input_dev;
632 struct ads7846_platform_data *pdata = spi->dev.platform_data;
633 struct spi_message *m;
634 struct spi_transfer *x;
638 dev_dbg(&spi->dev, "no IRQ?\n");
643 dev_dbg(&spi->dev, "no platform data?\n");
647 /* don't exceed max specified sample rate */
648 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
649 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
650 (spi->max_speed_hz/SAMPLE_BITS)/1000);
654 /* REVISIT when the irq can be triggered active-low, or if for some
655 * reason the touchscreen isn't hooked up, we don't need to access
658 if (pdata->get_pendown_state == NULL) {
659 dev_dbg(&spi->dev, "no get_pendown_state function?\n");
663 /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
664 * that even if the hardware can do that, the SPI controller driver
665 * may not. So we stick to very-portable 8 bit words, both RX and TX.
667 spi->bits_per_word = 8;
669 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
670 input_dev = input_allocate_device();
671 if (!ts || !input_dev) {
676 dev_set_drvdata(&spi->dev, ts);
677 spi->dev.power.power_state = PMSG_ON;
680 ts->input = input_dev;
682 init_timer(&ts->timer);
683 ts->timer.data = (unsigned long) ts;
684 ts->timer.function = ads7846_timer;
686 spin_lock_init(&ts->lock);
688 ts->model = pdata->model ? : 7846;
689 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
690 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
691 ts->pressure_max = pdata->pressure_max ? : ~0;
692 if (pdata->debounce_max) {
693 ts->debounce_max = pdata->debounce_max;
694 ts->debounce_tol = pdata->debounce_tol;
695 ts->debounce_rep = pdata->debounce_rep;
696 if (ts->debounce_rep > ts->debounce_max + 1)
697 ts->debounce_rep = ts->debounce_max - 1;
699 ts->debounce_tol = ~0;
700 ts->get_pendown_state = pdata->get_pendown_state;
702 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
704 input_dev->name = "ADS784x Touchscreen";
705 input_dev->phys = ts->phys;
706 input_dev->cdev.dev = &spi->dev;
708 input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
709 input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
710 input_set_abs_params(input_dev, ABS_X,
712 pdata->x_max ? : MAX_12BIT,
714 input_set_abs_params(input_dev, ABS_Y,
716 pdata->y_max ? : MAX_12BIT,
718 input_set_abs_params(input_dev, ABS_PRESSURE,
719 pdata->pressure_min, pdata->pressure_max, 0, 0);
721 /* set up the transfers to read touchscreen state; this assumes we
722 * use formula #2 for pressure, not #3.
729 /* y- still on; turn on only y+ (and ADC) */
731 x->tx_buf = &ts->read_y;
733 spi_message_add_tail(x, m);
736 x->rx_buf = &ts->tc.y;
738 spi_message_add_tail(x, m);
740 m->complete = ads7846_debounce;
746 /* turn y- off, x+ on, then leave in lowpower */
749 x->tx_buf = &ts->read_x;
751 spi_message_add_tail(x, m);
754 x->rx_buf = &ts->tc.x;
756 spi_message_add_tail(x, m);
758 m->complete = ads7846_debounce;
761 /* turn y+ off, x- on; we'll use formula #2 */
762 if (ts->model == 7846) {
767 ts->read_z1 = READ_Z1;
768 x->tx_buf = &ts->read_z1;
770 spi_message_add_tail(x, m);
773 x->rx_buf = &ts->tc.z1;
775 spi_message_add_tail(x, m);
777 m->complete = ads7846_debounce;
784 ts->read_z2 = READ_Z2;
785 x->tx_buf = &ts->read_z2;
787 spi_message_add_tail(x, m);
790 x->rx_buf = &ts->tc.z2;
792 spi_message_add_tail(x, m);
794 m->complete = ads7846_debounce;
803 ts->pwrdown = PWRDOWN;
804 x->tx_buf = &ts->pwrdown;
806 spi_message_add_tail(x, m);
809 x->rx_buf = &ts->dummy;
812 spi_message_add_tail(x, m);
814 m->complete = ads7846_rx;
819 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
820 spi->dev.driver->name, ts)) {
821 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
826 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
828 /* take a first sample, leaving nPENIRQ active; avoid
829 * the touchscreen, in case it's not connected.
831 (void) ads7846_read12_ser(&spi->dev,
832 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
836 ts->attr_group = &ads7846_attr_group;
839 ts->attr_group = &ads7845_attr_group;
842 ts->attr_group = &ads7843_attr_group;
845 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
849 err = input_register_device(input_dev);
851 goto err_remove_attr_group;
855 err_remove_attr_group:
856 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
858 free_irq(spi->irq, ts);
860 input_free_device(input_dev);
865 static int __devexit ads7846_remove(struct spi_device *spi)
867 struct ads7846 *ts = dev_get_drvdata(&spi->dev);
869 input_unregister_device(ts->input);
871 ads7846_suspend(spi, PMSG_SUSPEND);
873 sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
875 free_irq(ts->spi->irq, ts);
876 /* suspend left the IRQ disabled */
877 enable_irq(ts->spi->irq);
881 dev_dbg(&spi->dev, "unregistered touchscreen\n");
885 static struct spi_driver ads7846_driver = {
888 .bus = &spi_bus_type,
889 .owner = THIS_MODULE,
891 .probe = ads7846_probe,
892 .remove = __devexit_p(ads7846_remove),
893 .suspend = ads7846_suspend,
894 .resume = ads7846_resume,
897 static int __init ads7846_init(void)
899 /* grr, board-specific init should stay out of drivers!! */
901 #ifdef CONFIG_ARCH_OMAP
902 if (machine_is_omap_osk()) {
903 /* GPIO4 = PENIRQ; GPIO6 = BUSY */
904 omap_request_gpio(4);
905 omap_set_gpio_direction(4, 1);
906 omap_request_gpio(6);
907 omap_set_gpio_direction(6, 1);
909 // also TI 1510 Innovator, bitbanging through FPGA
911 // also Palm Tungsten T2
915 // also Dell Axim X50
916 // also HP iPaq H191x/H192x/H415x/H435x
917 // also Intel Lubbock (additional to UCB1400; as temperature sensor)
918 // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
920 // Atmel at91sam9261-EK uses ads7843
922 // also various AMD Au1x00 devel boards
924 return spi_register_driver(&ads7846_driver);
926 module_init(ads7846_init);
928 static void __exit ads7846_exit(void)
930 spi_unregister_driver(&ads7846_driver);
932 #ifdef CONFIG_ARCH_OMAP
933 if (machine_is_omap_osk()) {
940 module_exit(ads7846_exit);
942 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
943 MODULE_LICENSE("GPL");