2 * Copyright (C) 2006-2008 Michael Hennerich, Analog Devices Inc.
4 * Description: AD7877 based touchscreen, sensor (ADCs), DAC and GPIO driver
7 * Bugs: Enter bugs at http://blackfin.uclinux.org/
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, see the file COPYING, or write
21 * to the Free Software Foundation, Inc.,
22 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
25 * Copyright (c) 2005 David Brownell
26 * Copyright (c) 2006 Nokia Corporation
27 * Various changes: Imre Deak <imre.deak@nokia.com>
31 * Copyright (C) 2004-2005 Richard Purdie
32 * - omap_ts.[hc], ads7846.h, ts_osk.c
33 * Copyright (C) 2002 MontaVista Software
34 * Copyright (C) 2004 Texas Instruments
35 * Copyright (C) 2005 Dirk Behme
39 #include <linux/device.h>
40 #include <linux/init.h>
41 #include <linux/delay.h>
42 #include <linux/input.h>
43 #include <linux/interrupt.h>
44 #include <linux/slab.h>
45 #include <linux/spi/spi.h>
46 #include <linux/spi/ad7877.h>
49 #define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50)
51 #define MAX_SPI_FREQ_HZ 20000000
52 #define MAX_12BIT ((1<<12)-1)
54 #define AD7877_REG_ZEROS 0
55 #define AD7877_REG_CTRL1 1
56 #define AD7877_REG_CTRL2 2
57 #define AD7877_REG_ALERT 3
58 #define AD7877_REG_AUX1HIGH 4
59 #define AD7877_REG_AUX1LOW 5
60 #define AD7877_REG_BAT1HIGH 6
61 #define AD7877_REG_BAT1LOW 7
62 #define AD7877_REG_BAT2HIGH 8
63 #define AD7877_REG_BAT2LOW 9
64 #define AD7877_REG_TEMP1HIGH 10
65 #define AD7877_REG_TEMP1LOW 11
66 #define AD7877_REG_SEQ0 12
67 #define AD7877_REG_SEQ1 13
68 #define AD7877_REG_DAC 14
69 #define AD7877_REG_NONE1 15
70 #define AD7877_REG_EXTWRITE 15
71 #define AD7877_REG_XPLUS 16
72 #define AD7877_REG_YPLUS 17
73 #define AD7877_REG_Z2 18
74 #define AD7877_REG_aux1 19
75 #define AD7877_REG_aux2 20
76 #define AD7877_REG_aux3 21
77 #define AD7877_REG_bat1 22
78 #define AD7877_REG_bat2 23
79 #define AD7877_REG_temp1 24
80 #define AD7877_REG_temp2 25
81 #define AD7877_REG_Z1 26
82 #define AD7877_REG_GPIOCTRL1 27
83 #define AD7877_REG_GPIOCTRL2 28
84 #define AD7877_REG_GPIODATA 29
85 #define AD7877_REG_NONE2 30
86 #define AD7877_REG_NONE3 31
88 #define AD7877_SEQ_YPLUS_BIT (1<<11)
89 #define AD7877_SEQ_XPLUS_BIT (1<<10)
90 #define AD7877_SEQ_Z2_BIT (1<<9)
91 #define AD7877_SEQ_AUX1_BIT (1<<8)
92 #define AD7877_SEQ_AUX2_BIT (1<<7)
93 #define AD7877_SEQ_AUX3_BIT (1<<6)
94 #define AD7877_SEQ_BAT1_BIT (1<<5)
95 #define AD7877_SEQ_BAT2_BIT (1<<4)
96 #define AD7877_SEQ_TEMP1_BIT (1<<3)
97 #define AD7877_SEQ_TEMP2_BIT (1<<2)
98 #define AD7877_SEQ_Z1_BIT (1<<1)
109 AD7877_SEQ_TEMP1 = 8,
110 AD7877_SEQ_TEMP2 = 9,
112 AD7877_NR_SENSE = 11,
115 /* DAC Register Default RANGE 0 to Vcc, Volatge Mode, DAC On */
116 #define AD7877_DAC_CONF 0x1
118 /* If gpio3 is set AUX3/GPIO3 acts as GPIO Output */
119 #define AD7877_EXTW_GPIO_3_CONF 0x1C4
120 #define AD7877_EXTW_GPIO_DATA 0x200
123 #define AD7877_TMR(x) ((x & 0x3) << 0)
124 #define AD7877_REF(x) ((x & 0x1) << 2)
125 #define AD7877_POL(x) ((x & 0x1) << 3)
126 #define AD7877_FCD(x) ((x & 0x3) << 4)
127 #define AD7877_PM(x) ((x & 0x3) << 6)
128 #define AD7877_ACQ(x) ((x & 0x3) << 8)
129 #define AD7877_AVG(x) ((x & 0x3) << 10)
132 #define AD7877_SER (1 << 11) /* non-differential */
133 #define AD7877_DFR (0 << 11) /* differential */
135 #define AD7877_MODE_NOC (0) /* Do not convert */
136 #define AD7877_MODE_SCC (1) /* Single channel conversion */
137 #define AD7877_MODE_SEQ0 (2) /* Sequence 0 in Slave Mode */
138 #define AD7877_MODE_SEQ1 (3) /* Sequence 1 in Master Mode */
140 #define AD7877_CHANADD(x) ((x&0xF)<<7)
141 #define AD7877_READADD(x) ((x)<<2)
142 #define AD7877_WRITEADD(x) ((x)<<12)
144 #define AD7877_READ_CHAN(x) (AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_SER | \
145 AD7877_MODE_SCC | AD7877_CHANADD(AD7877_REG_ ## x) | \
146 AD7877_READADD(AD7877_REG_ ## x))
148 #define AD7877_MM_SEQUENCE (AD7877_SEQ_YPLUS_BIT | AD7877_SEQ_XPLUS_BIT | \
149 AD7877_SEQ_Z2_BIT | AD7877_SEQ_Z1_BIT)
152 * Non-touchscreen sensors only use single-ended conversions.
160 struct spi_message msg;
161 struct spi_transfer xfer[6];
165 struct input_dev *input;
168 struct spi_device *spi;
170 u16 vref_delay_usecs;
180 u8 first_conversion_delay;
183 u8 pen_down_acc_interval;
185 u16 conversion_data[AD7877_NR_SENSE];
187 struct spi_transfer xfer[AD7877_NR_SENSE + 2];
188 struct spi_message msg;
191 unsigned disabled:1; /* P: mutex */
192 unsigned gpio3:1; /* P: mutex */
193 unsigned gpio4:1; /* P: mutex */
196 struct timer_list timer; /* P: lock */
197 unsigned pending:1; /* P: lock */
201 module_param(gpio3, int, 0);
202 MODULE_PARM_DESC(gpio3, "If gpio3 is set to 1 AUX3 acts as GPIO3");
205 * ad7877_read/write are only used for initial setup and for sysfs controls.
206 * The main traffic is done using spi_async() in the interrupt handler.
209 static int ad7877_read(struct spi_device *spi, u16 reg)
214 req = kzalloc(sizeof *req, GFP_KERNEL);
218 spi_message_init(&req->msg);
220 req->command = (u16) (AD7877_WRITEADD(AD7877_REG_CTRL1) |
221 AD7877_READADD(reg));
222 req->xfer[0].tx_buf = &req->command;
223 req->xfer[0].len = 2;
225 req->xfer[1].rx_buf = &req->sample;
226 req->xfer[1].len = 2;
228 spi_message_add_tail(&req->xfer[0], &req->msg);
229 spi_message_add_tail(&req->xfer[1], &req->msg);
231 status = spi_sync(spi, &req->msg);
232 ret = status ? : req->sample;
239 static int ad7877_write(struct spi_device *spi, u16 reg, u16 val)
244 req = kzalloc(sizeof *req, GFP_KERNEL);
248 spi_message_init(&req->msg);
250 req->command = (u16) (AD7877_WRITEADD(reg) | (val & MAX_12BIT));
251 req->xfer[0].tx_buf = &req->command;
252 req->xfer[0].len = 2;
254 spi_message_add_tail(&req->xfer[0], &req->msg);
256 status = spi_sync(spi, &req->msg);
263 static int ad7877_read_adc(struct spi_device *spi, unsigned command)
265 struct ad7877 *ts = dev_get_drvdata(&spi->dev);
271 req = kzalloc(sizeof *req, GFP_KERNEL);
275 spi_message_init(&req->msg);
277 /* activate reference, so it has time to settle; */
278 req->ref_on = AD7877_WRITEADD(AD7877_REG_CTRL2) |
279 AD7877_POL(ts->stopacq_polarity) |
280 AD7877_AVG(0) | AD7877_PM(2) | AD7877_TMR(0) |
281 AD7877_ACQ(ts->acquisition_time) | AD7877_FCD(0);
283 req->reset = AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_MODE_NOC;
285 req->command = (u16) command;
287 req->xfer[0].tx_buf = &req->reset;
288 req->xfer[0].len = 2;
290 req->xfer[1].tx_buf = &req->ref_on;
291 req->xfer[1].len = 2;
292 req->xfer[1].delay_usecs = ts->vref_delay_usecs;
294 req->xfer[2].tx_buf = &req->command;
295 req->xfer[2].len = 2;
296 req->xfer[2].delay_usecs = ts->vref_delay_usecs;
298 req->xfer[3].rx_buf = &req->sample;
299 req->xfer[3].len = 2;
301 req->xfer[4].tx_buf = &ts->cmd_crtl2; /*REF OFF*/
302 req->xfer[4].len = 2;
304 req->xfer[5].tx_buf = &ts->cmd_crtl1; /*DEFAULT*/
305 req->xfer[5].len = 2;
307 /* group all the transfers together, so we can't interfere with
308 * reading touchscreen state; disable penirq while sampling
310 for (i = 0; i < 6; i++)
311 spi_message_add_tail(&req->xfer[i], &req->msg);
313 status = spi_sync(spi, &req->msg);
314 sample = req->sample;
318 return status ? : sample;
321 static void ad7877_rx(struct ad7877 *ts)
323 struct input_dev *input_dev = ts->input;
327 x = ts->conversion_data[AD7877_SEQ_XPOS] & MAX_12BIT;
328 y = ts->conversion_data[AD7877_SEQ_YPOS] & MAX_12BIT;
329 z1 = ts->conversion_data[AD7877_SEQ_Z1] & MAX_12BIT;
330 z2 = ts->conversion_data[AD7877_SEQ_Z2] & MAX_12BIT;
333 * The samples processed here are already preprocessed by the AD7877.
334 * The preprocessing function consists of an averaging filter.
335 * The combination of 'first conversion delay' and averaging provides a robust solution,
336 * discarding the spurious noise in the signal and keeping only the data of interest.
337 * The size of the averaging filter is programmable. (dev.platform_data, see linux/spi/ad7877.h)
338 * Other user-programmable conversion controls include variable acquisition time,
339 * and first conversion delay. Up to 16 averages can be taken per conversion.
342 if (likely(x && z1)) {
343 /* compute touch pressure resistance using equation #1 */
344 Rt = (z2 - z1) * x * ts->x_plate_ohms;
346 Rt = (Rt + 2047) >> 12;
348 input_report_abs(input_dev, ABS_X, x);
349 input_report_abs(input_dev, ABS_Y, y);
350 input_report_abs(input_dev, ABS_PRESSURE, Rt);
351 input_sync(input_dev);
355 static inline void ad7877_ts_event_release(struct ad7877 *ts)
357 struct input_dev *input_dev = ts->input;
359 input_report_abs(input_dev, ABS_PRESSURE, 0);
360 input_sync(input_dev);
363 static void ad7877_timer(unsigned long handle)
365 struct ad7877 *ts = (void *)handle;
367 ad7877_ts_event_release(ts);
370 static irqreturn_t ad7877_irq(int irq, void *handle)
372 struct ad7877 *ts = handle;
377 * The repeated conversion sequencer controlled by TMR kicked off
378 * too fast. We ignore the last and process the sample sequence
379 * currently in the queue. It can't be older than 9.4ms, and we
380 * need to avoid that ts->msg doesn't get issued twice while in work.
383 spin_lock_irqsave(&ts->lock, flags);
387 status = spi_async(ts->spi, &ts->msg);
389 dev_err(&ts->spi->dev, "spi_sync --> %d\n", status);
391 spin_unlock_irqrestore(&ts->lock, flags);
396 static void ad7877_callback(void *_ts)
398 struct ad7877 *ts = _ts;
400 spin_lock_irq(&ts->lock);
404 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
406 spin_unlock_irq(&ts->lock);
409 static void ad7877_disable(struct ad7877 *ts)
411 mutex_lock(&ts->mutex);
415 disable_irq(ts->spi->irq);
417 /* Wait for spi_async callback */
421 if (del_timer_sync(&ts->timer))
422 ad7877_ts_event_release(ts);
425 /* we know the chip's in lowpower mode since we always
426 * leave it that way after every request
429 mutex_unlock(&ts->mutex);
432 static void ad7877_enable(struct ad7877 *ts)
434 mutex_lock(&ts->mutex);
438 enable_irq(ts->spi->irq);
441 mutex_unlock(&ts->mutex);
444 #define SHOW(name) static ssize_t \
445 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
447 struct ad7877 *ts = dev_get_drvdata(dev); \
448 ssize_t v = ad7877_read_adc(ts->spi, \
449 AD7877_READ_CHAN(name)); \
452 return sprintf(buf, "%u\n", (unsigned) v); \
454 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
464 static ssize_t ad7877_disable_show(struct device *dev,
465 struct device_attribute *attr, char *buf)
467 struct ad7877 *ts = dev_get_drvdata(dev);
469 return sprintf(buf, "%u\n", ts->disabled);
472 static ssize_t ad7877_disable_store(struct device *dev,
473 struct device_attribute *attr,
474 const char *buf, size_t count)
476 struct ad7877 *ts = dev_get_drvdata(dev);
480 error = strict_strtoul(buf, 10, &val);
492 static DEVICE_ATTR(disable, 0664, ad7877_disable_show, ad7877_disable_store);
494 static ssize_t ad7877_dac_show(struct device *dev,
495 struct device_attribute *attr, char *buf)
497 struct ad7877 *ts = dev_get_drvdata(dev);
499 return sprintf(buf, "%u\n", ts->dac);
502 static ssize_t ad7877_dac_store(struct device *dev,
503 struct device_attribute *attr,
504 const char *buf, size_t count)
506 struct ad7877 *ts = dev_get_drvdata(dev);
510 error = strict_strtoul(buf, 10, &val);
514 mutex_lock(&ts->mutex);
515 ts->dac = val & 0xFF;
516 ad7877_write(ts->spi, AD7877_REG_DAC, (ts->dac << 4) | AD7877_DAC_CONF);
517 mutex_unlock(&ts->mutex);
522 static DEVICE_ATTR(dac, 0664, ad7877_dac_show, ad7877_dac_store);
524 static ssize_t ad7877_gpio3_show(struct device *dev,
525 struct device_attribute *attr, char *buf)
527 struct ad7877 *ts = dev_get_drvdata(dev);
529 return sprintf(buf, "%u\n", ts->gpio3);
532 static ssize_t ad7877_gpio3_store(struct device *dev,
533 struct device_attribute *attr,
534 const char *buf, size_t count)
536 struct ad7877 *ts = dev_get_drvdata(dev);
540 error = strict_strtoul(buf, 10, &val);
544 mutex_lock(&ts->mutex);
546 ad7877_write(ts->spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_DATA |
547 (ts->gpio4 << 4) | (ts->gpio3 << 5));
548 mutex_unlock(&ts->mutex);
553 static DEVICE_ATTR(gpio3, 0664, ad7877_gpio3_show, ad7877_gpio3_store);
555 static ssize_t ad7877_gpio4_show(struct device *dev,
556 struct device_attribute *attr, char *buf)
558 struct ad7877 *ts = dev_get_drvdata(dev);
560 return sprintf(buf, "%u\n", ts->gpio4);
563 static ssize_t ad7877_gpio4_store(struct device *dev,
564 struct device_attribute *attr,
565 const char *buf, size_t count)
567 struct ad7877 *ts = dev_get_drvdata(dev);
571 error = strict_strtoul(buf, 10, &val);
575 mutex_lock(&ts->mutex);
577 ad7877_write(ts->spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_DATA |
578 (ts->gpio4 << 4) | (ts->gpio3 << 5));
579 mutex_unlock(&ts->mutex);
584 static DEVICE_ATTR(gpio4, 0664, ad7877_gpio4_show, ad7877_gpio4_store);
586 static struct attribute *ad7877_attributes[] = {
587 &dev_attr_temp1.attr,
588 &dev_attr_temp2.attr,
593 &dev_attr_disable.attr,
595 &dev_attr_gpio4.attr,
599 static const struct attribute_group ad7877_attr_group = {
600 .attrs = ad7877_attributes,
603 static void ad7877_setup_ts_def_msg(struct spi_device *spi, struct ad7877 *ts)
605 struct spi_message *m;
608 ts->cmd_crtl2 = AD7877_WRITEADD(AD7877_REG_CTRL2) |
609 AD7877_POL(ts->stopacq_polarity) |
610 AD7877_AVG(ts->averaging) | AD7877_PM(1) |
611 AD7877_TMR(ts->pen_down_acc_interval) |
612 AD7877_ACQ(ts->acquisition_time) |
613 AD7877_FCD(ts->first_conversion_delay);
615 ad7877_write(spi, AD7877_REG_CTRL2, ts->cmd_crtl2);
617 ts->cmd_crtl1 = AD7877_WRITEADD(AD7877_REG_CTRL1) |
618 AD7877_READADD(AD7877_REG_XPLUS-1) |
619 AD7877_MODE_SEQ1 | AD7877_DFR;
621 ad7877_write(spi, AD7877_REG_CTRL1, ts->cmd_crtl1);
629 m->complete = ad7877_callback;
632 ts->xfer[0].tx_buf = &ts->cmd_crtl1;
635 spi_message_add_tail(&ts->xfer[0], m);
637 ts->xfer[1].tx_buf = &ts->cmd_dummy; /* Send ZERO */
640 spi_message_add_tail(&ts->xfer[1], m);
642 for (i = 0; i < 11; i++) {
643 ts->xfer[i + 2].rx_buf = &ts->conversion_data[AD7877_SEQ_YPOS + i];
644 ts->xfer[i + 2].len = 2;
645 spi_message_add_tail(&ts->xfer[i + 2], m);
649 static int __devinit ad7877_probe(struct spi_device *spi)
652 struct input_dev *input_dev;
653 struct ad7877_platform_data *pdata = spi->dev.platform_data;
658 dev_dbg(&spi->dev, "no IRQ?\n");
663 dev_dbg(&spi->dev, "no platform data?\n");
667 /* don't exceed max specified SPI CLK frequency */
668 if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
669 dev_dbg(&spi->dev, "SPI CLK %d Hz?\n",spi->max_speed_hz);
673 ts = kzalloc(sizeof(struct ad7877), GFP_KERNEL);
674 input_dev = input_allocate_device();
675 if (!ts || !input_dev) {
680 dev_set_drvdata(&spi->dev, ts);
682 ts->input = input_dev;
684 setup_timer(&ts->timer, ad7877_timer, (unsigned long) ts);
685 mutex_init(&ts->mutex);
686 spin_lock_init(&ts->lock);
688 ts->model = pdata->model ? : 7877;
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;
693 ts->stopacq_polarity = pdata->stopacq_polarity;
694 ts->first_conversion_delay = pdata->first_conversion_delay;
695 ts->acquisition_time = pdata->acquisition_time;
696 ts->averaging = pdata->averaging;
697 ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
699 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
701 input_dev->name = "AD7877 Touchscreen";
702 input_dev->phys = ts->phys;
703 input_dev->dev.parent = &spi->dev;
705 __set_bit(EV_ABS, input_dev->evbit);
706 __set_bit(ABS_X, input_dev->absbit);
707 __set_bit(ABS_Y, input_dev->absbit);
708 __set_bit(ABS_PRESSURE, input_dev->absbit);
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 ad7877_write(spi, AD7877_REG_SEQ1, AD7877_MM_SEQUENCE);
723 verify = ad7877_read(spi, AD7877_REG_SEQ1);
725 if (verify != AD7877_MM_SEQUENCE){
726 dev_err(&spi->dev, "%s: Failed to probe %s\n",
727 dev_name(&spi->dev), input_dev->name);
733 ad7877_write(spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_3_CONF);
735 ad7877_setup_ts_def_msg(spi, ts);
737 /* Request AD7877 /DAV GPIO interrupt */
739 err = request_irq(spi->irq, ad7877_irq, IRQF_TRIGGER_FALLING,
740 spi->dev.driver->name, ts);
742 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
746 err = sysfs_create_group(&spi->dev.kobj, &ad7877_attr_group);
750 err = device_create_file(&spi->dev,
751 gpio3 ? &dev_attr_gpio3 : &dev_attr_aux3);
753 goto err_remove_attr_group;
755 err = input_register_device(input_dev);
757 goto err_remove_attr;
762 device_remove_file(&spi->dev,
763 gpio3 ? &dev_attr_gpio3 : &dev_attr_aux3);
764 err_remove_attr_group:
765 sysfs_remove_group(&spi->dev.kobj, &ad7877_attr_group);
767 free_irq(spi->irq, ts);
769 input_free_device(input_dev);
771 dev_set_drvdata(&spi->dev, NULL);
775 static int __devexit ad7877_remove(struct spi_device *spi)
777 struct ad7877 *ts = dev_get_drvdata(&spi->dev);
779 sysfs_remove_group(&spi->dev.kobj, &ad7877_attr_group);
780 device_remove_file(&spi->dev,
781 gpio3 ? &dev_attr_gpio3 : &dev_attr_aux3);
784 free_irq(ts->spi->irq, ts);
786 input_unregister_device(ts->input);
789 dev_dbg(&spi->dev, "unregistered touchscreen\n");
790 dev_set_drvdata(&spi->dev, NULL);
796 static int ad7877_suspend(struct spi_device *spi, pm_message_t message)
798 struct ad7877 *ts = dev_get_drvdata(&spi->dev);
805 static int ad7877_resume(struct spi_device *spi)
807 struct ad7877 *ts = dev_get_drvdata(&spi->dev);
814 #define ad7877_suspend NULL
815 #define ad7877_resume NULL
818 static struct spi_driver ad7877_driver = {
821 .bus = &spi_bus_type,
822 .owner = THIS_MODULE,
824 .probe = ad7877_probe,
825 .remove = __devexit_p(ad7877_remove),
826 .suspend = ad7877_suspend,
827 .resume = ad7877_resume,
830 static int __init ad7877_init(void)
832 return spi_register_driver(&ad7877_driver);
834 module_init(ad7877_init);
836 static void __exit ad7877_exit(void)
838 spi_unregister_driver(&ad7877_driver);
840 module_exit(ad7877_exit);
842 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
843 MODULE_DESCRIPTION("AD7877 touchscreen Driver");
844 MODULE_LICENSE("GPL");