Input: add AD7877 touchscreen driver
authorMichael Hennerich <michael.hennerich@analog.com>
Tue, 10 Mar 2009 03:12:52 +0000 (20:12 -0700)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Tue, 10 Mar 2009 03:13:32 +0000 (20:13 -0700)
[dtor@mail.ru: locking and other fixups]
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
drivers/input/touchscreen/Kconfig
drivers/input/touchscreen/Makefile
drivers/input/touchscreen/ad7877.c [new file with mode: 0644]

index a31d43494a8ddb29112d0e333d226eb3e7d128d0..afeb7554bfe2d0ea1efdcd5084ce9a39e6d7b833 100644 (file)
@@ -29,6 +29,19 @@ config TOUCHSCREEN_ADS7846
          To compile this driver as a module, choose M here: the
          module will be called ads7846.
 
+config TOUCHSCREEN_AD7877
+       tristate "AD7877 based touchscreens"
+       depends on SPI_MASTER
+       help
+         Say Y here if you have a touchscreen interface using the
+         AD7877 controller, and your board-specific initialization
+         code includes that in its table of SPI devices.
+
+         If unsure, say N (but it's safe to say "Y").
+
+         To compile this driver as a module, choose M here: the
+         module will be called ad7877.
+
 config TOUCHSCREEN_BITSY
        tristate "Compaq iPAQ H3600 (Bitsy) touchscreen"
        depends on SA1100_BITSY
index 82dd918a4dec91c695e0da36db4c7362b8a01bae..45dfcd61be110a9cfc3ed7889c3b34e8b992dcaa 100644 (file)
@@ -6,6 +6,7 @@
 
 wm97xx-ts-y := wm97xx-core.o
 
+obj-$(CONFIG_TOUCHSCREEN_AD7877)       += ad7877.o
 obj-$(CONFIG_TOUCHSCREEN_ADS7846)      += ads7846.o
 obj-$(CONFIG_TOUCHSCREEN_ATMEL_TSADCC) += atmel_tsadcc.o
 obj-$(CONFIG_TOUCHSCREEN_BITSY)                += h3600_ts_input.o
diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
new file mode 100644 (file)
index 0000000..e4728a2
--- /dev/null
@@ -0,0 +1,844 @@
+/*
+ * Copyright (C) 2006-2008 Michael Hennerich, Analog Devices Inc.
+ *
+ * Description:        AD7877 based touchscreen, sensor (ADCs), DAC and GPIO driver
+ * Based on:   ads7846.c
+ *
+ * Bugs:        Enter bugs at http://blackfin.uclinux.org/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * History:
+ * Copyright (c) 2005 David Brownell
+ * Copyright (c) 2006 Nokia Corporation
+ * Various changes: Imre Deak <imre.deak@nokia.com>
+ *
+ * Using code from:
+ *  - corgi_ts.c
+ *     Copyright (C) 2004-2005 Richard Purdie
+ *  - omap_ts.[hc], ads7846.h, ts_osk.c
+ *     Copyright (C) 2002 MontaVista Software
+ *     Copyright (C) 2004 Texas Instruments
+ *     Copyright (C) 2005 Dirk Behme
+ */
+
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/ad7877.h>
+#include <asm/irq.h>
+
+#define        TS_PEN_UP_TIMEOUT       msecs_to_jiffies(50)
+
+#define MAX_SPI_FREQ_HZ                        20000000
+#define        MAX_12BIT                       ((1<<12)-1)
+
+#define AD7877_REG_ZEROS                       0
+#define AD7877_REG_CTRL1                       1
+#define AD7877_REG_CTRL2                       2
+#define AD7877_REG_ALERT                       3
+#define AD7877_REG_AUX1HIGH                    4
+#define AD7877_REG_AUX1LOW                     5
+#define AD7877_REG_BAT1HIGH                    6
+#define AD7877_REG_BAT1LOW                     7
+#define AD7877_REG_BAT2HIGH                    8
+#define AD7877_REG_BAT2LOW                     9
+#define AD7877_REG_TEMP1HIGH                   10
+#define AD7877_REG_TEMP1LOW                    11
+#define AD7877_REG_SEQ0                                12
+#define AD7877_REG_SEQ1                                13
+#define AD7877_REG_DAC                         14
+#define AD7877_REG_NONE1                       15
+#define AD7877_REG_EXTWRITE                    15
+#define AD7877_REG_XPLUS                       16
+#define AD7877_REG_YPLUS                       17
+#define AD7877_REG_Z2                          18
+#define AD7877_REG_aux1                                19
+#define AD7877_REG_aux2                                20
+#define AD7877_REG_aux3                                21
+#define AD7877_REG_bat1                                22
+#define AD7877_REG_bat2                                23
+#define AD7877_REG_temp1                       24
+#define AD7877_REG_temp2                       25
+#define AD7877_REG_Z1                          26
+#define AD7877_REG_GPIOCTRL1                   27
+#define AD7877_REG_GPIOCTRL2                   28
+#define AD7877_REG_GPIODATA                    29
+#define AD7877_REG_NONE2                       30
+#define AD7877_REG_NONE3                       31
+
+#define AD7877_SEQ_YPLUS_BIT                   (1<<11)
+#define AD7877_SEQ_XPLUS_BIT                   (1<<10)
+#define AD7877_SEQ_Z2_BIT                      (1<<9)
+#define AD7877_SEQ_AUX1_BIT                    (1<<8)
+#define AD7877_SEQ_AUX2_BIT                    (1<<7)
+#define AD7877_SEQ_AUX3_BIT                    (1<<6)
+#define AD7877_SEQ_BAT1_BIT                    (1<<5)
+#define AD7877_SEQ_BAT2_BIT                    (1<<4)
+#define AD7877_SEQ_TEMP1_BIT                   (1<<3)
+#define AD7877_SEQ_TEMP2_BIT                   (1<<2)
+#define AD7877_SEQ_Z1_BIT                      (1<<1)
+
+enum {
+       AD7877_SEQ_YPOS  = 0,
+       AD7877_SEQ_XPOS  = 1,
+       AD7877_SEQ_Z2    = 2,
+       AD7877_SEQ_AUX1  = 3,
+       AD7877_SEQ_AUX2  = 4,
+       AD7877_SEQ_AUX3  = 5,
+       AD7877_SEQ_BAT1  = 6,
+       AD7877_SEQ_BAT2  = 7,
+       AD7877_SEQ_TEMP1 = 8,
+       AD7877_SEQ_TEMP2 = 9,
+       AD7877_SEQ_Z1    = 10,
+       AD7877_NR_SENSE  = 11,
+};
+
+/* DAC Register Default RANGE 0 to Vcc, Volatge Mode, DAC On */
+#define AD7877_DAC_CONF                        0x1
+
+/* If gpio3 is set AUX3/GPIO3 acts as GPIO Output */
+#define AD7877_EXTW_GPIO_3_CONF                0x1C4
+#define AD7877_EXTW_GPIO_DATA          0x200
+
+/* Control REG 2 */
+#define AD7877_TMR(x)                  ((x & 0x3) << 0)
+#define AD7877_REF(x)                  ((x & 0x1) << 2)
+#define AD7877_POL(x)                  ((x & 0x1) << 3)
+#define AD7877_FCD(x)                  ((x & 0x3) << 4)
+#define AD7877_PM(x)                   ((x & 0x3) << 6)
+#define AD7877_ACQ(x)                  ((x & 0x3) << 8)
+#define AD7877_AVG(x)                  ((x & 0x3) << 10)
+
+/* Control REG 1 */
+#define        AD7877_SER                      (1 << 11)       /* non-differential */
+#define        AD7877_DFR                      (0 << 11)       /* differential */
+
+#define AD7877_MODE_NOC  (0)   /* Do not convert */
+#define AD7877_MODE_SCC  (1)   /* Single channel conversion */
+#define AD7877_MODE_SEQ0 (2)   /* Sequence 0 in Slave Mode */
+#define AD7877_MODE_SEQ1 (3)   /* Sequence 1 in Master Mode */
+
+#define AD7877_CHANADD(x)              ((x&0xF)<<7)
+#define AD7877_READADD(x)              ((x)<<2)
+#define AD7877_WRITEADD(x)             ((x)<<12)
+
+#define AD7877_READ_CHAN(x) (AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_SER | \
+               AD7877_MODE_SCC | AD7877_CHANADD(AD7877_REG_ ## x) | \
+               AD7877_READADD(AD7877_REG_ ## x))
+
+#define AD7877_MM_SEQUENCE (AD7877_SEQ_YPLUS_BIT | AD7877_SEQ_XPLUS_BIT | \
+               AD7877_SEQ_Z2_BIT | AD7877_SEQ_Z1_BIT)
+
+/*
+ * Non-touchscreen sensors only use single-ended conversions.
+ */
+
+struct ser_req {
+       u16                     reset;
+       u16                     ref_on;
+       u16                     command;
+       u16                     sample;
+       struct spi_message      msg;
+       struct spi_transfer     xfer[6];
+};
+
+struct ad7877 {
+       struct input_dev        *input;
+       char                    phys[32];
+
+       struct spi_device       *spi;
+       u16                     model;
+       u16                     vref_delay_usecs;
+       u16                     x_plate_ohms;
+       u16                     pressure_max;
+
+       u16                     cmd_crtl1;
+       u16                     cmd_crtl2;
+       u16                     cmd_dummy;
+       u16                     dac;
+
+       u8                      stopacq_polarity;
+       u8                      first_conversion_delay;
+       u8                      acquisition_time;
+       u8                      averaging;
+       u8                      pen_down_acc_interval;
+
+       u16                     conversion_data[AD7877_NR_SENSE];
+
+       struct spi_transfer     xfer[AD7877_NR_SENSE + 2];
+       struct spi_message      msg;
+
+       struct mutex            mutex;
+       unsigned                disabled:1;     /* P: mutex */
+       unsigned                gpio3:1;        /* P: mutex */
+       unsigned                gpio4:1;        /* P: mutex */
+
+       spinlock_t              lock;
+       struct timer_list       timer;          /* P: lock */
+       unsigned                pending:1;      /* P: lock */
+};
+
+static int gpio3;
+module_param(gpio3, int, 0);
+MODULE_PARM_DESC(gpio3, "If gpio3 is set to 1 AUX3 acts as GPIO3");
+
+/*
+ * ad7877_read/write are only used for initial setup and for sysfs controls.
+ * The main traffic is done using spi_async() in the interrupt handler.
+ */
+
+static int ad7877_read(struct spi_device *spi, u16 reg)
+{
+       struct ser_req *req;
+       int status, ret;
+
+       req = kzalloc(sizeof *req, GFP_KERNEL);
+       if (!req)
+               return -ENOMEM;
+
+       spi_message_init(&req->msg);
+
+       req->command = (u16) (AD7877_WRITEADD(AD7877_REG_CTRL1) |
+                       AD7877_READADD(reg));
+       req->xfer[0].tx_buf = &req->command;
+       req->xfer[0].len = 2;
+
+       req->xfer[1].rx_buf = &req->sample;
+       req->xfer[1].len = 2;
+
+       spi_message_add_tail(&req->xfer[0], &req->msg);
+       spi_message_add_tail(&req->xfer[1], &req->msg);
+
+       status = spi_sync(spi, &req->msg);
+       ret = status ? : req->sample;
+
+       kfree(req);
+
+       return ret;
+}
+
+static int ad7877_write(struct spi_device *spi, u16 reg, u16 val)
+{
+       struct ser_req *req;
+       int status;
+
+       req = kzalloc(sizeof *req, GFP_KERNEL);
+       if (!req)
+               return -ENOMEM;
+
+       spi_message_init(&req->msg);
+
+       req->command = (u16) (AD7877_WRITEADD(reg) | (val & MAX_12BIT));
+       req->xfer[0].tx_buf = &req->command;
+       req->xfer[0].len = 2;
+
+       spi_message_add_tail(&req->xfer[0], &req->msg);
+
+       status = spi_sync(spi, &req->msg);
+
+       kfree(req);
+
+       return status;
+}
+
+static int ad7877_read_adc(struct spi_device *spi, unsigned command)
+{
+       struct ad7877 *ts = dev_get_drvdata(&spi->dev);
+       struct ser_req *req;
+       int status;
+       int sample;
+       int i;
+
+       req = kzalloc(sizeof *req, GFP_KERNEL);
+       if (!req)
+               return -ENOMEM;
+
+       spi_message_init(&req->msg);
+
+       /* activate reference, so it has time to settle; */
+       req->ref_on = AD7877_WRITEADD(AD7877_REG_CTRL2) |
+                        AD7877_POL(ts->stopacq_polarity) |
+                        AD7877_AVG(0) | AD7877_PM(2) | AD7877_TMR(0) |
+                        AD7877_ACQ(ts->acquisition_time) | AD7877_FCD(0);
+
+       req->reset = AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_MODE_NOC;
+
+       req->command = (u16) command;
+
+       req->xfer[0].tx_buf = &req->reset;
+       req->xfer[0].len = 2;
+
+       req->xfer[1].tx_buf = &req->ref_on;
+       req->xfer[1].len = 2;
+       req->xfer[1].delay_usecs = ts->vref_delay_usecs;
+
+       req->xfer[2].tx_buf = &req->command;
+       req->xfer[2].len = 2;
+       req->xfer[2].delay_usecs = ts->vref_delay_usecs;
+
+       req->xfer[3].rx_buf = &req->sample;
+       req->xfer[3].len = 2;
+
+       req->xfer[4].tx_buf = &ts->cmd_crtl2;   /*REF OFF*/
+       req->xfer[4].len = 2;
+
+       req->xfer[5].tx_buf = &ts->cmd_crtl1;   /*DEFAULT*/
+       req->xfer[5].len = 2;
+
+       /* group all the transfers together, so we can't interfere with
+        * reading touchscreen state; disable penirq while sampling
+        */
+       for (i = 0; i < 6; i++)
+               spi_message_add_tail(&req->xfer[i], &req->msg);
+
+       status = spi_sync(spi, &req->msg);
+       sample = req->sample;
+
+       kfree(req);
+
+       return status ? : sample;
+}
+
+static void ad7877_rx(struct ad7877 *ts)
+{
+       struct input_dev *input_dev = ts->input;
+       unsigned Rt;
+       u16 x, y, z1, z2;
+
+       x = ts->conversion_data[AD7877_SEQ_XPOS] & MAX_12BIT;
+       y = ts->conversion_data[AD7877_SEQ_YPOS] & MAX_12BIT;
+       z1 = ts->conversion_data[AD7877_SEQ_Z1] & MAX_12BIT;
+       z2 = ts->conversion_data[AD7877_SEQ_Z2] & MAX_12BIT;
+
+       /*
+        * The samples processed here are already preprocessed by the AD7877.
+        * The preprocessing function consists of an averaging filter.
+        * The combination of 'first conversion delay' and averaging provides a robust solution,
+        * discarding the spurious noise in the signal and keeping only the data of interest.
+        * The size of the averaging filter is programmable. (dev.platform_data, see linux/spi/ad7877.h)
+        * Other user-programmable conversion controls include variable acquisition time,
+        * and first conversion delay. Up to 16 averages can be taken per conversion.
+        */
+
+       if (likely(x && z1)) {
+               /* compute touch pressure resistance using equation #1 */
+               Rt = (z2 - z1) * x * ts->x_plate_ohms;
+               Rt /= z1;
+               Rt = (Rt + 2047) >> 12;
+
+               input_report_abs(input_dev, ABS_X, x);
+               input_report_abs(input_dev, ABS_Y, y);
+               input_report_abs(input_dev, ABS_PRESSURE, Rt);
+               input_sync(input_dev);
+       }
+}
+
+static inline void ad7877_ts_event_release(struct ad7877 *ts)
+{
+       struct input_dev *input_dev = ts->input;
+
+       input_report_abs(input_dev, ABS_PRESSURE, 0);
+       input_sync(input_dev);
+}
+
+static void ad7877_timer(unsigned long handle)
+{
+       struct ad7877 *ts = (void *)handle;
+
+       ad7877_ts_event_release(ts);
+}
+
+static irqreturn_t ad7877_irq(int irq, void *handle)
+{
+       struct ad7877 *ts = handle;
+       unsigned long flags;
+       int status;
+
+       /*
+        * The repeated conversion sequencer controlled by TMR kicked off
+        * too fast. We ignore the last and process the sample sequence
+        * currently in the queue. It can't be older than 9.4ms, and we
+        * need to avoid that ts->msg doesn't get issued twice while in work.
+        */
+
+       spin_lock_irqsave(&ts->lock, flags);
+       if (!ts->pending) {
+               ts->pending = 1;
+
+               status = spi_async(ts->spi, &ts->msg);
+               if (status)
+                       dev_err(&ts->spi->dev, "spi_sync --> %d\n", status);
+       }
+       spin_unlock_irqrestore(&ts->lock, flags);
+
+       return IRQ_HANDLED;
+}
+
+static void ad7877_callback(void *_ts)
+{
+       struct ad7877 *ts = _ts;
+
+       spin_lock_irq(&ts->lock);
+
+       ad7877_rx(ts);
+       ts->pending = 0;
+       mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
+
+       spin_unlock_irq(&ts->lock);
+}
+
+static void ad7877_disable(struct ad7877 *ts)
+{
+       mutex_lock(&ts->mutex);
+
+       if (!ts->disabled) {
+               ts->disabled = 1;
+               disable_irq(ts->spi->irq);
+
+               /* Wait for spi_async callback */
+               while (ts->pending)
+                       msleep(1);
+
+               if (del_timer_sync(&ts->timer))
+                       ad7877_ts_event_release(ts);
+       }
+
+       /* we know the chip's in lowpower mode since we always
+        * leave it that way after every request
+        */
+
+       mutex_unlock(&ts->mutex);
+}
+
+static void ad7877_enable(struct ad7877 *ts)
+{
+       mutex_lock(&ts->mutex);
+
+       if (ts->disabled) {
+               ts->disabled = 0;
+               enable_irq(ts->spi->irq);
+       }
+
+       mutex_unlock(&ts->mutex);
+}
+
+#define SHOW(name) static ssize_t \
+name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
+{ \
+       struct ad7877   *ts = dev_get_drvdata(dev); \
+       ssize_t v = ad7877_read_adc(ts->spi, \
+                       AD7877_READ_CHAN(name)); \
+       if (v < 0) \
+               return v; \
+       return sprintf(buf, "%u\n", (unsigned) v); \
+} \
+static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
+
+SHOW(aux1)
+SHOW(aux2)
+SHOW(aux3)
+SHOW(bat1)
+SHOW(bat2)
+SHOW(temp1)
+SHOW(temp2)
+
+static ssize_t ad7877_disable_show(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+       struct ad7877   *ts = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%u\n", ts->disabled);
+}
+
+static ssize_t ad7877_disable_store(struct device *dev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t count)
+{
+       struct ad7877 *ts = dev_get_drvdata(dev);
+       unsigned long val;
+       int error;
+
+       error = strict_strtoul(buf, 10, &val);
+       if (error)
+               return error;
+
+       if (val)
+               ad7877_disable(ts);
+       else
+               ad7877_enable(ts);
+
+       return count;
+}
+
+static DEVICE_ATTR(disable, 0664, ad7877_disable_show, ad7877_disable_store);
+
+static ssize_t ad7877_dac_show(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+       struct ad7877   *ts = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%u\n", ts->dac);
+}
+
+static ssize_t ad7877_dac_store(struct device *dev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t count)
+{
+       struct ad7877 *ts = dev_get_drvdata(dev);
+       unsigned long val;
+       int error;
+
+       error = strict_strtoul(buf, 10, &val);
+       if (error)
+               return error;
+
+       mutex_lock(&ts->mutex);
+       ts->dac = val & 0xFF;
+       ad7877_write(ts->spi, AD7877_REG_DAC, (ts->dac << 4) | AD7877_DAC_CONF);
+       mutex_unlock(&ts->mutex);
+
+       return count;
+}
+
+static DEVICE_ATTR(dac, 0664, ad7877_dac_show, ad7877_dac_store);
+
+static ssize_t ad7877_gpio3_show(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+       struct ad7877   *ts = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%u\n", ts->gpio3);
+}
+
+static ssize_t ad7877_gpio3_store(struct device *dev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t count)
+{
+       struct ad7877 *ts = dev_get_drvdata(dev);
+       unsigned long val;
+       int error;
+
+       error = strict_strtoul(buf, 10, &val);
+       if (error)
+               return error;
+
+       mutex_lock(&ts->mutex);
+       ts->gpio3 = !!val;
+       ad7877_write(ts->spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_DATA |
+                (ts->gpio4 << 4) | (ts->gpio3 << 5));
+       mutex_unlock(&ts->mutex);
+
+       return count;
+}
+
+static DEVICE_ATTR(gpio3, 0664, ad7877_gpio3_show, ad7877_gpio3_store);
+
+static ssize_t ad7877_gpio4_show(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+       struct ad7877   *ts = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%u\n", ts->gpio4);
+}
+
+static ssize_t ad7877_gpio4_store(struct device *dev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t count)
+{
+       struct ad7877 *ts = dev_get_drvdata(dev);
+       unsigned long val;
+       int error;
+
+       error = strict_strtoul(buf, 10, &val);
+       if (error)
+               return error;
+
+       mutex_lock(&ts->mutex);
+       ts->gpio4 = !!val;
+       ad7877_write(ts->spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_DATA |
+                    (ts->gpio4 << 4) | (ts->gpio3 << 5));
+       mutex_unlock(&ts->mutex);
+
+       return count;
+}
+
+static DEVICE_ATTR(gpio4, 0664, ad7877_gpio4_show, ad7877_gpio4_store);
+
+static struct attribute *ad7877_attributes[] = {
+       &dev_attr_temp1.attr,
+       &dev_attr_temp2.attr,
+       &dev_attr_aux1.attr,
+       &dev_attr_aux2.attr,
+       &dev_attr_bat1.attr,
+       &dev_attr_bat2.attr,
+       &dev_attr_disable.attr,
+       &dev_attr_dac.attr,
+       &dev_attr_gpio4.attr,
+       NULL
+};
+
+static const struct attribute_group ad7877_attr_group = {
+       .attrs = ad7877_attributes,
+};
+
+static void ad7877_setup_ts_def_msg(struct spi_device *spi, struct ad7877 *ts)
+{
+       struct spi_message *m;
+       int i;
+
+       ts->cmd_crtl2 = AD7877_WRITEADD(AD7877_REG_CTRL2) |
+                       AD7877_POL(ts->stopacq_polarity) |
+                       AD7877_AVG(ts->averaging) | AD7877_PM(1) |
+                       AD7877_TMR(ts->pen_down_acc_interval) |
+                       AD7877_ACQ(ts->acquisition_time) |
+                       AD7877_FCD(ts->first_conversion_delay);
+
+       ad7877_write(spi, AD7877_REG_CTRL2, ts->cmd_crtl2);
+
+       ts->cmd_crtl1 = AD7877_WRITEADD(AD7877_REG_CTRL1) |
+                       AD7877_READADD(AD7877_REG_XPLUS-1) |
+                       AD7877_MODE_SEQ1 | AD7877_DFR;
+
+       ad7877_write(spi, AD7877_REG_CTRL1, ts->cmd_crtl1);
+
+       ts->cmd_dummy = 0;
+
+       m = &ts->msg;
+
+       spi_message_init(m);
+
+       m->complete = ad7877_callback;
+       m->context = ts;
+
+       ts->xfer[0].tx_buf = &ts->cmd_crtl1;
+       ts->xfer[0].len = 2;
+
+       spi_message_add_tail(&ts->xfer[0], m);
+
+       ts->xfer[1].tx_buf = &ts->cmd_dummy; /* Send ZERO */
+       ts->xfer[1].len = 2;
+
+       spi_message_add_tail(&ts->xfer[1], m);
+
+       for (i = 0; i < 11; i++) {
+               ts->xfer[i + 2].rx_buf = &ts->conversion_data[AD7877_SEQ_YPOS + i];
+               ts->xfer[i + 2].len = 2;
+               spi_message_add_tail(&ts->xfer[i + 2], m);
+       }
+}
+
+static int __devinit ad7877_probe(struct spi_device *spi)
+{
+       struct ad7877                   *ts;
+       struct input_dev                *input_dev;
+       struct ad7877_platform_data     *pdata = spi->dev.platform_data;
+       int                             err;
+       u16                             verify;
+
+       if (!spi->irq) {
+               dev_dbg(&spi->dev, "no IRQ?\n");
+               return -ENODEV;
+       }
+
+       if (!pdata) {
+               dev_dbg(&spi->dev, "no platform data?\n");
+               return -ENODEV;
+       }
+
+       /* don't exceed max specified SPI CLK frequency */
+       if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
+               dev_dbg(&spi->dev, "SPI CLK %d Hz?\n",spi->max_speed_hz);
+               return -EINVAL;
+       }
+
+       ts = kzalloc(sizeof(struct ad7877), GFP_KERNEL);
+       input_dev = input_allocate_device();
+       if (!ts || !input_dev) {
+               err = -ENOMEM;
+               goto err_free_mem;
+       }
+
+       dev_set_drvdata(&spi->dev, ts);
+       ts->spi = spi;
+       ts->input = input_dev;
+
+       setup_timer(&ts->timer, ad7877_timer, (unsigned long) ts);
+       mutex_init(&ts->mutex);
+       spin_lock_init(&ts->lock);
+
+       ts->model = pdata->model ? : 7877;
+       ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
+       ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
+       ts->pressure_max = pdata->pressure_max ? : ~0;
+
+       ts->stopacq_polarity = pdata->stopacq_polarity;
+       ts->first_conversion_delay = pdata->first_conversion_delay;
+       ts->acquisition_time = pdata->acquisition_time;
+       ts->averaging = pdata->averaging;
+       ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
+
+       snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
+
+       input_dev->name = "AD7877 Touchscreen";
+       input_dev->phys = ts->phys;
+       input_dev->dev.parent = &spi->dev;
+
+       __set_bit(EV_ABS, input_dev->evbit);
+       __set_bit(ABS_X, input_dev->absbit);
+       __set_bit(ABS_Y, input_dev->absbit);
+       __set_bit(ABS_PRESSURE, input_dev->absbit);
+
+       input_set_abs_params(input_dev, ABS_X,
+                       pdata->x_min ? : 0,
+                       pdata->x_max ? : MAX_12BIT,
+                       0, 0);
+       input_set_abs_params(input_dev, ABS_Y,
+                       pdata->y_min ? : 0,
+                       pdata->y_max ? : MAX_12BIT,
+                       0, 0);
+       input_set_abs_params(input_dev, ABS_PRESSURE,
+                       pdata->pressure_min, pdata->pressure_max, 0, 0);
+
+       ad7877_write(spi, AD7877_REG_SEQ1, AD7877_MM_SEQUENCE);
+
+       verify = ad7877_read(spi, AD7877_REG_SEQ1);
+
+       if (verify != AD7877_MM_SEQUENCE){
+               dev_err(&spi->dev, "%s: Failed to probe %s\n",
+                       dev_name(&spi->dev), input_dev->name);
+               err = -ENODEV;
+               goto err_free_mem;
+       }
+
+       if (gpio3)
+               ad7877_write(spi, AD7877_REG_EXTWRITE, AD7877_EXTW_GPIO_3_CONF);
+
+       ad7877_setup_ts_def_msg(spi, ts);
+
+       /* Request AD7877 /DAV GPIO interrupt */
+
+       err = request_irq(spi->irq, ad7877_irq, IRQF_TRIGGER_FALLING |
+                       IRQF_SAMPLE_RANDOM, spi->dev.driver->name, ts);
+       if (err) {
+               dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
+               goto err_free_mem;
+       }
+
+       err = sysfs_create_group(&spi->dev.kobj, &ad7877_attr_group);
+       if (err)
+               goto err_free_irq;
+
+       err = device_create_file(&spi->dev,
+                                gpio3 ? &dev_attr_gpio3 : &dev_attr_aux3);
+       if (err)
+               goto err_remove_attr_group;
+
+       err = input_register_device(input_dev);
+       if (err)
+               goto err_remove_attr;
+
+       return 0;
+
+err_remove_attr:
+       device_remove_file(&spi->dev,
+                          gpio3 ? &dev_attr_gpio3 : &dev_attr_aux3);
+err_remove_attr_group:
+       sysfs_remove_group(&spi->dev.kobj, &ad7877_attr_group);
+err_free_irq:
+       free_irq(spi->irq, ts);
+err_free_mem:
+       input_free_device(input_dev);
+       kfree(ts);
+       dev_set_drvdata(&spi->dev, NULL);
+       return err;
+}
+
+static int __devexit ad7877_remove(struct spi_device *spi)
+{
+       struct ad7877           *ts = dev_get_drvdata(&spi->dev);
+
+       sysfs_remove_group(&spi->dev.kobj, &ad7877_attr_group);
+       device_remove_file(&spi->dev,
+                          gpio3 ? &dev_attr_gpio3 : &dev_attr_aux3);
+
+       ad7877_disable(ts);
+       free_irq(ts->spi->irq, ts);
+
+       input_unregister_device(ts->input);
+       kfree(ts);
+
+       dev_dbg(&spi->dev, "unregistered touchscreen\n");
+       dev_set_drvdata(&spi->dev, NULL);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM
+static int ad7877_suspend(struct spi_device *spi, pm_message_t message)
+{
+       struct ad7877 *ts = dev_get_drvdata(&spi->dev);
+
+       ad7877_disable(ts);
+
+       return 0;
+}
+
+static int ad7877_resume(struct spi_device *spi)
+{
+       struct ad7877 *ts = dev_get_drvdata(&spi->dev);
+
+       ad7877_enable(ts);
+
+       return 0;
+}
+#else
+#define ad7877_suspend NULL
+#define ad7877_resume  NULL
+#endif
+
+static struct spi_driver ad7877_driver = {
+       .driver = {
+               .name   = "ad7877",
+               .bus    = &spi_bus_type,
+               .owner  = THIS_MODULE,
+       },
+       .probe          = ad7877_probe,
+       .remove         = __devexit_p(ad7877_remove),
+       .suspend        = ad7877_suspend,
+       .resume         = ad7877_resume,
+};
+
+static int __init ad7877_init(void)
+{
+       return spi_register_driver(&ad7877_driver);
+}
+module_init(ad7877_init);
+
+static void __exit ad7877_exit(void)
+{
+       spi_unregister_driver(&ad7877_driver);
+}
+module_exit(ad7877_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("AD7877 touchscreen Driver");
+MODULE_LICENSE("GPL");