Input: ad7879 - split bus logic out

The ad7879 driver is using the old bus method of only supporting one
at a time (I2C or SPI). So refactor it like the other input drivers
that support multiple busses simultaneously.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 104 insertions, 396 deletions

diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
index f947457c858b..1de19691c4a3 100644
--- a/drivers/input/touchscreen/ad7879.c
+++ b/drivers/input/touchscreen/ad7879.c
@@ -1,25 +1,9 @@
 /*
- * Copyright (C) 2008-2009 Michael Hennerich, Analog Devices Inc.
+ * AD7879/AD7889 based touchscreen and GPIO driver
  *
- * Description: AD7879/AD7889 based touchscreen, and GPIO driver
- *              (I2C/SPI Interface)
+ * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
  *
- * 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
+ * Licensed under the GPL-2 or later.
  *
  * History:
  * Copyright (c) 2005 David Brownell
@@ -49,6 +33,7 @@
 #include <linux/gpio.h>
 
 #include <linux/spi/ad7879.h>
+#include "ad7879.h"
 
 #define AD7879_REG_ZEROS                0
 #define AD7879_REG_CTRL1                1
@@ -119,29 +104,18 @@ enum {
 #define MAX_12BIT                       ((1<<12)-1)
 #define TS_PEN_UP_TIMEOUT               msecs_to_jiffies(50)
 
-#if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
-#define AD7879_DEVID            0x7A
-typedef struct spi_device       bus_device;
-#elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
-#define AD7879_DEVID            0x79
-typedef struct i2c_client       bus_device;
-#endif
-
 struct ad7879 {
-        bus_device              *bus;
+        const struct ad7879_bus_ops *bops;
+
+        struct device           *dev;
         struct input_dev        *input;
         struct timer_list       timer;
 #ifdef CONFIG_GPIOLIB
         struct gpio_chip        gc;
 #endif
+        unsigned int            irq;
         struct mutex            mutex;
         bool                    disabled;       /* P: mutex */
-
-#if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
-        struct spi_message      msg;
-        struct spi_transfer     xfer[AD7879_NR_SENSE + 1];
-        u16                     cmd;
-#endif
         u16                     conversion_data[AD7879_NR_SENSE];
         char                    phys[32];
         u8                      first_conversion_delay;
@@ -156,9 +130,20 @@ struct ad7879 {
         u16                     cmd_crtl3;
 };
 
-static int ad7879_read(bus_device *, u8);
-static int ad7879_write(bus_device *, u8, u16);
-static void ad7879_collect(struct ad7879 *);
+static int ad7879_read(struct ad7879 *ts, u8 reg)
+{
+        return ts->bops->read(ts->dev, reg);
+}
+
+static int ad7879_multi_read(struct ad7879 *ts, u8 first_reg, u8 count, u16 *buf)
+{
+        return ts->bops->multi_read(ts->dev, first_reg, count, buf);
+}
+
+static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
+{
+        return ts->bops->write(ts->dev, reg, val);
+}
 
 static void ad7879_report(struct ad7879 *ts)
 {
@@ -173,12 +158,14 @@ static void ad7879_report(struct ad7879 *ts)
 
         /*
          * The samples processed here are already preprocessed by the AD7879.
-         * The preprocessing function consists of a median and an averaging filter.
-         * The combination of these two techniques provides a robust solution,
-         * discarding the spurious noise in the signal and keeping only the data of interest.
-         * The size of both filters is programmable. (dev.platform_data, see linux/spi/ad7879.h)
-         * Other user-programmable conversion controls include variable acquisition time,
-         * and first conversion delay. Up to 16 averages can be taken per conversion.
+         * The preprocessing function consists of a median and an averaging
+         * filter.  The combination of these two techniques provides a robust
+         * solution, discarding the spurious noise in the signal and keeping
+         * only the data of interest.  The size of both filters is
+         * programmable. (dev.platform_data, see linux/spi/ad7879.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)) {
@@ -213,7 +200,7 @@ static irqreturn_t ad7879_irq(int irq, void *handle)
 {
         struct ad7879 *ts = handle;
 
-        ad7879_collect(ts);
+        ad7879_multi_read(ts, AD7879_REG_XPLUS, AD7879_NR_SENSE, ts->conversion_data);
         ad7879_report(ts);
 
         mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
@@ -223,42 +210,44 @@ static irqreturn_t ad7879_irq(int irq, void *handle)
 
 static void ad7879_setup(struct ad7879 *ts)
 {
-        ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
-        ad7879_write(ts->bus, AD7879_REG_CTRL3, ts->cmd_crtl3);
-        ad7879_write(ts->bus, AD7879_REG_CTRL1, ts->cmd_crtl1);
+        ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
+        ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
 }
 
-static void ad7879_disable(struct ad7879 *ts)
+void ad7879_disable(struct ad7879 *ts)
 {
         mutex_lock(&ts->mutex);
 
         if (!ts->disabled) {
 
                 ts->disabled = true;
-                disable_irq(ts->bus->irq);
+                disable_irq(ts->irq);
 
                 if (del_timer_sync(&ts->timer))
                         ad7879_ts_event_release(ts);
 
-                ad7879_write(ts->bus, AD7879_REG_CTRL2,
+                ad7879_write(ts, AD7879_REG_CTRL2,
                              AD7879_PM(AD7879_PM_SHUTDOWN));
         }
 
         mutex_unlock(&ts->mutex);
 }
+EXPORT_SYMBOL(ad7879_disable);
 
-static void ad7879_enable(struct ad7879 *ts)
+void ad7879_enable(struct ad7879 *ts)
 {
         mutex_lock(&ts->mutex);
 
         if (ts->disabled) {
                 ad7879_setup(ts);
                 ts->disabled = false;
-                enable_irq(ts->bus->irq);
+                enable_irq(ts->irq);
         }
 
         mutex_unlock(&ts->mutex);
 }
+EXPORT_SYMBOL(ad7879_enable);
 
 static ssize_t ad7879_disable_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
@@ -308,7 +297,7 @@ static int ad7879_gpio_direction_input(struct gpio_chip *chip,
 
         mutex_lock(&ts->mutex);
         ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
-        err = ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
         mutex_unlock(&ts->mutex);
 
         return err;
@@ -328,7 +317,7 @@ static int ad7879_gpio_direction_output(struct gpio_chip *chip,
         else
                 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 
-        err = ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
         mutex_unlock(&ts->mutex);
 
         return err;
@@ -340,7 +329,7 @@ static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
         u16 val;
 
         mutex_lock(&ts->mutex);
-        val = ad7879_read(ts->bus, AD7879_REG_CTRL2);
+        val = ad7879_read(ts, AD7879_REG_CTRL2);
         mutex_unlock(&ts->mutex);
 
         return !!(val & AD7879_GPIO_DATA);
@@ -357,14 +346,13 @@ static void ad7879_gpio_set_value(struct gpio_chip *chip,
         else
                 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 
-        ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
         mutex_unlock(&ts->mutex);
 }
 
-static int __devinit ad7879_gpio_add(struct device *dev)
+static int ad7879_gpio_add(struct ad7879 *ts,
+                           const struct ad7879_platform_data *pdata)
 {
-        struct ad7879 *ts = dev_get_drvdata(dev);
-        struct ad7879_platform_data *pdata = dev->platform_data;
         int ret = 0;
 
         if (pdata->gpio_export) {
@@ -377,72 +365,78 @@ static int __devinit ad7879_gpio_add(struct device *dev)
                 ts->gc.ngpio = 1;
                 ts->gc.label = "AD7879-GPIO";
                 ts->gc.owner = THIS_MODULE;
-                ts->gc.dev = dev;
+                ts->gc.dev = ts->dev;
 
                 ret = gpiochip_add(&ts->gc);
                 if (ret)
-                        dev_err(dev, "failed to register gpio %d\n",
+                        dev_err(ts->dev, "failed to register gpio %d\n",
                                 ts->gc.base);
         }
 
         return ret;
 }
 
-/*
- * We mark ad7879_gpio_remove inline so there is a chance the code
- * gets discarded when not needed. We can't do __devinit/__devexit
- * markup since it is used in both probe and remove methods.
- */
-static inline void ad7879_gpio_remove(struct device *dev)
+static void ad7879_gpio_remove(struct ad7879 *ts)
 {
-        struct ad7879 *ts = dev_get_drvdata(dev);
-        struct ad7879_platform_data *pdata = dev->platform_data;
+        const struct ad7879_platform_data *pdata = ts->dev->platform_data;
         int ret;
 
         if (pdata->gpio_export) {
                 ret = gpiochip_remove(&ts->gc);
                 if (ret)
-                        dev_err(dev, "failed to remove gpio %d\n",
+                        dev_err(ts->dev, "failed to remove gpio %d\n",
                                 ts->gc.base);
         }
 }
 #else
-static inline int ad7879_gpio_add(struct device *dev)
+static inline int ad7879_gpio_add(struct ad7879 *ts,
+                                  const struct ad7879_platform_data *pdata)
 {
         return 0;
 }
 
-static inline void ad7879_gpio_remove(struct device *dev)
+static inline void ad7879_gpio_remove(struct ad7879 *ts)
 {
 }
 #endif
 
-static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
+struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
+                            const struct ad7879_bus_ops *bops)
 {
+        struct ad7879_platform_data *pdata = dev->platform_data;
+        struct ad7879 *ts;
         struct input_dev *input_dev;
-        struct ad7879_platform_data *pdata = bus->dev.platform_data;
         int err;
         u16 revid;
 
-        if (!bus->irq) {
-                dev_err(&bus->dev, "no IRQ?\n");
-                return -ENODEV;
+        if (!irq) {
+                dev_err(dev, "no IRQ?\n");
+                err = -EINVAL;
+                goto err_out;
         }
 
         if (!pdata) {
-                dev_err(&bus->dev, "no platform data?\n");
-                return -ENODEV;
+                dev_err(dev, "no platform data?\n");
+                err = -EINVAL;
+                goto err_out;
         }
 
+        ts = kzalloc(sizeof(*ts), GFP_KERNEL);
         input_dev = input_allocate_device();
-        if (!input_dev)
-                return -ENOMEM;
+        if (!ts || !input_dev) {
+                err = -ENOMEM;
+                goto err_free_mem;
+        }
 
+        ts->bops = bops;
+        ts->dev = dev;
         ts->input = input_dev;
 
         setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
         mutex_init(&ts->mutex);
 
+        ts->irq = irq;
+
         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
         ts->pressure_max = pdata->pressure_max ? : ~0;
 
@@ -452,11 +446,12 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
         ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
         ts->median = pdata->median;
 
-        snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&bus->dev));
+        snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
 
         input_dev->name = "AD7879 Touchscreen";
         input_dev->phys = ts->phys;
-        input_dev->dev.parent = &bus->dev;
+        input_dev->dev.parent = dev;
+        input_dev->id.bustype = bops->bustype;
 
         __set_bit(EV_ABS, input_dev->evbit);
         __set_bit(ABS_X, input_dev->absbit);
@@ -474,17 +469,18 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
         input_set_abs_params(input_dev, ABS_PRESSURE,
                         pdata->pressure_min, pdata->pressure_max, 0, 0);
 
-        err = ad7879_write(bus, AD7879_REG_CTRL2, AD7879_RESET);
-
+        err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
         if (err < 0) {
-                dev_err(&bus->dev, "Failed to write %s\n", input_dev->name);
+                dev_err(dev, "Failed to write %s\n", input_dev->name);
                 goto err_free_mem;
         }
 
-        revid = ad7879_read(bus, AD7879_REG_REVID);
-
-        if ((revid & 0xFF) != AD7879_DEVID) {
-                dev_err(&bus->dev, "Failed to probe %s\n", input_dev->name);
+        revid = ad7879_read(ts, AD7879_REG_REVID);
+        input_dev->id.product = (revid & 0xff);
+        input_dev->id.version = revid >> 8;
+        if (input_dev->id.product != devid) {
+                dev_err(dev, "Failed to probe %s (%x vs %x)\n",
+                        input_dev->name, devid, revid);
                 err = -ENODEV;
                 goto err_free_mem;
         }
@@ -508,19 +504,19 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
 
         ad7879_setup(ts);
 
-        err = request_threaded_irq(bus->irq, NULL, ad7879_irq,
+        err = request_threaded_irq(ts->irq, NULL, ad7879_irq,
                                    IRQF_TRIGGER_FALLING,
-                                   bus->dev.driver->name, ts);
+                                   dev_name(dev), ts);
         if (err) {
-                dev_err(&bus->dev, "irq %d busy?\n", bus->irq);
+                dev_err(dev, "irq %d busy?\n", ts->irq);
                 goto err_free_mem;
         }
 
-        err = sysfs_create_group(&bus->dev.kobj, &ad7879_attr_group);
+        err = sysfs_create_group(&dev->kobj, &ad7879_attr_group);
         if (err)
                 goto err_free_irq;
 
-        err = ad7879_gpio_add(&bus->dev);
+        err = ad7879_gpio_add(ts, pdata);
         if (err)
                 goto err_remove_attr;
 
@@ -528,321 +524,33 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
         if (err)
                 goto err_remove_gpio;
 
-        dev_info(&bus->dev, "Rev.%d touchscreen, irq %d\n",
-                 revid >> 8, bus->irq);
-
-        return 0;
+        return ts;
 
 err_remove_gpio:
-        ad7879_gpio_remove(&bus->dev);
+        ad7879_gpio_remove(ts);
 err_remove_attr:
-        sysfs_remove_group(&bus->dev.kobj, &ad7879_attr_group);
+        sysfs_remove_group(&dev->kobj, &ad7879_attr_group);
 err_free_irq:
-        free_irq(bus->irq, ts);
+        free_irq(ts->irq, ts);
 err_free_mem:
         input_free_device(input_dev);
-
-        return err;
+        kfree(ts);
+err_out:
+        return ERR_PTR(err);
 }
+EXPORT_SYMBOL(ad7879_probe);
 
-static int __devexit ad7879_destroy(bus_device *bus, struct ad7879 *ts)
+void ad7879_remove(struct ad7879 *ts)
 {
-        ad7879_gpio_remove(&bus->dev);
+        ad7879_gpio_remove(ts);
         ad7879_disable(ts);
-        sysfs_remove_group(&ts->bus->dev.kobj, &ad7879_attr_group);
-        free_irq(ts->bus->irq, ts);
+        sysfs_remove_group(&ts->dev->kobj, &ad7879_attr_group);
+        free_irq(ts->irq, ts);
         input_unregister_device(ts->input);
-        dev_dbg(&bus->dev, "unregistered touchscreen\n");
-
-        return 0;
-}
-
-#ifdef CONFIG_PM
-static int ad7879_suspend(bus_device *bus, pm_message_t message)
-{
-        struct ad7879 *ts = dev_get_drvdata(&bus->dev);
-
-        ad7879_disable(ts);
-
-        return 0;
-}
-
-static int ad7879_resume(bus_device *bus)
-{
-        struct ad7879 *ts = dev_get_drvdata(&bus->dev);
-
-        ad7879_enable(ts);
-
-        return 0;
-}
-#else
-#define ad7879_suspend NULL
-#define ad7879_resume  NULL
-#endif
-
-#if defined(CONFIG_TOUCHSCREEN_AD7879_SPI) || defined(CONFIG_TOUCHSCREEN_AD7879_SPI_MODULE)
-#define MAX_SPI_FREQ_HZ         5000000
-#define AD7879_CMD_MAGIC        0xE000
-#define AD7879_CMD_READ         (1 << 10)
-#define AD7879_WRITECMD(reg)    (AD7879_CMD_MAGIC | (reg & 0xF))
-#define AD7879_READCMD(reg)     (AD7879_CMD_MAGIC | AD7879_CMD_READ | (reg & 0xF))
-
-struct ser_req {
-        u16                     command;
-        u16                     data;
-        struct spi_message      msg;
-        struct spi_transfer     xfer[2];
-};
-
-/*
- * ad7879_read/write are only used for initial setup and for sysfs controls.
- * The main traffic is done in ad7879_collect().
- */
-
-static int ad7879_read(struct spi_device *spi, u8 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) AD7879_READCMD(reg);
-        req->xfer[0].tx_buf = &req->command;
-        req->xfer[0].len = 2;
-
-        req->xfer[1].rx_buf = &req->data;
-        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->data;
-
-        kfree(req);
-
-        return ret;
-}
-
-static int ad7879_write(struct spi_device *spi, u8 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) AD7879_WRITECMD(reg);
-        req->xfer[0].tx_buf = &req->command;
-        req->xfer[0].len = 2;
-
-        req->data = val;
-        req->xfer[1].tx_buf = &req->data;
-        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);
-
-        kfree(req);
-
-        return status;
-}
-
-static void ad7879_collect(struct ad7879 *ts)
-{
-        int status = spi_sync(ts->bus, &ts->msg);
-
-        if (status)
-                dev_err(&ts->bus->dev, "spi_sync --> %d\n", status);
-}
-
-static void ad7879_setup_ts_def_msg(struct ad7879 *ts)
-{
-        struct spi_message *m;
-        int i;
-
-        ts->cmd = (u16) AD7879_READCMD(AD7879_REG_XPLUS);
-
-        m = &ts->msg;
-        spi_message_init(m);
-        ts->xfer[0].tx_buf = &ts->cmd;
-        ts->xfer[0].len = 2;
-
-        spi_message_add_tail(&ts->xfer[0], m);
-
-        for (i = 0; i < AD7879_NR_SENSE; i++) {
-                ts->xfer[i + 1].rx_buf = &ts->conversion_data[i];
-                ts->xfer[i + 1].len = 2;
-                spi_message_add_tail(&ts->xfer[i + 1], m);
-        }
-}
-
-static int __devinit ad7879_probe(struct spi_device *spi)
-{
-        struct ad7879 *ts;
-        int error;
-
-        /* don't exceed max specified SPI CLK frequency */
-        if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
-                dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
-                return -EINVAL;
-        }
-
-        ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
-        if (!ts)
-                return -ENOMEM;
-
-        dev_set_drvdata(&spi->dev, ts);
-        ts->bus = spi;
-
-        ad7879_setup_ts_def_msg(ts);
-
-        error = ad7879_construct(spi, ts);
-        if (error) {
-                dev_set_drvdata(&spi->dev, NULL);
-                kfree(ts);
-        }
-
-        return error;
-}
-
-static int __devexit ad7879_remove(struct spi_device *spi)
-{
-        struct ad7879 *ts = dev_get_drvdata(&spi->dev);
-
-        ad7879_destroy(spi, ts);
-        dev_set_drvdata(&spi->dev, NULL);
         kfree(ts);
-
-        return 0;
 }
-
-static struct spi_driver ad7879_driver = {
-        .driver = {
-                .name   = "ad7879",
-                .bus    = &spi_bus_type,
-                .owner  = THIS_MODULE,
-        },
-        .probe          = ad7879_probe,
-        .remove         = __devexit_p(ad7879_remove),
-        .suspend        = ad7879_suspend,
-        .resume         = ad7879_resume,
-};
-
-static int __init ad7879_init(void)
-{
-        return spi_register_driver(&ad7879_driver);
-}
-module_init(ad7879_init);
-
-static void __exit ad7879_exit(void)
-{
-        spi_unregister_driver(&ad7879_driver);
-}
-module_exit(ad7879_exit);
-
-#elif defined(CONFIG_TOUCHSCREEN_AD7879_I2C) || defined(CONFIG_TOUCHSCREEN_AD7879_I2C_MODULE)
-
-/* All registers are word-sized.
- * AD7879 uses a high-byte first convention.
- */
-static int ad7879_read(struct i2c_client *client, u8 reg)
-{
-        return swab16(i2c_smbus_read_word_data(client, reg));
-}
-
-static int ad7879_write(struct i2c_client *client, u8 reg, u16 val)
-{
-        return i2c_smbus_write_word_data(client, reg, swab16(val));
-}
-
-static void ad7879_collect(struct ad7879 *ts)
-{
-        int i;
-
-        for (i = 0; i < AD7879_NR_SENSE; i++)
-                ts->conversion_data[i] = ad7879_read(ts->bus,
-                                                     AD7879_REG_XPLUS + i);
-}
-
-static int __devinit ad7879_probe(struct i2c_client *client,
-                                        const struct i2c_device_id *id)
-{
-        struct ad7879 *ts;
-        int error;
-
-        if (!i2c_check_functionality(client->adapter,
-                                        I2C_FUNC_SMBUS_WORD_DATA)) {
-                dev_err(&client->dev, "SMBUS Word Data not Supported\n");
-                return -EIO;
-        }
-
-        ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
-        if (!ts)
-                return -ENOMEM;
-
-        i2c_set_clientdata(client, ts);
-        ts->bus = client;
-
-        error = ad7879_construct(client, ts);
-        if (error)
-                kfree(ts);
-
-        return error;
-}
-
-static int __devexit ad7879_remove(struct i2c_client *client)
-{
-        struct ad7879 *ts = dev_get_drvdata(&client->dev);
-
-        ad7879_destroy(client, ts);
-        kfree(ts);
-
-        return 0;
-}
-
-static const struct i2c_device_id ad7879_id[] = {
-        { "ad7879", 0 },
-        { "ad7889", 0 },
-        { }
-};
-MODULE_DEVICE_TABLE(i2c, ad7879_id);
-
-static struct i2c_driver ad7879_driver = {
-        .driver = {
-                .name   = "ad7879",
-                .owner  = THIS_MODULE,
-        },
-        .probe          = ad7879_probe,
-        .remove         = __devexit_p(ad7879_remove),
-        .suspend        = ad7879_suspend,
-        .resume         = ad7879_resume,
-        .id_table       = ad7879_id,
-};
-
-static int __init ad7879_init(void)
-{
-        return i2c_add_driver(&ad7879_driver);
-}
-module_init(ad7879_init);
-
-static void __exit ad7879_exit(void)
-{
-        i2c_del_driver(&ad7879_driver);
-}
-module_exit(ad7879_exit);
-#endif
+EXPORT_SYMBOL(ad7879_remove);
 
 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("spi:ad7879");