3 files changed, 806 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 90e8e92dfe47..a95a87cd1d59 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -185,6 +185,20 @@ config TOUCHSCREEN_UCB1400
           To compile this driver as a module, choose M here: the
           module will be called ucb1400_ts.
 
+config TOUCHSCREEN_WM97XX
+        tristate "Support for WM97xx AC97 touchscreen controllers"
+        depends on AC97_BUS
+        help
+          Say Y here if you have a Wolfson Microelectronics WM97xx
+          touchscreen connected to your system. Note that this option
+          only enables core driver, you will also need to select
+          support for appropriate chip below.
+
+          If unsure, say N.
+
+          To compile this driver as a module, choose M here: the
+          module will be called wm97xx-ts.
+
 config TOUCHSCREEN_USB_COMPOSITE
         tristate "USB Touchscreen Driver"
         depends on USB_ARCH_HAS_HCD
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 35d4097df35a..b4e7b5dbf649 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -4,6 +4,8 @@
 
 # Each configuration option enables a list of files.
 
+wm97xx-ts-y := wm97xx-core.o
+
 obj-$(CONFIG_TOUCHSCREEN_ADS7846)       += ads7846.o
 obj-$(CONFIG_TOUCHSCREEN_BITSY)         += h3600_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_CORGI)         += corgi_ts.o
@@ -19,3 +21,4 @@ obj-$(CONFIG_TOUCHSCREEN_PENMOUNT)	+= penmount.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)    += touchright.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)      += touchwin.o
 obj-$(CONFIG_TOUCHSCREEN_UCB1400)       += ucb1400_ts.o
+obj-$(CONFIG_TOUCHSCREEN_WM97XX)        += wm97xx-ts.o
diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c
new file mode 100644
index 000000000000..2910999e05a0
--- /dev/null
+++ b/drivers/input/touchscreen/wm97xx-core.c
@@ -0,0 +1,789 @@
+/*
+ * wm97xx-core.c  --  Touch screen driver core for Wolfson WM9705, WM9712
+ *                    and WM9713 AC97 Codecs.
+ *
+ * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
+ * Author: Liam Girdwood
+ *         liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
+ * Parts Copyright : Ian Molton <spyro@f2s.com>
+ *                   Andrew Zabolotny <zap@homelink.ru>
+ *                   Russell King <rmk@arm.linux.org.uk>
+ *
+ *  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.
+ *
+ * Notes:
+ *
+ *  Features:
+ *       - supports WM9705, WM9712, WM9713
+ *       - polling mode
+ *       - continuous mode (arch-dependent)
+ *       - adjustable rpu/dpp settings
+ *       - adjustable pressure current
+ *       - adjustable sample settle delay
+ *       - 4 and 5 wire touchscreens (5 wire is WM9712 only)
+ *       - pen down detection
+ *       - battery monitor
+ *       - sample AUX adcs
+ *       - power management
+ *       - codec GPIO
+ *       - codec event notification
+ * Todo
+ *       - Support for async sampling control for noisy LCDs.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/string.h>
+#include <linux/proc_fs.h>
+#include <linux/pm.h>
+#include <linux/interrupt.h>
+#include <linux/bitops.h>
+#include <linux/workqueue.h>
+#include <linux/wm97xx.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#define TS_NAME                 "wm97xx"
+#define WM_CORE_VERSION         "1.00"
+#define DEFAULT_PRESSURE        0xb0c0
+
+
+/*
+ * Touchscreen absolute values
+ *
+ * These parameters are used to help the input layer discard out of
+ * range readings and reduce jitter etc.
+ *
+ *   o min, max:- indicate the min and max values your touch screen returns
+ *   o fuzz:- use a higher number to reduce jitter
+ *
+ * The default values correspond to Mainstone II in QVGA mode
+ *
+ * Please read
+ * Documentation/input/input-programming.txt for more details.
+ */
+
+static int abs_x[3] = {350, 3900, 5};
+module_param_array(abs_x, int, NULL, 0);
+MODULE_PARM_DESC(abs_x, "Touchscreen absolute X min, max, fuzz");
+
+static int abs_y[3] = {320, 3750, 40};
+module_param_array(abs_y, int, NULL, 0);
+MODULE_PARM_DESC(abs_y, "Touchscreen absolute Y min, max, fuzz");
+
+static int abs_p[3] = {0, 150, 4};
+module_param_array(abs_p, int, NULL, 0);
+MODULE_PARM_DESC(abs_p, "Touchscreen absolute Pressure min, max, fuzz");
+
+/*
+ * wm97xx IO access, all IO locking done by AC97 layer
+ */
+int wm97xx_reg_read(struct wm97xx *wm, u16 reg)
+{
+        if (wm->ac97)
+                return wm->ac97->bus->ops->read(wm->ac97, reg);
+        else
+                return -1;
+}
+EXPORT_SYMBOL_GPL(wm97xx_reg_read);
+
+void wm97xx_reg_write(struct wm97xx *wm, u16 reg, u16 val)
+{
+        /* cache digitiser registers */
+        if (reg >= AC97_WM9713_DIG1 && reg <= AC97_WM9713_DIG3)
+                wm->dig[(reg - AC97_WM9713_DIG1) >> 1] = val;
+
+        /* cache gpio regs */
+        if (reg >= AC97_GPIO_CFG && reg <= AC97_MISC_AFE)
+                wm->gpio[(reg - AC97_GPIO_CFG) >> 1] = val;
+
+        /* wm9713 irq reg */
+        if (reg == 0x5a)
+                wm->misc = val;
+
+        if (wm->ac97)
+                wm->ac97->bus->ops->write(wm->ac97, reg, val);
+}
+EXPORT_SYMBOL_GPL(wm97xx_reg_write);
+
+/**
+ * wm97xx_read_aux_adc - Read the aux adc.
+ * @wm: wm97xx device.
+ * @adcsel: codec ADC to be read
+ *
+ * Reads the selected AUX ADC.
+ */
+
+int wm97xx_read_aux_adc(struct wm97xx *wm, u16 adcsel)
+{
+        int power_adc = 0, auxval;
+        u16 power = 0;
+
+        /* get codec */
+        mutex_lock(&wm->codec_mutex);
+
+        /* When the touchscreen is not in use, we may have to power up
+         * the AUX ADC before we can use sample the AUX inputs->
+         */
+        if (wm->id == WM9713_ID2 &&
+            (power = wm97xx_reg_read(wm, AC97_EXTENDED_MID)) & 0x8000) {
+                power_adc = 1;
+                wm97xx_reg_write(wm, AC97_EXTENDED_MID, power & 0x7fff);
+        }
+
+        /* Prepare the codec for AUX reading */
+        wm->codec->aux_prepare(wm);
+
+        /* Turn polling mode on to read AUX ADC */
+        wm->pen_probably_down = 1;
+        wm->codec->poll_sample(wm, adcsel, &auxval);
+
+        if (power_adc)
+                wm97xx_reg_write(wm, AC97_EXTENDED_MID, power | 0x8000);
+
+        wm->codec->dig_restore(wm);
+
+        wm->pen_probably_down = 0;
+
+        mutex_unlock(&wm->codec_mutex);
+        return auxval & 0xfff;
+}
+EXPORT_SYMBOL_GPL(wm97xx_read_aux_adc);
+
+/**
+ * wm97xx_get_gpio - Get the status of a codec GPIO.
+ * @wm: wm97xx device.
+ * @gpio: gpio
+ *
+ * Get the status of a codec GPIO pin
+ */
+
+enum wm97xx_gpio_status wm97xx_get_gpio(struct wm97xx *wm, u32 gpio)
+{
+        u16 status;
+        enum wm97xx_gpio_status ret;
+
+        mutex_lock(&wm->codec_mutex);
+        status = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
+
+        if (status & gpio)
+                ret = WM97XX_GPIO_HIGH;
+        else
+                ret = WM97XX_GPIO_LOW;
+
+        mutex_unlock(&wm->codec_mutex);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(wm97xx_get_gpio);
+
+/**
+ * wm97xx_set_gpio - Set the status of a codec GPIO.
+ * @wm: wm97xx device.
+ * @gpio: gpio
+ *
+ *
+ * Set the status of a codec GPIO pin
+ */
+
+void wm97xx_set_gpio(struct wm97xx *wm, u32 gpio,
+                                enum wm97xx_gpio_status status)
+{
+        u16 reg;
+
+        mutex_lock(&wm->codec_mutex);
+        reg = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
+
+        if (status & WM97XX_GPIO_HIGH)
+                reg |= gpio;
+        else
+                reg &= ~gpio;
+
+        if (wm->id == WM9712_ID2)
+                wm97xx_reg_write(wm, AC97_GPIO_STATUS, reg << 1);
+        else
+                wm97xx_reg_write(wm, AC97_GPIO_STATUS, reg);
+        mutex_unlock(&wm->codec_mutex);
+}
+EXPORT_SYMBOL_GPL(wm97xx_set_gpio);
+
+/*
+ * Codec GPIO pin configuration, this sets pin direction, polarity,
+ * stickyness and wake up.
+ */
+void wm97xx_config_gpio(struct wm97xx *wm, u32 gpio, enum wm97xx_gpio_dir dir,
+                   enum wm97xx_gpio_pol pol, enum wm97xx_gpio_sticky sticky,
+                   enum wm97xx_gpio_wake wake)
+{
+        u16 reg;
+
+        mutex_lock(&wm->codec_mutex);
+        reg = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
+
+        if (pol == WM97XX_GPIO_POL_HIGH)
+                reg |= gpio;
+        else
+                reg &= ~gpio;
+
+        wm97xx_reg_write(wm, AC97_GPIO_POLARITY, reg);
+        reg = wm97xx_reg_read(wm, AC97_GPIO_STICKY);
+
+        if (sticky == WM97XX_GPIO_STICKY)
+                reg |= gpio;
+        else
+                reg &= ~gpio;
+
+        wm97xx_reg_write(wm, AC97_GPIO_STICKY, reg);
+        reg = wm97xx_reg_read(wm, AC97_GPIO_WAKEUP);
+
+        if (wake == WM97XX_GPIO_WAKE)
+                reg |= gpio;
+        else
+                reg &= ~gpio;
+
+        wm97xx_reg_write(wm, AC97_GPIO_WAKEUP, reg);
+        reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
+
+        if (dir == WM97XX_GPIO_IN)
+                reg |= gpio;
+        else
+                reg &= ~gpio;
+
+        wm97xx_reg_write(wm, AC97_GPIO_CFG, reg);
+        mutex_unlock(&wm->codec_mutex);
+}
+EXPORT_SYMBOL_GPL(wm97xx_config_gpio);
+
+/*
+ * Handle a pen down interrupt.
+ */
+static void wm97xx_pen_irq_worker(struct work_struct *work)
+{
+        struct wm97xx *wm = container_of(work, struct wm97xx, pen_event_work);
+        int pen_was_down = wm->pen_is_down;
+
+        /* do we need to enable the touch panel reader */
+        if (wm->id == WM9705_ID2) {
+                if (wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD) &
+                                        WM97XX_PEN_DOWN)
+                        wm->pen_is_down = 1;
+                else
+                        wm->pen_is_down = 0;
+        } else {
+                u16 status, pol;
+                mutex_lock(&wm->codec_mutex);
+                status = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
+                pol = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
+
+                if (WM97XX_GPIO_13 & pol & status) {
+                        wm->pen_is_down = 1;
+                        wm97xx_reg_write(wm, AC97_GPIO_POLARITY, pol &
+                                                ~WM97XX_GPIO_13);
+                } else {
+                        wm->pen_is_down = 0;
+                        wm97xx_reg_write(wm, AC97_GPIO_POLARITY, pol |
+                                         WM97XX_GPIO_13);
+                }
+
+                if (wm->id == WM9712_ID2)
+                        wm97xx_reg_write(wm, AC97_GPIO_STATUS, (status &
+                                                ~WM97XX_GPIO_13) << 1);
+                else
+                        wm97xx_reg_write(wm, AC97_GPIO_STATUS, status &
+                                                ~WM97XX_GPIO_13);
+                mutex_unlock(&wm->codec_mutex);
+        }
+
+        /* If the system is not using continuous mode or it provides a
+         * pen down operation then we need to schedule polls while the
+         * pen is down.  Otherwise the machine driver is responsible
+         * for scheduling reads.
+         */
+        if (!wm->mach_ops->acc_enabled || wm->mach_ops->acc_pen_down) {
+                if (wm->pen_is_down && !pen_was_down) {
+                        /* Data is not availiable immediately on pen down */
+                        queue_delayed_work(wm->ts_workq, &wm->ts_reader, 1);
+                }
+
+                /* Let ts_reader report the pen up for debounce. */
+                if (!wm->pen_is_down && pen_was_down)
+                        wm->pen_is_down = 1;
+        }
+
+        if (!wm->pen_is_down && wm->mach_ops->acc_enabled)
+                wm->mach_ops->acc_pen_up(wm);
+
+        wm->mach_ops->irq_enable(wm, 1);
+}
+
+/*
+ * Codec PENDOWN irq handler
+ *
+ * We have to disable the codec interrupt in the handler because it
+ * can take upto 1ms to clear the interrupt source. We schedule a task
+ * in a work queue to do the actual interaction with the chip (it
+ * doesn't matter if we end up reenqueing it before it is executed
+ * since we don't touch the chip until it has run).  The interrupt is
+ * then enabled again in the slow handler when the source has been
+ * cleared.
+ */
+static irqreturn_t wm97xx_pen_interrupt(int irq, void *dev_id)
+{
+        struct wm97xx *wm = dev_id;
+
+        wm->mach_ops->irq_enable(wm, 0);
+        queue_work(wm->ts_workq, &wm->pen_event_work);
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * initialise pen IRQ handler and workqueue
+ */
+static int wm97xx_init_pen_irq(struct wm97xx *wm)
+{
+        u16 reg;
+
+        /* If an interrupt is supplied an IRQ enable operation must also be
+         * provided. */
+        BUG_ON(!wm->mach_ops->irq_enable);
+
+        if (request_irq(wm->pen_irq, wm97xx_pen_interrupt, IRQF_SHARED,
+                        "wm97xx-pen", wm)) {
+                dev_err(wm->dev,
+                        "Failed to register pen down interrupt, polling");
+                wm->pen_irq = 0;
+                return -EINVAL;
+        }
+
+        /* Configure GPIO as interrupt source on WM971x */
+        if (wm->id != WM9705_ID2) {
+                BUG_ON(!wm->mach_ops->irq_gpio);
+                reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
+                wm97xx_reg_write(wm, AC97_MISC_AFE,
+                                reg & ~(wm->mach_ops->irq_gpio));
+                reg = wm97xx_reg_read(wm, 0x5a);
+                wm97xx_reg_write(wm, 0x5a, reg & ~0x0001);
+        }
+
+        return 0;
+}
+
+static int wm97xx_read_samples(struct wm97xx *wm)
+{
+        struct wm97xx_data data;
+        int rc;
+
+        mutex_lock(&wm->codec_mutex);
+
+        if (wm->mach_ops && wm->mach_ops->acc_enabled)
+                rc = wm->mach_ops->acc_pen_down(wm);
+        else
+                rc = wm->codec->poll_touch(wm, &data);
+
+        if (rc & RC_PENUP) {
+                if (wm->pen_is_down) {
+                        wm->pen_is_down = 0;
+                        dev_dbg(wm->dev, "pen up\n");
+                        input_report_abs(wm->input_dev, ABS_PRESSURE, 0);
+                        input_sync(wm->input_dev);
+                } else if (!(rc & RC_AGAIN)) {
+                        /* We need high frequency updates only while
+                        * pen is down, the user never will be able to
+                        * touch screen faster than a few times per
+                        * second... On the other hand, when the user
+                        * is actively working with the touchscreen we
+                        * don't want to lose the quick response. So we
+                        * will slowly increase sleep time after the
+                        * pen is up and quicky restore it to ~one task
+                        * switch when pen is down again.
+                        */
+                        if (wm->ts_reader_interval < HZ / 10)
+                                wm->ts_reader_interval++;
+                }
+
+        } else if (rc & RC_VALID) {
+                dev_dbg(wm->dev,
+                        "pen down: x=%x:%d, y=%x:%d, pressure=%x:%d\n",
+                        data.x >> 12, data.x & 0xfff, data.y >> 12,
+                        data.y & 0xfff, data.p >> 12, data.p & 0xfff);
+                input_report_abs(wm->input_dev, ABS_X, data.x & 0xfff);
+                input_report_abs(wm->input_dev, ABS_Y, data.y & 0xfff);
+                input_report_abs(wm->input_dev, ABS_PRESSURE, data.p & 0xfff);
+                input_sync(wm->input_dev);
+                wm->pen_is_down = 1;
+                wm->ts_reader_interval = wm->ts_reader_min_interval;
+        } else if (rc & RC_PENDOWN) {
+                dev_dbg(wm->dev, "pen down\n");
+                wm->pen_is_down = 1;
+                wm->ts_reader_interval = wm->ts_reader_min_interval;
+        }
+
+        mutex_unlock(&wm->codec_mutex);
+        return rc;
+}
+
+/*
+* The touchscreen sample reader.
+*/
+static void wm97xx_ts_reader(struct work_struct *work)
+{
+        int rc;
+        struct wm97xx *wm = container_of(work, struct wm97xx, ts_reader.work);
+
+        BUG_ON(!wm->codec);
+
+        do {
+                rc = wm97xx_read_samples(wm);
+        } while (rc & RC_AGAIN);
+
+        if (wm->pen_is_down || !wm->pen_irq)
+                queue_delayed_work(wm->ts_workq, &wm->ts_reader,
+                                   wm->ts_reader_interval);
+}
+
+/**
+ * wm97xx_ts_input_open - Open the touch screen input device.
+ * @idev:       Input device to be opened.
+ *
+ * Called by the input sub system to open a wm97xx touchscreen device.
+ * Starts the touchscreen thread and touch digitiser.
+ */
+static int wm97xx_ts_input_open(struct input_dev *idev)
+{
+        struct wm97xx *wm = input_get_drvdata(idev);
+
+        wm->ts_workq = create_singlethread_workqueue("kwm97xx");
+        if (wm->ts_workq == NULL) {
+                dev_err(wm->dev,
+                        "Failed to create workqueue\n");
+                return -EINVAL;
+        }
+
+        /* start digitiser */
+        if (wm->mach_ops && wm->mach_ops->acc_enabled)
+                wm->codec->acc_enable(wm, 1);
+        wm->codec->dig_enable(wm, 1);
+
+        INIT_DELAYED_WORK(&wm->ts_reader, wm97xx_ts_reader);
+        INIT_WORK(&wm->pen_event_work, wm97xx_pen_irq_worker);
+
+        wm->ts_reader_min_interval = HZ >= 100 ? HZ / 100 : 1;
+        if (wm->ts_reader_min_interval < 1)
+                wm->ts_reader_min_interval = 1;
+        wm->ts_reader_interval = wm->ts_reader_min_interval;
+
+        wm->pen_is_down = 0;
+        if (wm->pen_irq)
+                wm97xx_init_pen_irq(wm);
+        else
+                dev_err(wm->dev, "No IRQ specified\n");
+
+        /* If we either don't have an interrupt for pen down events or
+         * failed to acquire it then we need to poll.
+         */
+        if (wm->pen_irq == 0)
+                queue_delayed_work(wm->ts_workq, &wm->ts_reader,
+                                   wm->ts_reader_interval);
+
+        return 0;
+}
+
+/**
+ * wm97xx_ts_input_close - Close the touch screen input device.
+ * @idev:       Input device to be closed.
+ *
+ * Called by the input sub system to close a wm97xx touchscreen
+ * device.  Kills the touchscreen thread and stops the touch
+ * digitiser.
+ */
+
+static void wm97xx_ts_input_close(struct input_dev *idev)
+{
+        struct wm97xx *wm = input_get_drvdata(idev);
+        u16 reg;
+
+        if (wm->pen_irq) {
+                /* Return the interrupt to GPIO usage (disabling it) */
+                if (wm->id != WM9705_ID2) {
+                        BUG_ON(!wm->mach_ops->irq_gpio);
+                        reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
+                        wm97xx_reg_write(wm, AC97_MISC_AFE,
+                                         reg | wm->mach_ops->irq_gpio);
+                }
+
+                free_irq(wm->pen_irq, wm);
+        }
+
+        wm->pen_is_down = 0;
+
+        /* Balance out interrupt disables/enables */
+        if (cancel_work_sync(&wm->pen_event_work))
+                wm->mach_ops->irq_enable(wm, 1);
+
+        /* ts_reader rearms itself so we need to explicitly stop it
+         * before we destroy the workqueue.
+         */
+        cancel_delayed_work_sync(&wm->ts_reader);
+
+        destroy_workqueue(wm->ts_workq);
+
+        /* stop digitiser */
+        wm->codec->dig_enable(wm, 0);
+        if (wm->mach_ops && wm->mach_ops->acc_enabled)
+                wm->codec->acc_enable(wm, 0);
+}
+
+static int wm97xx_probe(struct device *dev)
+{
+        struct wm97xx *wm;
+        int ret = 0, id = 0;
+
+        wm = kzalloc(sizeof(struct wm97xx), GFP_KERNEL);
+        if (!wm)
+                return -ENOMEM;
+        mutex_init(&wm->codec_mutex);
+
+        wm->dev = dev;
+        dev->driver_data = wm;
+        wm->ac97 = to_ac97_t(dev);
+
+        /* check that we have a supported codec */
+        id = wm97xx_reg_read(wm, AC97_VENDOR_ID1);
+        if (id != WM97XX_ID1) {
+                dev_err(dev, "Device with vendor %04x is not a wm97xx\n", id);
+                ret = -ENODEV;
+                goto alloc_err;
+        }
+
+        wm->id = wm97xx_reg_read(wm, AC97_VENDOR_ID2);
+
+        dev_info(wm->dev, "detected a wm97%02x codec\n", wm->id & 0xff);
+
+        switch (wm->id & 0xff) {
+#ifdef CONFIG_TOUCHSCREEN_WM9705
+        case 0x05:
+                wm->codec = &wm9705_codec;
+                break;
+#endif
+#ifdef CONFIG_TOUCHSCREEN_WM9712
+        case 0x12:
+                wm->codec = &wm9712_codec;
+                break;
+#endif
+#ifdef CONFIG_TOUCHSCREEN_WM9713
+        case 0x13:
+                wm->codec = &wm9713_codec;
+                break;
+#endif
+        default:
+                dev_err(wm->dev, "Support for wm97%02x not compiled in.\n",
+                        wm->id & 0xff);
+                ret = -ENODEV;
+                goto alloc_err;
+        }
+
+        wm->input_dev = input_allocate_device();
+        if (wm->input_dev == NULL) {
+                ret = -ENOMEM;
+                goto alloc_err;
+        }
+
+        /* set up touch configuration */
+        wm->input_dev->name = "wm97xx touchscreen";
+        wm->input_dev->open = wm97xx_ts_input_open;
+        wm->input_dev->close = wm97xx_ts_input_close;
+        set_bit(EV_ABS, wm->input_dev->evbit);
+        set_bit(ABS_X, wm->input_dev->absbit);
+        set_bit(ABS_Y, wm->input_dev->absbit);
+        set_bit(ABS_PRESSURE, wm->input_dev->absbit);
+        input_set_abs_params(wm->input_dev, ABS_X, abs_x[0], abs_x[1],
+                             abs_x[2], 0);
+        input_set_abs_params(wm->input_dev, ABS_Y, abs_y[0], abs_y[1],
+                             abs_y[2], 0);
+        input_set_abs_params(wm->input_dev, ABS_PRESSURE, abs_p[0], abs_p[1],
+                             abs_p[2], 0);
+        input_set_drvdata(wm->input_dev, wm);
+        wm->input_dev->dev.parent = dev;
+        ret = input_register_device(wm->input_dev);
+        if (ret < 0)
+                goto dev_alloc_err;
+
+        /* set up physical characteristics */
+        wm->codec->phy_init(wm);
+
+        /* load gpio cache */
+        wm->gpio[0] = wm97xx_reg_read(wm, AC97_GPIO_CFG);
+        wm->gpio[1] = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
+        wm->gpio[2] = wm97xx_reg_read(wm, AC97_GPIO_STICKY);
+        wm->gpio[3] = wm97xx_reg_read(wm, AC97_GPIO_WAKEUP);
+        wm->gpio[4] = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
+        wm->gpio[5] = wm97xx_reg_read(wm, AC97_MISC_AFE);
+
+        /* register our battery device */
+        wm->battery_dev = platform_device_alloc("wm97xx-battery", -1);
+        if (!wm->battery_dev) {
+                ret = -ENOMEM;
+                goto batt_err;
+        }
+        platform_set_drvdata(wm->battery_dev, wm);
+        wm->battery_dev->dev.parent = dev;
+        ret = platform_device_add(wm->battery_dev);
+        if (ret < 0)
+                goto batt_reg_err;
+
+        /* register our extended touch device (for machine specific
+         * extensions) */
+        wm->touch_dev = platform_device_alloc("wm97xx-touch", -1);
+        if (!wm->touch_dev) {
+                ret = -ENOMEM;
+                goto touch_err;
+        }
+        platform_set_drvdata(wm->touch_dev, wm);
+        wm->touch_dev->dev.parent = dev;
+        ret = platform_device_add(wm->touch_dev);
+        if (ret < 0)
+                goto touch_reg_err;
+
+        return ret;
+
+ touch_reg_err:
+        platform_device_put(wm->touch_dev);
+ touch_err:
+        platform_device_unregister(wm->battery_dev);
+        wm->battery_dev = NULL;
+ batt_reg_err:
+        platform_device_put(wm->battery_dev);
+ batt_err:
+        input_unregister_device(wm->input_dev);
+        wm->input_dev = NULL;
+ dev_alloc_err:
+        input_free_device(wm->input_dev);
+ alloc_err:
+        kfree(wm);
+
+        return ret;
+}
+
+static int wm97xx_remove(struct device *dev)
+{
+        struct wm97xx *wm = dev_get_drvdata(dev);
+
+        platform_device_unregister(wm->battery_dev);
+        platform_device_unregister(wm->touch_dev);
+        input_unregister_device(wm->input_dev);
+        kfree(wm);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int wm97xx_suspend(struct device *dev, pm_message_t state)
+{
+        struct wm97xx *wm = dev_get_drvdata(dev);
+
+        if (wm->input_dev->users)
+                cancel_delayed_work_sync(&wm->ts_reader);
+
+        return 0;
+}
+
+static int wm97xx_resume(struct device *dev)
+{
+        struct wm97xx *wm = dev_get_drvdata(dev);
+
+        /* restore digitiser and gpios */
+        if (wm->id == WM9713_ID2) {
+                wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig[0]);
+                wm97xx_reg_write(wm, 0x5a, wm->misc);
+                if (wm->input_dev->users) {
+                        u16 reg;
+                        reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) & 0x7fff;
+                        wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
+                }
+        }
+
+        wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig[1]);
+        wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2]);
+
+        wm97xx_reg_write(wm, AC97_GPIO_CFG, wm->gpio[0]);
+        wm97xx_reg_write(wm, AC97_GPIO_POLARITY, wm->gpio[1]);
+        wm97xx_reg_write(wm, AC97_GPIO_STICKY, wm->gpio[2]);
+        wm97xx_reg_write(wm, AC97_GPIO_WAKEUP, wm->gpio[3]);
+        wm97xx_reg_write(wm, AC97_GPIO_STATUS, wm->gpio[4]);
+        wm97xx_reg_write(wm, AC97_MISC_AFE, wm->gpio[5]);
+
+        if (wm->input_dev->users && !wm->pen_irq) {
+                wm->ts_reader_interval = wm->ts_reader_min_interval;
+                queue_delayed_work(wm->ts_workq, &wm->ts_reader,
+                                   wm->ts_reader_interval);
+        }
+
+        return 0;
+}
+
+#else
+#define wm97xx_suspend          NULL
+#define wm97xx_resume           NULL
+#endif
+
+/*
+ * Machine specific operations
+ */
+int wm97xx_register_mach_ops(struct wm97xx *wm,
+                             struct wm97xx_mach_ops *mach_ops)
+{
+        mutex_lock(&wm->codec_mutex);
+        if (wm->mach_ops) {
+                mutex_unlock(&wm->codec_mutex);
+                return -EINVAL;
+        }
+        wm->mach_ops = mach_ops;
+        mutex_unlock(&wm->codec_mutex);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(wm97xx_register_mach_ops);
+
+void wm97xx_unregister_mach_ops(struct wm97xx *wm)
+{
+        mutex_lock(&wm->codec_mutex);
+        wm->mach_ops = NULL;
+        mutex_unlock(&wm->codec_mutex);
+}
+EXPORT_SYMBOL_GPL(wm97xx_unregister_mach_ops);
+
+static struct device_driver wm97xx_driver = {
+        .name =         "ac97",
+        .bus =          &ac97_bus_type,
+        .owner =        THIS_MODULE,
+        .probe =        wm97xx_probe,
+        .remove =       wm97xx_remove,
+        .suspend =      wm97xx_suspend,
+        .resume =       wm97xx_resume,
+};
+
+static int __init wm97xx_init(void)
+{
+        return driver_register(&wm97xx_driver);
+}
+
+static void __exit wm97xx_exit(void)
+{
+        driver_unregister(&wm97xx_driver);
+}
+
+module_init(wm97xx_init);
+module_exit(wm97xx_exit);
+
+/* Module information */
+MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
+MODULE_DESCRIPTION("WM97xx Core - Touch Screen / AUX ADC / GPIO Driver");
+MODULE_LICENSE("GPL");