Input: add support for WM97xx familty touchscreens

Add support for the touchscreen controllers provided by Wolfson
Microelectronics WM97xx series chips in both polled and streaming
modes.

These drivers have been maintained out of tree since 2003. During
that time the driver the primary maintainer was Liam Girdwood and
a number of people have made contributions including Dmitry Baryshkov,
Stanley Cai, Rodolfo Giometti, Russell King, Marc Kleine-Budde,
Ian Molton, Vincent Sanders, Andrew Zabolotny, Graeme Gregory,
Mike Arthur and myself. Apologies to anyone I have omitted.

Signed-off-by: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
Signed-off-by: Graeme Gregory <gg@opensource.wolfsonmicro.com>
Signed-off-by: Mike Arthur <mike.arthur@wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

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");