/*
 * 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 <lrg@slimlogic.co.uk>
 * 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/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>
#include <linux/slab.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] = {150, 4000, 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] = {200, 4000, 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;
        int rc = 0;
        int timeout = 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;

        while (rc != RC_VALID && timeout++ < 5)
                rc = 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;

        if (timeout >= 5) {
                dev_err(wm->dev,
                        "timeout reading auxadc %d, disabling digitiser\n",
                        adcsel);
                wm->codec->dig_enable(wm, false);
        }

        mutex_unlock(&wm->codec_mutex);
        return (rc == RC_VALID ? auxval & 0xfff : -EBUSY);
}
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 && wm->variant != WM97xx_WM1613)
                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);

/*
 * Configure the WM97XX_PRP value to use while system is suspended.
 * If a value other than 0 is set then WM97xx pen detection will be
 * left enabled in the configured mode while the system is in suspend,
 * the device has users and suspend has not been disabled via the
 * wakeup sysfs entries.
 *
 * @wm:   WM97xx device to configure
 * @mode: WM97XX_PRP value to configure while suspended
 */
void wm97xx_set_suspend_mode(struct wm97xx *wm, u16 mode)
{
        wm->suspend_mode = mode;
        device_init_wakeup(&wm->input_dev->dev, mode != 0);
}
EXPORT_SYMBOL_GPL(wm97xx_set_suspend_mode);

/*
 * 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 && wm->variant != WM97xx_WM1613)
                        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 available 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 up to 1ms to clear the interrupt source. We schedule a task
 * in a work queue to do the actual interaction with the chip.  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;

        if (!work_pending(&wm->pen_event_work)) {
                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_report_key(wm->input_dev, BTN_TOUCH, 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);

                if (abs_x[0] > (data.x & 0xfff) ||
                    abs_x[1] < (data.x & 0xfff) ||
                    abs_y[0] > (data.y & 0xfff) ||
                    abs_y[1] < (data.y & 0xfff)) {
                        dev_dbg(wm->dev, "Measurement out of range, dropping it\n");
                        rc = RC_AGAIN;
                        goto out;
                }

                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_report_key(wm->input_dev, BTN_TOUCH, 1);
                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;
        }

out:
        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 = alloc_ordered_workqueue("kwm97xx", 0);
        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;
        struct wm97xx_pdata *pdata = dev_get_platdata(dev);
        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_set_drvdata(dev, 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);

        wm->variant = WM97xx_GENERIC;

        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;
        }

        /* 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);

        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->phys = "wm97xx";
        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(EV_KEY, wm->input_dev->evbit);
        __set_bit(BTN_TOUCH, wm->input_dev->keybit);

        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;

        /* 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;
        wm->battery_dev->dev.platform_data = pdata ? pdata->batt_pdata : NULL;
        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;
        wm->touch_dev->dev.platform_data = pdata;
        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_del(wm->battery_dev);
 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;
}

static int __maybe_unused wm97xx_suspend(struct device *dev)
{
        struct wm97xx *wm = dev_get_drvdata(dev);
        u16 reg;
        int suspend_mode;

        if (device_may_wakeup(&wm->input_dev->dev))
                suspend_mode = wm->suspend_mode;
        else
                suspend_mode = 0;

        if (wm->input_dev->users)
                cancel_delayed_work_sync(&wm->ts_reader);

        /* Power down the digitiser (bypassing the cache for resume) */
        reg = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER2);
        reg &= ~WM97XX_PRP_DET_DIG;
        if (wm->input_dev->users)
                reg |= suspend_mode;
        wm->ac97->bus->ops->write(wm->ac97, AC97_WM97XX_DIGITISER2, reg);

        /* WM9713 has an additional power bit - turn it off if there
         * are no users or if suspend mode is zero. */
        if (wm->id == WM9713_ID2 &&
            (!wm->input_dev->users || !suspend_mode)) {
                reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) | 0x8000;
                wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
        }

        return 0;
}

static int __maybe_unused 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;
}

static SIMPLE_DEV_PM_OPS(wm97xx_pm_ops, wm97xx_suspend, wm97xx_resume);

/*
 * 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 =         "wm97xx-ts",
        .bus =          &ac97_bus_type,
        .owner =        THIS_MODULE,
        .probe =        wm97xx_probe,
        .remove =       wm97xx_remove,
        .pm =           &wm97xx_pm_ops,
};

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 <lrg@slimlogic.co.uk>");
MODULE_DESCRIPTION("WM97xx Core - Touch Screen / AUX ADC / GPIO Driver");
MODULE_LICENSE("GPL");