drivers/mfd/wm8994-core.c - kernel/msm-4.9 - Gitiles

 /*
  * wm8994-core.c  --  Device access for Wolfson WM8994
  *
  * Copyright 2009 Wolfson Microelectronics PLC.
  *
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  *
  *  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.
  *
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/mfd/core.h>
 #include <linux/regulator/consumer.h>
 #include <linux/regulator/machine.h>

 #include <linux/mfd/wm8994/core.h>
 #include <linux/mfd/wm8994/pdata.h>
 #include <linux/mfd/wm8994/registers.h>

 static int wm8994_read(struct wm8994 *wm8994, unsigned short reg,
 		       int bytes, void *dest)
 {
 	int ret, i;
 	u16 *buf = dest;

 	BUG_ON(bytes % 2);
 	BUG_ON(bytes <= 0);

 	ret = wm8994->read_dev(wm8994, reg, bytes, dest);
 	if (ret < 0)
 		return ret;

 	for (i = 0; i < bytes / 2; i++) {
 		buf[i] = be16_to_cpu(buf[i]);

 		dev_vdbg(wm8994->dev, "Read %04x from R%d(0x%x)\n",
 			 buf[i], reg + i, reg + i);
 	}

 	return 0;
 }

 /**
  * wm8994_reg_read: Read a single WM8994 register.
  *
  * @wm8994: Device to read from.
  * @reg: Register to read.
  */
 int wm8994_reg_read(struct wm8994 *wm8994, unsigned short reg)
 {
 	unsigned short val;
 	int ret;

 	mutex_lock(&wm8994->io_lock);

 	ret = wm8994_read(wm8994, reg, 2, &val);

 	mutex_unlock(&wm8994->io_lock);

 	if (ret < 0)
 		return ret;
 	else
 		return val;
 }
 EXPORT_SYMBOL_GPL(wm8994_reg_read);

 /**
  * wm8994_bulk_read: Read multiple WM8994 registers
  *
  * @wm8994: Device to read from
  * @reg: First register
  * @count: Number of registers
  * @buf: Buffer to fill.
  */
 int wm8994_bulk_read(struct wm8994 *wm8994, unsigned short reg,
 		     int count, u16 *buf)
 {
 	int ret;

 	mutex_lock(&wm8994->io_lock);

 	ret = wm8994_read(wm8994, reg, count * 2, buf);

 	mutex_unlock(&wm8994->io_lock);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(wm8994_bulk_read);

 static int wm8994_write(struct wm8994 *wm8994, unsigned short reg,
 			int bytes, void *src)
 {
 	u16 *buf = src;
 	int i;

 	BUG_ON(bytes % 2);
 	BUG_ON(bytes <= 0);

 	for (i = 0; i < bytes / 2; i++) {
 		dev_vdbg(wm8994->dev, "Write %04x to R%d(0x%x)\n",
 			 buf[i], reg + i, reg + i);

 		buf[i] = cpu_to_be16(buf[i]);
 	}

 	return wm8994->write_dev(wm8994, reg, bytes, src);
 }

 /**
  * wm8994_reg_write: Write a single WM8994 register.
  *
  * @wm8994: Device to write to.
  * @reg: Register to write to.
  * @val: Value to write.
  */
 int wm8994_reg_write(struct wm8994 *wm8994, unsigned short reg,
 		     unsigned short val)
 {
 	int ret;

 	mutex_lock(&wm8994->io_lock);

 	ret = wm8994_write(wm8994, reg, 2, &val);

 	mutex_unlock(&wm8994->io_lock);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(wm8994_reg_write);

 /**
  * wm8994_set_bits: Set the value of a bitfield in a WM8994 register
  *
  * @wm8994: Device to write to.
  * @reg: Register to write to.
  * @mask: Mask of bits to set.
  * @val: Value to set (unshifted)
  */
 int wm8994_set_bits(struct wm8994 *wm8994, unsigned short reg,
 		    unsigned short mask, unsigned short val)
 {
 	int ret;
 	u16 r;

 	mutex_lock(&wm8994->io_lock);

 	ret = wm8994_read(wm8994, reg, 2, &r);
 	if (ret < 0)
 		goto out;

 	r &= ~mask;
 	r |= val;

 	ret = wm8994_write(wm8994, reg, 2, &r);

 out:
 	mutex_unlock(&wm8994->io_lock);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(wm8994_set_bits);

 static struct mfd_cell wm8994_regulator_devs[] = {
 	{ .name = "wm8994-ldo", .id = 1 },
 	{ .name = "wm8994-ldo", .id = 2 },
 };

 static struct mfd_cell wm8994_devs[] = {
 	{ .name = "wm8994-codec" },
 	{ .name = "wm8994-gpio" },
 };

 /*
  * Supplies for the main bulk of CODEC; the LDO supplies are ignored
  * and should be handled via the standard regulator API supply
  * management.
  */
 static const char *wm8994_main_supplies[] = {
 	"DBVDD",
 	"DCVDD",
 	"AVDD1",
 	"AVDD2",
 	"CPVDD",
 	"SPKVDD1",
 	"SPKVDD2",
 };

 #ifdef CONFIG_PM
 static int wm8994_device_suspend(struct device *dev)
 {
 	struct wm8994 *wm8994 = dev_get_drvdata(dev);
 	int ret;

 	/* GPIO configuration state is saved here since we may be configuring
 	 * the GPIO alternate functions even if we're not using the gpiolib
 	 * driver for them.
 	 */
 	ret = wm8994_read(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
 			  &wm8994->gpio_regs);
 	if (ret < 0)
 		dev_err(dev, "Failed to save GPIO registers: %d\n", ret);

 	/* For similar reasons we also stash the regulator states */
 	ret = wm8994_read(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
 			  &wm8994->ldo_regs);
 	if (ret < 0)
 		dev_err(dev, "Failed to save LDO registers: %d\n", ret);

 	ret = regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
 				     wm8994->supplies);
 	if (ret != 0) {
 		dev_err(dev, "Failed to disable supplies: %d\n", ret);
 		return ret;
 	}

 	return 0;
 }

 static int wm8994_device_resume(struct device *dev)
 {
 	struct wm8994 *wm8994 = dev_get_drvdata(dev);
 	int ret;

 	ret = regulator_bulk_enable(ARRAY_SIZE(wm8994_main_supplies),
 				    wm8994->supplies);
 	if (ret != 0) {
 		dev_err(dev, "Failed to enable supplies: %d\n", ret);
 		return ret;
 	}

 	ret = wm8994_write(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
 			   &wm8994->ldo_regs);
 	if (ret < 0)
 		dev_err(dev, "Failed to restore LDO registers: %d\n", ret);

 	ret = wm8994_write(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
 			   &wm8994->gpio_regs);
 	if (ret < 0)
 		dev_err(dev, "Failed to restore GPIO registers: %d\n", ret);

 	return 0;
 }
 #endif

 #ifdef CONFIG_REGULATOR
 static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
 {
 	struct wm8994_ldo_pdata *ldo_pdata;

 	if (!pdata)
 		return 0;

 	ldo_pdata = &pdata->ldo[ldo];

 	if (!ldo_pdata->init_data)
 		return 0;

 	return ldo_pdata->init_data->num_consumer_supplies != 0;
 }
 #else
 static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
 {
 	return 0;
 }
 #endif

 /*
  * Instantiate the generic non-control parts of the device.
  */
 static int wm8994_device_init(struct wm8994 *wm8994, unsigned long id, int irq)
 {
 	struct wm8994_pdata *pdata = wm8994->dev->platform_data;
 	int ret, i;

 	mutex_init(&wm8994->io_lock);
 	dev_set_drvdata(wm8994->dev, wm8994);

 	/* Add the on-chip regulators first for bootstrapping */
 	ret = mfd_add_devices(wm8994->dev, -1,
 			      wm8994_regulator_devs,
 			      ARRAY_SIZE(wm8994_regulator_devs),
 			      NULL, 0);
 	if (ret != 0) {
 		dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
 		goto err;
 	}

 	wm8994->supplies = kzalloc(sizeof(struct regulator_bulk_data) *
 				   ARRAY_SIZE(wm8994_main_supplies),
 				   GFP_KERNEL);
 	if (!wm8994->supplies)
 		goto err;

 	for (i = 0; i < ARRAY_SIZE(wm8994_main_supplies); i++)
 		wm8994->supplies[i].supply = wm8994_main_supplies[i];

 	ret = regulator_bulk_get(wm8994->dev, ARRAY_SIZE(wm8994_main_supplies),
 				 wm8994->supplies);
 	if (ret != 0) {
 		dev_err(wm8994->dev, "Failed to get supplies: %d\n", ret);
 		goto err_supplies;
 	}

 	ret = regulator_bulk_enable(ARRAY_SIZE(wm8994_main_supplies),
 				    wm8994->supplies);
 	if (ret != 0) {
 		dev_err(wm8994->dev, "Failed to enable supplies: %d\n", ret);
 		goto err_get;
 	}

 	ret = wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET);
 	if (ret < 0) {
 		dev_err(wm8994->dev, "Failed to read ID register\n");
 		goto err_enable;
 	}
 	if (ret != 0x8994) {
 		dev_err(wm8994->dev, "Device is not a WM8994, ID is %x\n",
 			ret);
 		ret = -EINVAL;
 		goto err_enable;
 	}

 	ret = wm8994_reg_read(wm8994, WM8994_CHIP_REVISION);
 	if (ret < 0) {
 		dev_err(wm8994->dev, "Failed to read revision register: %d\n",
 			ret);
 		goto err_enable;
 	}

 	switch (ret) {
 	case 0:
 	case 1:
 		dev_warn(wm8994->dev, "revision %c not fully supported\n",
 			'A' + ret);
 		break;
 	default:
 		dev_info(wm8994->dev, "revision %c\n", 'A' + ret);
 		break;
 	}


 	if (pdata) {
 		wm8994->gpio_base = pdata->gpio_base;

 		/* GPIO configuration is only applied if it's non-zero */
 		for (i = 0; i < ARRAY_SIZE(pdata->gpio_defaults); i++) {
 			if (pdata->gpio_defaults[i]) {
 				wm8994_set_bits(wm8994, WM8994_GPIO_1 + i,
 						0xffff,
 						pdata->gpio_defaults[i]);
 			}
 		}
 	}

 	/* In some system designs where the regulators are not in use,
 	 * we can achieve a small reduction in leakage currents by
 	 * floating LDO outputs.  This bit makes no difference if the
 	 * LDOs are enabled, it only affects cases where the LDOs were
 	 * in operation and are then disabled.
 	 */
 	for (i = 0; i < WM8994_NUM_LDO_REGS; i++) {
 		if (wm8994_ldo_in_use(pdata, i))
 			wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
 					WM8994_LDO1_DISCH, WM8994_LDO1_DISCH);
 		else
 			wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
 					WM8994_LDO1_DISCH, 0);
 	}

 	ret = mfd_add_devices(wm8994->dev, -1,
 			      wm8994_devs, ARRAY_SIZE(wm8994_devs),
 			      NULL, 0);
 	if (ret != 0) {
 		dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
 		goto err_enable;
 	}

 	return 0;

 err_enable:
 	regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
 			       wm8994->supplies);
 err_get:
 	regulator_bulk_free(ARRAY_SIZE(wm8994_main_supplies), wm8994->supplies);
 err_supplies:
 	kfree(wm8994->supplies);
 err:
 	mfd_remove_devices(wm8994->dev);
 	kfree(wm8994);
 	return ret;
 }

 static void wm8994_device_exit(struct wm8994 *wm8994)
 {
 	mfd_remove_devices(wm8994->dev);
 	regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
 			       wm8994->supplies);
 	regulator_bulk_free(ARRAY_SIZE(wm8994_main_supplies), wm8994->supplies);
 	kfree(wm8994->supplies);
 	kfree(wm8994);
 }

 static int wm8994_i2c_read_device(struct wm8994 *wm8994, unsigned short reg,
 				  int bytes, void *dest)
 {
 	struct i2c_client *i2c = wm8994->control_data;
 	int ret;
 	u16 r = cpu_to_be16(reg);

 	ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
 	if (ret < 0)
 		return ret;
 	if (ret != 2)
 		return -EIO;

 	ret = i2c_master_recv(i2c, dest, bytes);
 	if (ret < 0)
 		return ret;
 	if (ret != bytes)
 		return -EIO;
 	return 0;
 }

 /* Currently we allocate the write buffer on the stack; this is OK for
  * small writes - if we need to do large writes this will need to be
  * revised.
  */
 static int wm8994_i2c_write_device(struct wm8994 *wm8994, unsigned short reg,
 				   int bytes, void *src)
 {
 	struct i2c_client *i2c = wm8994->control_data;
 	unsigned char msg[bytes + 2];
 	int ret;

 	reg = cpu_to_be16(reg);
 	memcpy(&msg[0], &reg, 2);
 	memcpy(&msg[2], src, bytes);

 	ret = i2c_master_send(i2c, msg, bytes + 2);
 	if (ret < 0)
 		return ret;
 	if (ret < bytes + 2)
 		return -EIO;

 	return 0;
 }

 static int wm8994_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
 	struct wm8994 *wm8994;

 	wm8994 = kzalloc(sizeof(struct wm8994), GFP_KERNEL);
 	if (wm8994 == NULL) {
 		kfree(i2c);
 		return -ENOMEM;
 	}

 	i2c_set_clientdata(i2c, wm8994);
 	wm8994->dev = &i2c->dev;
 	wm8994->control_data = i2c;
 	wm8994->read_dev = wm8994_i2c_read_device;
 	wm8994->write_dev = wm8994_i2c_write_device;

 	return wm8994_device_init(wm8994, id->driver_data, i2c->irq);
 }

 static int wm8994_i2c_remove(struct i2c_client *i2c)
 {
 	struct wm8994 *wm8994 = i2c_get_clientdata(i2c);

 	wm8994_device_exit(wm8994);

 	return 0;
 }

 #ifdef CONFIG_PM
 static int wm8994_i2c_suspend(struct i2c_client *i2c, pm_message_t state)
 {
 	return wm8994_device_suspend(&i2c->dev);
 }

 static int wm8994_i2c_resume(struct i2c_client *i2c)
 {
 	return wm8994_device_resume(&i2c->dev);
 }
 #else
 #define wm8994_i2c_suspend NULL
 #define wm8994_i2c_resume NULL
 #endif

 static const struct i2c_device_id wm8994_i2c_id[] = {
 	{ "wm8994", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, wm8994_i2c_id);

 static struct i2c_driver wm8994_i2c_driver = {
 	.driver = {
 		   .name = "wm8994",
 		   .owner = THIS_MODULE,
 	},
 	.probe = wm8994_i2c_probe,
 	.remove = wm8994_i2c_remove,
 	.suspend = wm8994_i2c_suspend,
 	.resume = wm8994_i2c_resume,
 	.id_table = wm8994_i2c_id,
 };

 static int __init wm8994_i2c_init(void)
 {
 	int ret;

 	ret = i2c_add_driver(&wm8994_i2c_driver);
 	if (ret != 0)
 		pr_err("Failed to register wm8994 I2C driver: %d\n", ret);

 	return ret;
 }
 module_init(wm8994_i2c_init);

 static void __exit wm8994_i2c_exit(void)
 {
 	i2c_del_driver(&wm8994_i2c_driver);
 }
 module_exit(wm8994_i2c_exit);

 MODULE_DESCRIPTION("Core support for the WM8994 audio CODEC");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
	/*
	* wm8994-core.c -- Device access for Wolfson WM8994
	*
	* Copyright 2009 Wolfson Microelectronics PLC.
	*
	* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
	*
	* 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.
	*
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/i2c.h>
	#include <linux/delay.h>
	#include <linux/mfd/core.h>
	#include <linux/regulator/consumer.h>
	#include <linux/regulator/machine.h>

	#include <linux/mfd/wm8994/core.h>
	#include <linux/mfd/wm8994/pdata.h>
	#include <linux/mfd/wm8994/registers.h>

	static int wm8994_read(struct wm8994 *wm8994, unsigned short reg,
	int bytes, void *dest)
	{
	int ret, i;
	u16 *buf = dest;

	BUG_ON(bytes % 2);
	BUG_ON(bytes <= 0);

	ret = wm8994->read_dev(wm8994, reg, bytes, dest);
	if (ret < 0)
	return ret;

	for (i = 0; i < bytes / 2; i++) {
	buf[i] = be16_to_cpu(buf[i]);

	dev_vdbg(wm8994->dev, "Read %04x from R%d(0x%x)\n",
	buf[i], reg + i, reg + i);
	}

	return 0;
	}

	/**
	* wm8994_reg_read: Read a single WM8994 register.
	*
	* @wm8994: Device to read from.
	* @reg: Register to read.
	*/
	int wm8994_reg_read(struct wm8994 *wm8994, unsigned short reg)
	{
	unsigned short val;
	int ret;

	mutex_lock(&wm8994->io_lock);

	ret = wm8994_read(wm8994, reg, 2, &val);

	mutex_unlock(&wm8994->io_lock);

	if (ret < 0)
	return ret;
	else
	return val;
	}
	EXPORT_SYMBOL_GPL(wm8994_reg_read);

	/**
	* wm8994_bulk_read: Read multiple WM8994 registers
	*
	* @wm8994: Device to read from
	* @reg: First register
	* @count: Number of registers
	* @buf: Buffer to fill.
	*/
	int wm8994_bulk_read(struct wm8994 *wm8994, unsigned short reg,
	int count, u16 *buf)
	{
	int ret;

	mutex_lock(&wm8994->io_lock);

	ret = wm8994_read(wm8994, reg, count * 2, buf);

	mutex_unlock(&wm8994->io_lock);

	return ret;
	}
	EXPORT_SYMBOL_GPL(wm8994_bulk_read);

	static int wm8994_write(struct wm8994 *wm8994, unsigned short reg,
	int bytes, void *src)
	{
	u16 *buf = src;
	int i;

	BUG_ON(bytes % 2);
	BUG_ON(bytes <= 0);

	for (i = 0; i < bytes / 2; i++) {
	dev_vdbg(wm8994->dev, "Write %04x to R%d(0x%x)\n",
	buf[i], reg + i, reg + i);

	buf[i] = cpu_to_be16(buf[i]);
	}

	return wm8994->write_dev(wm8994, reg, bytes, src);
	}

	/**
	* wm8994_reg_write: Write a single WM8994 register.
	*
	* @wm8994: Device to write to.
	* @reg: Register to write to.
	* @val: Value to write.
	*/
	int wm8994_reg_write(struct wm8994 *wm8994, unsigned short reg,
	unsigned short val)
	{
	int ret;

	mutex_lock(&wm8994->io_lock);

	ret = wm8994_write(wm8994, reg, 2, &val);

	mutex_unlock(&wm8994->io_lock);

	return ret;
	}
	EXPORT_SYMBOL_GPL(wm8994_reg_write);

	/**
	* wm8994_set_bits: Set the value of a bitfield in a WM8994 register
	*
	* @wm8994: Device to write to.
	* @reg: Register to write to.
	* @mask: Mask of bits to set.
	* @val: Value to set (unshifted)
	*/
	int wm8994_set_bits(struct wm8994 *wm8994, unsigned short reg,
	unsigned short mask, unsigned short val)
	{
	int ret;
	u16 r;

	mutex_lock(&wm8994->io_lock);

	ret = wm8994_read(wm8994, reg, 2, &r);
	if (ret < 0)
	goto out;

	r &= ~mask;
	r \|= val;

	ret = wm8994_write(wm8994, reg, 2, &r);

	out:
	mutex_unlock(&wm8994->io_lock);

	return ret;
	}
	EXPORT_SYMBOL_GPL(wm8994_set_bits);

	static struct mfd_cell wm8994_regulator_devs[] = {
	{ .name = "wm8994-ldo", .id = 1 },
	{ .name = "wm8994-ldo", .id = 2 },
	};

	static struct mfd_cell wm8994_devs[] = {
	{ .name = "wm8994-codec" },
	{ .name = "wm8994-gpio" },
	};

	/*
	* Supplies for the main bulk of CODEC; the LDO supplies are ignored
	* and should be handled via the standard regulator API supply
	* management.
	*/
	static const char *wm8994_main_supplies[] = {
	"DBVDD",
	"DCVDD",
	"AVDD1",
	"AVDD2",
	"CPVDD",
	"SPKVDD1",
	"SPKVDD2",
	};

	#ifdef CONFIG_PM
	static int wm8994_device_suspend(struct device *dev)
	{
	struct wm8994 *wm8994 = dev_get_drvdata(dev);
	int ret;

	/* GPIO configuration state is saved here since we may be configuring
	* the GPIO alternate functions even if we're not using the gpiolib
	* driver for them.
	*/
	ret = wm8994_read(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
	&wm8994->gpio_regs);
	if (ret < 0)
	dev_err(dev, "Failed to save GPIO registers: %d\n", ret);

	/* For similar reasons we also stash the regulator states */
	ret = wm8994_read(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
	&wm8994->ldo_regs);
	if (ret < 0)
	dev_err(dev, "Failed to save LDO registers: %d\n", ret);

	ret = regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
	wm8994->supplies);
	if (ret != 0) {
	dev_err(dev, "Failed to disable supplies: %d\n", ret);
	return ret;
	}

	return 0;
	}

	static int wm8994_device_resume(struct device *dev)
	{
	struct wm8994 *wm8994 = dev_get_drvdata(dev);
	int ret;

	ret = regulator_bulk_enable(ARRAY_SIZE(wm8994_main_supplies),
	wm8994->supplies);
	if (ret != 0) {
	dev_err(dev, "Failed to enable supplies: %d\n", ret);
	return ret;
	}

	ret = wm8994_write(wm8994, WM8994_LDO_1, WM8994_NUM_LDO_REGS * 2,
	&wm8994->ldo_regs);
	if (ret < 0)
	dev_err(dev, "Failed to restore LDO registers: %d\n", ret);

	ret = wm8994_write(wm8994, WM8994_GPIO_1, WM8994_NUM_GPIO_REGS * 2,
	&wm8994->gpio_regs);
	if (ret < 0)
	dev_err(dev, "Failed to restore GPIO registers: %d\n", ret);

	return 0;
	}
	#endif

	#ifdef CONFIG_REGULATOR
	static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
	{
	struct wm8994_ldo_pdata *ldo_pdata;

	if (!pdata)
	return 0;

	ldo_pdata = &pdata->ldo[ldo];

	if (!ldo_pdata->init_data)
	return 0;

	return ldo_pdata->init_data->num_consumer_supplies != 0;
	}
	#else
	static int wm8994_ldo_in_use(struct wm8994_pdata *pdata, int ldo)
	{
	return 0;
	}
	#endif

	/*
	* Instantiate the generic non-control parts of the device.
	*/
	static int wm8994_device_init(struct wm8994 *wm8994, unsigned long id, int irq)
	{
	struct wm8994_pdata *pdata = wm8994->dev->platform_data;
	int ret, i;

	mutex_init(&wm8994->io_lock);
	dev_set_drvdata(wm8994->dev, wm8994);

	/* Add the on-chip regulators first for bootstrapping */
	ret = mfd_add_devices(wm8994->dev, -1,
	wm8994_regulator_devs,
	ARRAY_SIZE(wm8994_regulator_devs),
	NULL, 0);
	if (ret != 0) {
	dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
	goto err;
	}

	wm8994->supplies = kzalloc(sizeof(struct regulator_bulk_data) *
	ARRAY_SIZE(wm8994_main_supplies),
	GFP_KERNEL);
	if (!wm8994->supplies)
	goto err;

	for (i = 0; i < ARRAY_SIZE(wm8994_main_supplies); i++)
	wm8994->supplies[i].supply = wm8994_main_supplies[i];

	ret = regulator_bulk_get(wm8994->dev, ARRAY_SIZE(wm8994_main_supplies),
	wm8994->supplies);
	if (ret != 0) {
	dev_err(wm8994->dev, "Failed to get supplies: %d\n", ret);
	goto err_supplies;
	}

	ret = regulator_bulk_enable(ARRAY_SIZE(wm8994_main_supplies),
	wm8994->supplies);
	if (ret != 0) {
	dev_err(wm8994->dev, "Failed to enable supplies: %d\n", ret);
	goto err_get;
	}

	ret = wm8994_reg_read(wm8994, WM8994_SOFTWARE_RESET);
	if (ret < 0) {
	dev_err(wm8994->dev, "Failed to read ID register\n");
	goto err_enable;
	}
	if (ret != 0x8994) {
	dev_err(wm8994->dev, "Device is not a WM8994, ID is %x\n",
	ret);
	ret = -EINVAL;
	goto err_enable;
	}

	ret = wm8994_reg_read(wm8994, WM8994_CHIP_REVISION);
	if (ret < 0) {
	dev_err(wm8994->dev, "Failed to read revision register: %d\n",
	ret);
	goto err_enable;
	}

	switch (ret) {
	case 0:
	case 1:
	dev_warn(wm8994->dev, "revision %c not fully supported\n",
	'A' + ret);
	break;
	default:
	dev_info(wm8994->dev, "revision %c\n", 'A' + ret);
	break;
	}


	if (pdata) {
	wm8994->gpio_base = pdata->gpio_base;

	/* GPIO configuration is only applied if it's non-zero */
	for (i = 0; i < ARRAY_SIZE(pdata->gpio_defaults); i++) {
	if (pdata->gpio_defaults[i]) {
	wm8994_set_bits(wm8994, WM8994_GPIO_1 + i,
	0xffff,
	pdata->gpio_defaults[i]);
	}
	}
	}

	/* In some system designs where the regulators are not in use,
	* we can achieve a small reduction in leakage currents by
	* floating LDO outputs. This bit makes no difference if the
	* LDOs are enabled, it only affects cases where the LDOs were
	* in operation and are then disabled.
	*/
	for (i = 0; i < WM8994_NUM_LDO_REGS; i++) {
	if (wm8994_ldo_in_use(pdata, i))
	wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
	WM8994_LDO1_DISCH, WM8994_LDO1_DISCH);
	else
	wm8994_set_bits(wm8994, WM8994_LDO_1 + i,
	WM8994_LDO1_DISCH, 0);
	}

	ret = mfd_add_devices(wm8994->dev, -1,
	wm8994_devs, ARRAY_SIZE(wm8994_devs),
	NULL, 0);
	if (ret != 0) {
	dev_err(wm8994->dev, "Failed to add children: %d\n", ret);
	goto err_enable;
	}

	return 0;

	err_enable:
	regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
	wm8994->supplies);
	err_get:
	regulator_bulk_free(ARRAY_SIZE(wm8994_main_supplies), wm8994->supplies);
	err_supplies:
	kfree(wm8994->supplies);
	err:
	mfd_remove_devices(wm8994->dev);
	kfree(wm8994);
	return ret;
	}

	static void wm8994_device_exit(struct wm8994 *wm8994)
	{
	mfd_remove_devices(wm8994->dev);
	regulator_bulk_disable(ARRAY_SIZE(wm8994_main_supplies),
	wm8994->supplies);
	regulator_bulk_free(ARRAY_SIZE(wm8994_main_supplies), wm8994->supplies);
	kfree(wm8994->supplies);
	kfree(wm8994);
	}

	static int wm8994_i2c_read_device(struct wm8994 *wm8994, unsigned short reg,
	int bytes, void *dest)
	{
	struct i2c_client *i2c = wm8994->control_data;
	int ret;
	u16 r = cpu_to_be16(reg);

	ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
	if (ret < 0)
	return ret;
	if (ret != 2)
	return -EIO;

	ret = i2c_master_recv(i2c, dest, bytes);
	if (ret < 0)
	return ret;
	if (ret != bytes)
	return -EIO;
	return 0;
	}

	/* Currently we allocate the write buffer on the stack; this is OK for
	* small writes - if we need to do large writes this will need to be
	* revised.
	*/
	static int wm8994_i2c_write_device(struct wm8994 *wm8994, unsigned short reg,
	int bytes, void *src)
	{
	struct i2c_client *i2c = wm8994->control_data;
	unsigned char msg[bytes + 2];
	int ret;

	reg = cpu_to_be16(reg);
	memcpy(&msg[0], &reg, 2);
	memcpy(&msg[2], src, bytes);

	ret = i2c_master_send(i2c, msg, bytes + 2);
	if (ret < 0)
	return ret;
	if (ret < bytes + 2)
	return -EIO;

	return 0;
	}

	static int wm8994_i2c_probe(struct i2c_client *i2c,
	const struct i2c_device_id *id)
	{
	struct wm8994 *wm8994;

	wm8994 = kzalloc(sizeof(struct wm8994), GFP_KERNEL);
	if (wm8994 == NULL) {
	kfree(i2c);
	return -ENOMEM;
	}

	i2c_set_clientdata(i2c, wm8994);
	wm8994->dev = &i2c->dev;
	wm8994->control_data = i2c;
	wm8994->read_dev = wm8994_i2c_read_device;
	wm8994->write_dev = wm8994_i2c_write_device;

	return wm8994_device_init(wm8994, id->driver_data, i2c->irq);
	}

	static int wm8994_i2c_remove(struct i2c_client *i2c)
	{
	struct wm8994 *wm8994 = i2c_get_clientdata(i2c);

	wm8994_device_exit(wm8994);

	return 0;
	}

	#ifdef CONFIG_PM
	static int wm8994_i2c_suspend(struct i2c_client *i2c, pm_message_t state)
	{
	return wm8994_device_suspend(&i2c->dev);
	}

	static int wm8994_i2c_resume(struct i2c_client *i2c)
	{
	return wm8994_device_resume(&i2c->dev);
	}
	#else
	#define wm8994_i2c_suspend NULL
	#define wm8994_i2c_resume NULL
	#endif

	static const struct i2c_device_id wm8994_i2c_id[] = {
	{ "wm8994", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, wm8994_i2c_id);

	static struct i2c_driver wm8994_i2c_driver = {
	.driver = {
	.name = "wm8994",
	.owner = THIS_MODULE,
	},
	.probe = wm8994_i2c_probe,
	.remove = wm8994_i2c_remove,
	.suspend = wm8994_i2c_suspend,
	.resume = wm8994_i2c_resume,
	.id_table = wm8994_i2c_id,
	};

	static int __init wm8994_i2c_init(void)
	{
	int ret;

	ret = i2c_add_driver(&wm8994_i2c_driver);
	if (ret != 0)
	pr_err("Failed to register wm8994 I2C driver: %d\n", ret);

	return ret;
	}
	module_init(wm8994_i2c_init);

	static void __exit wm8994_i2c_exit(void)
	{
	i2c_del_driver(&wm8994_i2c_driver);
	}
	module_exit(wm8994_i2c_exit);

	MODULE_DESCRIPTION("Core support for the WM8994 audio CODEC");
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");