drivers/iio/adc/exynos_adc.c - pub/scm/linux/kernel/git/monstr/linux - Git at Google

 /*
  *  exynos_adc.c - Support for ADC in EXYNOS SoCs
  *
  *  8 ~ 10 channel, 10/12-bit ADC
  *
  *  Copyright (C) 2013 Naveen Krishna Chatradhi <ch.naveen@samsung.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.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/regulator/consumer.h>
 #include <linux/of_platform.h>
 #include <linux/err.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/machine.h>
 #include <linux/iio/driver.h>

 enum adc_version {
 	ADC_V1,
 	ADC_V2
 };

 /* EXYNOS4412/5250 ADC_V1 registers definitions */
 #define ADC_V1_CON(x)		((x) + 0x00)
 #define ADC_V1_DLY(x)		((x) + 0x08)
 #define ADC_V1_DATX(x)		((x) + 0x0C)
 #define ADC_V1_INTCLR(x)	((x) + 0x18)
 #define ADC_V1_MUX(x)		((x) + 0x1c)

 /* Future ADC_V2 registers definitions */
 #define ADC_V2_CON1(x)		((x) + 0x00)
 #define ADC_V2_CON2(x)		((x) + 0x04)
 #define ADC_V2_STAT(x)		((x) + 0x08)
 #define ADC_V2_INT_EN(x)	((x) + 0x10)
 #define ADC_V2_INT_ST(x)	((x) + 0x14)
 #define ADC_V2_VER(x)		((x) + 0x20)

 /* Bit definitions for ADC_V1 */
 #define ADC_V1_CON_RES		(1u << 16)
 #define ADC_V1_CON_PRSCEN	(1u << 14)
 #define ADC_V1_CON_PRSCLV(x)	(((x) & 0xFF) << 6)
 #define ADC_V1_CON_STANDBY	(1u << 2)

 /* Bit definitions for ADC_V2 */
 #define ADC_V2_CON1_SOFT_RESET	(1u << 2)

 #define ADC_V2_CON2_OSEL	(1u << 10)
 #define ADC_V2_CON2_ESEL	(1u << 9)
 #define ADC_V2_CON2_HIGHF	(1u << 8)
 #define ADC_V2_CON2_C_TIME(x)	(((x) & 7) << 4)
 #define ADC_V2_CON2_ACH_SEL(x)	(((x) & 0xF) << 0)
 #define ADC_V2_CON2_ACH_MASK	0xF

 #define MAX_ADC_V2_CHANNELS	10
 #define MAX_ADC_V1_CHANNELS	8

 /* Bit definitions common for ADC_V1 and ADC_V2 */
 #define ADC_CON_EN_START	(1u << 0)
 #define ADC_DATX_MASK		0xFFF

 #define EXYNOS_ADC_TIMEOUT	(msecs_to_jiffies(1000))

 struct exynos_adc {
 	void __iomem		*regs;
 	void __iomem		*enable_reg;
 	struct clk		*clk;
 	unsigned int		irq;
 	struct regulator	*vdd;

 	struct completion	completion;

 	u32			value;
 	unsigned int            version;
 };

 static const struct of_device_id exynos_adc_match[] = {
 	{ .compatible = "samsung,exynos-adc-v1", .data = (void *)ADC_V1 },
 	{ .compatible = "samsung,exynos-adc-v2", .data = (void *)ADC_V2 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, exynos_adc_match);

 static inline unsigned int exynos_adc_get_version(struct platform_device *pdev)
 {
 	const struct of_device_id *match;

 	match = of_match_node(exynos_adc_match, pdev->dev.of_node);
 	return (unsigned int)match->data;
 }

 static int exynos_read_raw(struct iio_dev *indio_dev,
 				struct iio_chan_spec const *chan,
 				int *val,
 				int *val2,
 				long mask)
 {
 	struct exynos_adc *info = iio_priv(indio_dev);
 	unsigned long timeout;
 	u32 con1, con2;

 	if (mask != IIO_CHAN_INFO_RAW)
 		return -EINVAL;

 	mutex_lock(&indio_dev->mlock);

 	/* Select the channel to be used and Trigger conversion */
 	if (info->version == ADC_V2) {
 		con2 = readl(ADC_V2_CON2(info->regs));
 		con2 &= ~ADC_V2_CON2_ACH_MASK;
 		con2 |= ADC_V2_CON2_ACH_SEL(chan->address);
 		writel(con2, ADC_V2_CON2(info->regs));

 		con1 = readl(ADC_V2_CON1(info->regs));
 		writel(con1 | ADC_CON_EN_START,
 				ADC_V2_CON1(info->regs));
 	} else {
 		writel(chan->address, ADC_V1_MUX(info->regs));

 		con1 = readl(ADC_V1_CON(info->regs));
 		writel(con1 | ADC_CON_EN_START,
 				ADC_V1_CON(info->regs));
 	}

 	timeout = wait_for_completion_interruptible_timeout
 			(&info->completion, EXYNOS_ADC_TIMEOUT);
 	*val = info->value;

 	mutex_unlock(&indio_dev->mlock);

 	if (timeout == 0)
 		return -ETIMEDOUT;

 	return IIO_VAL_INT;
 }

 static irqreturn_t exynos_adc_isr(int irq, void *dev_id)
 {
 	struct exynos_adc *info = (struct exynos_adc *)dev_id;

 	/* Read value */
 	info->value = readl(ADC_V1_DATX(info->regs)) &
 						ADC_DATX_MASK;
 	/* clear irq */
 	if (info->version == ADC_V2)
 		writel(1, ADC_V2_INT_ST(info->regs));
 	else
 		writel(1, ADC_V1_INTCLR(info->regs));

 	complete(&info->completion);

 	return IRQ_HANDLED;
 }

 static int exynos_adc_reg_access(struct iio_dev *indio_dev,
 			      unsigned reg, unsigned writeval,
 			      unsigned *readval)
 {
 	struct exynos_adc *info = iio_priv(indio_dev);

 	if (readval == NULL)
 		return -EINVAL;

 	*readval = readl(info->regs + reg);

 	return 0;
 }

 static const struct iio_info exynos_adc_iio_info = {
 	.read_raw = &exynos_read_raw,
 	.debugfs_reg_access = &exynos_adc_reg_access,
 	.driver_module = THIS_MODULE,
 };

 #define ADC_CHANNEL(_index, _id) {			\
 	.type = IIO_VOLTAGE,				\
 	.indexed = 1,					\
 	.channel = _index,				\
 	.address = _index,				\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 	.datasheet_name = _id,				\
 }

 static const struct iio_chan_spec exynos_adc_iio_channels[] = {
 	ADC_CHANNEL(0, "adc0"),
 	ADC_CHANNEL(1, "adc1"),
 	ADC_CHANNEL(2, "adc2"),
 	ADC_CHANNEL(3, "adc3"),
 	ADC_CHANNEL(4, "adc4"),
 	ADC_CHANNEL(5, "adc5"),
 	ADC_CHANNEL(6, "adc6"),
 	ADC_CHANNEL(7, "adc7"),
 	ADC_CHANNEL(8, "adc8"),
 	ADC_CHANNEL(9, "adc9"),
 };

 static int exynos_adc_remove_devices(struct device *dev, void *c)
 {
 	struct platform_device *pdev = to_platform_device(dev);

 	platform_device_unregister(pdev);

 	return 0;
 }

 static void exynos_adc_hw_init(struct exynos_adc *info)
 {
 	u32 con1, con2;

 	if (info->version == ADC_V2) {
 		con1 = ADC_V2_CON1_SOFT_RESET;
 		writel(con1, ADC_V2_CON1(info->regs));

 		con2 = ADC_V2_CON2_OSEL | ADC_V2_CON2_ESEL |
 			ADC_V2_CON2_HIGHF | ADC_V2_CON2_C_TIME(0);
 		writel(con2, ADC_V2_CON2(info->regs));

 		/* Enable interrupts */
 		writel(1, ADC_V2_INT_EN(info->regs));
 	} else {
 		/* set default prescaler values and Enable prescaler */
 		con1 =  ADC_V1_CON_PRSCLV(49) | ADC_V1_CON_PRSCEN;

 		/* Enable 12-bit ADC resolution */
 		con1 |= ADC_V1_CON_RES;
 		writel(con1, ADC_V1_CON(info->regs));
 	}
 }

 static int exynos_adc_probe(struct platform_device *pdev)
 {
 	struct exynos_adc *info = NULL;
 	struct device_node *np = pdev->dev.of_node;
 	struct iio_dev *indio_dev = NULL;
 	struct resource	*mem;
 	int ret = -ENODEV;
 	int irq;

 	if (!np)
 		return ret;

 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(struct exynos_adc));
 	if (!indio_dev) {
 		dev_err(&pdev->dev, "failed allocating iio device\n");
 		return -ENOMEM;
 	}

 	info = iio_priv(indio_dev);

 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	info->regs = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(info->regs))
 		return PTR_ERR(info->regs);

 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 	info->enable_reg = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(info->enable_reg))
 		return PTR_ERR(info->enable_reg);

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(&pdev->dev, "no irq resource?\n");
 		return irq;
 	}

 	info->irq = irq;

 	init_completion(&info->completion);

 	ret = request_irq(info->irq, exynos_adc_isr,
 					0, dev_name(&pdev->dev), info);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed requesting irq, irq = %d\n",
 							info->irq);
 		return ret;
 	}

 	writel(1, info->enable_reg);

 	info->clk = devm_clk_get(&pdev->dev, "adc");
 	if (IS_ERR(info->clk)) {
 		dev_err(&pdev->dev, "failed getting clock, err = %ld\n",
 							PTR_ERR(info->clk));
 		ret = PTR_ERR(info->clk);
 		goto err_irq;
 	}

 	info->vdd = devm_regulator_get(&pdev->dev, "vdd");
 	if (IS_ERR(info->vdd)) {
 		dev_err(&pdev->dev, "failed getting regulator, err = %ld\n",
 							PTR_ERR(info->vdd));
 		ret = PTR_ERR(info->vdd);
 		goto err_irq;
 	}

 	info->version = exynos_adc_get_version(pdev);

 	platform_set_drvdata(pdev, indio_dev);

 	indio_dev->name = dev_name(&pdev->dev);
 	indio_dev->dev.parent = &pdev->dev;
 	indio_dev->dev.of_node = pdev->dev.of_node;
 	indio_dev->info = &exynos_adc_iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = exynos_adc_iio_channels;

 	if (info->version == ADC_V1)
 		indio_dev->num_channels = MAX_ADC_V1_CHANNELS;
 	else
 		indio_dev->num_channels = MAX_ADC_V2_CHANNELS;

 	ret = iio_device_register(indio_dev);
 	if (ret)
 		goto err_irq;

 	ret = regulator_enable(info->vdd);
 	if (ret)
 		goto err_iio_dev;

 	clk_prepare_enable(info->clk);

 	exynos_adc_hw_init(info);

 	ret = of_platform_populate(np, exynos_adc_match, NULL, &pdev->dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed adding child nodes\n");
 		goto err_of_populate;
 	}

 	return 0;

 err_of_populate:
 	device_for_each_child(&pdev->dev, NULL,
 				exynos_adc_remove_devices);
 	regulator_disable(info->vdd);
 	clk_disable_unprepare(info->clk);
 err_iio_dev:
 	iio_device_unregister(indio_dev);
 err_irq:
 	free_irq(info->irq, info);
 	return ret;
 }

 static int exynos_adc_remove(struct platform_device *pdev)
 {
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct exynos_adc *info = iio_priv(indio_dev);

 	device_for_each_child(&pdev->dev, NULL,
 				exynos_adc_remove_devices);
 	regulator_disable(info->vdd);
 	clk_disable_unprepare(info->clk);
 	writel(0, info->enable_reg);
 	iio_device_unregister(indio_dev);
 	free_irq(info->irq, info);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int exynos_adc_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct exynos_adc *info = iio_priv(indio_dev);
 	u32 con;

 	if (info->version == ADC_V2) {
 		con = readl(ADC_V2_CON1(info->regs));
 		con &= ~ADC_CON_EN_START;
 		writel(con, ADC_V2_CON1(info->regs));
 	} else {
 		con = readl(ADC_V1_CON(info->regs));
 		con |= ADC_V1_CON_STANDBY;
 		writel(con, ADC_V1_CON(info->regs));
 	}

 	clk_disable_unprepare(info->clk);
 	writel(0, info->enable_reg);
 	regulator_disable(info->vdd);

 	return 0;
 }

 static int exynos_adc_resume(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct exynos_adc *info = iio_priv(indio_dev);
 	int ret;

 	ret = regulator_enable(info->vdd);
 	if (ret)
 		return ret;

 	writel(1, info->enable_reg);
 	clk_prepare_enable(info->clk);

 	exynos_adc_hw_init(info);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(exynos_adc_pm_ops,
 			exynos_adc_suspend,
 			exynos_adc_resume);

 static struct platform_driver exynos_adc_driver = {
 	.probe		= exynos_adc_probe,
 	.remove		= exynos_adc_remove,
 	.driver		= {
 		.name	= "exynos-adc",
 		.owner	= THIS_MODULE,
 		.of_match_table = exynos_adc_match,
 		.pm	= &exynos_adc_pm_ops,
 	},
 };

 module_platform_driver(exynos_adc_driver);

 MODULE_AUTHOR("Naveen Krishna Chatradhi <ch.naveen@samsung.com>");
 MODULE_DESCRIPTION("Samsung EXYNOS5 ADC driver");
 MODULE_LICENSE("GPL v2");
	/*
	* exynos_adc.c - Support for ADC in EXYNOS SoCs
	*
	* 8 ~ 10 channel, 10/12-bit ADC
	*
	* Copyright (C) 2013 Naveen Krishna Chatradhi <ch.naveen@samsung.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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/interrupt.h>
	#include <linux/delay.h>
	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/io.h>
	#include <linux/clk.h>
	#include <linux/completion.h>
	#include <linux/of.h>
	#include <linux/of_irq.h>
	#include <linux/regulator/consumer.h>
	#include <linux/of_platform.h>
	#include <linux/err.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/machine.h>
	#include <linux/iio/driver.h>

	enum adc_version {
	ADC_V1,
	ADC_V2
	};

	/* EXYNOS4412/5250 ADC_V1 registers definitions */
	#define ADC_V1_CON(x) ((x) + 0x00)
	#define ADC_V1_DLY(x) ((x) + 0x08)
	#define ADC_V1_DATX(x) ((x) + 0x0C)
	#define ADC_V1_INTCLR(x) ((x) + 0x18)
	#define ADC_V1_MUX(x) ((x) + 0x1c)

	/* Future ADC_V2 registers definitions */
	#define ADC_V2_CON1(x) ((x) + 0x00)
	#define ADC_V2_CON2(x) ((x) + 0x04)
	#define ADC_V2_STAT(x) ((x) + 0x08)
	#define ADC_V2_INT_EN(x) ((x) + 0x10)
	#define ADC_V2_INT_ST(x) ((x) + 0x14)
	#define ADC_V2_VER(x) ((x) + 0x20)

	/* Bit definitions for ADC_V1 */
	#define ADC_V1_CON_RES (1u << 16)
	#define ADC_V1_CON_PRSCEN (1u << 14)
	#define ADC_V1_CON_PRSCLV(x) (((x) & 0xFF) << 6)
	#define ADC_V1_CON_STANDBY (1u << 2)

	/* Bit definitions for ADC_V2 */
	#define ADC_V2_CON1_SOFT_RESET (1u << 2)

	#define ADC_V2_CON2_OSEL (1u << 10)
	#define ADC_V2_CON2_ESEL (1u << 9)
	#define ADC_V2_CON2_HIGHF (1u << 8)
	#define ADC_V2_CON2_C_TIME(x) (((x) & 7) << 4)
	#define ADC_V2_CON2_ACH_SEL(x) (((x) & 0xF) << 0)
	#define ADC_V2_CON2_ACH_MASK 0xF

	#define MAX_ADC_V2_CHANNELS 10
	#define MAX_ADC_V1_CHANNELS 8

	/* Bit definitions common for ADC_V1 and ADC_V2 */
	#define ADC_CON_EN_START (1u << 0)
	#define ADC_DATX_MASK 0xFFF

	#define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(1000))

	struct exynos_adc {
	void __iomem *regs;
	void __iomem *enable_reg;
	struct clk *clk;
	unsigned int irq;
	struct regulator *vdd;

	struct completion completion;

	u32 value;
	unsigned int version;
	};

	static const struct of_device_id exynos_adc_match[] = {
	{ .compatible = "samsung,exynos-adc-v1", .data = (void *)ADC_V1 },
	{ .compatible = "samsung,exynos-adc-v2", .data = (void *)ADC_V2 },
	{},
	};
	MODULE_DEVICE_TABLE(of, exynos_adc_match);

	static inline unsigned int exynos_adc_get_version(struct platform_device *pdev)
	{
	const struct of_device_id *match;

	match = of_match_node(exynos_adc_match, pdev->dev.of_node);
	return (unsigned int)match->data;
	}

	static int exynos_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long mask)
	{
	struct exynos_adc *info = iio_priv(indio_dev);
	unsigned long timeout;
	u32 con1, con2;

	if (mask != IIO_CHAN_INFO_RAW)
	return -EINVAL;

	mutex_lock(&indio_dev->mlock);

	/* Select the channel to be used and Trigger conversion */
	if (info->version == ADC_V2) {
	con2 = readl(ADC_V2_CON2(info->regs));
	con2 &= ~ADC_V2_CON2_ACH_MASK;
	con2 \|= ADC_V2_CON2_ACH_SEL(chan->address);
	writel(con2, ADC_V2_CON2(info->regs));

	con1 = readl(ADC_V2_CON1(info->regs));
	writel(con1 \| ADC_CON_EN_START,
	ADC_V2_CON1(info->regs));
	} else {
	writel(chan->address, ADC_V1_MUX(info->regs));

	con1 = readl(ADC_V1_CON(info->regs));
	writel(con1 \| ADC_CON_EN_START,
	ADC_V1_CON(info->regs));
	}

	timeout = wait_for_completion_interruptible_timeout
	(&info->completion, EXYNOS_ADC_TIMEOUT);
	*val = info->value;

	mutex_unlock(&indio_dev->mlock);

	if (timeout == 0)
	return -ETIMEDOUT;

	return IIO_VAL_INT;
	}

	static irqreturn_t exynos_adc_isr(int irq, void *dev_id)
	{
	struct exynos_adc info = (struct exynos_adc )dev_id;

	/* Read value */
	info->value = readl(ADC_V1_DATX(info->regs)) &
	ADC_DATX_MASK;
	/* clear irq */
	if (info->version == ADC_V2)
	writel(1, ADC_V2_INT_ST(info->regs));
	else
	writel(1, ADC_V1_INTCLR(info->regs));

	complete(&info->completion);

	return IRQ_HANDLED;
	}

	static int exynos_adc_reg_access(struct iio_dev *indio_dev,
	unsigned reg, unsigned writeval,
	unsigned *readval)
	{
	struct exynos_adc *info = iio_priv(indio_dev);

	if (readval == NULL)
	return -EINVAL;

	*readval = readl(info->regs + reg);

	return 0;
	}

	static const struct iio_info exynos_adc_iio_info = {
	.read_raw = &exynos_read_raw,
	.debugfs_reg_access = &exynos_adc_reg_access,
	.driver_module = THIS_MODULE,
	};

	#define ADC_CHANNEL(_index, _id) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = _index, \
	.address = _index, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.datasheet_name = _id, \
	}

	static const struct iio_chan_spec exynos_adc_iio_channels[] = {
	ADC_CHANNEL(0, "adc0"),
	ADC_CHANNEL(1, "adc1"),
	ADC_CHANNEL(2, "adc2"),
	ADC_CHANNEL(3, "adc3"),
	ADC_CHANNEL(4, "adc4"),
	ADC_CHANNEL(5, "adc5"),
	ADC_CHANNEL(6, "adc6"),
	ADC_CHANNEL(7, "adc7"),
	ADC_CHANNEL(8, "adc8"),
	ADC_CHANNEL(9, "adc9"),
	};

	static int exynos_adc_remove_devices(struct device dev, void c)
	{
	struct platform_device *pdev = to_platform_device(dev);

	platform_device_unregister(pdev);

	return 0;
	}

	static void exynos_adc_hw_init(struct exynos_adc *info)
	{
	u32 con1, con2;

	if (info->version == ADC_V2) {
	con1 = ADC_V2_CON1_SOFT_RESET;
	writel(con1, ADC_V2_CON1(info->regs));

	con2 = ADC_V2_CON2_OSEL \| ADC_V2_CON2_ESEL \|
	ADC_V2_CON2_HIGHF \| ADC_V2_CON2_C_TIME(0);
	writel(con2, ADC_V2_CON2(info->regs));

	/* Enable interrupts */
	writel(1, ADC_V2_INT_EN(info->regs));
	} else {
	/* set default prescaler values and Enable prescaler */
	con1 = ADC_V1_CON_PRSCLV(49) \| ADC_V1_CON_PRSCEN;

	/* Enable 12-bit ADC resolution */
	con1 \|= ADC_V1_CON_RES;
	writel(con1, ADC_V1_CON(info->regs));
	}
	}

	static int exynos_adc_probe(struct platform_device *pdev)
	{
	struct exynos_adc *info = NULL;
	struct device_node *np = pdev->dev.of_node;
	struct iio_dev *indio_dev = NULL;
	struct resource *mem;
	int ret = -ENODEV;
	int irq;

	if (!np)
	return ret;

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(struct exynos_adc));
	if (!indio_dev) {
	dev_err(&pdev->dev, "failed allocating iio device\n");
	return -ENOMEM;
	}

	info = iio_priv(indio_dev);

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	info->regs = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(info->regs))
	return PTR_ERR(info->regs);

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	info->enable_reg = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(info->enable_reg))
	return PTR_ERR(info->enable_reg);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
	dev_err(&pdev->dev, "no irq resource?\n");
	return irq;
	}

	info->irq = irq;

	init_completion(&info->completion);

	ret = request_irq(info->irq, exynos_adc_isr,
	0, dev_name(&pdev->dev), info);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed requesting irq, irq = %d\n",
	info->irq);
	return ret;
	}

	writel(1, info->enable_reg);

	info->clk = devm_clk_get(&pdev->dev, "adc");
	if (IS_ERR(info->clk)) {
	dev_err(&pdev->dev, "failed getting clock, err = %ld\n",
	PTR_ERR(info->clk));
	ret = PTR_ERR(info->clk);
	goto err_irq;
	}

	info->vdd = devm_regulator_get(&pdev->dev, "vdd");
	if (IS_ERR(info->vdd)) {
	dev_err(&pdev->dev, "failed getting regulator, err = %ld\n",
	PTR_ERR(info->vdd));
	ret = PTR_ERR(info->vdd);
	goto err_irq;
	}

	info->version = exynos_adc_get_version(pdev);

	platform_set_drvdata(pdev, indio_dev);

	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->dev.parent = &pdev->dev;
	indio_dev->dev.of_node = pdev->dev.of_node;
	indio_dev->info = &exynos_adc_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = exynos_adc_iio_channels;

	if (info->version == ADC_V1)
	indio_dev->num_channels = MAX_ADC_V1_CHANNELS;
	else
	indio_dev->num_channels = MAX_ADC_V2_CHANNELS;

	ret = iio_device_register(indio_dev);
	if (ret)
	goto err_irq;

	ret = regulator_enable(info->vdd);
	if (ret)
	goto err_iio_dev;

	clk_prepare_enable(info->clk);

	exynos_adc_hw_init(info);

	ret = of_platform_populate(np, exynos_adc_match, NULL, &pdev->dev);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed adding child nodes\n");
	goto err_of_populate;
	}

	return 0;

	err_of_populate:
	device_for_each_child(&pdev->dev, NULL,
	exynos_adc_remove_devices);
	regulator_disable(info->vdd);
	clk_disable_unprepare(info->clk);
	err_iio_dev:
	iio_device_unregister(indio_dev);
	err_irq:
	free_irq(info->irq, info);
	return ret;
	}

	static int exynos_adc_remove(struct platform_device *pdev)
	{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct exynos_adc *info = iio_priv(indio_dev);

	device_for_each_child(&pdev->dev, NULL,
	exynos_adc_remove_devices);
	regulator_disable(info->vdd);
	clk_disable_unprepare(info->clk);
	writel(0, info->enable_reg);
	iio_device_unregister(indio_dev);
	free_irq(info->irq, info);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int exynos_adc_suspend(struct device *dev)
	{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct exynos_adc *info = iio_priv(indio_dev);
	u32 con;

	if (info->version == ADC_V2) {
	con = readl(ADC_V2_CON1(info->regs));
	con &= ~ADC_CON_EN_START;
	writel(con, ADC_V2_CON1(info->regs));
	} else {
	con = readl(ADC_V1_CON(info->regs));
	con \|= ADC_V1_CON_STANDBY;
	writel(con, ADC_V1_CON(info->regs));
	}

	clk_disable_unprepare(info->clk);
	writel(0, info->enable_reg);
	regulator_disable(info->vdd);

	return 0;
	}

	static int exynos_adc_resume(struct device *dev)
	{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	struct exynos_adc *info = iio_priv(indio_dev);
	int ret;

	ret = regulator_enable(info->vdd);
	if (ret)
	return ret;

	writel(1, info->enable_reg);
	clk_prepare_enable(info->clk);

	exynos_adc_hw_init(info);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(exynos_adc_pm_ops,
	exynos_adc_suspend,
	exynos_adc_resume);

	static struct platform_driver exynos_adc_driver = {
	.probe = exynos_adc_probe,
	.remove = exynos_adc_remove,
	.driver = {
	.name = "exynos-adc",
	.owner = THIS_MODULE,
	.of_match_table = exynos_adc_match,
	.pm = &exynos_adc_pm_ops,
	},
	};

	module_platform_driver(exynos_adc_driver);

	MODULE_AUTHOR("Naveen Krishna Chatradhi <ch.naveen@samsung.com>");
	MODULE_DESCRIPTION("Samsung EXYNOS5 ADC driver");
	MODULE_LICENSE("GPL v2");