drivers/iio/adc/fsl-imx25-gcq.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
  *
  * This is the driver for the imx25 GCQ (Generic Conversion Queue)
  * connected to the imx25 ADC.
  */

 #include <dt-bindings/iio/adc/fsl-imx25-gcq.h>
 #include <linux/clk.h>
 #include <linux/iio/iio.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/imx25-tsadc.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>

 #define MX25_GCQ_TIMEOUT (msecs_to_jiffies(2000))

 static const char * const driver_name = "mx25-gcq";

 enum mx25_gcq_cfgs {
 	MX25_CFG_XP = 0,
 	MX25_CFG_YP,
 	MX25_CFG_XN,
 	MX25_CFG_YN,
 	MX25_CFG_WIPER,
 	MX25_CFG_INAUX0,
 	MX25_CFG_INAUX1,
 	MX25_CFG_INAUX2,
 	MX25_NUM_CFGS,
 };

 struct mx25_gcq_priv {
 	struct regmap *regs;
 	struct completion completed;
 	struct clk *clk;
 	int irq;
 	struct regulator *vref[4];
 	u32 channel_vref_mv[MX25_NUM_CFGS];
 };

 #define MX25_CQG_CHAN(chan, id) {\
 	.type = IIO_VOLTAGE,\
 	.indexed = 1,\
 	.channel = chan,\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 			      BIT(IIO_CHAN_INFO_SCALE),\
 	.datasheet_name = id,\
 }

 static const struct iio_chan_spec mx25_gcq_channels[MX25_NUM_CFGS] = {
 	MX25_CQG_CHAN(MX25_CFG_XP, "xp"),
 	MX25_CQG_CHAN(MX25_CFG_YP, "yp"),
 	MX25_CQG_CHAN(MX25_CFG_XN, "xn"),
 	MX25_CQG_CHAN(MX25_CFG_YN, "yn"),
 	MX25_CQG_CHAN(MX25_CFG_WIPER, "wiper"),
 	MX25_CQG_CHAN(MX25_CFG_INAUX0, "inaux0"),
 	MX25_CQG_CHAN(MX25_CFG_INAUX1, "inaux1"),
 	MX25_CQG_CHAN(MX25_CFG_INAUX2, "inaux2"),
 };

 static const char * const mx25_gcq_refp_names[] = {
 	[MX25_ADC_REFP_YP] = "yp",
 	[MX25_ADC_REFP_XP] = "xp",
 	[MX25_ADC_REFP_INT] = "int",
 	[MX25_ADC_REFP_EXT] = "ext",
 };

 static irqreturn_t mx25_gcq_irq(int irq, void *data)
 {
 	struct mx25_gcq_priv *priv = data;
 	u32 stats;

 	regmap_read(priv->regs, MX25_ADCQ_SR, &stats);

 	if (stats & MX25_ADCQ_SR_EOQ) {
 		regmap_update_bits(priv->regs, MX25_ADCQ_MR,
 				   MX25_ADCQ_MR_EOQ_IRQ, MX25_ADCQ_MR_EOQ_IRQ);
 		complete(&priv->completed);
 	}

 	/* Disable conversion queue run */
 	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS, 0);

 	/* Acknowledge all possible irqs */
 	regmap_write(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR |
 		     MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR |
 		     MX25_ADCQ_SR_EOQ | MX25_ADCQ_SR_PD);

 	return IRQ_HANDLED;
 }

 static int mx25_gcq_get_raw_value(struct device *dev,
 				  struct iio_chan_spec const *chan,
 				  struct mx25_gcq_priv *priv,
 				  int *val)
 {
 	long timeout;
 	u32 data;

 	/* Setup the configuration we want to use */
 	regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
 		     MX25_ADCQ_ITEM(0, chan->channel));

 	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_EOQ_IRQ, 0);

 	/* Trigger queue for one run */
 	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS,
 			   MX25_ADCQ_CR_FQS);

 	timeout = wait_for_completion_interruptible_timeout(
 		&priv->completed, MX25_GCQ_TIMEOUT);
 	if (timeout < 0) {
 		dev_err(dev, "ADC wait for measurement failed\n");
 		return timeout;
 	} else if (timeout == 0) {
 		dev_err(dev, "ADC timed out\n");
 		return -ETIMEDOUT;
 	}

 	regmap_read(priv->regs, MX25_ADCQ_FIFO, &data);

 	*val = MX25_ADCQ_FIFO_DATA(data);

 	return IIO_VAL_INT;
 }

 static int mx25_gcq_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan, int *val,
 			     int *val2, long mask)
 {
 	struct mx25_gcq_priv *priv = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&indio_dev->mlock);
 		ret = mx25_gcq_get_raw_value(&indio_dev->dev, chan, priv, val);
 		mutex_unlock(&indio_dev->mlock);
 		return ret;

 	case IIO_CHAN_INFO_SCALE:
 		*val = priv->channel_vref_mv[chan->channel];
 		*val2 = 12;
 		return IIO_VAL_FRACTIONAL_LOG2;

 	default:
 		return -EINVAL;
 	}
 }

 static const struct iio_info mx25_gcq_iio_info = {
 	.read_raw = mx25_gcq_read_raw,
 };

 static const struct regmap_config mx25_gcq_regconfig = {
 	.max_register = 0x5c,
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,
 };

 static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
 			       struct mx25_gcq_priv *priv)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *child;
 	struct device *dev = &pdev->dev;
 	unsigned int refp_used[4] = {};
 	int ret, i;

 	/*
 	 * Setup all configurations registers with a default conversion
 	 * configuration for each input
 	 */
 	for (i = 0; i < MX25_NUM_CFGS; ++i)
 		regmap_write(priv->regs, MX25_ADCQ_CFG(i),
 			     MX25_ADCQ_CFG_YPLL_OFF |
 			     MX25_ADCQ_CFG_XNUR_OFF |
 			     MX25_ADCQ_CFG_XPUL_OFF |
 			     MX25_ADCQ_CFG_REFP_INT |
 			     MX25_ADCQ_CFG_IN(i) |
 			     MX25_ADCQ_CFG_REFN_NGND2);

 	/*
 	 * First get all regulators to store them in channel_vref_mv if
 	 * necessary. Later we use that information for proper IIO scale
 	 * information.
 	 */
 	priv->vref[MX25_ADC_REFP_INT] = NULL;
 	priv->vref[MX25_ADC_REFP_EXT] =
 		devm_regulator_get_optional(&pdev->dev, "vref-ext");
 	priv->vref[MX25_ADC_REFP_XP] =
 		devm_regulator_get_optional(&pdev->dev, "vref-xp");
 	priv->vref[MX25_ADC_REFP_YP] =
 		devm_regulator_get_optional(&pdev->dev, "vref-yp");

 	for_each_child_of_node(np, child) {
 		u32 reg;
 		u32 refp = MX25_ADCQ_CFG_REFP_INT;
 		u32 refn = MX25_ADCQ_CFG_REFN_NGND2;

 		ret = of_property_read_u32(child, "reg", &reg);
 		if (ret) {
 			dev_err(dev, "Failed to get reg property\n");
 			of_node_put(child);
 			return ret;
 		}

 		if (reg >= MX25_NUM_CFGS) {
 			dev_err(dev,
 				"reg value is greater than the number of available configuration registers\n");
 			of_node_put(child);
 			return -EINVAL;
 		}

 		of_property_read_u32(child, "fsl,adc-refp", &refp);
 		of_property_read_u32(child, "fsl,adc-refn", &refn);

 		switch (refp) {
 		case MX25_ADC_REFP_EXT:
 		case MX25_ADC_REFP_XP:
 		case MX25_ADC_REFP_YP:
 			if (IS_ERR(priv->vref[refp])) {
 				dev_err(dev, "Error, trying to use external voltage reference without a vref-%s regulator.",
 					mx25_gcq_refp_names[refp]);
 				of_node_put(child);
 				return PTR_ERR(priv->vref[refp]);
 			}
 			priv->channel_vref_mv[reg] =
 				regulator_get_voltage(priv->vref[refp]);
 			/* Conversion from uV to mV */
 			priv->channel_vref_mv[reg] /= 1000;
 			break;
 		case MX25_ADC_REFP_INT:
 			priv->channel_vref_mv[reg] = 2500;
 			break;
 		default:
 			dev_err(dev, "Invalid positive reference %d\n", refp);
 			of_node_put(child);
 			return -EINVAL;
 		}

 		++refp_used[refp];

 		/*
 		 * Shift the read values to the correct positions within the
 		 * register.
 		 */
 		refp = MX25_ADCQ_CFG_REFP(refp);
 		refn = MX25_ADCQ_CFG_REFN(refn);

 		if ((refp & MX25_ADCQ_CFG_REFP_MASK) != refp) {
 			dev_err(dev, "Invalid fsl,adc-refp property value\n");
 			of_node_put(child);
 			return -EINVAL;
 		}
 		if ((refn & MX25_ADCQ_CFG_REFN_MASK) != refn) {
 			dev_err(dev, "Invalid fsl,adc-refn property value\n");
 			of_node_put(child);
 			return -EINVAL;
 		}

 		regmap_update_bits(priv->regs, MX25_ADCQ_CFG(reg),
 				   MX25_ADCQ_CFG_REFP_MASK |
 				   MX25_ADCQ_CFG_REFN_MASK,
 				   refp | refn);
 	}
 	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
 			   MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST,
 			   MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST);

 	regmap_write(priv->regs, MX25_ADCQ_CR,
 		     MX25_ADCQ_CR_PDMSK | MX25_ADCQ_CR_QSM_FQS);

 	/* Remove unused regulators */
 	for (i = 0; i != 4; ++i) {
 		if (!refp_used[i]) {
 			if (!IS_ERR_OR_NULL(priv->vref[i]))
 				devm_regulator_put(priv->vref[i]);
 			priv->vref[i] = NULL;
 		}
 	}

 	return 0;
 }

 static int mx25_gcq_probe(struct platform_device *pdev)
 {
 	struct iio_dev *indio_dev;
 	struct mx25_gcq_priv *priv;
 	struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent);
 	struct device *dev = &pdev->dev;
 	void __iomem *mem;
 	int ret;
 	int i;

 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
 	if (!indio_dev)
 		return -ENOMEM;

 	priv = iio_priv(indio_dev);

 	mem = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mem))
 		return PTR_ERR(mem);

 	priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_gcq_regconfig);
 	if (IS_ERR(priv->regs)) {
 		dev_err(dev, "Failed to initialize regmap\n");
 		return PTR_ERR(priv->regs);
 	}

 	init_completion(&priv->completed);

 	ret = mx25_gcq_setup_cfgs(pdev, priv);
 	if (ret)
 		return ret;

 	for (i = 0; i != 4; ++i) {
 		if (!priv->vref[i])
 			continue;

 		ret = regulator_enable(priv->vref[i]);
 		if (ret)
 			goto err_regulator_disable;
 	}

 	priv->clk = tsadc->clk;
 	ret = clk_prepare_enable(priv->clk);
 	if (ret) {
 		dev_err(dev, "Failed to enable clock\n");
 		goto err_vref_disable;
 	}

 	priv->irq = platform_get_irq(pdev, 0);
 	if (priv->irq <= 0) {
 		ret = priv->irq;
 		if (!ret)
 			ret = -ENXIO;
 		goto err_clk_unprepare;
 	}

 	ret = request_irq(priv->irq, mx25_gcq_irq, 0, pdev->name, priv);
 	if (ret) {
 		dev_err(dev, "Failed requesting IRQ\n");
 		goto err_clk_unprepare;
 	}

 	indio_dev->dev.parent = &pdev->dev;
 	indio_dev->channels = mx25_gcq_channels;
 	indio_dev->num_channels = ARRAY_SIZE(mx25_gcq_channels);
 	indio_dev->info = &mx25_gcq_iio_info;
 	indio_dev->name = driver_name;

 	ret = iio_device_register(indio_dev);
 	if (ret) {
 		dev_err(dev, "Failed to register iio device\n");
 		goto err_irq_free;
 	}

 	platform_set_drvdata(pdev, indio_dev);

 	return 0;

 err_irq_free:
 	free_irq(priv->irq, priv);
 err_clk_unprepare:
 	clk_disable_unprepare(priv->clk);
 err_vref_disable:
 	i = 4;
 err_regulator_disable:
 	for (; i-- > 0;) {
 		if (priv->vref[i])
 			regulator_disable(priv->vref[i]);
 	}
 	return ret;
 }

 static int mx25_gcq_remove(struct platform_device *pdev)
 {
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct mx25_gcq_priv *priv = iio_priv(indio_dev);
 	int i;

 	iio_device_unregister(indio_dev);
 	free_irq(priv->irq, priv);
 	clk_disable_unprepare(priv->clk);
 	for (i = 4; i-- > 0;) {
 		if (priv->vref[i])
 			regulator_disable(priv->vref[i]);
 	}

 	return 0;
 }

 static const struct of_device_id mx25_gcq_ids[] = {
 	{ .compatible = "fsl,imx25-gcq", },
 	{ /* Sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, mx25_gcq_ids);

 static struct platform_driver mx25_gcq_driver = {
 	.driver		= {
 		.name	= "mx25-gcq",
 		.of_match_table = mx25_gcq_ids,
 	},
 	.probe		= mx25_gcq_probe,
 	.remove		= mx25_gcq_remove,
 };
 module_platform_driver(mx25_gcq_driver);

 MODULE_DESCRIPTION("ADC driver for Freescale mx25");
 MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
	*
	* This is the driver for the imx25 GCQ (Generic Conversion Queue)
	* connected to the imx25 ADC.
	*/

	#include <dt-bindings/iio/adc/fsl-imx25-gcq.h>
	#include <linux/clk.h>
	#include <linux/iio/iio.h>
	#include <linux/interrupt.h>
	#include <linux/mfd/imx25-tsadc.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/regulator/consumer.h>

	#define MX25_GCQ_TIMEOUT (msecs_to_jiffies(2000))

	static const char * const driver_name = "mx25-gcq";

	enum mx25_gcq_cfgs {
	MX25_CFG_XP = 0,
	MX25_CFG_YP,
	MX25_CFG_XN,
	MX25_CFG_YN,
	MX25_CFG_WIPER,
	MX25_CFG_INAUX0,
	MX25_CFG_INAUX1,
	MX25_CFG_INAUX2,
	MX25_NUM_CFGS,
	};

	struct mx25_gcq_priv {
	struct regmap *regs;
	struct completion completed;
	struct clk *clk;
	int irq;
	struct regulator *vref[4];
	u32 channel_vref_mv[MX25_NUM_CFGS];
	};

	#define MX25_CQG_CHAN(chan, id) {\
	.type = IIO_VOLTAGE,\
	.indexed = 1,\
	.channel = chan,\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \| \
	BIT(IIO_CHAN_INFO_SCALE),\
	.datasheet_name = id,\
	}

	static const struct iio_chan_spec mx25_gcq_channels[MX25_NUM_CFGS] = {
	MX25_CQG_CHAN(MX25_CFG_XP, "xp"),
	MX25_CQG_CHAN(MX25_CFG_YP, "yp"),
	MX25_CQG_CHAN(MX25_CFG_XN, "xn"),
	MX25_CQG_CHAN(MX25_CFG_YN, "yn"),
	MX25_CQG_CHAN(MX25_CFG_WIPER, "wiper"),
	MX25_CQG_CHAN(MX25_CFG_INAUX0, "inaux0"),
	MX25_CQG_CHAN(MX25_CFG_INAUX1, "inaux1"),
	MX25_CQG_CHAN(MX25_CFG_INAUX2, "inaux2"),
	};

	static const char * const mx25_gcq_refp_names[] = {
	[MX25_ADC_REFP_YP] = "yp",
	[MX25_ADC_REFP_XP] = "xp",
	[MX25_ADC_REFP_INT] = "int",
	[MX25_ADC_REFP_EXT] = "ext",
	};

	static irqreturn_t mx25_gcq_irq(int irq, void *data)
	{
	struct mx25_gcq_priv *priv = data;
	u32 stats;

	regmap_read(priv->regs, MX25_ADCQ_SR, &stats);

	if (stats & MX25_ADCQ_SR_EOQ) {
	regmap_update_bits(priv->regs, MX25_ADCQ_MR,
	MX25_ADCQ_MR_EOQ_IRQ, MX25_ADCQ_MR_EOQ_IRQ);
	complete(&priv->completed);
	}

	/* Disable conversion queue run */
	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS, 0);

	/* Acknowledge all possible irqs */
	regmap_write(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR \|
	MX25_ADCQ_SR_FUR \| MX25_ADCQ_SR_FOR \|
	MX25_ADCQ_SR_EOQ \| MX25_ADCQ_SR_PD);

	return IRQ_HANDLED;
	}

	static int mx25_gcq_get_raw_value(struct device *dev,
	struct iio_chan_spec const *chan,
	struct mx25_gcq_priv *priv,
	int *val)
	{
	long timeout;
	u32 data;

	/* Setup the configuration we want to use */
	regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0,
	MX25_ADCQ_ITEM(0, chan->channel));

	regmap_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_EOQ_IRQ, 0);

	/* Trigger queue for one run */
	regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS,
	MX25_ADCQ_CR_FQS);

	timeout = wait_for_completion_interruptible_timeout(
	&priv->completed, MX25_GCQ_TIMEOUT);
	if (timeout < 0) {
	dev_err(dev, "ADC wait for measurement failed\n");
	return timeout;
	} else if (timeout == 0) {
	dev_err(dev, "ADC timed out\n");
	return -ETIMEDOUT;
	}

	regmap_read(priv->regs, MX25_ADCQ_FIFO, &data);

	*val = MX25_ADCQ_FIFO_DATA(data);

	return IIO_VAL_INT;
	}

	static int mx25_gcq_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const chan, int val,
	int *val2, long mask)
	{
	struct mx25_gcq_priv *priv = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	mutex_lock(&indio_dev->mlock);
	ret = mx25_gcq_get_raw_value(&indio_dev->dev, chan, priv, val);
	mutex_unlock(&indio_dev->mlock);
	return ret;

	case IIO_CHAN_INFO_SCALE:
	*val = priv->channel_vref_mv[chan->channel];
	*val2 = 12;
	return IIO_VAL_FRACTIONAL_LOG2;

	default:
	return -EINVAL;
	}
	}

	static const struct iio_info mx25_gcq_iio_info = {
	.read_raw = mx25_gcq_read_raw,
	};

	static const struct regmap_config mx25_gcq_regconfig = {
	.max_register = 0x5c,
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
	};

	static int mx25_gcq_setup_cfgs(struct platform_device *pdev,
	struct mx25_gcq_priv *priv)
	{
	struct device_node *np = pdev->dev.of_node;
	struct device_node *child;
	struct device *dev = &pdev->dev;
	unsigned int refp_used[4] = {};
	int ret, i;

	/*
	* Setup all configurations registers with a default conversion
	* configuration for each input
	*/
	for (i = 0; i < MX25_NUM_CFGS; ++i)
	regmap_write(priv->regs, MX25_ADCQ_CFG(i),
	MX25_ADCQ_CFG_YPLL_OFF \|
	MX25_ADCQ_CFG_XNUR_OFF \|
	MX25_ADCQ_CFG_XPUL_OFF \|
	MX25_ADCQ_CFG_REFP_INT \|
	MX25_ADCQ_CFG_IN(i) \|
	MX25_ADCQ_CFG_REFN_NGND2);

	/*
	* First get all regulators to store them in channel_vref_mv if
	* necessary. Later we use that information for proper IIO scale
	* information.
	*/
	priv->vref[MX25_ADC_REFP_INT] = NULL;
	priv->vref[MX25_ADC_REFP_EXT] =
	devm_regulator_get_optional(&pdev->dev, "vref-ext");
	priv->vref[MX25_ADC_REFP_XP] =
	devm_regulator_get_optional(&pdev->dev, "vref-xp");
	priv->vref[MX25_ADC_REFP_YP] =
	devm_regulator_get_optional(&pdev->dev, "vref-yp");

	for_each_child_of_node(np, child) {
	u32 reg;
	u32 refp = MX25_ADCQ_CFG_REFP_INT;
	u32 refn = MX25_ADCQ_CFG_REFN_NGND2;

	ret = of_property_read_u32(child, "reg", &reg);
	if (ret) {
	dev_err(dev, "Failed to get reg property\n");
	of_node_put(child);
	return ret;
	}

	if (reg >= MX25_NUM_CFGS) {
	dev_err(dev,
	"reg value is greater than the number of available configuration registers\n");
	of_node_put(child);
	return -EINVAL;
	}

	of_property_read_u32(child, "fsl,adc-refp", &refp);
	of_property_read_u32(child, "fsl,adc-refn", &refn);

	switch (refp) {
	case MX25_ADC_REFP_EXT:
	case MX25_ADC_REFP_XP:
	case MX25_ADC_REFP_YP:
	if (IS_ERR(priv->vref[refp])) {
	dev_err(dev, "Error, trying to use external voltage reference without a vref-%s regulator.",
	mx25_gcq_refp_names[refp]);
	of_node_put(child);
	return PTR_ERR(priv->vref[refp]);
	}
	priv->channel_vref_mv[reg] =
	regulator_get_voltage(priv->vref[refp]);
	/* Conversion from uV to mV */
	priv->channel_vref_mv[reg] /= 1000;
	break;
	case MX25_ADC_REFP_INT:
	priv->channel_vref_mv[reg] = 2500;
	break;
	default:
	dev_err(dev, "Invalid positive reference %d\n", refp);
	of_node_put(child);
	return -EINVAL;
	}

	++refp_used[refp];

	/*
	* Shift the read values to the correct positions within the
	* register.
	*/
	refp = MX25_ADCQ_CFG_REFP(refp);
	refn = MX25_ADCQ_CFG_REFN(refn);

	if ((refp & MX25_ADCQ_CFG_REFP_MASK) != refp) {
	dev_err(dev, "Invalid fsl,adc-refp property value\n");
	of_node_put(child);
	return -EINVAL;
	}
	if ((refn & MX25_ADCQ_CFG_REFN_MASK) != refn) {
	dev_err(dev, "Invalid fsl,adc-refn property value\n");
	of_node_put(child);
	return -EINVAL;
	}

	regmap_update_bits(priv->regs, MX25_ADCQ_CFG(reg),
	MX25_ADCQ_CFG_REFP_MASK \|
	MX25_ADCQ_CFG_REFN_MASK,
	refp \| refn);
	}
	regmap_update_bits(priv->regs, MX25_ADCQ_CR,
	MX25_ADCQ_CR_FRST \| MX25_ADCQ_CR_QRST,
	MX25_ADCQ_CR_FRST \| MX25_ADCQ_CR_QRST);

	regmap_write(priv->regs, MX25_ADCQ_CR,
	MX25_ADCQ_CR_PDMSK \| MX25_ADCQ_CR_QSM_FQS);

	/* Remove unused regulators */
	for (i = 0; i != 4; ++i) {
	if (!refp_used[i]) {
	if (!IS_ERR_OR_NULL(priv->vref[i]))
	devm_regulator_put(priv->vref[i]);
	priv->vref[i] = NULL;
	}
	}

	return 0;
	}

	static int mx25_gcq_probe(struct platform_device *pdev)
	{
	struct iio_dev *indio_dev;
	struct mx25_gcq_priv *priv;
	struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent);
	struct device *dev = &pdev->dev;
	void __iomem *mem;
	int ret;
	int i;

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
	if (!indio_dev)
	return -ENOMEM;

	priv = iio_priv(indio_dev);

	mem = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(mem))
	return PTR_ERR(mem);

	priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_gcq_regconfig);
	if (IS_ERR(priv->regs)) {
	dev_err(dev, "Failed to initialize regmap\n");
	return PTR_ERR(priv->regs);
	}

	init_completion(&priv->completed);

	ret = mx25_gcq_setup_cfgs(pdev, priv);
	if (ret)
	return ret;

	for (i = 0; i != 4; ++i) {
	if (!priv->vref[i])
	continue;

	ret = regulator_enable(priv->vref[i]);
	if (ret)
	goto err_regulator_disable;
	}

	priv->clk = tsadc->clk;
	ret = clk_prepare_enable(priv->clk);
	if (ret) {
	dev_err(dev, "Failed to enable clock\n");
	goto err_vref_disable;
	}

	priv->irq = platform_get_irq(pdev, 0);
	if (priv->irq <= 0) {
	ret = priv->irq;
	if (!ret)
	ret = -ENXIO;
	goto err_clk_unprepare;
	}

	ret = request_irq(priv->irq, mx25_gcq_irq, 0, pdev->name, priv);
	if (ret) {
	dev_err(dev, "Failed requesting IRQ\n");
	goto err_clk_unprepare;
	}

	indio_dev->dev.parent = &pdev->dev;
	indio_dev->channels = mx25_gcq_channels;
	indio_dev->num_channels = ARRAY_SIZE(mx25_gcq_channels);
	indio_dev->info = &mx25_gcq_iio_info;
	indio_dev->name = driver_name;

	ret = iio_device_register(indio_dev);
	if (ret) {
	dev_err(dev, "Failed to register iio device\n");
	goto err_irq_free;
	}

	platform_set_drvdata(pdev, indio_dev);

	return 0;

	err_irq_free:
	free_irq(priv->irq, priv);
	err_clk_unprepare:
	clk_disable_unprepare(priv->clk);
	err_vref_disable:
	i = 4;
	err_regulator_disable:
	for (; i-- > 0;) {
	if (priv->vref[i])
	regulator_disable(priv->vref[i]);
	}
	return ret;
	}

	static int mx25_gcq_remove(struct platform_device *pdev)
	{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct mx25_gcq_priv *priv = iio_priv(indio_dev);
	int i;

	iio_device_unregister(indio_dev);
	free_irq(priv->irq, priv);
	clk_disable_unprepare(priv->clk);
	for (i = 4; i-- > 0;) {
	if (priv->vref[i])
	regulator_disable(priv->vref[i]);
	}

	return 0;
	}

	static const struct of_device_id mx25_gcq_ids[] = {
	{ .compatible = "fsl,imx25-gcq", },
	{ /* Sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, mx25_gcq_ids);

	static struct platform_driver mx25_gcq_driver = {
	.driver = {
	.name = "mx25-gcq",
	.of_match_table = mx25_gcq_ids,
	},
	.probe = mx25_gcq_probe,
	.remove = mx25_gcq_remove,
	};
	module_platform_driver(mx25_gcq_driver);

	MODULE_DESCRIPTION("ADC driver for Freescale mx25");
	MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
	MODULE_LICENSE("GPL v2");