drivers/iio/adc/ingenic-adc.c - SHIFTPHONES/kernel/common - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 /*
  * ADC driver for the Ingenic JZ47xx SoCs
  * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>
  *
  * based on drivers/mfd/jz4740-adc.c
  */

 #include <dt-bindings/iio/adc/ingenic,adc.h>
 #include <linux/clk.h>
 #include <linux/iio/iio.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>

 #define JZ_ADC_REG_ENABLE		0x00
 #define JZ_ADC_REG_CFG			0x04
 #define JZ_ADC_REG_CTRL			0x08
 #define JZ_ADC_REG_STATUS		0x0c
 #define JZ_ADC_REG_ADTCH		0x18
 #define JZ_ADC_REG_ADBDAT		0x1c
 #define JZ_ADC_REG_ADSDAT		0x20

 #define JZ_ADC_REG_CFG_BAT_MD		BIT(4)

 #define JZ_ADC_AUX_VREF				3300
 #define JZ_ADC_AUX_VREF_BITS			12
 #define JZ_ADC_BATTERY_LOW_VREF			2500
 #define JZ_ADC_BATTERY_LOW_VREF_BITS		12
 #define JZ4725B_ADC_BATTERY_HIGH_VREF		7500
 #define JZ4725B_ADC_BATTERY_HIGH_VREF_BITS	10
 #define JZ4740_ADC_BATTERY_HIGH_VREF		(7500 * 0.986)
 #define JZ4740_ADC_BATTERY_HIGH_VREF_BITS	12

 struct ingenic_adc_soc_data {
 	unsigned int battery_high_vref;
 	unsigned int battery_high_vref_bits;
 	const int *battery_raw_avail;
 	size_t battery_raw_avail_size;
 	const int *battery_scale_avail;
 	size_t battery_scale_avail_size;
 };

 struct ingenic_adc {
 	void __iomem *base;
 	struct clk *clk;
 	struct mutex lock;
 	const struct ingenic_adc_soc_data *soc_data;
 	bool low_vref_mode;
 };

 static void ingenic_adc_set_config(struct ingenic_adc *adc,
 				   uint32_t mask,
 				   uint32_t val)
 {
 	uint32_t cfg;

 	clk_enable(adc->clk);
 	mutex_lock(&adc->lock);

 	cfg = readl(adc->base + JZ_ADC_REG_CFG) & ~mask;
 	cfg |= val;
 	writel(cfg, adc->base + JZ_ADC_REG_CFG);

 	mutex_unlock(&adc->lock);
 	clk_disable(adc->clk);
 }

 static void ingenic_adc_enable(struct ingenic_adc *adc,
 			       int engine,
 			       bool enabled)
 {
 	u8 val;

 	mutex_lock(&adc->lock);
 	val = readb(adc->base + JZ_ADC_REG_ENABLE);

 	if (enabled)
 		val |= BIT(engine);
 	else
 		val &= ~BIT(engine);

 	writeb(val, adc->base + JZ_ADC_REG_ENABLE);
 	mutex_unlock(&adc->lock);
 }

 static int ingenic_adc_capture(struct ingenic_adc *adc,
 			       int engine)
 {
 	u8 val;
 	int ret;

 	ingenic_adc_enable(adc, engine, true);
 	ret = readb_poll_timeout(adc->base + JZ_ADC_REG_ENABLE, val,
 				 !(val & BIT(engine)), 250, 1000);
 	if (ret)
 		ingenic_adc_enable(adc, engine, false);

 	return ret;
 }

 static int ingenic_adc_write_raw(struct iio_dev *iio_dev,
 				 struct iio_chan_spec const *chan,
 				 int val,
 				 int val2,
 				 long m)
 {
 	struct ingenic_adc *adc = iio_priv(iio_dev);

 	switch (m) {
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->channel) {
 		case INGENIC_ADC_BATTERY:
 			if (val > JZ_ADC_BATTERY_LOW_VREF) {
 				ingenic_adc_set_config(adc,
 						       JZ_ADC_REG_CFG_BAT_MD,
 						       0);
 				adc->low_vref_mode = false;
 			} else {
 				ingenic_adc_set_config(adc,
 						       JZ_ADC_REG_CFG_BAT_MD,
 						       JZ_ADC_REG_CFG_BAT_MD);
 				adc->low_vref_mode = true;
 			}
 			return 0;
 		default:
 			return -EINVAL;
 		}
 	default:
 		return -EINVAL;
 	}
 }

 static const int jz4725b_adc_battery_raw_avail[] = {
 	0, 1, (1 << JZ_ADC_BATTERY_LOW_VREF_BITS) - 1,
 };

 static const int jz4725b_adc_battery_scale_avail[] = {
 	JZ4725B_ADC_BATTERY_HIGH_VREF, JZ4725B_ADC_BATTERY_HIGH_VREF_BITS,
 	JZ_ADC_BATTERY_LOW_VREF, JZ_ADC_BATTERY_LOW_VREF_BITS,
 };

 static const int jz4740_adc_battery_raw_avail[] = {
 	0, 1, (1 << JZ_ADC_BATTERY_LOW_VREF_BITS) - 1,
 };

 static const int jz4740_adc_battery_scale_avail[] = {
 	JZ4740_ADC_BATTERY_HIGH_VREF, JZ4740_ADC_BATTERY_HIGH_VREF_BITS,
 	JZ_ADC_BATTERY_LOW_VREF, JZ_ADC_BATTERY_LOW_VREF_BITS,
 };

 static const struct ingenic_adc_soc_data jz4725b_adc_soc_data = {
 	.battery_high_vref = JZ4725B_ADC_BATTERY_HIGH_VREF,
 	.battery_high_vref_bits = JZ4725B_ADC_BATTERY_HIGH_VREF_BITS,
 	.battery_raw_avail = jz4725b_adc_battery_raw_avail,
 	.battery_raw_avail_size = ARRAY_SIZE(jz4725b_adc_battery_raw_avail),
 	.battery_scale_avail = jz4725b_adc_battery_scale_avail,
 	.battery_scale_avail_size = ARRAY_SIZE(jz4725b_adc_battery_scale_avail),
 };

 static const struct ingenic_adc_soc_data jz4740_adc_soc_data = {
 	.battery_high_vref = JZ4740_ADC_BATTERY_HIGH_VREF,
 	.battery_high_vref_bits = JZ4740_ADC_BATTERY_HIGH_VREF_BITS,
 	.battery_raw_avail = jz4740_adc_battery_raw_avail,
 	.battery_raw_avail_size = ARRAY_SIZE(jz4740_adc_battery_raw_avail),
 	.battery_scale_avail = jz4740_adc_battery_scale_avail,
 	.battery_scale_avail_size = ARRAY_SIZE(jz4740_adc_battery_scale_avail),
 };

 static int ingenic_adc_read_avail(struct iio_dev *iio_dev,
 				  struct iio_chan_spec const *chan,
 				  const int **vals,
 				  int *type,
 				  int *length,
 				  long m)
 {
 	struct ingenic_adc *adc = iio_priv(iio_dev);

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		*type = IIO_VAL_INT;
 		*length = adc->soc_data->battery_raw_avail_size;
 		*vals = adc->soc_data->battery_raw_avail;
 		return IIO_AVAIL_RANGE;
 	case IIO_CHAN_INFO_SCALE:
 		*type = IIO_VAL_FRACTIONAL_LOG2;
 		*length = adc->soc_data->battery_scale_avail_size;
 		*vals = adc->soc_data->battery_scale_avail;
 		return IIO_AVAIL_LIST;
 	default:
 		return -EINVAL;
 	};
 }

 static int ingenic_adc_read_raw(struct iio_dev *iio_dev,
 				struct iio_chan_spec const *chan,
 				int *val,
 				int *val2,
 				long m)
 {
 	struct ingenic_adc *adc = iio_priv(iio_dev);
 	int ret;

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		clk_enable(adc->clk);
 		ret = ingenic_adc_capture(adc, chan->channel);
 		if (ret) {
 			clk_disable(adc->clk);
 			return ret;
 		}

 		switch (chan->channel) {
 		case INGENIC_ADC_AUX:
 			*val = readw(adc->base + JZ_ADC_REG_ADSDAT);
 			break;
 		case INGENIC_ADC_BATTERY:
 			*val = readw(adc->base + JZ_ADC_REG_ADBDAT);
 			break;
 		}

 		clk_disable(adc->clk);

 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->channel) {
 		case INGENIC_ADC_AUX:
 			*val = JZ_ADC_AUX_VREF;
 			*val2 = JZ_ADC_AUX_VREF_BITS;
 			break;
 		case INGENIC_ADC_BATTERY:
 			if (adc->low_vref_mode) {
 				*val = JZ_ADC_BATTERY_LOW_VREF;
 				*val2 = JZ_ADC_BATTERY_LOW_VREF_BITS;
 			} else {
 				*val = adc->soc_data->battery_high_vref;
 				*val2 = adc->soc_data->battery_high_vref_bits;
 			}
 			break;
 		}

 		return IIO_VAL_FRACTIONAL_LOG2;
 	default:
 		return -EINVAL;
 	}
 }

 static void ingenic_adc_clk_cleanup(void *data)
 {
 	clk_unprepare(data);
 }

 static const struct iio_info ingenic_adc_info = {
 	.write_raw = ingenic_adc_write_raw,
 	.read_raw = ingenic_adc_read_raw,
 	.read_avail = ingenic_adc_read_avail,
 };

 static const struct iio_chan_spec ingenic_channels[] = {
 	{
 		.extend_name = "aux",
 		.type = IIO_VOLTAGE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.indexed = 1,
 		.channel = INGENIC_ADC_AUX,
 	},
 	{
 		.extend_name = "battery",
 		.type = IIO_VOLTAGE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW) |
 						BIT(IIO_CHAN_INFO_SCALE),
 		.indexed = 1,
 		.channel = INGENIC_ADC_BATTERY,
 	},
 };

 static int ingenic_adc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct iio_dev *iio_dev;
 	struct ingenic_adc *adc;
 	struct resource *mem_base;
 	const struct ingenic_adc_soc_data *soc_data;
 	int ret;

 	soc_data = device_get_match_data(dev);
 	if (!soc_data)
 		return -EINVAL;

 	iio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
 	if (!iio_dev)
 		return -ENOMEM;

 	adc = iio_priv(iio_dev);
 	mutex_init(&adc->lock);
 	adc->soc_data = soc_data;

 	mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	adc->base = devm_ioremap_resource(dev, mem_base);
 	if (IS_ERR(adc->base))
 		return PTR_ERR(adc->base);

 	adc->clk = devm_clk_get(dev, "adc");
 	if (IS_ERR(adc->clk)) {
 		dev_err(dev, "Unable to get clock\n");
 		return PTR_ERR(adc->clk);
 	}

 	ret = clk_prepare_enable(adc->clk);
 	if (ret) {
 		dev_err(dev, "Failed to enable clock\n");
 		return ret;
 	}

 	/* Put hardware in a known passive state. */
 	writeb(0x00, adc->base + JZ_ADC_REG_ENABLE);
 	writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
 	clk_disable(adc->clk);

 	ret = devm_add_action_or_reset(dev, ingenic_adc_clk_cleanup, adc->clk);
 	if (ret) {
 		dev_err(dev, "Unable to add action\n");
 		return ret;
 	}

 	iio_dev->dev.parent = dev;
 	iio_dev->name = "jz-adc";
 	iio_dev->modes = INDIO_DIRECT_MODE;
 	iio_dev->channels = ingenic_channels;
 	iio_dev->num_channels = ARRAY_SIZE(ingenic_channels);
 	iio_dev->info = &ingenic_adc_info;

 	ret = devm_iio_device_register(dev, iio_dev);
 	if (ret)
 		dev_err(dev, "Unable to register IIO device\n");

 	return ret;
 }

 #ifdef CONFIG_OF
 static const struct of_device_id ingenic_adc_of_match[] = {
 	{ .compatible = "ingenic,jz4725b-adc", .data = &jz4725b_adc_soc_data, },
 	{ .compatible = "ingenic,jz4740-adc", .data = &jz4740_adc_soc_data, },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, ingenic_adc_of_match);
 #endif

 static struct platform_driver ingenic_adc_driver = {
 	.driver = {
 		.name = "ingenic-adc",
 		.of_match_table = of_match_ptr(ingenic_adc_of_match),
 	},
 	.probe = ingenic_adc_probe,
 };
 module_platform_driver(ingenic_adc_driver);
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* ADC driver for the Ingenic JZ47xx SoCs
	* Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>
	*
	* based on drivers/mfd/jz4740-adc.c
	*/

	#include <dt-bindings/iio/adc/ingenic,adc.h>
	#include <linux/clk.h>
	#include <linux/iio/iio.h>
	#include <linux/io.h>
	#include <linux/iopoll.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/platform_device.h>

	#define JZ_ADC_REG_ENABLE 0x00
	#define JZ_ADC_REG_CFG 0x04
	#define JZ_ADC_REG_CTRL 0x08
	#define JZ_ADC_REG_STATUS 0x0c
	#define JZ_ADC_REG_ADTCH 0x18
	#define JZ_ADC_REG_ADBDAT 0x1c
	#define JZ_ADC_REG_ADSDAT 0x20

	#define JZ_ADC_REG_CFG_BAT_MD BIT(4)

	#define JZ_ADC_AUX_VREF 3300
	#define JZ_ADC_AUX_VREF_BITS 12
	#define JZ_ADC_BATTERY_LOW_VREF 2500
	#define JZ_ADC_BATTERY_LOW_VREF_BITS 12
	#define JZ4725B_ADC_BATTERY_HIGH_VREF 7500
	#define JZ4725B_ADC_BATTERY_HIGH_VREF_BITS 10
	#define JZ4740_ADC_BATTERY_HIGH_VREF (7500 * 0.986)
	#define JZ4740_ADC_BATTERY_HIGH_VREF_BITS 12

	struct ingenic_adc_soc_data {
	unsigned int battery_high_vref;
	unsigned int battery_high_vref_bits;
	const int *battery_raw_avail;
	size_t battery_raw_avail_size;
	const int *battery_scale_avail;
	size_t battery_scale_avail_size;
	};

	struct ingenic_adc {
	void __iomem *base;
	struct clk *clk;
	struct mutex lock;
	const struct ingenic_adc_soc_data *soc_data;
	bool low_vref_mode;
	};

	static void ingenic_adc_set_config(struct ingenic_adc *adc,
	uint32_t mask,
	uint32_t val)
	{
	uint32_t cfg;

	clk_enable(adc->clk);
	mutex_lock(&adc->lock);

	cfg = readl(adc->base + JZ_ADC_REG_CFG) & ~mask;
	cfg \|= val;
	writel(cfg, adc->base + JZ_ADC_REG_CFG);

	mutex_unlock(&adc->lock);
	clk_disable(adc->clk);
	}

	static void ingenic_adc_enable(struct ingenic_adc *adc,
	int engine,
	bool enabled)
	{
	u8 val;

	mutex_lock(&adc->lock);
	val = readb(adc->base + JZ_ADC_REG_ENABLE);

	if (enabled)
	val \|= BIT(engine);
	else
	val &= ~BIT(engine);

	writeb(val, adc->base + JZ_ADC_REG_ENABLE);
	mutex_unlock(&adc->lock);
	}

	static int ingenic_adc_capture(struct ingenic_adc *adc,
	int engine)
	{
	u8 val;
	int ret;

	ingenic_adc_enable(adc, engine, true);
	ret = readb_poll_timeout(adc->base + JZ_ADC_REG_ENABLE, val,
	!(val & BIT(engine)), 250, 1000);
	if (ret)
	ingenic_adc_enable(adc, engine, false);

	return ret;
	}

	static int ingenic_adc_write_raw(struct iio_dev *iio_dev,
	struct iio_chan_spec const *chan,
	int val,
	int val2,
	long m)
	{
	struct ingenic_adc *adc = iio_priv(iio_dev);

	switch (m) {
	case IIO_CHAN_INFO_SCALE:
	switch (chan->channel) {
	case INGENIC_ADC_BATTERY:
	if (val > JZ_ADC_BATTERY_LOW_VREF) {
	ingenic_adc_set_config(adc,
	JZ_ADC_REG_CFG_BAT_MD,
	0);
	adc->low_vref_mode = false;
	} else {
	ingenic_adc_set_config(adc,
	JZ_ADC_REG_CFG_BAT_MD,
	JZ_ADC_REG_CFG_BAT_MD);
	adc->low_vref_mode = true;
	}
	return 0;
	default:
	return -EINVAL;
	}
	default:
	return -EINVAL;
	}
	}

	static const int jz4725b_adc_battery_raw_avail[] = {
	0, 1, (1 << JZ_ADC_BATTERY_LOW_VREF_BITS) - 1,
	};

	static const int jz4725b_adc_battery_scale_avail[] = {
	JZ4725B_ADC_BATTERY_HIGH_VREF, JZ4725B_ADC_BATTERY_HIGH_VREF_BITS,
	JZ_ADC_BATTERY_LOW_VREF, JZ_ADC_BATTERY_LOW_VREF_BITS,
	};

	static const int jz4740_adc_battery_raw_avail[] = {
	0, 1, (1 << JZ_ADC_BATTERY_LOW_VREF_BITS) - 1,
	};

	static const int jz4740_adc_battery_scale_avail[] = {
	JZ4740_ADC_BATTERY_HIGH_VREF, JZ4740_ADC_BATTERY_HIGH_VREF_BITS,
	JZ_ADC_BATTERY_LOW_VREF, JZ_ADC_BATTERY_LOW_VREF_BITS,
	};

	static const struct ingenic_adc_soc_data jz4725b_adc_soc_data = {
	.battery_high_vref = JZ4725B_ADC_BATTERY_HIGH_VREF,
	.battery_high_vref_bits = JZ4725B_ADC_BATTERY_HIGH_VREF_BITS,
	.battery_raw_avail = jz4725b_adc_battery_raw_avail,
	.battery_raw_avail_size = ARRAY_SIZE(jz4725b_adc_battery_raw_avail),
	.battery_scale_avail = jz4725b_adc_battery_scale_avail,
	.battery_scale_avail_size = ARRAY_SIZE(jz4725b_adc_battery_scale_avail),
	};

	static const struct ingenic_adc_soc_data jz4740_adc_soc_data = {
	.battery_high_vref = JZ4740_ADC_BATTERY_HIGH_VREF,
	.battery_high_vref_bits = JZ4740_ADC_BATTERY_HIGH_VREF_BITS,
	.battery_raw_avail = jz4740_adc_battery_raw_avail,
	.battery_raw_avail_size = ARRAY_SIZE(jz4740_adc_battery_raw_avail),
	.battery_scale_avail = jz4740_adc_battery_scale_avail,
	.battery_scale_avail_size = ARRAY_SIZE(jz4740_adc_battery_scale_avail),
	};

	static int ingenic_adc_read_avail(struct iio_dev *iio_dev,
	struct iio_chan_spec const *chan,
	const int **vals,
	int *type,
	int *length,
	long m)
	{
	struct ingenic_adc *adc = iio_priv(iio_dev);

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	*type = IIO_VAL_INT;
	*length = adc->soc_data->battery_raw_avail_size;
	*vals = adc->soc_data->battery_raw_avail;
	return IIO_AVAIL_RANGE;
	case IIO_CHAN_INFO_SCALE:
	*type = IIO_VAL_FRACTIONAL_LOG2;
	*length = adc->soc_data->battery_scale_avail_size;
	*vals = adc->soc_data->battery_scale_avail;
	return IIO_AVAIL_LIST;
	default:
	return -EINVAL;
	};
	}

	static int ingenic_adc_read_raw(struct iio_dev *iio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long m)
	{
	struct ingenic_adc *adc = iio_priv(iio_dev);
	int ret;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	clk_enable(adc->clk);
	ret = ingenic_adc_capture(adc, chan->channel);
	if (ret) {
	clk_disable(adc->clk);
	return ret;
	}

	switch (chan->channel) {
	case INGENIC_ADC_AUX:
	*val = readw(adc->base + JZ_ADC_REG_ADSDAT);
	break;
	case INGENIC_ADC_BATTERY:
	*val = readw(adc->base + JZ_ADC_REG_ADBDAT);
	break;
	}

	clk_disable(adc->clk);

	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	switch (chan->channel) {
	case INGENIC_ADC_AUX:
	*val = JZ_ADC_AUX_VREF;
	*val2 = JZ_ADC_AUX_VREF_BITS;
	break;
	case INGENIC_ADC_BATTERY:
	if (adc->low_vref_mode) {
	*val = JZ_ADC_BATTERY_LOW_VREF;
	*val2 = JZ_ADC_BATTERY_LOW_VREF_BITS;
	} else {
	*val = adc->soc_data->battery_high_vref;
	*val2 = adc->soc_data->battery_high_vref_bits;
	}
	break;
	}

	return IIO_VAL_FRACTIONAL_LOG2;
	default:
	return -EINVAL;
	}
	}

	static void ingenic_adc_clk_cleanup(void *data)
	{
	clk_unprepare(data);
	}

	static const struct iio_info ingenic_adc_info = {
	.write_raw = ingenic_adc_write_raw,
	.read_raw = ingenic_adc_read_raw,
	.read_avail = ingenic_adc_read_avail,
	};

	static const struct iio_chan_spec ingenic_channels[] = {
	{
	.extend_name = "aux",
	.type = IIO_VOLTAGE,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	.indexed = 1,
	.channel = INGENIC_ADC_AUX,
	},
	{
	.extend_name = "battery",
	.type = IIO_VOLTAGE,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	.info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	.indexed = 1,
	.channel = INGENIC_ADC_BATTERY,
	},
	};

	static int ingenic_adc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct iio_dev *iio_dev;
	struct ingenic_adc *adc;
	struct resource *mem_base;
	const struct ingenic_adc_soc_data *soc_data;
	int ret;

	soc_data = device_get_match_data(dev);
	if (!soc_data)
	return -EINVAL;

	iio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
	if (!iio_dev)
	return -ENOMEM;

	adc = iio_priv(iio_dev);
	mutex_init(&adc->lock);
	adc->soc_data = soc_data;

	mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	adc->base = devm_ioremap_resource(dev, mem_base);
	if (IS_ERR(adc->base))
	return PTR_ERR(adc->base);

	adc->clk = devm_clk_get(dev, "adc");
	if (IS_ERR(adc->clk)) {
	dev_err(dev, "Unable to get clock\n");
	return PTR_ERR(adc->clk);
	}

	ret = clk_prepare_enable(adc->clk);
	if (ret) {
	dev_err(dev, "Failed to enable clock\n");
	return ret;
	}

	/* Put hardware in a known passive state. */
	writeb(0x00, adc->base + JZ_ADC_REG_ENABLE);
	writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
	clk_disable(adc->clk);

	ret = devm_add_action_or_reset(dev, ingenic_adc_clk_cleanup, adc->clk);
	if (ret) {
	dev_err(dev, "Unable to add action\n");
	return ret;
	}

	iio_dev->dev.parent = dev;
	iio_dev->name = "jz-adc";
	iio_dev->modes = INDIO_DIRECT_MODE;
	iio_dev->channels = ingenic_channels;
	iio_dev->num_channels = ARRAY_SIZE(ingenic_channels);
	iio_dev->info = &ingenic_adc_info;

	ret = devm_iio_device_register(dev, iio_dev);
	if (ret)
	dev_err(dev, "Unable to register IIO device\n");

	return ret;
	}

	#ifdef CONFIG_OF
	static const struct of_device_id ingenic_adc_of_match[] = {
	{ .compatible = "ingenic,jz4725b-adc", .data = &jz4725b_adc_soc_data, },
	{ .compatible = "ingenic,jz4740-adc", .data = &jz4740_adc_soc_data, },
	{ },
	};
	MODULE_DEVICE_TABLE(of, ingenic_adc_of_match);
	#endif

	static struct platform_driver ingenic_adc_driver = {
	.driver = {
	.name = "ingenic-adc",
	.of_match_table = of_match_ptr(ingenic_adc_of_match),
	},
	.probe = ingenic_adc_probe,
	};
	module_platform_driver(ingenic_adc_driver);
	MODULE_LICENSE("GPL v2");