drivers/iio/adc/adi-axi-adc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Analog Devices Generic AXI ADC IP core
  * Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
  *
  * Copyright 2012-2020 Analog Devices Inc.
  */

 #include <linux/bitfield.h>
 #include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>

 #include <linux/fpga/adi-axi-common.h>

 #include <linux/iio/backend.h>
 #include <linux/iio/buffer-dmaengine.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>

 /*
  * Register definitions:
  *   https://wiki.analog.com/resources/fpga/docs/axi_adc_ip#register_map
  */

 /* ADC controls */

 #define ADI_AXI_REG_RSTN			0x0040
 #define   ADI_AXI_REG_RSTN_CE_N			BIT(2)
 #define   ADI_AXI_REG_RSTN_MMCM_RSTN		BIT(1)
 #define   ADI_AXI_REG_RSTN_RSTN			BIT(0)

 #define ADI_AXI_ADC_REG_CTRL			0x0044
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)

 /* ADC Channel controls */

 #define ADI_AXI_REG_CHAN_CTRL(c)		(0x0400 + (c) * 0x40)
 #define   ADI_AXI_REG_CHAN_CTRL_LB_OWR		BIT(11)
 #define   ADI_AXI_REG_CHAN_CTRL_PN_SEL_OWR	BIT(10)
 #define   ADI_AXI_REG_CHAN_CTRL_IQCOR_EN	BIT(9)
 #define   ADI_AXI_REG_CHAN_CTRL_DCFILT_EN	BIT(8)
 #define   ADI_AXI_REG_CHAN_CTRL_FMT_MASK	GENMASK(6, 4)
 #define   ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT	BIT(6)
 #define   ADI_AXI_REG_CHAN_CTRL_FMT_TYPE	BIT(5)
 #define   ADI_AXI_REG_CHAN_CTRL_FMT_EN		BIT(4)
 #define   ADI_AXI_REG_CHAN_CTRL_PN_TYPE_OWR	BIT(1)
 #define   ADI_AXI_REG_CHAN_CTRL_ENABLE		BIT(0)

 #define ADI_AXI_ADC_REG_CHAN_STATUS(c)		(0x0404 + (c) * 0x40)
 #define   ADI_AXI_ADC_CHAN_STAT_PN_MASK		GENMASK(2, 1)

 #define ADI_AXI_ADC_REG_CHAN_CTRL_3(c)		(0x0418 + (c) * 0x40)
 #define   ADI_AXI_ADC_CHAN_PN_SEL_MASK		GENMASK(19, 16)

 /* IO Delays */
 #define ADI_AXI_ADC_REG_DELAY(l)		(0x0800 + (l) * 0x4)
 #define   AXI_ADC_DELAY_CTRL_MASK		GENMASK(4, 0)

 #define ADI_AXI_ADC_MAX_IO_NUM_LANES		15

 #define ADI_AXI_REG_CHAN_CTRL_DEFAULTS		\
 	(ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT |	\
 	 ADI_AXI_REG_CHAN_CTRL_FMT_EN |		\
 	 ADI_AXI_REG_CHAN_CTRL_ENABLE)

 struct adi_axi_adc_state {
 	struct regmap *regmap;
 	struct device *dev;
 	/* lock to protect multiple accesses to the device registers */
 	struct mutex lock;
 };

 static int axi_adc_enable(struct iio_backend *back)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 	int ret;

 	ret = regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
 			      ADI_AXI_REG_RSTN_MMCM_RSTN);
 	if (ret)
 		return ret;

 	fsleep(10000);
 	return regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
 			       ADI_AXI_REG_RSTN_RSTN | ADI_AXI_REG_RSTN_MMCM_RSTN);
 }

 static void axi_adc_disable(struct iio_backend *back)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

 	regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
 }

 static int axi_adc_data_format_set(struct iio_backend *back, unsigned int chan,
 				   const struct iio_backend_data_fmt *data)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 	u32 val;

 	if (!data->enable)
 		return regmap_clear_bits(st->regmap,
 					 ADI_AXI_REG_CHAN_CTRL(chan),
 					 ADI_AXI_REG_CHAN_CTRL_FMT_EN);

 	val = FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_EN, true);
 	if (data->sign_extend)
 		val |= FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT, true);
 	if (data->type == IIO_BACKEND_OFFSET_BINARY)
 		val |= FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_TYPE, true);

 	return regmap_update_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
 				  ADI_AXI_REG_CHAN_CTRL_FMT_MASK, val);
 }

 static int axi_adc_data_sample_trigger(struct iio_backend *back,
 				       enum iio_backend_sample_trigger trigger)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

 	switch (trigger) {
 	case IIO_BACKEND_SAMPLE_TRIGGER_EDGE_RISING:
 		return regmap_clear_bits(st->regmap, ADI_AXI_ADC_REG_CTRL,
 					 ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK);
 	case IIO_BACKEND_SAMPLE_TRIGGER_EDGE_FALLING:
 		return regmap_set_bits(st->regmap, ADI_AXI_ADC_REG_CTRL,
 				       ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK);
 	default:
 		return -EINVAL;
 	}
 }

 static int axi_adc_iodelays_set(struct iio_backend *back, unsigned int lane,
 				unsigned int tap)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 	int ret;
 	u32 val;

 	if (tap > FIELD_MAX(AXI_ADC_DELAY_CTRL_MASK))
 		return -EINVAL;
 	if (lane > ADI_AXI_ADC_MAX_IO_NUM_LANES)
 		return -EINVAL;

 	guard(mutex)(&st->lock);
 	ret = regmap_write(st->regmap, ADI_AXI_ADC_REG_DELAY(lane), tap);
 	if (ret)
 		return ret;
 	/*
 	 * If readback is ~0, that means there are issues with the
 	 * delay_clk.
 	 */
 	ret = regmap_read(st->regmap, ADI_AXI_ADC_REG_DELAY(lane), &val);
 	if (ret)
 		return ret;
 	if (val == U32_MAX)
 		return -EIO;

 	return 0;
 }

 static int axi_adc_test_pattern_set(struct iio_backend *back,
 				    unsigned int chan,
 				    enum iio_backend_test_pattern pattern)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

 	switch (pattern) {
 	case IIO_BACKEND_NO_TEST_PATTERN:
 		/* nothing to do */
 		return 0;
 	case IIO_BACKEND_ADI_PRBS_9A:
 		return regmap_update_bits(st->regmap, ADI_AXI_ADC_REG_CHAN_CTRL_3(chan),
 					  ADI_AXI_ADC_CHAN_PN_SEL_MASK,
 					  FIELD_PREP(ADI_AXI_ADC_CHAN_PN_SEL_MASK, 0));
 	default:
 		return -EINVAL;
 	}
 }

 static int axi_adc_chan_status(struct iio_backend *back, unsigned int chan,
 			       bool *error)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 	int ret;
 	u32 val;

 	guard(mutex)(&st->lock);
 	/* reset test bits by setting them */
 	ret = regmap_write(st->regmap, ADI_AXI_ADC_REG_CHAN_STATUS(chan),
 			   ADI_AXI_ADC_CHAN_STAT_PN_MASK);
 	if (ret)
 		return ret;

 	/* let's give enough time to validate or erroring the incoming pattern */
 	fsleep(1000);

 	ret = regmap_read(st->regmap, ADI_AXI_ADC_REG_CHAN_STATUS(chan), &val);
 	if (ret)
 		return ret;

 	if (ADI_AXI_ADC_CHAN_STAT_PN_MASK & val)
 		*error = true;
 	else
 		*error = false;

 	return 0;
 }

 static int axi_adc_chan_enable(struct iio_backend *back, unsigned int chan)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

 	return regmap_set_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
 			       ADI_AXI_REG_CHAN_CTRL_ENABLE);
 }

 static int axi_adc_chan_disable(struct iio_backend *back, unsigned int chan)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

 	return regmap_clear_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
 				 ADI_AXI_REG_CHAN_CTRL_ENABLE);
 }

 static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
 						 struct iio_dev *indio_dev)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 	const char *dma_name;

 	if (device_property_read_string(st->dev, "dma-names", &dma_name))
 		dma_name = "rx";

 	return iio_dmaengine_buffer_setup(st->dev, indio_dev, dma_name);
 }

 static void axi_adc_free_buffer(struct iio_backend *back,
 				struct iio_buffer *buffer)
 {
 	iio_dmaengine_buffer_free(buffer);
 }

 static const struct regmap_config axi_adc_regmap_config = {
 	.val_bits = 32,
 	.reg_bits = 32,
 	.reg_stride = 4,
 };

 static const struct iio_backend_ops adi_axi_adc_generic = {
 	.enable = axi_adc_enable,
 	.disable = axi_adc_disable,
 	.data_format_set = axi_adc_data_format_set,
 	.chan_enable = axi_adc_chan_enable,
 	.chan_disable = axi_adc_chan_disable,
 	.request_buffer = axi_adc_request_buffer,
 	.free_buffer = axi_adc_free_buffer,
 	.data_sample_trigger = axi_adc_data_sample_trigger,
 	.iodelay_set = axi_adc_iodelays_set,
 	.test_pattern_set = axi_adc_test_pattern_set,
 	.chan_status = axi_adc_chan_status,
 };

 static int adi_axi_adc_probe(struct platform_device *pdev)
 {
 	const unsigned int *expected_ver;
 	struct adi_axi_adc_state *st;
 	void __iomem *base;
 	unsigned int ver;
 	struct clk *clk;
 	int ret;

 	st = devm_kzalloc(&pdev->dev, sizeof(*st), GFP_KERNEL);
 	if (!st)
 		return -ENOMEM;

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

 	st->dev = &pdev->dev;
 	st->regmap = devm_regmap_init_mmio(&pdev->dev, base,
 					   &axi_adc_regmap_config);
 	if (IS_ERR(st->regmap))
 		return PTR_ERR(st->regmap);

 	expected_ver = device_get_match_data(&pdev->dev);
 	if (!expected_ver)
 		return -ENODEV;

 	clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	/*
 	 * Force disable the core. Up to the frontend to enable us. And we can
 	 * still read/write registers...
 	 */
 	ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
 	if (ret)
 		return ret;

 	ret = regmap_read(st->regmap, ADI_AXI_REG_VERSION, &ver);
 	if (ret)
 		return ret;

 	if (ADI_AXI_PCORE_VER_MAJOR(ver) != ADI_AXI_PCORE_VER_MAJOR(*expected_ver)) {
 		dev_err(&pdev->dev,
 			"Major version mismatch. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
 			ADI_AXI_PCORE_VER_MAJOR(*expected_ver),
 			ADI_AXI_PCORE_VER_MINOR(*expected_ver),
 			ADI_AXI_PCORE_VER_PATCH(*expected_ver),
 			ADI_AXI_PCORE_VER_MAJOR(ver),
 			ADI_AXI_PCORE_VER_MINOR(ver),
 			ADI_AXI_PCORE_VER_PATCH(ver));
 		return -ENODEV;
 	}

 	ret = devm_iio_backend_register(&pdev->dev, &adi_axi_adc_generic, st);
 	if (ret)
 		return ret;

 	dev_info(&pdev->dev, "AXI ADC IP core (%d.%.2d.%c) probed\n",
 		 ADI_AXI_PCORE_VER_MAJOR(ver),
 		 ADI_AXI_PCORE_VER_MINOR(ver),
 		 ADI_AXI_PCORE_VER_PATCH(ver));

 	return 0;
 }

 static unsigned int adi_axi_adc_10_0_a_info = ADI_AXI_PCORE_VER(10, 0, 'a');

 /* Match table for of_platform binding */
 static const struct of_device_id adi_axi_adc_of_match[] = {
 	{ .compatible = "adi,axi-adc-10.0.a", .data = &adi_axi_adc_10_0_a_info },
 	{ /* end of list */ }
 };
 MODULE_DEVICE_TABLE(of, adi_axi_adc_of_match);

 static struct platform_driver adi_axi_adc_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
 		.of_match_table = adi_axi_adc_of_match,
 	},
 	.probe = adi_axi_adc_probe,
 };
 module_platform_driver(adi_axi_adc_driver);

 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 MODULE_DESCRIPTION("Analog Devices Generic AXI ADC IP core driver");
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(IIO_DMAENGINE_BUFFER);
 MODULE_IMPORT_NS(IIO_BACKEND);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Analog Devices Generic AXI ADC IP core
	* Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
	*
	* Copyright 2012-2020 Analog Devices Inc.
	*/

	#include <linux/bitfield.h>
	#include <linux/cleanup.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/delay.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/property.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>

	#include <linux/fpga/adi-axi-common.h>

	#include <linux/iio/backend.h>
	#include <linux/iio/buffer-dmaengine.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/iio.h>

	/*
	* Register definitions:
	* https://wiki.analog.com/resources/fpga/docs/axi_adc_ip#register_map
	*/

	/* ADC controls */

	#define ADI_AXI_REG_RSTN 0x0040
	#define ADI_AXI_REG_RSTN_CE_N BIT(2)
	#define ADI_AXI_REG_RSTN_MMCM_RSTN BIT(1)
	#define ADI_AXI_REG_RSTN_RSTN BIT(0)

	#define ADI_AXI_ADC_REG_CTRL 0x0044
	#define ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK BIT(1)

	/* ADC Channel controls */

	#define ADI_AXI_REG_CHAN_CTRL(c) (0x0400 + (c) * 0x40)
	#define ADI_AXI_REG_CHAN_CTRL_LB_OWR BIT(11)
	#define ADI_AXI_REG_CHAN_CTRL_PN_SEL_OWR BIT(10)
	#define ADI_AXI_REG_CHAN_CTRL_IQCOR_EN BIT(9)
	#define ADI_AXI_REG_CHAN_CTRL_DCFILT_EN BIT(8)
	#define ADI_AXI_REG_CHAN_CTRL_FMT_MASK GENMASK(6, 4)
	#define ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT BIT(6)
	#define ADI_AXI_REG_CHAN_CTRL_FMT_TYPE BIT(5)
	#define ADI_AXI_REG_CHAN_CTRL_FMT_EN BIT(4)
	#define ADI_AXI_REG_CHAN_CTRL_PN_TYPE_OWR BIT(1)
	#define ADI_AXI_REG_CHAN_CTRL_ENABLE BIT(0)

	#define ADI_AXI_ADC_REG_CHAN_STATUS(c) (0x0404 + (c) * 0x40)
	#define ADI_AXI_ADC_CHAN_STAT_PN_MASK GENMASK(2, 1)

	#define ADI_AXI_ADC_REG_CHAN_CTRL_3(c) (0x0418 + (c) * 0x40)
	#define ADI_AXI_ADC_CHAN_PN_SEL_MASK GENMASK(19, 16)

	/* IO Delays */
	#define ADI_AXI_ADC_REG_DELAY(l) (0x0800 + (l) * 0x4)
	#define AXI_ADC_DELAY_CTRL_MASK GENMASK(4, 0)

	#define ADI_AXI_ADC_MAX_IO_NUM_LANES 15

	#define ADI_AXI_REG_CHAN_CTRL_DEFAULTS \
	(ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT \| \
	ADI_AXI_REG_CHAN_CTRL_FMT_EN \| \
	ADI_AXI_REG_CHAN_CTRL_ENABLE)

	struct adi_axi_adc_state {
	struct regmap *regmap;
	struct device *dev;
	/* lock to protect multiple accesses to the device registers */
	struct mutex lock;
	};

	static int axi_adc_enable(struct iio_backend *back)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
	int ret;

	ret = regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
	ADI_AXI_REG_RSTN_MMCM_RSTN);
	if (ret)
	return ret;

	fsleep(10000);
	return regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
	ADI_AXI_REG_RSTN_RSTN \| ADI_AXI_REG_RSTN_MMCM_RSTN);
	}

	static void axi_adc_disable(struct iio_backend *back)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

	regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
	}

	static int axi_adc_data_format_set(struct iio_backend *back, unsigned int chan,
	const struct iio_backend_data_fmt *data)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
	u32 val;

	if (!data->enable)
	return regmap_clear_bits(st->regmap,
	ADI_AXI_REG_CHAN_CTRL(chan),
	ADI_AXI_REG_CHAN_CTRL_FMT_EN);

	val = FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_EN, true);
	if (data->sign_extend)
	val \|= FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT, true);
	if (data->type == IIO_BACKEND_OFFSET_BINARY)
	val \|= FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_TYPE, true);

	return regmap_update_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
	ADI_AXI_REG_CHAN_CTRL_FMT_MASK, val);
	}

	static int axi_adc_data_sample_trigger(struct iio_backend *back,
	enum iio_backend_sample_trigger trigger)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

	switch (trigger) {
	case IIO_BACKEND_SAMPLE_TRIGGER_EDGE_RISING:
	return regmap_clear_bits(st->regmap, ADI_AXI_ADC_REG_CTRL,
	ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK);
	case IIO_BACKEND_SAMPLE_TRIGGER_EDGE_FALLING:
	return regmap_set_bits(st->regmap, ADI_AXI_ADC_REG_CTRL,
	ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK);
	default:
	return -EINVAL;
	}
	}

	static int axi_adc_iodelays_set(struct iio_backend *back, unsigned int lane,
	unsigned int tap)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
	int ret;
	u32 val;

	if (tap > FIELD_MAX(AXI_ADC_DELAY_CTRL_MASK))
	return -EINVAL;
	if (lane > ADI_AXI_ADC_MAX_IO_NUM_LANES)
	return -EINVAL;

	guard(mutex)(&st->lock);
	ret = regmap_write(st->regmap, ADI_AXI_ADC_REG_DELAY(lane), tap);
	if (ret)
	return ret;
	/*
	* If readback is ~0, that means there are issues with the
	* delay_clk.
	*/
	ret = regmap_read(st->regmap, ADI_AXI_ADC_REG_DELAY(lane), &val);
	if (ret)
	return ret;
	if (val == U32_MAX)
	return -EIO;

	return 0;
	}

	static int axi_adc_test_pattern_set(struct iio_backend *back,
	unsigned int chan,
	enum iio_backend_test_pattern pattern)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

	switch (pattern) {
	case IIO_BACKEND_NO_TEST_PATTERN:
	/* nothing to do */
	return 0;
	case IIO_BACKEND_ADI_PRBS_9A:
	return regmap_update_bits(st->regmap, ADI_AXI_ADC_REG_CHAN_CTRL_3(chan),
	ADI_AXI_ADC_CHAN_PN_SEL_MASK,
	FIELD_PREP(ADI_AXI_ADC_CHAN_PN_SEL_MASK, 0));
	default:
	return -EINVAL;
	}
	}

	static int axi_adc_chan_status(struct iio_backend *back, unsigned int chan,
	bool *error)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
	int ret;
	u32 val;

	guard(mutex)(&st->lock);
	/* reset test bits by setting them */
	ret = regmap_write(st->regmap, ADI_AXI_ADC_REG_CHAN_STATUS(chan),
	ADI_AXI_ADC_CHAN_STAT_PN_MASK);
	if (ret)
	return ret;

	/* let's give enough time to validate or erroring the incoming pattern */
	fsleep(1000);

	ret = regmap_read(st->regmap, ADI_AXI_ADC_REG_CHAN_STATUS(chan), &val);
	if (ret)
	return ret;

	if (ADI_AXI_ADC_CHAN_STAT_PN_MASK & val)
	*error = true;
	else
	*error = false;

	return 0;
	}

	static int axi_adc_chan_enable(struct iio_backend *back, unsigned int chan)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

	return regmap_set_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
	ADI_AXI_REG_CHAN_CTRL_ENABLE);
	}

	static int axi_adc_chan_disable(struct iio_backend *back, unsigned int chan)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);

	return regmap_clear_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
	ADI_AXI_REG_CHAN_CTRL_ENABLE);
	}

	static struct iio_buffer axi_adc_request_buffer(struct iio_backend back,
	struct iio_dev *indio_dev)
	{
	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
	const char *dma_name;

	if (device_property_read_string(st->dev, "dma-names", &dma_name))
	dma_name = "rx";

	return iio_dmaengine_buffer_setup(st->dev, indio_dev, dma_name);
	}

	static void axi_adc_free_buffer(struct iio_backend *back,
	struct iio_buffer *buffer)
	{
	iio_dmaengine_buffer_free(buffer);
	}

	static const struct regmap_config axi_adc_regmap_config = {
	.val_bits = 32,
	.reg_bits = 32,
	.reg_stride = 4,
	};

	static const struct iio_backend_ops adi_axi_adc_generic = {
	.enable = axi_adc_enable,
	.disable = axi_adc_disable,
	.data_format_set = axi_adc_data_format_set,
	.chan_enable = axi_adc_chan_enable,
	.chan_disable = axi_adc_chan_disable,
	.request_buffer = axi_adc_request_buffer,
	.free_buffer = axi_adc_free_buffer,
	.data_sample_trigger = axi_adc_data_sample_trigger,
	.iodelay_set = axi_adc_iodelays_set,
	.test_pattern_set = axi_adc_test_pattern_set,
	.chan_status = axi_adc_chan_status,
	};

	static int adi_axi_adc_probe(struct platform_device *pdev)
	{
	const unsigned int *expected_ver;
	struct adi_axi_adc_state *st;
	void __iomem *base;
	unsigned int ver;
	struct clk *clk;
	int ret;

	st = devm_kzalloc(&pdev->dev, sizeof(*st), GFP_KERNEL);
	if (!st)
	return -ENOMEM;

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

	st->dev = &pdev->dev;
	st->regmap = devm_regmap_init_mmio(&pdev->dev, base,
	&axi_adc_regmap_config);
	if (IS_ERR(st->regmap))
	return PTR_ERR(st->regmap);

	expected_ver = device_get_match_data(&pdev->dev);
	if (!expected_ver)
	return -ENODEV;

	clk = devm_clk_get_enabled(&pdev->dev, NULL);
	if (IS_ERR(clk))
	return PTR_ERR(clk);

	/*
	* Force disable the core. Up to the frontend to enable us. And we can
	* still read/write registers...
	*/
	ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
	if (ret)
	return ret;

	ret = regmap_read(st->regmap, ADI_AXI_REG_VERSION, &ver);
	if (ret)
	return ret;

	if (ADI_AXI_PCORE_VER_MAJOR(ver) != ADI_AXI_PCORE_VER_MAJOR(*expected_ver)) {
	dev_err(&pdev->dev,
	"Major version mismatch. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
	ADI_AXI_PCORE_VER_MAJOR(*expected_ver),
	ADI_AXI_PCORE_VER_MINOR(*expected_ver),
	ADI_AXI_PCORE_VER_PATCH(*expected_ver),
	ADI_AXI_PCORE_VER_MAJOR(ver),
	ADI_AXI_PCORE_VER_MINOR(ver),
	ADI_AXI_PCORE_VER_PATCH(ver));
	return -ENODEV;
	}

	ret = devm_iio_backend_register(&pdev->dev, &adi_axi_adc_generic, st);
	if (ret)
	return ret;

	dev_info(&pdev->dev, "AXI ADC IP core (%d.%.2d.%c) probed\n",
	ADI_AXI_PCORE_VER_MAJOR(ver),
	ADI_AXI_PCORE_VER_MINOR(ver),
	ADI_AXI_PCORE_VER_PATCH(ver));

	return 0;
	}

	static unsigned int adi_axi_adc_10_0_a_info = ADI_AXI_PCORE_VER(10, 0, 'a');

	/* Match table for of_platform binding */
	static const struct of_device_id adi_axi_adc_of_match[] = {
	{ .compatible = "adi,axi-adc-10.0.a", .data = &adi_axi_adc_10_0_a_info },
	{ /* end of list */ }
	};
	MODULE_DEVICE_TABLE(of, adi_axi_adc_of_match);

	static struct platform_driver adi_axi_adc_driver = {
	.driver = {
	.name = KBUILD_MODNAME,
	.of_match_table = adi_axi_adc_of_match,
	},
	.probe = adi_axi_adc_probe,
	};
	module_platform_driver(adi_axi_adc_driver);

	MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
	MODULE_DESCRIPTION("Analog Devices Generic AXI ADC IP core driver");
	MODULE_LICENSE("GPL v2");
	MODULE_IMPORT_NS(IIO_DMAENGINE_BUFFER);
	MODULE_IMPORT_NS(IIO_BACKEND);