drivers/staging/iio/frequency/ad9832.c - linux/kernel/git/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * AD9832 SPI DDS driver
  *
  * Copyright 2011 Analog Devices Inc.
  */

 #include <asm/div64.h>

 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/sysfs.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>

 #include "ad9832.h"

 #include "dds.h"

 /* Registers */

 #define AD9832_FREQ0LL		0x0
 #define AD9832_FREQ0HL		0x1
 #define AD9832_FREQ0LM		0x2
 #define AD9832_FREQ0HM		0x3
 #define AD9832_FREQ1LL		0x4
 #define AD9832_FREQ1HL		0x5
 #define AD9832_FREQ1LM		0x6
 #define AD9832_FREQ1HM		0x7
 #define AD9832_PHASE0L		0x8
 #define AD9832_PHASE0H		0x9
 #define AD9832_PHASE1L		0xA
 #define AD9832_PHASE1H		0xB
 #define AD9832_PHASE2L		0xC
 #define AD9832_PHASE2H		0xD
 #define AD9832_PHASE3L		0xE
 #define AD9832_PHASE3H		0xF

 #define AD9832_PHASE_SYM	0x10
 #define AD9832_FREQ_SYM		0x11
 #define AD9832_PINCTRL_EN	0x12
 #define AD9832_OUTPUT_EN	0x13

 /* Command Control Bits */

 #define AD9832_CMD_PHA8BITSW	0x1
 #define AD9832_CMD_PHA16BITSW	0x0
 #define AD9832_CMD_FRE8BITSW	0x3
 #define AD9832_CMD_FRE16BITSW	0x2
 #define AD9832_CMD_FPSELECT	0x6
 #define AD9832_CMD_SYNCSELSRC	0x8
 #define AD9832_CMD_SLEEPRESCLR	0xC

 #define AD9832_FREQ		BIT(11)
 #define AD9832_PHASE(x)		(((x) & 3) << 9)
 #define AD9832_SYNC		BIT(13)
 #define AD9832_SELSRC		BIT(12)
 #define AD9832_SLEEP		BIT(13)
 #define AD9832_RESET		BIT(12)
 #define AD9832_CLR		BIT(11)
 #define CMD_SHIFT		12
 #define ADD_SHIFT		8
 #define AD9832_FREQ_BITS	32
 #define AD9832_PHASE_BITS	12
 #define RES_MASK(bits)		((1 << (bits)) - 1)

 /**
  * struct ad9832_state - driver instance specific data
  * @spi:		spi_device
  * @avdd:		supply regulator for the analog section
  * @dvdd:		supply regulator for the digital section
  * @mclk:		external master clock
  * @ctrl_fp:		cached frequency/phase control word
  * @ctrl_ss:		cached sync/selsrc control word
  * @ctrl_src:		cached sleep/reset/clr word
  * @xfer:		default spi transfer
  * @msg:		default spi message
  * @freq_xfer:		tuning word spi transfer
  * @freq_msg:		tuning word spi message
  * @phase_xfer:		tuning word spi transfer
  * @phase_msg:		tuning word spi message
  * @lock:		protect sensor state
  * @data:		spi transmit buffer
  * @phase_data:		tuning word spi transmit buffer
  * @freq_data:		tuning word spi transmit buffer
  */

 struct ad9832_state {
 	struct spi_device		*spi;
 	struct regulator		*avdd;
 	struct regulator		*dvdd;
 	struct clk			*mclk;
 	unsigned short			ctrl_fp;
 	unsigned short			ctrl_ss;
 	unsigned short			ctrl_src;
 	struct spi_transfer		xfer;
 	struct spi_message		msg;
 	struct spi_transfer		freq_xfer[4];
 	struct spi_message		freq_msg;
 	struct spi_transfer		phase_xfer[2];
 	struct spi_message		phase_msg;
 	struct mutex			lock;	/* protect sensor state */
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 */
 	union {
 		__be16			freq_data[4]____cacheline_aligned;
 		__be16			phase_data[2];
 		__be16			data;
 	};
 };

 static unsigned long ad9832_calc_freqreg(unsigned long mclk, unsigned long fout)
 {
 	unsigned long long freqreg = (u64)fout *
 				     (u64)((u64)1L << AD9832_FREQ_BITS);
 	do_div(freqreg, mclk);
 	return freqreg;
 }

 static int ad9832_write_frequency(struct ad9832_state *st,
 				  unsigned int addr, unsigned long fout)
 {
 	unsigned long regval;

 	if (fout > (clk_get_rate(st->mclk) / 2))
 		return -EINVAL;

 	regval = ad9832_calc_freqreg(clk_get_rate(st->mclk), fout);

 	st->freq_data[0] = cpu_to_be16((AD9832_CMD_FRE8BITSW << CMD_SHIFT) |
 					(addr << ADD_SHIFT) |
 					((regval >> 24) & 0xFF));
 	st->freq_data[1] = cpu_to_be16((AD9832_CMD_FRE16BITSW << CMD_SHIFT) |
 					((addr - 1) << ADD_SHIFT) |
 					((regval >> 16) & 0xFF));
 	st->freq_data[2] = cpu_to_be16((AD9832_CMD_FRE8BITSW << CMD_SHIFT) |
 					((addr - 2) << ADD_SHIFT) |
 					((regval >> 8) & 0xFF));
 	st->freq_data[3] = cpu_to_be16((AD9832_CMD_FRE16BITSW << CMD_SHIFT) |
 					((addr - 3) << ADD_SHIFT) |
 					((regval >> 0) & 0xFF));

 	return spi_sync(st->spi, &st->freq_msg);
 }

 static int ad9832_write_phase(struct ad9832_state *st,
 			      unsigned long addr, unsigned long phase)
 {
 	if (phase > BIT(AD9832_PHASE_BITS))
 		return -EINVAL;

 	st->phase_data[0] = cpu_to_be16((AD9832_CMD_PHA8BITSW << CMD_SHIFT) |
 					(addr << ADD_SHIFT) |
 					((phase >> 8) & 0xFF));
 	st->phase_data[1] = cpu_to_be16((AD9832_CMD_PHA16BITSW << CMD_SHIFT) |
 					((addr - 1) << ADD_SHIFT) |
 					(phase & 0xFF));

 	return spi_sync(st->spi, &st->phase_msg);
 }

 static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
 			    const char *buf, size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ad9832_state *st = iio_priv(indio_dev);
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 	int ret;
 	unsigned long val;

 	ret = kstrtoul(buf, 10, &val);
 	if (ret)
 		goto error_ret;

 	mutex_lock(&st->lock);
 	switch ((u32)this_attr->address) {
 	case AD9832_FREQ0HM:
 	case AD9832_FREQ1HM:
 		ret = ad9832_write_frequency(st, this_attr->address, val);
 		break;
 	case AD9832_PHASE0H:
 	case AD9832_PHASE1H:
 	case AD9832_PHASE2H:
 	case AD9832_PHASE3H:
 		ret = ad9832_write_phase(st, this_attr->address, val);
 		break;
 	case AD9832_PINCTRL_EN:
 		if (val)
 			st->ctrl_ss &= ~AD9832_SELSRC;
 		else
 			st->ctrl_ss |= AD9832_SELSRC;
 		st->data = cpu_to_be16((AD9832_CMD_SYNCSELSRC << CMD_SHIFT) |
 					st->ctrl_ss);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
 	case AD9832_FREQ_SYM:
 		if (val == 1) {
 			st->ctrl_fp |= AD9832_FREQ;
 		} else if (val == 0) {
 			st->ctrl_fp &= ~AD9832_FREQ;
 		} else {
 			ret = -EINVAL;
 			break;
 		}
 		st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) |
 					st->ctrl_fp);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
 	case AD9832_PHASE_SYM:
 		if (val > 3) {
 			ret = -EINVAL;
 			break;
 		}

 		st->ctrl_fp &= ~AD9832_PHASE(3);
 		st->ctrl_fp |= AD9832_PHASE(val);

 		st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) |
 					st->ctrl_fp);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
 	case AD9832_OUTPUT_EN:
 		if (val)
 			st->ctrl_src &= ~(AD9832_RESET | AD9832_SLEEP |
 					AD9832_CLR);
 		else
 			st->ctrl_src |= AD9832_RESET;

 		st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
 					st->ctrl_src);
 		ret = spi_sync(st->spi, &st->msg);
 		break;
 	default:
 		ret = -ENODEV;
 	}
 	mutex_unlock(&st->lock);

 error_ret:
 	return ret ? ret : len;
 }

 /*
  * see dds.h for further information
  */

 static IIO_DEV_ATTR_FREQ(0, 0, 0200, NULL, ad9832_write, AD9832_FREQ0HM);
 static IIO_DEV_ATTR_FREQ(0, 1, 0200, NULL, ad9832_write, AD9832_FREQ1HM);
 static IIO_DEV_ATTR_FREQSYMBOL(0, 0200, NULL, ad9832_write, AD9832_FREQ_SYM);
 static IIO_CONST_ATTR_FREQ_SCALE(0, "1"); /* 1Hz */

 static IIO_DEV_ATTR_PHASE(0, 0, 0200, NULL, ad9832_write, AD9832_PHASE0H);
 static IIO_DEV_ATTR_PHASE(0, 1, 0200, NULL, ad9832_write, AD9832_PHASE1H);
 static IIO_DEV_ATTR_PHASE(0, 2, 0200, NULL, ad9832_write, AD9832_PHASE2H);
 static IIO_DEV_ATTR_PHASE(0, 3, 0200, NULL, ad9832_write, AD9832_PHASE3H);
 static IIO_DEV_ATTR_PHASESYMBOL(0, 0200, NULL,
 				ad9832_write, AD9832_PHASE_SYM);
 static IIO_CONST_ATTR_PHASE_SCALE(0, "0.0015339808"); /* 2PI/2^12 rad*/

 static IIO_DEV_ATTR_PINCONTROL_EN(0, 0200, NULL,
 				ad9832_write, AD9832_PINCTRL_EN);
 static IIO_DEV_ATTR_OUT_ENABLE(0, 0200, NULL,
 				ad9832_write, AD9832_OUTPUT_EN);

 static struct attribute *ad9832_attributes[] = {
 	&iio_dev_attr_out_altvoltage0_frequency0.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_frequency1.dev_attr.attr,
 	&iio_const_attr_out_altvoltage0_frequency_scale.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_phase0.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_phase1.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_phase2.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_phase3.dev_attr.attr,
 	&iio_const_attr_out_altvoltage0_phase_scale.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_pincontrol_en.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_frequencysymbol.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_phasesymbol.dev_attr.attr,
 	&iio_dev_attr_out_altvoltage0_out_enable.dev_attr.attr,
 	NULL,
 };

 static const struct attribute_group ad9832_attribute_group = {
 	.attrs = ad9832_attributes,
 };

 static const struct iio_info ad9832_info = {
 	.attrs = &ad9832_attribute_group,
 };

 static int ad9832_probe(struct spi_device *spi)
 {
 	struct ad9832_platform_data *pdata = dev_get_platdata(&spi->dev);
 	struct iio_dev *indio_dev;
 	struct ad9832_state *st;
 	int ret;

 	if (!pdata) {
 		dev_dbg(&spi->dev, "no platform data?\n");
 		return -ENODEV;
 	}

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

 	spi_set_drvdata(spi, indio_dev);
 	st = iio_priv(indio_dev);

 	st->avdd = devm_regulator_get(&spi->dev, "avdd");
 	if (IS_ERR(st->avdd))
 		return PTR_ERR(st->avdd);

 	ret = regulator_enable(st->avdd);
 	if (ret) {
 		dev_err(&spi->dev, "Failed to enable specified AVDD supply\n");
 		return ret;
 	}

 	st->dvdd = devm_regulator_get(&spi->dev, "dvdd");
 	if (IS_ERR(st->dvdd)) {
 		ret = PTR_ERR(st->dvdd);
 		goto error_disable_avdd;
 	}

 	ret = regulator_enable(st->dvdd);
 	if (ret) {
 		dev_err(&spi->dev, "Failed to enable specified DVDD supply\n");
 		goto error_disable_avdd;
 	}

 	st->mclk = devm_clk_get(&spi->dev, "mclk");
 	if (IS_ERR(st->mclk)) {
 		ret = PTR_ERR(st->mclk);
 		goto error_disable_dvdd;
 	}

 	ret = clk_prepare_enable(st->mclk);
 	if (ret < 0)
 		goto error_disable_dvdd;

 	st->spi = spi;
 	mutex_init(&st->lock);

 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->info = &ad9832_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	/* Setup default messages */

 	st->xfer.tx_buf = &st->data;
 	st->xfer.len = 2;

 	spi_message_init(&st->msg);
 	spi_message_add_tail(&st->xfer, &st->msg);

 	st->freq_xfer[0].tx_buf = &st->freq_data[0];
 	st->freq_xfer[0].len = 2;
 	st->freq_xfer[0].cs_change = 1;
 	st->freq_xfer[1].tx_buf = &st->freq_data[1];
 	st->freq_xfer[1].len = 2;
 	st->freq_xfer[1].cs_change = 1;
 	st->freq_xfer[2].tx_buf = &st->freq_data[2];
 	st->freq_xfer[2].len = 2;
 	st->freq_xfer[2].cs_change = 1;
 	st->freq_xfer[3].tx_buf = &st->freq_data[3];
 	st->freq_xfer[3].len = 2;

 	spi_message_init(&st->freq_msg);
 	spi_message_add_tail(&st->freq_xfer[0], &st->freq_msg);
 	spi_message_add_tail(&st->freq_xfer[1], &st->freq_msg);
 	spi_message_add_tail(&st->freq_xfer[2], &st->freq_msg);
 	spi_message_add_tail(&st->freq_xfer[3], &st->freq_msg);

 	st->phase_xfer[0].tx_buf = &st->phase_data[0];
 	st->phase_xfer[0].len = 2;
 	st->phase_xfer[0].cs_change = 1;
 	st->phase_xfer[1].tx_buf = &st->phase_data[1];
 	st->phase_xfer[1].len = 2;

 	spi_message_init(&st->phase_msg);
 	spi_message_add_tail(&st->phase_xfer[0], &st->phase_msg);
 	spi_message_add_tail(&st->phase_xfer[1], &st->phase_msg);

 	st->ctrl_src = AD9832_SLEEP | AD9832_RESET | AD9832_CLR;
 	st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) |
 					st->ctrl_src);
 	ret = spi_sync(st->spi, &st->msg);
 	if (ret) {
 		dev_err(&spi->dev, "device init failed\n");
 		goto error_unprepare_mclk;
 	}

 	ret = ad9832_write_frequency(st, AD9832_FREQ0HM, pdata->freq0);
 	if (ret)
 		goto error_unprepare_mclk;

 	ret = ad9832_write_frequency(st, AD9832_FREQ1HM, pdata->freq1);
 	if (ret)
 		goto error_unprepare_mclk;

 	ret = ad9832_write_phase(st, AD9832_PHASE0H, pdata->phase0);
 	if (ret)
 		goto error_unprepare_mclk;

 	ret = ad9832_write_phase(st, AD9832_PHASE1H, pdata->phase1);
 	if (ret)
 		goto error_unprepare_mclk;

 	ret = ad9832_write_phase(st, AD9832_PHASE2H, pdata->phase2);
 	if (ret)
 		goto error_unprepare_mclk;

 	ret = ad9832_write_phase(st, AD9832_PHASE3H, pdata->phase3);
 	if (ret)
 		goto error_unprepare_mclk;

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

 	return 0;

 error_unprepare_mclk:
 	clk_disable_unprepare(st->mclk);
 error_disable_dvdd:
 	regulator_disable(st->dvdd);
 error_disable_avdd:
 	regulator_disable(st->avdd);

 	return ret;
 }

 static int ad9832_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad9832_state *st = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	clk_disable_unprepare(st->mclk);
 	regulator_disable(st->dvdd);
 	regulator_disable(st->avdd);

 	return 0;
 }

 static const struct spi_device_id ad9832_id[] = {
 	{"ad9832", 0},
 	{"ad9835", 0},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad9832_id);

 static struct spi_driver ad9832_driver = {
 	.driver = {
 		.name	= "ad9832",
 	},
 	.probe		= ad9832_probe,
 	.remove		= ad9832_remove,
 	.id_table	= ad9832_id,
 };
 module_spi_driver(ad9832_driver);

 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 MODULE_DESCRIPTION("Analog Devices AD9832/AD9835 DDS");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* AD9832 SPI DDS driver
	*
	* Copyright 2011 Analog Devices Inc.
	*/

	#include <asm/div64.h>

	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/regulator/consumer.h>
	#include <linux/slab.h>
	#include <linux/spi/spi.h>
	#include <linux/sysfs.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>

	#include "ad9832.h"

	#include "dds.h"

	/* Registers */

	#define AD9832_FREQ0LL 0x0
	#define AD9832_FREQ0HL 0x1
	#define AD9832_FREQ0LM 0x2
	#define AD9832_FREQ0HM 0x3
	#define AD9832_FREQ1LL 0x4
	#define AD9832_FREQ1HL 0x5
	#define AD9832_FREQ1LM 0x6
	#define AD9832_FREQ1HM 0x7
	#define AD9832_PHASE0L 0x8
	#define AD9832_PHASE0H 0x9
	#define AD9832_PHASE1L 0xA
	#define AD9832_PHASE1H 0xB
	#define AD9832_PHASE2L 0xC
	#define AD9832_PHASE2H 0xD
	#define AD9832_PHASE3L 0xE
	#define AD9832_PHASE3H 0xF

	#define AD9832_PHASE_SYM 0x10
	#define AD9832_FREQ_SYM 0x11
	#define AD9832_PINCTRL_EN 0x12
	#define AD9832_OUTPUT_EN 0x13

	/* Command Control Bits */

	#define AD9832_CMD_PHA8BITSW 0x1
	#define AD9832_CMD_PHA16BITSW 0x0
	#define AD9832_CMD_FRE8BITSW 0x3
	#define AD9832_CMD_FRE16BITSW 0x2
	#define AD9832_CMD_FPSELECT 0x6
	#define AD9832_CMD_SYNCSELSRC 0x8
	#define AD9832_CMD_SLEEPRESCLR 0xC

	#define AD9832_FREQ BIT(11)
	#define AD9832_PHASE(x) (((x) & 3) << 9)
	#define AD9832_SYNC BIT(13)
	#define AD9832_SELSRC BIT(12)
	#define AD9832_SLEEP BIT(13)
	#define AD9832_RESET BIT(12)
	#define AD9832_CLR BIT(11)
	#define CMD_SHIFT 12
	#define ADD_SHIFT 8
	#define AD9832_FREQ_BITS 32
	#define AD9832_PHASE_BITS 12
	#define RES_MASK(bits) ((1 << (bits)) - 1)

	/**
	* struct ad9832_state - driver instance specific data
	* @spi: spi_device
	* @avdd: supply regulator for the analog section
	* @dvdd: supply regulator for the digital section
	* @mclk: external master clock
	* @ctrl_fp: cached frequency/phase control word
	* @ctrl_ss: cached sync/selsrc control word
	* @ctrl_src: cached sleep/reset/clr word
	* @xfer: default spi transfer
	* @msg: default spi message
	* @freq_xfer: tuning word spi transfer
	* @freq_msg: tuning word spi message
	* @phase_xfer: tuning word spi transfer
	* @phase_msg: tuning word spi message
	* @lock: protect sensor state
	* @data: spi transmit buffer
	* @phase_data: tuning word spi transmit buffer
	* @freq_data: tuning word spi transmit buffer
	*/

	struct ad9832_state {
	struct spi_device *spi;
	struct regulator *avdd;
	struct regulator *dvdd;
	struct clk *mclk;
	unsigned short ctrl_fp;
	unsigned short ctrl_ss;
	unsigned short ctrl_src;
	struct spi_transfer xfer;
	struct spi_message msg;
	struct spi_transfer freq_xfer[4];
	struct spi_message freq_msg;
	struct spi_transfer phase_xfer[2];
	struct spi_message phase_msg;
	struct mutex lock; /* protect sensor state */
	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	*/
	union {
	__be16 freq_data[4]____cacheline_aligned;
	__be16 phase_data[2];
	__be16 data;
	};
	};

	static unsigned long ad9832_calc_freqreg(unsigned long mclk, unsigned long fout)
	{
	unsigned long long freqreg = (u64)fout *
	(u64)((u64)1L << AD9832_FREQ_BITS);
	do_div(freqreg, mclk);
	return freqreg;
	}

	static int ad9832_write_frequency(struct ad9832_state *st,
	unsigned int addr, unsigned long fout)
	{
	unsigned long regval;

	if (fout > (clk_get_rate(st->mclk) / 2))
	return -EINVAL;

	regval = ad9832_calc_freqreg(clk_get_rate(st->mclk), fout);

	st->freq_data[0] = cpu_to_be16((AD9832_CMD_FRE8BITSW << CMD_SHIFT) \|
	(addr << ADD_SHIFT) \|
	((regval >> 24) & 0xFF));
	st->freq_data[1] = cpu_to_be16((AD9832_CMD_FRE16BITSW << CMD_SHIFT) \|
	((addr - 1) << ADD_SHIFT) \|
	((regval >> 16) & 0xFF));
	st->freq_data[2] = cpu_to_be16((AD9832_CMD_FRE8BITSW << CMD_SHIFT) \|
	((addr - 2) << ADD_SHIFT) \|
	((regval >> 8) & 0xFF));
	st->freq_data[3] = cpu_to_be16((AD9832_CMD_FRE16BITSW << CMD_SHIFT) \|
	((addr - 3) << ADD_SHIFT) \|
	((regval >> 0) & 0xFF));

	return spi_sync(st->spi, &st->freq_msg);
	}

	static int ad9832_write_phase(struct ad9832_state *st,
	unsigned long addr, unsigned long phase)
	{
	if (phase > BIT(AD9832_PHASE_BITS))
	return -EINVAL;

	st->phase_data[0] = cpu_to_be16((AD9832_CMD_PHA8BITSW << CMD_SHIFT) \|
	(addr << ADD_SHIFT) \|
	((phase >> 8) & 0xFF));
	st->phase_data[1] = cpu_to_be16((AD9832_CMD_PHA16BITSW << CMD_SHIFT) \|
	((addr - 1) << ADD_SHIFT) \|
	(phase & 0xFF));

	return spi_sync(st->spi, &st->phase_msg);
	}

	static ssize_t ad9832_write(struct device dev, struct device_attribute attr,
	const char *buf, size_t len)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ad9832_state *st = iio_priv(indio_dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int ret;
	unsigned long val;

	ret = kstrtoul(buf, 10, &val);
	if (ret)
	goto error_ret;

	mutex_lock(&st->lock);
	switch ((u32)this_attr->address) {
	case AD9832_FREQ0HM:
	case AD9832_FREQ1HM:
	ret = ad9832_write_frequency(st, this_attr->address, val);
	break;
	case AD9832_PHASE0H:
	case AD9832_PHASE1H:
	case AD9832_PHASE2H:
	case AD9832_PHASE3H:
	ret = ad9832_write_phase(st, this_attr->address, val);
	break;
	case AD9832_PINCTRL_EN:
	if (val)
	st->ctrl_ss &= ~AD9832_SELSRC;
	else
	st->ctrl_ss \|= AD9832_SELSRC;
	st->data = cpu_to_be16((AD9832_CMD_SYNCSELSRC << CMD_SHIFT) \|
	st->ctrl_ss);
	ret = spi_sync(st->spi, &st->msg);
	break;
	case AD9832_FREQ_SYM:
	if (val == 1) {
	st->ctrl_fp \|= AD9832_FREQ;
	} else if (val == 0) {
	st->ctrl_fp &= ~AD9832_FREQ;
	} else {
	ret = -EINVAL;
	break;
	}
	st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) \|
	st->ctrl_fp);
	ret = spi_sync(st->spi, &st->msg);
	break;
	case AD9832_PHASE_SYM:
	if (val > 3) {
	ret = -EINVAL;
	break;
	}

	st->ctrl_fp &= ~AD9832_PHASE(3);
	st->ctrl_fp \|= AD9832_PHASE(val);

	st->data = cpu_to_be16((AD9832_CMD_FPSELECT << CMD_SHIFT) \|
	st->ctrl_fp);
	ret = spi_sync(st->spi, &st->msg);
	break;
	case AD9832_OUTPUT_EN:
	if (val)
	st->ctrl_src &= ~(AD9832_RESET \| AD9832_SLEEP \|
	AD9832_CLR);
	else
	st->ctrl_src \|= AD9832_RESET;

	st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) \|
	st->ctrl_src);
	ret = spi_sync(st->spi, &st->msg);
	break;
	default:
	ret = -ENODEV;
	}
	mutex_unlock(&st->lock);

	error_ret:
	return ret ? ret : len;
	}

	/*
	* see dds.h for further information
	*/

	static IIO_DEV_ATTR_FREQ(0, 0, 0200, NULL, ad9832_write, AD9832_FREQ0HM);
	static IIO_DEV_ATTR_FREQ(0, 1, 0200, NULL, ad9832_write, AD9832_FREQ1HM);
	static IIO_DEV_ATTR_FREQSYMBOL(0, 0200, NULL, ad9832_write, AD9832_FREQ_SYM);
	static IIO_CONST_ATTR_FREQ_SCALE(0, "1"); /* 1Hz */

	static IIO_DEV_ATTR_PHASE(0, 0, 0200, NULL, ad9832_write, AD9832_PHASE0H);
	static IIO_DEV_ATTR_PHASE(0, 1, 0200, NULL, ad9832_write, AD9832_PHASE1H);
	static IIO_DEV_ATTR_PHASE(0, 2, 0200, NULL, ad9832_write, AD9832_PHASE2H);
	static IIO_DEV_ATTR_PHASE(0, 3, 0200, NULL, ad9832_write, AD9832_PHASE3H);
	static IIO_DEV_ATTR_PHASESYMBOL(0, 0200, NULL,
	ad9832_write, AD9832_PHASE_SYM);
	static IIO_CONST_ATTR_PHASE_SCALE(0, "0.0015339808"); /* 2PI/2^12 rad*/

	static IIO_DEV_ATTR_PINCONTROL_EN(0, 0200, NULL,
	ad9832_write, AD9832_PINCTRL_EN);
	static IIO_DEV_ATTR_OUT_ENABLE(0, 0200, NULL,
	ad9832_write, AD9832_OUTPUT_EN);

	static struct attribute *ad9832_attributes[] = {
	&iio_dev_attr_out_altvoltage0_frequency0.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_frequency1.dev_attr.attr,
	&iio_const_attr_out_altvoltage0_frequency_scale.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_phase0.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_phase1.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_phase2.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_phase3.dev_attr.attr,
	&iio_const_attr_out_altvoltage0_phase_scale.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_pincontrol_en.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_frequencysymbol.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_phasesymbol.dev_attr.attr,
	&iio_dev_attr_out_altvoltage0_out_enable.dev_attr.attr,
	NULL,
	};

	static const struct attribute_group ad9832_attribute_group = {
	.attrs = ad9832_attributes,
	};

	static const struct iio_info ad9832_info = {
	.attrs = &ad9832_attribute_group,
	};

	static int ad9832_probe(struct spi_device *spi)
	{
	struct ad9832_platform_data *pdata = dev_get_platdata(&spi->dev);
	struct iio_dev *indio_dev;
	struct ad9832_state *st;
	int ret;

	if (!pdata) {
	dev_dbg(&spi->dev, "no platform data?\n");
	return -ENODEV;
	}

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

	spi_set_drvdata(spi, indio_dev);
	st = iio_priv(indio_dev);

	st->avdd = devm_regulator_get(&spi->dev, "avdd");
	if (IS_ERR(st->avdd))
	return PTR_ERR(st->avdd);

	ret = regulator_enable(st->avdd);
	if (ret) {
	dev_err(&spi->dev, "Failed to enable specified AVDD supply\n");
	return ret;
	}

	st->dvdd = devm_regulator_get(&spi->dev, "dvdd");
	if (IS_ERR(st->dvdd)) {
	ret = PTR_ERR(st->dvdd);
	goto error_disable_avdd;
	}

	ret = regulator_enable(st->dvdd);
	if (ret) {
	dev_err(&spi->dev, "Failed to enable specified DVDD supply\n");
	goto error_disable_avdd;
	}

	st->mclk = devm_clk_get(&spi->dev, "mclk");
	if (IS_ERR(st->mclk)) {
	ret = PTR_ERR(st->mclk);
	goto error_disable_dvdd;
	}

	ret = clk_prepare_enable(st->mclk);
	if (ret < 0)
	goto error_disable_dvdd;

	st->spi = spi;
	mutex_init(&st->lock);

	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &ad9832_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* Setup default messages */

	st->xfer.tx_buf = &st->data;
	st->xfer.len = 2;

	spi_message_init(&st->msg);
	spi_message_add_tail(&st->xfer, &st->msg);

	st->freq_xfer[0].tx_buf = &st->freq_data[0];
	st->freq_xfer[0].len = 2;
	st->freq_xfer[0].cs_change = 1;
	st->freq_xfer[1].tx_buf = &st->freq_data[1];
	st->freq_xfer[1].len = 2;
	st->freq_xfer[1].cs_change = 1;
	st->freq_xfer[2].tx_buf = &st->freq_data[2];
	st->freq_xfer[2].len = 2;
	st->freq_xfer[2].cs_change = 1;
	st->freq_xfer[3].tx_buf = &st->freq_data[3];
	st->freq_xfer[3].len = 2;

	spi_message_init(&st->freq_msg);
	spi_message_add_tail(&st->freq_xfer[0], &st->freq_msg);
	spi_message_add_tail(&st->freq_xfer[1], &st->freq_msg);
	spi_message_add_tail(&st->freq_xfer[2], &st->freq_msg);
	spi_message_add_tail(&st->freq_xfer[3], &st->freq_msg);

	st->phase_xfer[0].tx_buf = &st->phase_data[0];
	st->phase_xfer[0].len = 2;
	st->phase_xfer[0].cs_change = 1;
	st->phase_xfer[1].tx_buf = &st->phase_data[1];
	st->phase_xfer[1].len = 2;

	spi_message_init(&st->phase_msg);
	spi_message_add_tail(&st->phase_xfer[0], &st->phase_msg);
	spi_message_add_tail(&st->phase_xfer[1], &st->phase_msg);

	st->ctrl_src = AD9832_SLEEP \| AD9832_RESET \| AD9832_CLR;
	st->data = cpu_to_be16((AD9832_CMD_SLEEPRESCLR << CMD_SHIFT) \|
	st->ctrl_src);
	ret = spi_sync(st->spi, &st->msg);
	if (ret) {
	dev_err(&spi->dev, "device init failed\n");
	goto error_unprepare_mclk;
	}

	ret = ad9832_write_frequency(st, AD9832_FREQ0HM, pdata->freq0);
	if (ret)
	goto error_unprepare_mclk;

	ret = ad9832_write_frequency(st, AD9832_FREQ1HM, pdata->freq1);
	if (ret)
	goto error_unprepare_mclk;

	ret = ad9832_write_phase(st, AD9832_PHASE0H, pdata->phase0);
	if (ret)
	goto error_unprepare_mclk;

	ret = ad9832_write_phase(st, AD9832_PHASE1H, pdata->phase1);
	if (ret)
	goto error_unprepare_mclk;

	ret = ad9832_write_phase(st, AD9832_PHASE2H, pdata->phase2);
	if (ret)
	goto error_unprepare_mclk;

	ret = ad9832_write_phase(st, AD9832_PHASE3H, pdata->phase3);
	if (ret)
	goto error_unprepare_mclk;

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

	return 0;

	error_unprepare_mclk:
	clk_disable_unprepare(st->mclk);
	error_disable_dvdd:
	regulator_disable(st->dvdd);
	error_disable_avdd:
	regulator_disable(st->avdd);

	return ret;
	}

	static int ad9832_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad9832_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	clk_disable_unprepare(st->mclk);
	regulator_disable(st->dvdd);
	regulator_disable(st->avdd);

	return 0;
	}

	static const struct spi_device_id ad9832_id[] = {
	{"ad9832", 0},
	{"ad9835", 0},
	{}
	};
	MODULE_DEVICE_TABLE(spi, ad9832_id);

	static struct spi_driver ad9832_driver = {
	.driver = {
	.name = "ad9832",
	},
	.probe = ad9832_probe,
	.remove = ad9832_remove,
	.id_table = ad9832_id,
	};
	module_spi_driver(ad9832_driver);

	MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
	MODULE_DESCRIPTION("Analog Devices AD9832/AD9835 DDS");
	MODULE_LICENSE("GPL v2");