Re: [PATCH 3/3] IIO: DDS: AD9833 / AD9834 driver

[Jonathan Cameron <jic23@cam.ac.uk>]

On 12/13/10 16:27, michael.hennerich@analog.com wrote:
> From: Michael Hennerich <michael.hennerich@analog.com>
> 
> Changes since RFC/v1:
> IIO: Apply list review feedback
> 
> Apply list review feedback:
> 	Rename attributes to fit IIO convention used in other drivers.
> 	Fix typos.
> 	Provide ddsX_out_enable as opposed to ddsX_out_disable.
> 	Use proper __devexit marking.
> 	Use strict_strtoul() to avoid negatives.
> 
Couple of nitpicks inline. Subject to changes due to changes in macros
suggested in previous patch (or you convincing me otherwise):
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
> Reviewed-by: Datta Shubhrajyoti <shubhrajyoti@ti.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
> ---
>  drivers/staging/iio/dds/Kconfig  |    7 +
>  drivers/staging/iio/dds/Makefile |    1 +
>  drivers/staging/iio/dds/ad9834.c |  482 ++++++++++++++++++++++++++++++++++++++
>  drivers/staging/iio/dds/ad9834.h |  112 +++++++++
>  4 files changed, 602 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/staging/iio/dds/ad9834.c
>  create mode 100644 drivers/staging/iio/dds/ad9834.h
> 
> diff --git a/drivers/staging/iio/dds/Kconfig b/drivers/staging/iio/dds/Kconfig
> index 7969be2..4c9cce3 100644
> --- a/drivers/staging/iio/dds/Kconfig
> +++ b/drivers/staging/iio/dds/Kconfig
> @@ -17,6 +17,13 @@ config AD9832
>  	  Say yes here to build support for Analog Devices DDS chip
>  	  ad9832 and ad9835, provides direct access via sysfs.
> 
> +config AD9834
> +	tristate "Analog Devices ad9833/4/ driver"
> +	depends on SPI
> +	help
> +	  Say yes here to build support for Analog Devices DDS chip
> +	  AD9833 and AD9834, provides direct access via sysfs.
> +
>  config AD9850
>  	tristate "Analog Devices ad9850/1 driver"
>  	depends on SPI
> diff --git a/drivers/staging/iio/dds/Makefile b/drivers/staging/iio/dds/Makefile
> index 6f274ac..1477461 100644
> --- a/drivers/staging/iio/dds/Makefile
> +++ b/drivers/staging/iio/dds/Makefile
> @@ -4,6 +4,7 @@
> 
>  obj-$(CONFIG_AD5930) += ad5930.o
>  obj-$(CONFIG_AD9832) += ad9832.o
> +obj-$(CONFIG_AD9834) += ad9834.o
>  obj-$(CONFIG_AD9850) += ad9850.o
>  obj-$(CONFIG_AD9852) += ad9852.o
>  obj-$(CONFIG_AD9910) += ad9910.o
> diff --git a/drivers/staging/iio/dds/ad9834.c b/drivers/staging/iio/dds/ad9834.c
> new file mode 100644
> index 0000000..df3d68c
> --- /dev/null
> +++ b/drivers/staging/iio/dds/ad9834.c
> @@ -0,0 +1,482 @@
> +/*
> + * AD9834 SPI DAC driver
> + *
> + * Copyright 2010 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2 or later.
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/workqueue.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +#include <linux/list.h>
> +#include <linux/spi/spi.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/err.h>
> +#include <asm/div64.h>
> +
> +#include "../iio.h"
> +#include "../sysfs.h"
> +#include "dds.h"
> +
> +#include "ad9834.h"
> +
> +static unsigned int ad9834_calc_freqreg(unsigned long mclk, unsigned long fout)
> +{
> +	unsigned long long freqreg = (u64) fout * (u64) (1 << AD9834_FREQ_BITS);
> +	do_div(freqreg, mclk);
> +	return freqreg;
> +}
> +
> +static int ad9834_write_frequency(struct ad9834_state *st,
> +				  unsigned long addr, unsigned long fout)
> +{
> +	unsigned long regval;
> +
> +	if (fout > (st->mclk / 2))
> +		return -EINVAL;
> +
> +	regval = ad9834_calc_freqreg(st->mclk, fout);
> +
> +	st->freq_data[0] = cpu_to_be16(addr | (regval &
> +				       RES_MASK(AD9834_FREQ_BITS / 2)));
> +	st->freq_data[1] = cpu_to_be16(addr | ((regval >>
> +				       (AD9834_FREQ_BITS / 2)) &
> +				       RES_MASK(AD9834_FREQ_BITS / 2)));
> +
> +	return spi_sync(st->spi, &st->freq_msg);;
> +}
> +
> +static int ad9834_write_phase(struct ad9834_state *st,
> +				  unsigned long addr, unsigned long phase)
> +{
> +	if (phase > (1 << AD9834_PHASE_BITS))
> +		return -EINVAL;
> +	st->data = cpu_to_be16(addr | phase);
> +
> +	return spi_sync(st->spi, &st->msg);
> +}
> +
> +static ssize_t ad9834_write(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf,
> +		size_t len)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad9834_state *st = dev_info->dev_data;
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	int ret;
> +	long val;
> +
> +	ret = strict_strtoul(buf, 10, &val);
> +	if (ret)
> +		goto error_ret;
> +
> +	mutex_lock(&dev_info->mlock);
> +	switch (this_attr->address) {
> +	case AD9834_REG_FREQ0:
> +	case AD9834_REG_FREQ1:
> +		ret = ad9834_write_frequency(st, this_attr->address, val);
> +		break;
> +	case AD9834_REG_PHASE0:
> +	case AD9834_REG_PHASE1:
> +		ret = ad9834_write_phase(st, this_attr->address, val);
> +		break;
> +	case AD9834_OPBITEN:
> +		if (st->control & AD9834_MODE) {
> +			ret = -EINVAL;  /* AD9843 reserved mode */
> +			break;
> +		}
> +
> +		if (val)
> +			st->control |= AD9834_OPBITEN;
> +		else
> +			st->control &= ~AD9834_OPBITEN;
> +
> +		st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +		ret = spi_sync(st->spi, &st->msg);
> +		break;
> +	case AD9834_PIN_SW:
> +		if (val)
> +			st->control |= AD9834_PIN_SW;
> +		else
> +			st->control &= ~AD9834_PIN_SW;
> +		st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +		ret = spi_sync(st->spi, &st->msg);
> +		break;
> +	case AD9834_FSEL:
> +	case AD9834_PSEL:
> +		if (val == 0)
> +			st->control &= ~(this_attr->address | AD9834_PIN_SW);
> +		else if (val == 1) {
> +			st->control |= this_attr->address;
> +			st->control &= ~AD9834_PIN_SW;
> +		} else {
> +			ret = -EINVAL;
> +			break;
> +		}
> +		st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +		ret = spi_sync(st->spi, &st->msg);
> +		break;
> +	case AD9834_RESET:
> +		if (val)
> +			st->control &= ~AD9834_RESET;
> +		else
> +			st->control |= AD9834_RESET;
> +
> +		st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +		ret = spi_sync(st->spi, &st->msg);
> +		break;
> +	default:
> +		ret = -ENODEV;
> +	}
> +	mutex_unlock(&dev_info->mlock);
> +
> +error_ret:
> +	return ret ? ret : len;
> +}
> +
> +static ssize_t ad9834_store_wavetype(struct device *dev,
> +				 struct device_attribute *attr,
> +				 const char *buf,
> +				 size_t len)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad9834_state *st = dev_info->dev_data;
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	int ret = 0;
> +	bool is_ad9833 = st->devid == ID_AD9833;
> +
> +	mutex_lock(&dev_info->mlock);
> +
> +	switch (this_attr->address) {
> +	case 0:
> +		if (sysfs_streq(buf, "sine")) {
> +			st->control &= ~AD9834_MODE;
> +			if (is_ad9833)
> +				st->control &= ~AD9834_OPBITEN;
> +		} else if (sysfs_streq(buf, "triangle")) {
> +			if (is_ad9833) {
> +				st->control &= ~AD9834_OPBITEN;
> +				st->control |= AD9834_MODE;
> +			} else if (st->control & AD9834_OPBITEN) {
> +				ret = -EINVAL;	/* AD9843 reserved mode */
> +			} else {
> +				st->control |= AD9834_MODE;
> +			}
> +		} else if (is_ad9833 && sysfs_streq(buf, "square")) {
> +			st->control &= ~AD9834_MODE;
> +			st->control |= AD9834_OPBITEN;
> +		} else {
> +			ret = -EINVAL;
> +		}
> +
> +		break;
> +	case 1:
> +		if (sysfs_streq(buf, "square") &&
> +			!(st->control & AD9834_MODE)) {
> +			st->control &= ~AD9834_MODE;
> +			st->control |= AD9834_OPBITEN;
> +		} else {
> +			ret = -EINVAL;
> +		}
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	if (!ret) {
> +		st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +		ret = spi_sync(st->spi, &st->msg);
> +	}
> +		mutex_unlock(&dev_info->mlock);
In correct tabbing on previous line? (or my email client has messed up)
> +
> +	return ret ? ret : len;
> +}
> +
> +static ssize_t ad9834_show_name(struct device *dev,
> +				 struct device_attribute *attr,
> +				 char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad9834_state *st = iio_dev_get_devdata(dev_info);
> +
> +	return sprintf(buf, "%s\n", spi_get_device_id(st->spi)->name);
> +}
> +static IIO_DEVICE_ATTR(name, S_IRUGO, ad9834_show_name, NULL, 0);
> +
> +static ssize_t ad9834_show_out0_wavetype_available(struct device *dev,
> +						struct device_attribute *attr,
> +						char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad9834_state *st = iio_dev_get_devdata(dev_info);
> +	char *str;
> +
> +	if (st->devid == ID_AD9833)
> +		str = "sine triangle square";
> +	else if (st->control & AD9834_OPBITEN)
> +		str = "sine";
> +	else
> +		str = "sine triangle";
> +
> +	return sprintf(buf, "%s\n", str);
> +}
> +
> +
> +static IIO_DEVICE_ATTR(dds0_out0_wavetype_available, S_IRUGO,
> +		       ad9834_show_out0_wavetype_available, NULL, 0);
> +
> +static ssize_t ad9834_show_out1_wavetype_available(struct device *dev,
> +						struct device_attribute *attr,
> +						char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad9834_state *st = iio_dev_get_devdata(dev_info);
> +	char *str;
> +
> +	if (st->control & AD9834_MODE)
> +		str = "";
I 'think' that the is_visible below makes this first condition impossible?
I've never used the is_visible stuff so not entirely sure I've understood
it correctly...
That probably means that you can use a const attr for this...
> +	else
> +		str = "square";
> +
> +	return sprintf(buf, "%s\n", str);
> +}
> +
> +static IIO_DEVICE_ATTR(dds0_out1_wavetype_available, S_IRUGO,
> +		       ad9834_show_out1_wavetype_available, NULL, 0);
> +
> +/**
> + * see dds.h for further information
> + */
> +
> +static IIO_DEV_ATTR_FREQ(0, 0, ad9834_write, AD9834_REG_FREQ0);
> +static IIO_DEV_ATTR_FREQ(0, 1, ad9834_write, AD9834_REG_FREQ1);
> +static IIO_DEV_ATTR_FREQSYMBOL(0, ad9834_write, AD9834_FSEL);
> +static IIO_CONST_ATTR_FREQ_SCALE(0, "1"); /* 1Hz */
> +
> +static IIO_DEV_ATTR_PHASE(0, 0, ad9834_write, AD9834_REG_PHASE0);
> +static IIO_DEV_ATTR_PHASE(0, 1, ad9834_write, AD9834_REG_PHASE1);
> +static IIO_DEV_ATTR_PHASESYMBOL(0, ad9834_write, AD9834_PSEL);
> +static IIO_CONST_ATTR_PHASE_SCALE(0, "0.0015339808"); /* 2PI/2^12 rad*/
> +
> +static IIO_DEV_ATTR_PINCONTROL_EN(0, ad9834_write, AD9834_PIN_SW);
> +static IIO_DEV_ATTR_OUT_ENABLE(0, ad9834_write, AD9834_RESET);
> +static IIO_DEV_ATTR_OUTY_ENABLE(0, 1, ad9834_write, AD9834_OPBITEN);
> +static IIO_DEV_ATTR_OUT_WAVETYPE(0, 0, ad9834_store_wavetype, 0);
> +static IIO_DEV_ATTR_OUT_WAVETYPE(0, 1, ad9834_store_wavetype, 1);
> +
> +static struct attribute *ad9834_attributes[] = {
> +	&iio_dev_attr_dds0_freq0.dev_attr.attr,
> +	&iio_dev_attr_dds0_freq1.dev_attr.attr,
> +	&iio_const_attr_dds0_freq_scale.dev_attr.attr,
> +	&iio_dev_attr_dds0_phase0.dev_attr.attr,
> +	&iio_dev_attr_dds0_phase1.dev_attr.attr,
> +	&iio_const_attr_dds0_phase_scale.dev_attr.attr,
> +	&iio_dev_attr_dds0_pincontrol_en.dev_attr.attr,
> +	&iio_dev_attr_dds0_freqsymbol.dev_attr.attr,
> +	&iio_dev_attr_dds0_phasesymbol.dev_attr.attr,
> +	&iio_dev_attr_dds0_out_enable.dev_attr.attr,
> +	&iio_dev_attr_dds0_out1_enable.dev_attr.attr,
> +	&iio_dev_attr_dds0_out0_wavetype.dev_attr.attr,
> +	&iio_dev_attr_dds0_out1_wavetype.dev_attr.attr,
> +	&iio_dev_attr_dds0_out0_wavetype_available.dev_attr.attr,
> +	&iio_dev_attr_dds0_out1_wavetype_available.dev_attr.attr,
> +	&iio_dev_attr_name.dev_attr.attr,
> +	NULL,
> +};
> +
> +static mode_t ad9834_attr_is_visible(struct kobject *kobj,
> +				     struct attribute *attr, int n)
> +{
> +	struct device *dev = container_of(kobj, struct device, kobj);
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad9834_state *st = iio_dev_get_devdata(dev_info);
> +
> +	mode_t mode = attr->mode;
> +
> +	if (st->devid == ID_AD9834)
> +		return mode;
> +
> +	if ((attr == &iio_dev_attr_dds0_out1_enable.dev_attr.attr) ||
> +	   	(attr == &iio_dev_attr_dds0_out1_wavetype.dev_attr.attr) ||
> +		(attr ==
> +		&iio_dev_attr_dds0_out1_wavetype_available.dev_attr.attr))
> +		mode = 0;
> +
> +	return mode;
> +}
> +
> +static const struct attribute_group ad9834_attribute_group = {
> +	.attrs = ad9834_attributes,
> +	.is_visible = ad9834_attr_is_visible,
> +};
> +
> +static int __devinit ad9834_probe(struct spi_device *spi)
> +{
> +	struct ad9834_platform_data *pdata = spi->dev.platform_data;
> +	struct ad9834_state *st;
> +	int ret;
> +
> +	if (!pdata) {
> +		dev_dbg(&spi->dev, "no platform data?\n");
> +		return -ENODEV;
> +	}
> +
> +	st = kzalloc(sizeof(*st), GFP_KERNEL);
> +	if (st == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +
> +	st->reg = regulator_get(&spi->dev, "vcc");
> +	if (!IS_ERR(st->reg)) {
> +		ret = regulator_enable(st->reg);
> +		if (ret)
> +			goto error_put_reg;
> +	}
> +
> +	st->mclk = pdata->mclk;
> +
> +	spi_set_drvdata(spi, st);
> +
> +	st->spi = spi;
> +	st->devid = spi_get_device_id(spi)->driver_data;
> +
> +	st->indio_dev = iio_allocate_device();
> +	if (st->indio_dev == NULL) {
> +		ret = -ENOMEM;
> +		goto error_disable_reg;
> +	}
> +
> +	st->indio_dev->dev.parent = &spi->dev;
> +	st->indio_dev->attrs = &ad9834_attribute_group;
> +	st->indio_dev->dev_data = (void *)(st);
nitpick: technically superflous brackets...

> +	st->indio_dev->driver_module = THIS_MODULE;
> +	st->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;
> +
> +	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);
> +
> +	st->control = AD9834_B28 | AD9834_RESET;
> +
> +	if (!pdata->en_div2)
> +		st->control |= AD9834_DIV2;
> +
> +	if (!pdata->en_signbit_msb_out && (st->devid == ID_AD9834))
> +		st->control |= AD9834_SIGN_PIB;
> +
> +	st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +	ret = spi_sync(st->spi, &st->msg);
> +	if (ret) {
> +		dev_err(&spi->dev, "device init failed\n");
> +		goto error_free_device;
> +	}
> +
> +	ret = ad9834_write_frequency(st, AD9834_REG_FREQ0, pdata->freq0);
> +	if (ret)
> +		goto error_free_device;
> +
> +	ret = ad9834_write_frequency(st, AD9834_REG_FREQ1, pdata->freq1);
> +	if (ret)
> +		goto error_free_device;
> +
> +	ret = ad9834_write_phase(st, AD9834_REG_PHASE0, pdata->phase0);
> +	if (ret)
> +		goto error_free_device;
> +
> +	ret = ad9834_write_phase(st, AD9834_REG_PHASE1, pdata->phase1);
> +	if (ret)
> +		goto error_free_device;
> +
> +	st->control &= ~AD9834_RESET;
> +	st->data = cpu_to_be16(AD9834_REG_CMD | st->control);
> +	ret = spi_sync(st->spi, &st->msg);
> +	if (ret)
> +		goto error_free_device;
> +
> +	ret = iio_device_register(st->indio_dev);
> +	if (ret)
> +		goto error_free_device;
> +
> +	return 0;
> +
> +error_free_device:
> +	iio_free_device(st->indio_dev);
> +error_disable_reg:
> +	if (!IS_ERR(st->reg))
> +		regulator_disable(st->reg);
> +error_put_reg:
> +	if (!IS_ERR(st->reg))
> +		regulator_put(st->reg);
> +	kfree(st);
> +error_ret:
> +	return ret;
> +}
> +
> +static int __devexit ad9834_remove(struct spi_device *spi)
> +{
> +	struct ad9834_state *st = spi_get_drvdata(spi);
> +	struct iio_dev *indio_dev = st->indio_dev;
> +
nitpick: could just use st->indio_dev in the next call and lose the
line above.  It's the only use in this function.
> +	iio_device_unregister(indio_dev);
> +	if (!IS_ERR(st->reg)) {
> +		regulator_disable(st->reg);
> +		regulator_put(st->reg);
> +	}
> +	kfree(st);
> +	return 0;
> +}
> +
> +static const struct spi_device_id ad9834_id[] = {
> +	{"ad9833", ID_AD9833},
> +	{"ad9834", ID_AD9834},
> +	{}
> +};
> +
> +static struct spi_driver ad9834_driver = {
> +	.driver = {
> +		.name	= "ad9834",
> +		.bus	= &spi_bus_type,
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe		= ad9834_probe,
> +	.remove		= __devexit_p(ad9834_remove),
> +	.id_table	= ad9834_id,
> +};
> +
> +static int __init ad9834_init(void)
> +{
> +	return spi_register_driver(&ad9834_driver);
> +}
> +module_init(ad9834_init);
> +
> +static void __exit ad9834_exit(void)
> +{
> +	spi_unregister_driver(&ad9834_driver);
> +}
> +module_exit(ad9834_exit);
> +
> +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
> +MODULE_DESCRIPTION("Analog Devices AD9833/AD9834 DDS");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("spi:ad9834");
> diff --git a/drivers/staging/iio/dds/ad9834.h b/drivers/staging/iio/dds/ad9834.h
> new file mode 100644
> index 0000000..0fc3b88
> --- /dev/null
> +++ b/drivers/staging/iio/dds/ad9834.h
> @@ -0,0 +1,112 @@
> +/*
> + * AD9834 SPI DDS driver
> + *
> + * Copyright 2010 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2 or later.
> + */
> +#ifndef IIO_DDS_AD9834_H_
> +#define IIO_DDS_AD9834_H_
> +
> +/* Registers */
> +
> +#define AD9834_REG_CMD		(0 << 14)
> +#define AD9834_REG_FREQ0	(1 << 14)
> +#define AD9834_REG_FREQ1	(2 << 14)
> +#define AD9834_REG_PHASE0	(6 << 13)
> +#define AD9834_REG_PHASE1	(7 << 13)
> +
> +/* Command Control Bits */
> +
> +#define AD9834_B28		(1 << 13)
> +#define AD9834_HLB		(1 << 12)
> +#define AD9834_FSEL		(1 << 11)
> +#define AD9834_PSEL		(1 << 10)
> +#define AD9834_PIN_SW		(1 << 9)
> +#define AD9834_RESET		(1 << 8)
> +#define AD9834_SLEEP1		(1 << 7)
> +#define AD9834_SLEEP12		(1 << 6)
> +#define AD9834_OPBITEN		(1 << 5)
> +#define AD9834_SIGN_PIB		(1 << 4)
> +#define AD9834_DIV2		(1 << 3)
> +#define AD9834_MODE		(1 << 1)
> +
> +#define AD9834_FREQ_BITS	28
> +#define AD9834_PHASE_BITS	12
> +
> +#define RES_MASK(bits)	((1 << (bits)) - 1)
> +
> +/**
> + * struct ad9834_state - driver instance specific data
> + * @indio_dev:		the industrial I/O device
> + * @spi:		spi_device
> + * @reg:		supply regulator
> + * @mclk:		external master clock
> + * @control:		cached control word
> + * @xfer:		default spi transfer
> + * @msg:		default spi message
> + * @freq_xfer:		tuning word spi transfer
> + * @freq_msg:		tuning word spi message
> + * @data:		spi transmit buffer
> + * @freq_data:		tuning word spi transmit buffer
> + */
> +
> +struct ad9834_state {
> +	struct iio_dev			*indio_dev;
> +	struct spi_device		*spi;
> +	struct regulator		*reg;
> +	unsigned int			mclk;
> +	unsigned short			control;
> +	unsigned short			devid;
> +	struct spi_transfer		xfer;
> +	struct spi_message		msg;
> +	struct spi_transfer		freq_xfer[2];
> +	struct spi_message		freq_msg;
> +
> +	/*
> +	 * DMA (thus cache coherency maintenance) requires the
> +	 * transfer buffers to live in their own cache lines.
> +	 */
> +	unsigned short			data ____cacheline_aligned;
> +	unsigned short			freq_data[2] ;
> +};
> +
> +
> +/*
> + * TODO: struct ad7887_platform_data needs to go into include/linux/iio
> + */
> +
> +/**
> + * struct ad9834_platform_data - platform specific information
> + * @mclk:		master clock in Hz
> + * @freq0:		power up freq0 tuning word in Hz
> + * @freq1:		power up freq1 tuning word in Hz
> + * @phase0:		power up phase0 value [0..4095] correlates with 0..2PI
> + * @phase1:		power up phase1 value [0..4095] correlates with 0..2PI
> + * @en_div2:		digital output/2 is passed to the SIGN BIT OUT pin
> + * @en_signbit_msb_out:	the MSB (or MSB/2) of the DAC data is connected to the
> + *			SIGN BIT OUT pin. en_div2 controls whether it is the MSB
> + *			or MSB/2 that is output. if en_signbit_msb_out=false,
> + *			the on-board comparator is connected to SIGN BIT OUT
> + */
> +
> +struct ad9834_platform_data {
> +	unsigned int		mclk;
> +	unsigned int		freq0;
> +	unsigned int		freq1;
> +	unsigned short		phase0;
> +	unsigned short		phase1;
> +	bool			en_div2;
> +	bool			en_signbit_msb_out;
> +};
> +
> +/**
> + * ad9834_supported_device_ids:
> + */
> +
> +enum ad9834_supported_device_ids {
> +	ID_AD9833,
> +	ID_AD9834,
> +};
> +
> +#endif /* IIO_DDS_AD9834_H_ */
> --
> 1.6.0.2
> 
>