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

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

On 12/14/10 11:01, Hennerich, Michael wrote:
>> Jonathan Cameron wrote on 2010-12-13:
>>> 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)
> 
> Your email client doing the right thing.
> 
>>> +
>>> +   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?
> 
> No - the is_visible prevents this file to be available on the AD9833.
> However this expresses a dependency on the AD9834 between the two outputs, where
> the 'square' output on out1 is not available in case out0 is set to 'triangle'
ah, I'd missed that.
> 
>> 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...
> 
> No
> 
>>> +   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...
> 
> ok
> 
>>> +   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.
> 
> ok
> 
>>> +   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
>>>
>>>
> 
>