Re: [PATCH] IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4

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On 02/07/11 13:29, michael.hennerich@xxxxxxxxxx wrote:
> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> 
> This patch adds support for the:
> AD7606/AD7606-6/AD7606-4 8/6/4-Channel Data Acquisition
> system (DAS) with 16-Bit, Bipolar, Simultaneous Sampling ADC.
> 
> Changes since V1:
> IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4: Apply review feedback
> 
> Rename sysfs node oversampling to oversampling_ratio.
> Kconfig: Add GPIOLIB dependency.
> Use range in mV to better match HWMON.
> Rename ad7606_check_oversampling.
> Fix various comments and style.
> Reorder is_visible cases.
> Use new gpio_request_one/array and friends.
> Drop check for SPI max_speed_hz.
> 
Hi Michael.

I think there is a race condition in ad7606_scan_direct. Pretty
unlikely but at least a first glance a small reordering makes it impossible.

I haven't checked but think it wasn't to be a dependance on GENERIC_GPIO
instead of GPIOLIB. 


Few nitpicks / suggestions inline.


> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
Acked-by: Jonathan Cameron <jic23@xxxxxxxxx>

Fix the bits above and send on to Greg.
> ---
>  drivers/staging/iio/Documentation/sysfs-bus-iio |   25 +
>  drivers/staging/iio/adc/Kconfig                 |   28 ++
>  drivers/staging/iio/adc/Makefile                |    6 +
>  drivers/staging/iio/adc/ad7606.h                |  117 +++++
>  drivers/staging/iio/adc/ad7606_core.c           |  549 +++++++++++++++++++++++
>  drivers/staging/iio/adc/ad7606_par.c            |  188 ++++++++
>  drivers/staging/iio/adc/ad7606_ring.c           |  259 +++++++++++
>  drivers/staging/iio/adc/ad7606_spi.c            |  126 ++++++
>  8 files changed, 1298 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/staging/iio/adc/ad7606.h
>  create mode 100644 drivers/staging/iio/adc/ad7606_core.c
>  create mode 100644 drivers/staging/iio/adc/ad7606_par.c
>  create mode 100644 drivers/staging/iio/adc/ad7606_ring.c
>  create mode 100644 drivers/staging/iio/adc/ad7606_spi.c
> 
> diff --git a/drivers/staging/iio/Documentation/sysfs-bus-iio b/drivers/staging/iio/Documentation/sysfs-bus-iio
> index 8e5d8d1..4116abc 100644
> --- a/drivers/staging/iio/Documentation/sysfs-bus-iio
> +++ b/drivers/staging/iio/Documentation/sysfs-bus-iio
> @@ -53,6 +53,31 @@ Description:
>  		When the internal sampling clock can only take a small
>  		discrete set of values, this file lists those available.
> 
> +What:		/sys/bus/iio/devices/deviceX/range
> +KernelVersion:	2.6.38
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +		Hardware dependent ADC Full Scale Range.
Units specified please.
> +
> +What:		/sys/bus/iio/devices/deviceX/range_available
> +KernelVersion:	2.6.38
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +		Hardware dependent supported vales for ADC Full Scale Range.
> +
> +What:		/sys/bus/iio/devices/deviceX/oversampling_ratio
> +KernelVersion:	2.6.38
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +		Hardware dependent ADC oversampling. Controls the sampling ratio
> +		of the digital filter if available.
> +
> +What:		/sys/bus/iio/devices/deviceX/oversampling_ratio_available
> +KernelVersion:	2.6.38
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +		Hardware dependent values supported by the oversampling filter.
> +
>  What:		/sys/bus/iio/devices/deviceX/inY_raw
>  What:		/sys/bus/iio/devices/deviceX/inY_supply_raw
>  KernelVersion:	2.6.35
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> index 86869cd..c622a6c 100644
> --- a/drivers/staging/iio/adc/Kconfig
> +++ b/drivers/staging/iio/adc/Kconfig
> @@ -62,6 +62,34 @@ config AD7314
>  	  Say yes here to build support for Analog Devices AD7314
>  	  temperature sensors.
> 
> +config AD7606
> +	tristate "Analog Devices AD7606 ADC driver"
> +	depends on GPIOLIB
Is that the correct depend?  I think we need Generic GPIO but it is at least
in theary posible to have that without GPIOLIB.
> +	select IIO_RING_BUFFER
> +	select IIO_TRIGGER
> +	select IIO_SW_RING
> +	help
> +	  Say yes here to build support for Analog Devices:
> +	  ad7606, ad7606-6, ad7606-4 analog to digital convertors (ADC).
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ad7606.
> +
> +config AD7606_IFACE_PARALLEL
> +	bool "parallel interface support"
> +	depends on AD7606
> +	help
> +	  Say yes here to include parallel interface support on the AD7606
> +	  ADC driver.
> +
> +config AD7606_IFACE_SPI
> +	bool "spi interface support"
> +	depends on AD7606
> +	depends on SPI
> +	help
> +	  Say yes here to include parallel interface support on the AD7606
> +	  ADC driver.
> +
>  config AD799X
>  	tristate "Analog Devices AD799x ADC driver"
>  	depends on I2C
> diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
> index 6f231a2..cb73346 100644
> --- a/drivers/staging/iio/adc/Makefile
> +++ b/drivers/staging/iio/adc/Makefile
> @@ -7,6 +7,12 @@ max1363-y += max1363_ring.o
> 
>  obj-$(CONFIG_MAX1363) += max1363.o
> 
> +ad7606-y := ad7606_core.o
> +ad7606-$(CONFIG_IIO_RING_BUFFER) += ad7606_ring.o
> +ad7606-$(CONFIG_AD7606_IFACE_PARALLEL) += ad7606_par.o
> +ad7606-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o
> +obj-$(CONFIG_AD7606) += ad7606.o
> +
>  ad799x-y := ad799x_core.o
>  ad799x-$(CONFIG_AD799X_RING_BUFFER) += ad799x_ring.o
>  obj-$(CONFIG_AD799X) += ad799x.o
> diff --git a/drivers/staging/iio/adc/ad7606.h b/drivers/staging/iio/adc/ad7606.h
> new file mode 100644
> index 0000000..338bade
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7606.h
> @@ -0,0 +1,117 @@
> +/*
> + * AD7606 ADC driver
> + *
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#ifndef IIO_ADC_AD7606_H_
> +#define IIO_ADC_AD7606_H_
> +
> +/*
> + * TODO: struct ad7606_platform_data needs to go into include/linux/iio
> + */
> +
> +/**
> + * struct ad7606_platform_data - platform/board specifc information
> + * @default_os:		default oversampling value {0, 2, 4, 8, 16, 32, 64}
> + * @default_range:	default range +/-{5000, 10000} mVolt
> + * @gpio_convst:	number of gpio connected to the CONVST pin
> + * @gpio_reset:		gpio connected to the RESET pin, if not used set to -1
> + * @gpio_range:		gpio connected to the RANGE pin, if not used set to -1
> + * @gpio_os0:		gpio connected to the OS0 pin, if not used set to -1
> + * @gpio_os1:		gpio connected to the OS1 pin, if not used set to -1
> + * @gpio_os2:		gpio connected to the OS2 pin, if not used set to -1
> + * @gpio_frstdata:	gpio connected to the FRSTDAT pin, if not used set to -1
> + * @gpio_stby:		gpio connected to the STBY pin, if not used set to -1
> + */
> +
> +struct ad7606_platform_data {
> +	unsigned			default_os;
> +	unsigned			default_range;
> +	unsigned			gpio_convst;
> +	unsigned			gpio_reset;
> +	unsigned			gpio_range;
> +	unsigned			gpio_os0;
> +	unsigned			gpio_os1;
> +	unsigned			gpio_os2;
> +	unsigned			gpio_frstdata;
> +	unsigned			gpio_stby;
> +};
> +
> +/**
> + * struct ad7606_chip_info - chip specifc information
> + * @name:		indentification string for chip
> + * @bits:		accuracy of the adc in bits
> + * @bits:		output coding [s]igned or [u]nsigned
> + * @int_vref_mv:	the internal reference voltage
> + * @num_channels:	number of physical inputs on chip
> + */
> +
> +struct ad7606_chip_info {
> +	char				name[10];
> +	u8				bits;
> +	char				sign;
> +	u16				int_vref_mv;
> +	unsigned			num_channels;
> +};
> +
> +/**
> + * struct ad7606_state - driver instance specific data
> + */
> +
> +struct ad7606_state {
> +	struct iio_dev			*indio_dev;
> +	struct device			*dev;
> +	const struct ad7606_chip_info	*chip_info;
> +	struct ad7606_platform_data	*pdata;
> +	struct regulator		*reg;
> +	struct work_struct		poll_work;
> +	wait_queue_head_t		wq_data_avail;
> +	atomic_t			protect_ring;
> +	size_t				d_size;
> +	const struct ad7606_bus_ops	*bops;
> +	int				irq;
> +	unsigned			id;
> +	unsigned			range;
> +	unsigned			oversampling;
> +	bool				done;
> +	bool				have_frstdata;
> +	bool				have_os;
> +	bool				have_stby;
> +	bool				have_reset;
> +	bool				have_range;
> +	void __iomem			*base_address;
> +
> +	/*
> +	 * DMA (thus cache coherency maintenance) requires the
> +	 * transfer buffers to live in their own cache lines.
> +	 */
> +
> +	unsigned short			data[8] ____cacheline_aligned;
> +};
> +
> +struct ad7606_bus_ops {
> +	/* more methods added in future? */
> +	int (*read_block)(struct device *, int, void *);
> +};
> +
> +void ad7606_suspend(struct ad7606_state *st);
> +void ad7606_resume(struct ad7606_state *st);
> +struct ad7606_state *ad7606_probe(struct device *dev, int irq,
> +			      void __iomem *base_address, unsigned id,
> +			      const struct ad7606_bus_ops *bops);
> +int ad7606_remove(struct ad7606_state *st);
> +int ad7606_reset(struct ad7606_state *st);
> +
> +enum ad7606_supported_device_ids {
> +	ID_AD7606_8,
> +	ID_AD7606_6,
> +	ID_AD7606_4
> +};
> +
> +int ad7606_scan_from_ring(struct ad7606_state *st, unsigned ch);
> +int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev);
> +void ad7606_ring_cleanup(struct iio_dev *indio_dev);
> +#endif /* IIO_ADC_AD7606_H_ */
> diff --git a/drivers/staging/iio/adc/ad7606_core.c b/drivers/staging/iio/adc/ad7606_core.c
> new file mode 100644
> index 0000000..65481e1
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7606_core.c
> @@ -0,0 +1,549 @@
> +/*
> + * AD7606 SPI ADC driver
> + *
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#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/regulator/consumer.h>
> +#include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/delay.h>
> +
> +#include "../iio.h"
> +#include "../sysfs.h"
> +#include "../ring_generic.h"
> +#include "adc.h"
> +
> +#include "ad7606.h"
> +
> +int ad7606_reset(struct ad7606_state *st)
> +{
> +	if (st->have_reset) {
> +		gpio_set_value(st->pdata->gpio_reset, 1);
> +		ndelay(100); /* t_reset >= 100ns */
> +		gpio_set_value(st->pdata->gpio_reset, 0);
> +		return 0;
> +	}
> +
> +	return -ENODEV;
> +}
> +
> +static int ad7606_scan_direct(struct ad7606_state *st, unsigned ch)
> +{
> +	int ret;
> +
> +	gpio_set_value(st->pdata->gpio_convst, 1);
  Race condition if for whatever reason the interrupt occurs here?
> +	st->done = false;
> +
> +	ret = wait_event_interruptible(st->wq_data_avail, st->done);
> +	if (ret)
> +		goto error_ret;
> +
> +	if (st->have_frstdata) {
> +		st->bops->read_block(st->dev, 1, st->data);
> +		if (!gpio_get_value(st->pdata->gpio_frstdata)) {
> +			/* This should never happen */
> +			ad7606_reset(st);
> +			ret = -EIO;
> +			goto error_ret;
> +		}
> +		st->bops->read_block(st->dev,
> +			st->chip_info->num_channels - 1, &st->data[1]);
> +	} else {
> +		st->bops->read_block(st->dev,
> +			st->chip_info->num_channels, st->data);
> +	}
> +
> +	ret = st->data[ch];
> +
> +error_ret:
> +	gpio_set_value(st->pdata->gpio_convst, 0);
> +
> +	return ret;
> +}
> +
> +static ssize_t ad7606_scan(struct device *dev,
> +			    struct device_attribute *attr,
> +			    char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = dev_info->dev_data;
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	int ret;
> +
> +	mutex_lock(&dev_info->mlock);
> +	if (iio_ring_enabled(dev_info))
> +		ret = ad7606_scan_from_ring(st, this_attr->address);
> +	else
> +		ret = ad7606_scan_direct(st, this_attr->address);
> +	mutex_unlock(&dev_info->mlock);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	return sprintf(buf, "%d\n", (short) ret);
> +}
> +
> +static IIO_DEV_ATTR_IN_RAW(0, ad7606_scan, 0);
> +static IIO_DEV_ATTR_IN_RAW(1, ad7606_scan, 1);
> +static IIO_DEV_ATTR_IN_RAW(2, ad7606_scan, 2);
> +static IIO_DEV_ATTR_IN_RAW(3, ad7606_scan, 3);
> +static IIO_DEV_ATTR_IN_RAW(4, ad7606_scan, 4);
> +static IIO_DEV_ATTR_IN_RAW(5, ad7606_scan, 5);
> +static IIO_DEV_ATTR_IN_RAW(6, ad7606_scan, 6);
> +static IIO_DEV_ATTR_IN_RAW(7, ad7606_scan, 7);
> +
> +static ssize_t ad7606_show_scale(struct device *dev,
> +				struct device_attribute *attr,
> +				char *buf)
> +{
> +	/* Driver currently only support internal vref */
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
> +	unsigned int scale_uv = (st->range * 1000 * 2) >> st->chip_info->bits;
> +
> +	return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
> +}
> +static IIO_DEVICE_ATTR(in_scale, S_IRUGO, ad7606_show_scale, NULL, 0);
> +
> +static ssize_t ad7606_show_name(struct device *dev,
> +				 struct device_attribute *attr,
> +				 char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
> +
> +	return sprintf(buf, "%s\n", st->chip_info->name);
> +}
> +
> +static IIO_DEVICE_ATTR(name, S_IRUGO, ad7606_show_name, NULL, 0);
> +
> +static ssize_t ad7606_show_range(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
> +
> +	return sprintf(buf, "%u\n", st->range);
> +}
> +
> +static ssize_t ad7606_store_range(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
> +	unsigned long lval;
> +
> +	if (strict_strtoul(buf, 10, &lval))
> +		return -EINVAL;
> +	if (!(lval == 5000 || lval == 10000)) {
> +		dev_err(dev, "range is not supported\n");
> +		return -EINVAL;
> +	}
> +	mutex_lock(&dev_info->mlock);
> +	gpio_set_value(st->pdata->gpio_range, lval == 10000);
> +	st->range = lval;
> +	mutex_unlock(&dev_info->mlock);
> +
> +	return count;
> +}
> +
> +static IIO_DEVICE_ATTR(range, S_IRUGO | S_IWUSR, \
> +		       ad7606_show_range, ad7606_store_range, 0);
> +static IIO_CONST_ATTR(range_available, "5000 10000");
> +
> +static ssize_t ad7606_show_oversampling_ratio(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
> +
> +	return sprintf(buf, "%u\n", st->oversampling);
> +}
> +
> +static int ad7606_oversampling_get_index(unsigned val)
> +{
> +	unsigned char supported[] = {0, 2, 4, 8, 16, 32, 64};
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(supported); i++)
> +		if (val == supported[i])
> +			return i;
> +
> +	return -EINVAL;
> +}
> +
> +static ssize_t ad7606_store_oversampling_ratio(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct iio_dev *dev_info = dev_get_drvdata(dev);
> +	struct ad7606_state *st = iio_dev_get_devdata(dev_info);
> +	unsigned long lval;
> +	int ret;
> +
> +	if (strict_strtoul(buf, 10, &lval))
> +		return -EINVAL;
> +
> +	ret = ad7606_oversampling_get_index(lval);
> +	if (ret < 0) {
> +		dev_err(dev, "oversampling %lu is not supported\n", lval);
> +		return ret;
> +	}
> +
> +	mutex_lock(&dev_info->mlock);
> +	gpio_set_value(st->pdata->gpio_os0, (ret >> 0) & 1);
> +	gpio_set_value(st->pdata->gpio_os1, (ret >> 1) & 1);
> +	gpio_set_value(st->pdata->gpio_os1, (ret >> 2) & 1);
> +	st->oversampling = lval;
> +	mutex_unlock(&dev_info->mlock);
> +
> +	return count;
> +}
> +
> +static IIO_DEVICE_ATTR(oversampling_ratio, S_IRUGO | S_IWUSR,
> +		       ad7606_show_oversampling_ratio,
> +		       ad7606_store_oversampling_ratio, 0);
> +static IIO_CONST_ATTR(oversampling_ratio_available, "0 2 4 8 16 32 64");
> +
> +static struct attribute *ad7606_attributes[] = {
> +	&iio_dev_attr_in0_raw.dev_attr.attr,
> +	&iio_dev_attr_in1_raw.dev_attr.attr,
> +	&iio_dev_attr_in2_raw.dev_attr.attr,
> +	&iio_dev_attr_in3_raw.dev_attr.attr,
> +	&iio_dev_attr_in4_raw.dev_attr.attr,
> +	&iio_dev_attr_in5_raw.dev_attr.attr,
> +	&iio_dev_attr_in6_raw.dev_attr.attr,
> +	&iio_dev_attr_in7_raw.dev_attr.attr,
> +	&iio_dev_attr_in_scale.dev_attr.attr,
> +	&iio_dev_attr_name.dev_attr.attr,
> +	&iio_dev_attr_range.dev_attr.attr,
> +	&iio_const_attr_range_available.dev_attr.attr,
> +	&iio_dev_attr_oversampling_ratio.dev_attr.attr,
> +	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static mode_t ad7606_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 ad7606_state *st = iio_dev_get_devdata(dev_info);
> +
> +	mode_t mode = attr->mode;
> +
> +	if (st->chip_info->num_channels <= 6 &&
> +		(attr == &iio_dev_attr_in7_raw.dev_attr.attr ||
> +		attr == &iio_dev_attr_in6_raw.dev_attr.attr))
> +		mode = 0;
> +	else if (st->chip_info->num_channels <= 4 &&
> +		(attr == &iio_dev_attr_in5_raw.dev_attr.attr ||
> +		attr == &iio_dev_attr_in4_raw.dev_attr.attr))
> +		mode = 0;
> +	else if (!st->have_os &&
> +		(attr == &iio_dev_attr_oversampling_ratio.dev_attr.attr ||
> +		attr ==
> +		&iio_const_attr_oversampling_ratio_available.dev_attr.attr))
> +		mode = 0;
> +	else if (!st->have_range &&
> +		(attr == &iio_dev_attr_range.dev_attr.attr ||
> +		attr == &iio_const_attr_range_available.dev_attr.attr))
> +			mode = 0;
> +
> +	return mode;
> +}
> +
> +static const struct attribute_group ad7606_attribute_group = {
> +	.attrs = ad7606_attributes,
> +	.is_visible = ad7606_attr_is_visible,
> +};
> +
> +static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
> +	/*
> +	 * More devices added in future
> +	 */
> +	[ID_AD7606_8] = {
> +		.name = "ad7606",
> +		.bits = 16,
> +		.sign = IIO_SCAN_EL_TYPE_SIGNED,
> +		.int_vref_mv = 2500,
> +		.num_channels = 8,
> +	},
> +	[ID_AD7606_6] = {
> +		.name = "ad7606-6",
> +		.bits = 16,
> +		.sign = IIO_SCAN_EL_TYPE_SIGNED,
> +		.int_vref_mv = 2500,
> +		.num_channels = 6,
> +	},
> +	[ID_AD7606_4] = {
> +		.name = "ad7606-4",
> +		.bits = 16,
> +		.sign = IIO_SCAN_EL_TYPE_SIGNED,
> +		.int_vref_mv = 2500,
> +		.num_channels = 4,
> +	},
> +};
> +
> +static int ad7606_request_gpios(struct ad7606_state *st)
> +{
> +	struct gpio gpio_array[3] = {
> +		[0] = {
> +			.gpio =  st->pdata->gpio_os0,
> +			.flags = GPIOF_DIR_OUT | ((st->oversampling & 1) ?
> +				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
> +			.label = "AD7606_OS0",
> +		},
> +		[1] = {
> +			.gpio =  st->pdata->gpio_os1,
> +			.flags = GPIOF_DIR_OUT | ((st->oversampling & 2) ?
> +				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
> +			.label = "AD7606_OS1",
> +		},
> +		[2] = {
> +			.gpio =  st->pdata->gpio_os2,
> +			.flags = GPIOF_DIR_OUT | ((st->oversampling & 4) ?
> +				 GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
> +			.label = "AD7606_OS2",
> +		},
> +	};
> +	int ret;
> +
> +	ret = gpio_request_one(st->pdata->gpio_convst, GPIOF_OUT_INIT_LOW,
> +			       "AD7606_CONVST");
> +	if (ret) {
> +		dev_err(st->dev, "failed to request GPIO CONVST\n");
> +		return ret;
> +	}
> +
> +	ret = gpio_request_array(gpio_array, ARRAY_SIZE(gpio_array));
> +	if (!ret) {
> +		st->have_os = true;
> +	}
> +
> +	ret = gpio_request_one(st->pdata->gpio_reset, GPIOF_OUT_INIT_LOW,
> +			       "AD7606_RESET");
> +	if (!ret)
> +		st->have_reset = true;
> +
> +	ret = gpio_request_one(st->pdata->gpio_range, GPIOF_DIR_OUT |
> +			       ((st->range == 10000) ? GPIOF_INIT_HIGH :
> +			       	GPIOF_INIT_LOW), "AD7606_RANGE");
> +	if (!ret)
> +		st->have_range = true;
> +
> +	ret = gpio_request_one(st->pdata->gpio_stby, GPIOF_OUT_INIT_HIGH,
> +			       "AD7606_STBY");
> +	if (!ret)
> +		st->have_stby = true;
> +
> +	if (gpio_is_valid(st->pdata->gpio_frstdata)) {
> +		ret = gpio_request_one(st->pdata->gpio_frstdata, GPIOF_IN,
> +				       "AD7606_FRSTDATA");
> +		if (!ret)
> +			st->have_frstdata = true;
> +	}
> +
> +	return 0;
> +}
> +
> +static void ad7606_free_gpios(struct ad7606_state *st)
> +{
> +	if (st->have_range)
> +		gpio_free(st->pdata->gpio_range);
> +
> +	if (st->have_stby)
> +		gpio_free(st->pdata->gpio_stby);
> +
> +	if (st->have_os) {
> +		gpio_free(st->pdata->gpio_os0);
> +		gpio_free(st->pdata->gpio_os1);
> +		gpio_free(st->pdata->gpio_os2);
> +	}
> +
> +	if (st->have_reset)
> +		gpio_free(st->pdata->gpio_reset);
> +
> +	if (st->have_frstdata)
> +		gpio_free(st->pdata->gpio_frstdata);
> +
> +	gpio_free(st->pdata->gpio_convst);
> +}
> +
> +/**
> + *  Interrupt handler
> + */
> +static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
> +{
> +	struct ad7606_state *st = dev_id;
> +
> +	if (iio_ring_enabled(st->indio_dev)) {
> +		if (!work_pending(&st->poll_work))
> +			schedule_work(&st->poll_work);
> +	} else {
> +		st->done = true;
> +		wake_up_interruptible(&st->wq_data_avail);
> +	}
> +
> +	return IRQ_HANDLED;
> +};
> +
> +struct ad7606_state *ad7606_probe(struct device *dev, int irq,
> +			      void __iomem *base_address,
> +			      unsigned id,
> +			      const struct ad7606_bus_ops *bops)
> +{
> +	struct ad7606_platform_data *pdata = dev->platform_data;
> +	struct ad7606_state *st;
> +	int ret;
> +
> +	st = kzalloc(sizeof(*st), GFP_KERNEL);
> +	if (st == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +
> +	st->dev = dev;
> +	st->id = id;
> +	st->irq = irq;
> +	st->bops = bops;
> +	st->base_address = base_address;
> +	st->range = pdata->default_range == 10000 ? 10000 : 5000;
> +
> +	ret = ad7606_oversampling_get_index(pdata->default_os);
> +	if (ret < 0) {
> +		dev_warn(dev, "oversampling %d is not supported\n",
> +			 pdata->default_os);
> +		st->oversampling = 0;
> +	} else {
> +		st->oversampling = pdata->default_os;
> +	}
> +
> +	st->reg = regulator_get(dev, "vcc");
> +	if (!IS_ERR(st->reg)) {
> +		ret = regulator_enable(st->reg);
> +		if (ret)
> +			goto error_put_reg;
> +	}
> +
> +	st->pdata = pdata;
> +	st->chip_info = &ad7606_chip_info_tbl[id];
> +
> +	atomic_set(&st->protect_ring, 0);
> +
> +	st->indio_dev = iio_allocate_device();
> +	if (st->indio_dev == NULL) {
> +		ret = -ENOMEM;
> +		goto error_disable_reg;
> +	}
> +
> +	st->indio_dev->dev.parent = dev;
> +	st->indio_dev->attrs = &ad7606_attribute_group;
> +	st->indio_dev->dev_data = (void *)(st);
> +	st->indio_dev->driver_module = THIS_MODULE;
> +	st->indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	init_waitqueue_head(&st->wq_data_avail);
> +
> +	ret = ad7606_request_gpios(st);
> +	if (ret)
> +		goto error_free_device;
> +
> +	ret = ad7606_reset(st);
> +	if (ret)
> +		dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
> +
> +	ret = request_irq(st->irq, ad7606_interrupt,
> +		IRQF_TRIGGER_FALLING, st->chip_info->name, st);
> +	if (ret)
> +		goto error_free_gpios;
> +
> +	ret = ad7606_register_ring_funcs_and_init(st->indio_dev);
> +	if (ret)
> +		goto error_free_irq;
> +
> +	ret = iio_device_register(st->indio_dev);
> +	if (ret)
> +		goto error_free_irq;
> +
> +	ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
> +	if (ret)
> +		goto error_cleanup_ring;
> +
> +	return st;
> +
> +error_cleanup_ring:
> +	ad7606_ring_cleanup(st->indio_dev);
> +	iio_device_unregister(st->indio_dev);
> +
> +error_free_irq:
> +	free_irq(st->irq, st);
> +
> +error_free_gpios:
> +	ad7606_free_gpios(st);
> +
> +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 ERR_PTR(ret);
> +}
> +
> +int ad7606_remove(struct ad7606_state *st)
> +{
> +	struct iio_dev *indio_dev = st->indio_dev;
> +	iio_ring_buffer_unregister(indio_dev->ring);
> +	ad7606_ring_cleanup(indio_dev);
> +	iio_device_unregister(indio_dev);
> +	free_irq(st->irq, st);
> +	if (!IS_ERR(st->reg)) {
> +		regulator_disable(st->reg);
> +		regulator_put(st->reg);
> +	}
> +
> +	ad7606_free_gpios(st);
> +
> +	kfree(st);
> +	return 0;
> +}
> +
> +void ad7606_suspend(struct ad7606_state *st)
> +{
> +	if (st->have_stby) {
> +		if (st->have_range)
> +			gpio_set_value(st->pdata->gpio_range, 1);
> +		gpio_set_value(st->pdata->gpio_stby, 0);
> +	}
> +}
> +
> +void ad7606_resume(struct ad7606_state *st)
> +{
> +	if (st->have_stby) {
> +		if (st->have_range)
> +			gpio_set_value(st->pdata->gpio_range,
> +					st->range == 10000);
> +
> +		gpio_set_value(st->pdata->gpio_stby, 1);
> +		ad7606_reset(st);
> +	}
> +}
> +
> +MODULE_AUTHOR("Michael Hennerich <hennerich@xxxxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/staging/iio/adc/ad7606_par.c b/drivers/staging/iio/adc/ad7606_par.c
> new file mode 100644
> index 0000000..43a554c
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7606_par.c
> @@ -0,0 +1,188 @@
> +/*
> + * AD7606 Parallel Interface ADC driver
> + *
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +
> +#include "ad7606.h"
> +
> +static int ad7606_par16_read_block(struct device *dev,
> +				 int count, void *buf)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ad7606_state *st = platform_get_drvdata(pdev);
> +
> +	insw((unsigned long) st->base_address, buf, count);
> +
> +	return 0;
> +}
> +
> +static const struct ad7606_bus_ops ad7606_par16_bops = {
> +	.read_block	= ad7606_par16_read_block,
> +};
> +
> +static int ad7606_par8_read_block(struct device *dev,
> +				 int count, void *buf)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ad7606_state *st = platform_get_drvdata(pdev);
> +
> +	insb((unsigned long) st->base_address, buf, count * 2);
> +
> +	return 0;
> +}
> +
> +static const struct ad7606_bus_ops ad7606_par8_bops = {
> +	.read_block	= ad7606_par8_read_block,
> +};
> +
> +static int __devinit ad7606_par_probe(struct platform_device *pdev)
> +{
> +	struct resource *res;
> +	struct ad7606_state *st;
> +	void __iomem *addr;
> +	resource_size_t remap_size;
> +	int ret, irq;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "no irq\n");
> +		return -ENODEV;
> +	}
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -ENODEV;
> +
> +	remap_size = resource_size(res);
> +
> +	/* Request the regions */
> +	if (!request_mem_region(res->start, remap_size, "iio-ad7606")) {
> +		ret = -EBUSY;
> +		goto out1;
> +	}
> +	addr = ioremap(res->start, remap_size);
> +	if (!addr) {
> +		ret = -ENOMEM;
> +		goto out1;
> +	}
> +
> +	st = ad7606_probe(&pdev->dev, irq, addr,
> +			  platform_get_device_id(pdev)->driver_data,
> +			  remap_size > 1 ? &ad7606_par16_bops :
> +			  &ad7606_par8_bops);
> +
> +	if (IS_ERR(st))  {
> +		ret = PTR_ERR(st);
> +		goto out2;
> +	}
> +
> +	platform_set_drvdata(pdev, st);
> +
> +	return 0;
> +
> +out2:
> +	iounmap(addr);
> +out1:
> +	release_mem_region(res->start, remap_size);
> +
> +	return ret;
> +}
> +
> +static int __devexit ad7606_par_remove(struct platform_device *pdev)
> +{
> +	struct ad7606_state *st = platform_get_drvdata(pdev);
> +	struct resource *res;
> +
> +	ad7606_remove(st);
> +
> +	iounmap(st->base_address);
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	release_mem_region(res->start, resource_size(res));
> +
> +	platform_set_drvdata(pdev, NULL);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int ad7606_par_suspend(struct device *dev)
> +{
> +	struct ad7606_state *st = dev_get_drvdata(dev);
> +
> +	ad7606_suspend(st);
> +
> +	return 0;
> +}
> +
> +static int ad7606_par_resume(struct device *dev)
> +{
> +	struct ad7606_state *st = dev_get_drvdata(dev);
> +
> +	ad7606_resume(st);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ad7606_pm_ops = {
> +	.suspend = ad7606_par_suspend,
> +	.resume  = ad7606_par_resume,
> +};
> +#define AD7606_PAR_PM_OPS (&ad7606_pm_ops)
> +
> +#else
> +#define AD7606_PAR_PM_OPS NULL
> +#endif  /* CONFIG_PM */
> +
> +static struct platform_device_id ad7606_driver_ids[] = {
> +	{
> +		.name		= "ad7606-8",
> +		.driver_data	= ID_AD7606_8,
> +	}, {
> +		.name		= "ad7606-6",
> +		.driver_data	= ID_AD7606_6,
> +	}, {
> +		.name		= "ad7606-4",
> +		.driver_data	= ID_AD7606_4,
> +	},
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(platform, ad7606_driver_ids);
> +
> +static struct platform_driver ad7606_driver = {
> +	.probe = ad7606_par_probe,
> +	.remove	= __devexit_p(ad7606_par_remove),
> +	.id_table = ad7606_driver_ids,
> +	.driver = {
> +		.name	 = "ad7606",
> +		.owner	= THIS_MODULE,
> +		.pm    = AD7606_PAR_PM_OPS,
> +	},
> +};
> +
> +static int __init ad7606_init(void)
> +{
> +	return platform_driver_register(&ad7606_driver);
> +}
> +
> +static void __exit ad7606_cleanup(void)
> +{
> +	platform_driver_unregister(&ad7606_driver);
> +}
> +
> +module_init(ad7606_init);
> +module_exit(ad7606_cleanup);
> +
> +MODULE_AUTHOR("Michael Hennerich <hennerich@xxxxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:ad7606_par");
> diff --git a/drivers/staging/iio/adc/ad7606_ring.c b/drivers/staging/iio/adc/ad7606_ring.c
> new file mode 100644
> index 0000000..3506ef6
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7606_ring.c
> @@ -0,0 +1,259 @@
> +/*
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + *
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/gpio.h>
> +#include <linux/workqueue.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +
> +#include "../iio.h"
> +#include "../ring_generic.h"
> +#include "../ring_sw.h"
> +#include "../trigger.h"
> +#include "../sysfs.h"
> +
> +#include "ad7606.h"
> +
> +static IIO_SCAN_EL_C(in0, 0, 0, NULL);
> +static IIO_SCAN_EL_C(in1, 1, 0, NULL);
> +static IIO_SCAN_EL_C(in2, 2, 0, NULL);
> +static IIO_SCAN_EL_C(in3, 3, 0, NULL);
> +static IIO_SCAN_EL_C(in4, 4, 0, NULL);
> +static IIO_SCAN_EL_C(in5, 5, 0, NULL);
> +static IIO_SCAN_EL_C(in6, 6, 0, NULL);
> +static IIO_SCAN_EL_C(in7, 7, 0, NULL);
> +
> +static ssize_t ad7606_show_type(struct device *dev,
> +				struct device_attribute *attr,
> +				char *buf)
> +{
> +	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
> +	struct iio_dev *indio_dev = ring->indio_dev;
> +	struct ad7606_state *st = indio_dev->dev_data;
> +
> +	return sprintf(buf, "%c%d/%d\n", st->chip_info->sign,
> +		       st->chip_info->bits, st->chip_info->bits);
> +}
> +static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7606_show_type, NULL, 0);
> +
> +static struct attribute *ad7606_scan_el_attrs[] = {
> +	&iio_scan_el_in0.dev_attr.attr,
> +	&iio_const_attr_in0_index.dev_attr.attr,
> +	&iio_scan_el_in1.dev_attr.attr,
> +	&iio_const_attr_in1_index.dev_attr.attr,
> +	&iio_scan_el_in2.dev_attr.attr,
> +	&iio_const_attr_in2_index.dev_attr.attr,
> +	&iio_scan_el_in3.dev_attr.attr,
> +	&iio_const_attr_in3_index.dev_attr.attr,
> +	&iio_scan_el_in4.dev_attr.attr,
> +	&iio_const_attr_in4_index.dev_attr.attr,
> +	&iio_scan_el_in5.dev_attr.attr,
> +	&iio_const_attr_in5_index.dev_attr.attr,
> +	&iio_scan_el_in6.dev_attr.attr,
> +	&iio_const_attr_in6_index.dev_attr.attr,
> +	&iio_scan_el_in7.dev_attr.attr,
> +	&iio_const_attr_in7_index.dev_attr.attr,
> +	&iio_dev_attr_in_type.dev_attr.attr,
> +	NULL,
> +};
> +
> +static mode_t ad7606_scan_el_attr_is_visible(struct kobject *kobj,
> +				     struct attribute *attr, int n)
> +{
> +	struct device *dev = container_of(kobj, struct device, kobj);
> +	struct iio_ring_buffer *ring = dev_get_drvdata(dev);
> +	struct iio_dev *indio_dev = ring->indio_dev;
> +	struct ad7606_state *st = indio_dev->dev_data;
> +
> +	mode_t mode = attr->mode;
> +
> +	if (st->chip_info->num_channels <= 6 &&
> +		(attr == &iio_scan_el_in7.dev_attr.attr ||
> +		attr == &iio_const_attr_in7_index.dev_attr.attr ||
> +		attr == &iio_scan_el_in6.dev_attr.attr ||
> +		attr == &iio_const_attr_in6_index.dev_attr.attr))
> +		mode = 0;
> +	else if (st->chip_info->num_channels <= 4 &&
> +		(attr == &iio_scan_el_in5.dev_attr.attr ||
> +		attr == &iio_const_attr_in5_index.dev_attr.attr ||
> +		attr == &iio_scan_el_in4.dev_attr.attr ||
> +		attr == &iio_const_attr_in4_index.dev_attr.attr))
> +		mode = 0;
> +
> +	return mode;
> +}
> +
> +static struct attribute_group ad7606_scan_el_group = {
> +	.name = "scan_elements",
> +	.attrs = ad7606_scan_el_attrs,
> +	.is_visible = ad7606_scan_el_attr_is_visible,
> +};
> +
> +int ad7606_scan_from_ring(struct ad7606_state *st, unsigned ch)
> +{
> +	struct iio_ring_buffer *ring = st->indio_dev->ring;
> +	int ret;
> +	u16 *ring_data;
> +
> +	ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
> +	if (ring_data == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +	ret = ring->access.read_last(ring, (u8 *) ring_data);
> +	if (ret)
> +		goto error_free_ring_data;
> +
> +	ret = ring_data[ch];
> +
> +error_free_ring_data:
> +	kfree(ring_data);
> +error_ret:
> +	return ret;
> +}
> +
> +/**
> + * ad7606_ring_preenable() setup the parameters of the ring before enabling
> + *
> + * The complex nature of the setting of the nuber of bytes per datum is due
> + * to this driver currently ensuring that the timestamp is stored at an 8
> + * byte boundary.
> + **/
> +static int ad7606_ring_preenable(struct iio_dev *indio_dev)
> +{
> +	struct ad7606_state *st = indio_dev->dev_data;
> +	struct iio_ring_buffer *ring = indio_dev->ring;
> +	size_t d_size;
> +
> +	d_size = st->chip_info->num_channels *
> +		 st->chip_info->bits / 8 + sizeof(s64);
> +
> +	if (d_size % sizeof(s64))
> +		d_size += sizeof(s64) - (d_size % sizeof(s64));
> +
> +	if (ring->access.set_bytes_per_datum)
> +		ring->access.set_bytes_per_datum(ring, d_size);
> +
> +	st->d_size = d_size;
> +
> +	return 0;
> +}
> +
> +/**
> + * ad7606_poll_func_th() th of trigger launched polling to ring buffer
> + *
> + **/
> +static void ad7606_poll_func_th(struct iio_dev *indio_dev, s64 time)
> +{
> +	struct ad7606_state *st = indio_dev->dev_data;
> +	gpio_set_value(st->pdata->gpio_convst, 1);
> +
> +	return;
> +}
> +/**
> + * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
> + * @work_s:	the work struct through which this was scheduled
> + *
> + * Currently there is no option in this driver to disable the saving of
> + * timestamps within the ring.
> + * I think the one copy of this at a time was to avoid problems if the
> + * trigger was set far too high and the reads then locked up the computer.
> + **/
> +static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
> +{
> +	struct ad7606_state *st = container_of(work_s, struct ad7606_state,
> +						poll_work);
> +	struct iio_dev *indio_dev = st->indio_dev;
> +	struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
> +	struct iio_ring_buffer *ring = indio_dev->ring;
> +	s64 time_ns;
> +	__u8 *buf;
> +
> +	/* Ensure only one copy of this function running at a time */
> +	if (atomic_inc_return(&st->protect_ring) > 1)
> +		return;
> +
> +	buf = kzalloc(st->d_size, GFP_KERNEL);
> +	if (buf == NULL)
> +		return;
> +
> +	if (st->have_frstdata) {

Worth adding some error handling round the read blocks?  All we can
do if it happens here is not push anything into the ring, but even
that might be better than pushing garbage in.

> +		st->bops->read_block(st->dev, 1, buf);
> +		if (!gpio_get_value(st->pdata->gpio_frstdata)) {
> +			/* This should never happen. However
> +			 * some signal glitch caused by bad PCB desgin or
> +			 * electrostatic discharge, could cause an extra read
> +			 * or clock. This allows recovery.
> +			 */
> +			ad7606_reset(st);
> +			goto done;
> +		}
> +		st->bops->read_block(st->dev,
> +			st->chip_info->num_channels - 1, buf + 2);
> +	} else {
> +		st->bops->read_block(st->dev,
> +			st->chip_info->num_channels, buf);
> +	}
> +
> +	time_ns = iio_get_time_ns();
> +	memcpy(buf + st->d_size - sizeof(s64), &time_ns, sizeof(time_ns));
> +
> +	ring->access.store_to(&sw_ring->buf, buf, time_ns);
> +done:
> +	gpio_set_value(st->pdata->gpio_convst, 0);
> +	kfree(buf);
> +	atomic_dec(&st->protect_ring);
> +}
> +
> +int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
> +{
> +	struct ad7606_state *st = indio_dev->dev_data;
> +	int ret;
> +
> +	indio_dev->ring = iio_sw_rb_allocate(indio_dev);
> +	if (!indio_dev->ring) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +
> +	/* Effectively select the ring buffer implementation */
> +	iio_ring_sw_register_funcs(&indio_dev->ring->access);
Given the pollfunc simply sets a gpio and can't sleep, it is
probably the first example we have in tree of a device that 
ought to register it's function in the first of the trigger
lists rather than the second. It's for this purpose that we
have two lists in the first place (I was actualy thinking
of removing the immediate one given we didn't have any users
as yet).

> +	ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7606_poll_func_th);
> +	if (ret)
> +		goto error_deallocate_sw_rb;
> +
> +	/* Ring buffer functions - here trigger setup related */
> +
> +	indio_dev->ring->preenable = &ad7606_ring_preenable;
> +	indio_dev->ring->postenable = &iio_triggered_ring_postenable;
> +	indio_dev->ring->predisable = &iio_triggered_ring_predisable;
> +	indio_dev->ring->scan_el_attrs = &ad7606_scan_el_group;
> +
> +	INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
> +
> +	/* Flag that polled ring buffering is possible */
> +	indio_dev->modes |= INDIO_RING_TRIGGERED;
> +	return 0;
> +error_deallocate_sw_rb:
> +	iio_sw_rb_free(indio_dev->ring);
> +error_ret:
> +	return ret;
> +}
> +
> +void ad7606_ring_cleanup(struct iio_dev *indio_dev)
> +{
> +	if (indio_dev->trig) {
> +		iio_put_trigger(indio_dev->trig);
> +		iio_trigger_dettach_poll_func(indio_dev->trig,
> +					      indio_dev->pollfunc);
> +	}
> +	kfree(indio_dev->pollfunc);
> +	iio_sw_rb_free(indio_dev->ring);
> +}
> diff --git a/drivers/staging/iio/adc/ad7606_spi.c b/drivers/staging/iio/adc/ad7606_spi.c
> new file mode 100644
> index 0000000..d738491
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7606_spi.c
> @@ -0,0 +1,126 @@
> +/*
> + * AD7606 SPI ADC driver
> + *
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +#include <linux/types.h>
> +#include <linux/err.h>
> +#include "ad7606.h"
> +
> +#define MAX_SPI_FREQ_HZ		23500000	/* VDRIVE above 4.75 V */
> +
> +static int ad7606_spi_read_block(struct device *dev,
> +				 int count, void *buf)
> +{
> +	struct spi_device *spi = to_spi_device(dev);
> +	int i, ret;
> +	unsigned short *data = buf;
> +
> +	ret = spi_read(spi, (u8 *)buf, count * 2);
> +	if (ret < 0) {
> +		dev_err(&spi->dev, "SPI read error\n");
> +		return ret;
> +	}
> +
> +	for (i = 0; i < count; i++)
> +		data[i] = be16_to_cpu(data[i]);
> +
> +	return 0;
> +}
> +
> +static const struct ad7606_bus_ops ad7606_spi_bops = {
> +	.read_block	= ad7606_spi_read_block,
> +};
> +
> +static int __devinit ad7606_spi_probe(struct spi_device *spi)
> +{
> +	struct ad7606_state *st;
> +
> +	st = ad7606_probe(&spi->dev, spi->irq, NULL,
> +			   spi_get_device_id(spi)->driver_data,
> +			   &ad7606_spi_bops);
> +
> +	if (IS_ERR(st))
> +		return PTR_ERR(st);
> +
> +	spi_set_drvdata(spi, st);
> +
> +	return 0;
> +}
> +
> +static int __devexit ad7606_spi_remove(struct spi_device *spi)
> +{
> +	struct ad7606_state *st = dev_get_drvdata(&spi->dev);
> +
> +	return ad7606_remove(st);
> +}
> +

Nitpick: The next few functions are the same for both buses. Could
just roll the dev_get_drvdata into the ad7606_suspend etc and get
rid of the definitions from here entirely.  It doesn't really
matter and perhaps one can argue they should be here for clarity.

> +#ifdef CONFIG_PM
> +static int ad7606_spi_suspend(struct device *dev)
> +{
> +	struct ad7606_state *st = dev_get_drvdata(dev);
> +
> +	ad7606_suspend(st);
> +
> +	return 0;
> +}
> +
> +static int ad7606_spi_resume(struct device *dev)
> +{
> +	struct ad7606_state *st = dev_get_drvdata(dev);
> +
> +	ad7606_resume(st);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ad7606_pm_ops = {
> +	.suspend = ad7606_spi_suspend,
> +	.resume  = ad7606_spi_resume,
> +};
> +#define AD7606_SPI_PM_OPS (&ad7606_pm_ops)
> +
> +#else
> +#define AD7606_SPI_PM_OPS NULL
> +#endif
> +
> +static const struct spi_device_id ad7606_id[] = {
> +	{"ad7606-8", ID_AD7606_8},
> +	{"ad7606-6", ID_AD7606_6},
> +	{"ad7606-4", ID_AD7606_4},
> +	{}
> +};
> +
> +static struct spi_driver ad7606_driver = {
> +	.driver = {
> +		.name = "ad7606",
> +		.bus = &spi_bus_type,
> +		.owner = THIS_MODULE,
> +		.pm    = AD7606_SPI_PM_OPS,
> +	},
> +	.probe = ad7606_spi_probe,
> +	.remove = __devexit_p(ad7606_spi_remove),
> +	.id_table = ad7606_id,
> +};
> +
> +static int __init ad7606_spi_init(void)
> +{
> +	return spi_register_driver(&ad7606_driver);
> +}
> +module_init(ad7606_spi_init);
> +
> +static void __exit ad7606_spi_exit(void)
> +{
> +	spi_unregister_driver(&ad7606_driver);
> +}
> +module_exit(ad7606_spi_exit);
> +
> +MODULE_AUTHOR("Michael Hennerich <hennerich@xxxxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("spi:ad7606_spi");
> --
> 1.6.0.2
> 
> 

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