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

[Michael Hennerich <michael.hennerich@analog.com>]

On 02/08/2011 08:36 PM, Jonathan Cameron wrote:
> On 02/07/11 13:29, michael.hennerich@analog.com wrote:
>   
>> From: Michael Hennerich <michael.hennerich@analog.com>
>>
>> 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@analog.com>
>>     
> Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
>
> 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@vger.kernel.org
>> +Description:
>> +             Hardware dependent ADC Full Scale Range.
>>     
> Units specified please.
>   
ok
>> +
>> +What:                /sys/bus/iio/devices/deviceX/range_available
>> +KernelVersion:       2.6.38
>> +Contact:     linux-iio@vger.kernel.org
>> +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@vger.kernel.org
>> +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@vger.kernel.org
>> +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.
>   
Well - before I utilized gpio_request_one() and friends the dependency
was on GENERIC_GPIO.
However  gpio_request_one() is defined as a function only in gpiolib,
there could have been inline
replacements in case of !GPIOLIB, but unfortunately thats not the case.
>> +     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?
>   
Good catch!
>> +     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@blackfin.uclinux.org>");
>> +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@blackfin.uclinux.org>");
>> +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.
>   
Ok.
>   
>> +             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).
>
>   
Please don't remove.

>> +     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.
>
>   
I prefer the leave this as is. suspend/resume belong to the bus.

>> +#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@blackfin.uclinux.org>");
>> +MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_ALIAS("spi:ad7606_spi");
>> --
>> 1.6.0.2
>>
>>
>>     
>   


-- 
Greetings,
Michael

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