Re: [PATCH] iio: adc: Replace, rewrite ad7745 from scratch.

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

One quick nitpick on submission format:
Please put version in the email subject
[PATCH V3] iio:...

That way it's easy to spot which one to bother reading ;)

On 09/16/11 15:47, michael.hennerich@analog.com wrote:
> From: Michael Hennerich <michael.hennerich@analog.com>
> 
> The existing ad7745 driver didn't conform with the IIO spec for such devices.
> It was way simpler to rewrite the existing driver, than actually fixing it.
> 
> Changes since V1:
> 
> Fix file header description.
> Fix erroneous defines.
> Pin channels to expected places in the iio_chan_spec array, to avoid magic numbers.
> Use msleep instead of busy waiting mdelay.
> Fix indention style.
> Drop _bias and use _offset attribute.
> 
> Changes since V2:
> Increase accuracy of cap scale.
> Fix channel spec for VIN.
Some formatting nitpicks. I'll fix them up.

I don't think Greg's tree is visible anywhere so I'll pull this through mine
and push on to him.  Thanks,

> 
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
> ---
>  drivers/staging/iio/adc/Kconfig  |    2 +-
>  drivers/staging/iio/adc/Makefile |    2 +-
>  drivers/staging/iio/adc/ad7745.c |  672 --------------------------------
>  drivers/staging/iio/adc/ad7746.c |  800 ++++++++++++++++++++++++++++++++++++++
>  drivers/staging/iio/adc/ad7746.h |   29 ++
>  5 files changed, 831 insertions(+), 674 deletions(-)
>  delete mode 100644 drivers/staging/iio/adc/ad7745.c
>  create mode 100644 drivers/staging/iio/adc/ad7746.c
>  create mode 100644 drivers/staging/iio/adc/ad7746.h
> 
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> index 7867ab1..0482073 100644
> --- a/drivers/staging/iio/adc/Kconfig
> +++ b/drivers/staging/iio/adc/Kconfig
> @@ -144,7 +144,7 @@ config AD7793
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called AD7793.
>  
> -config AD7745
> +config AD7746
>  	tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
>  	depends on I2C
>  	help
... snip old driver out as we don't care ;)....
> diff --git a/drivers/staging/iio/adc/ad7746.c b/drivers/staging/iio/adc/ad7746.c
> new file mode 100644
> index 0000000..b2011f5
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7746.c
> @@ -0,0 +1,800 @@
> +/*
> + * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
> + *
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +
> +#include "../iio.h"
> +#include "../sysfs.h"
> +
> +#include "ad7746.h"
> +
> +/*
> + * AD7746 Register Definition
> + */
> +
> +#define AD7746_REG_STATUS		0
> +#define AD7746_REG_CAP_DATA_HIGH	1
> +#define AD7746_REG_CAP_DATA_MID		2
> +#define AD7746_REG_CAP_DATA_LOW		3
> +#define AD7746_REG_VT_DATA_HIGH		4
> +#define AD7746_REG_VT_DATA_MID		5
> +#define AD7746_REG_VT_DATA_LOW		6
> +#define AD7746_REG_CAP_SETUP		7
> +#define AD7746_REG_VT_SETUP		8
> +#define AD7746_REG_EXC_SETUP		9
> +#define AD7746_REG_CFG			10
> +#define AD7746_REG_CAPDACA		11
> +#define AD7746_REG_CAPDACB		12
> +#define AD7746_REG_CAP_OFFH		13
> +#define AD7746_REG_CAP_OFFL		14
> +#define AD7746_REG_CAP_GAINH		15
> +#define AD7746_REG_CAP_GAINL		16
> +#define AD7746_REG_VOLT_GAINH		17
> +#define AD7746_REG_VOLT_GAINL		18
> +
> +/* Status Register Bit Designations (AD7746_REG_STATUS) */
> +#define AD7746_STATUS_EXCERR		(1 << 3)
> +#define AD7746_STATUS_RDY		(1 << 2)
> +#define AD7746_STATUS_RDYVT		(1 << 1)
> +#define AD7746_STATUS_RDYCAP		(1 << 0)
> +
> +/* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
> +#define AD7746_CAPSETUP_CAPEN		(1 << 7)
> +#define AD7746_CAPSETUP_CIN2		(1 << 6) /* AD7746 only */
> +#define AD7746_CAPSETUP_CAPDIFF		(1 << 5)
> +#define AD7746_CAPSETUP_CACHOP		(1 << 0)
> +
> +/* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
> +#define AD7746_VTSETUP_VTEN		(1 << 7)
> +#define AD7746_VTSETUP_VTMD_INT_TEMP	(0 << 5)
> +#define AD7746_VTSETUP_VTMD_EXT_TEMP	(1 << 5)
> +#define AD7746_VTSETUP_VTMD_VDD_MON	(2 << 5)
> +#define AD7746_VTSETUP_VTMD_EXT_VIN	(3 << 5)
> +#define AD7746_VTSETUP_EXTREF		(1 << 4)
> +#define AD7746_VTSETUP_VTSHORT		(1 << 1)
> +#define AD7746_VTSETUP_VTCHOP		(1 << 0)
> +
> +/* Excitation Setup Register Bit Designations (AD7746_REG_EXC_SETUP) */
> +#define AD7746_EXCSETUP_CLKCTRL		(1 << 7)
> +#define AD7746_EXCSETUP_EXCON		(1 << 6)
> +#define AD7746_EXCSETUP_EXCB		(1 << 5)
> +#define AD7746_EXCSETUP_NEXCB		(1 << 4)
> +#define AD7746_EXCSETUP_EXCA		(1 << 3)
> +#define AD7746_EXCSETUP_NEXCA		(1 << 2)
> +#define AD7746_EXCSETUP_EXCLVL(x)	(((x) & 0x3) << 0)
> +
> +/* Config Register Bit Designations (AD7746_REG_CFG) */
> +#define AD7746_CONF_VTFS(x)		((x) << 6)
> +#define AD7746_CONF_CAPFS(x)		((x) << 3)
> +#define AD7746_CONF_MODE_IDLE		(0 << 0)
> +#define AD7746_CONF_MODE_CONT_CONV	(1 << 0)
> +#define AD7746_CONF_MODE_SINGLE_CONV	(2 << 0)
> +#define AD7746_CONF_MODE_PWRDN		(3 << 0)
> +#define AD7746_CONF_MODE_OFFS_CAL	(5 << 0)
> +#define AD7746_CONF_MODE_GAIN_CAL	(6 << 0)
> +
> +/* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
> +#define AD7746_CAPDAC_DACEN		(1 << 7)
> +#define AD7746_CAPDAC_DACP(x)		((x) & 0x7F)
> +
> +/*
> + * struct ad7746_chip_info - chip specifc information
> + */
> +
> +struct ad7746_chip_info {
> +	struct i2c_client *client;
> +	/*
> +	 * Capacitive channel digital filter setup;
> +	 * conversion time/update rate setup per channel
> +	 */
> +	u8	config;
> +	u8	cap_setup;
> +	u8	vt_setup;
> +	u8	capdac[2][2];
> +	s8	capdac_set;
> +};
> +
> +enum ad7746_chan {
> +	VIN,
> +	VIN_VDD,
> +	TEMP_INT,
> +	TEMP_EXT,
> +	CIN1,
> +	CIN1_DIFF,
> +	CIN2,
> +	CIN2_DIFF,
> +};
> +
> +static const struct iio_chan_spec ad7746_channels[] = {
> +	[VIN] = {
> +		.type = IIO_VOLTAGE,
> +		.indexed = 1,
> +		.channel = 0,
> +		.info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),
> +		.address = AD7746_REG_VT_DATA_HIGH << 8 |
> +			AD7746_VTSETUP_VTMD_EXT_VIN,
> +	},
> +	[VIN_VDD] = {
> +		.type = IIO_VOLTAGE,
> +		.indexed = 1,
> +		.channel = 1,
> +		.extend_name = "supply",
> +		.info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),
> +		.address = AD7746_REG_VT_DATA_HIGH << 8 |
> +			AD7746_VTSETUP_VTMD_VDD_MON,
> +	},
> +	[TEMP_INT] = {
> +		.type = IIO_TEMP,
> +		.indexed = 1,
> +		.channel = 0,
> +		.processed_val = IIO_PROCESSED,
> +		.address = AD7746_REG_VT_DATA_HIGH << 8 |
> +			AD7746_VTSETUP_VTMD_INT_TEMP,
> +	},
> +	[TEMP_EXT] = {
> +		.type = IIO_TEMP,
> +		.indexed = 1,
> +		.channel = 1,
> +		.processed_val = IIO_PROCESSED,
> +		.address = AD7746_REG_VT_DATA_HIGH << 8 |
> +			AD7746_VTSETUP_VTMD_EXT_TEMP,
> +	},
> +	[CIN1] = {
> +		.type = IIO_CAPACITANCE,
> +		.indexed = 1,
> +		.channel = 0,
> +		.info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
> +		(1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_SCALE_SHARED),
> +		.address = AD7746_REG_CAP_DATA_HIGH << 8,
> +	},
> +	[CIN1_DIFF] = {
> +		.type = IIO_CAPACITANCE,
> +		.differential = 1,
> +		.indexed = 1,
> +		.channel = 0,
> +		.channel2 = 2,
> +		.info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
> +		(1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_SCALE_SHARED),
> +		.address = AD7746_REG_CAP_DATA_HIGH << 8 |
> +			AD7746_CAPSETUP_CAPDIFF
> +	},
> +	[CIN2] = {
> +		.type = IIO_CAPACITANCE,
> +		.indexed = 1,
> +		.channel = 1,
> +		.info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
> +		(1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_SCALE_SHARED),
> +		.address = AD7746_REG_CAP_DATA_HIGH << 8 |
> +			AD7746_CAPSETUP_CIN2,
> +	},
> +	[CIN2_DIFF] = {
> +		.type = IIO_CAPACITANCE,
> +		.differential = 1,
> +		.indexed = 1,
> +		.channel = 1,
> +		.channel2 = 3,
> +		.info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
> +		(1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
> +		(1 << IIO_CHAN_INFO_SCALE_SHARED),
> +		.address = AD7746_REG_CAP_DATA_HIGH << 8 |
> +			AD7746_CAPSETUP_CAPDIFF | AD7746_CAPSETUP_CIN2,
> +	}
> +};
> +
> +/* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
> +static const unsigned char ad7746_vt_filter_rate_table[][2] = {
> +	{50, 20 + 1}, {31, 32 + 1}, {16, 62 + 1}, {8, 122 + 1},
> +};
> +
> +static const unsigned char ad7746_cap_filter_rate_table[][2] = {
> +	{91, 11 + 1}, {84, 12 + 1}, {50, 20 + 1}, {26, 38 + 1},
> +	{16, 62 + 1}, {13, 77 + 1}, {11, 92 + 1}, {9, 110 + 1},
> +};
> +
> +static int ad7746_select_channel(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan)
> +{
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +	int ret, delay;
> +	u8 vt_setup, cap_setup;
> +
> +	switch (chan->type) {
> +	case IIO_CAPACITANCE:
> +		cap_setup = (chan->address & 0xFF) | AD7746_CAPSETUP_CAPEN;
> +		vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
> +		delay = ad7746_cap_filter_rate_table[(chip->config >> 3) &
> +			0x7][1];
> +
> +		if (chip->capdac_set != chan->channel) {
> +			ret = i2c_smbus_write_byte_data(chip->client,
> +				AD7746_REG_CAPDACA,
> +				chip->capdac[chan->channel][0]);
> +			if (ret < 0)
> +				return ret;
> +			ret = i2c_smbus_write_byte_data(chip->client,
> +				AD7746_REG_CAPDACB,
> +				chip->capdac[chan->channel][1]);
> +			if (ret < 0)
> +				return ret;
> +
> +			chip->capdac_set = chan->channel;
> +		}
> +		break;
> +	case IIO_VOLTAGE:
> +	case IIO_TEMP:
> +		vt_setup = (chan->address & 0xFF) | AD7746_VTSETUP_VTEN;
> +		cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
> +		delay = ad7746_cap_filter_rate_table[(chip->config >> 6) &
> +			0x3][1];
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (chip->cap_setup != cap_setup) {
> +		ret = i2c_smbus_write_byte_data(chip->client,
> +						AD7746_REG_CAP_SETUP,
> +						cap_setup);
> +		if (ret < 0)
> +			return ret;
> +
> +		chip->cap_setup = cap_setup;
> +	}
> +
> +	if (chip->vt_setup != vt_setup) {
> +		ret = i2c_smbus_write_byte_data(chip->client,
> +						AD7746_REG_VT_SETUP,
> +						vt_setup);
> +		if (ret < 0)
> +			return ret;
> +
> +		chip->vt_setup = vt_setup;
> +	}
> +
> +	return delay;
> +}
> +
> +static inline ssize_t ad7746_start_calib(struct device *dev,
> +					 struct device_attribute *attr,
> +					 const char *buf,
> +					 size_t len,
> +					 u8 regval)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +	bool doit;
> +	int ret, timeout = 10;
> +
> +	ret = strtobool(buf, &doit);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!doit)
> +		return 0;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	regval |= chip->config;
> +	ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
> +	if (ret < 0) {
> +		mutex_unlock(&indio_dev->mlock);
> +		return ret;
> +	}
> +
> +	do {
> +		msleep(20);
> +		ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
> +		if (ret < 0) {
> +			mutex_unlock(&indio_dev->mlock);
> +			return ret;
> +		}
> +	} while ((ret == regval) && timeout--);
> +
> +	mutex_unlock(&indio_dev->mlock);
> +	return len;
> +}
Blank line here please.
> +static ssize_t ad7746_start_offset_calib(struct device *dev,
> +					 struct device_attribute *attr,
> +					 const char *buf,
> +					 size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	int ret = ad7746_select_channel(indio_dev,
> +			      &ad7746_channels[to_iio_dev_attr(attr)->address]);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ad7746_start_calib(dev, attr, buf, len,
> +				  AD7746_CONF_MODE_OFFS_CAL);
> +}
Blank line.
> +static ssize_t ad7746_start_gain_calib(struct device *dev,
> +				       struct device_attribute *attr,
> +				       const char *buf,
> +				       size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	int ret = ad7746_select_channel(indio_dev,
> +			      &ad7746_channels[to_iio_dev_attr(attr)->address]);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ad7746_start_calib(dev, attr, buf, len,
> +				  AD7746_CONF_MODE_GAIN_CAL);
> +}
> +
> +static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
> +		       S_IWUSR, NULL, ad7746_start_offset_calib, CIN1);
> +static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
> +		       S_IWUSR, NULL, ad7746_start_offset_calib, CIN2);
> +static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
> +		       S_IWUSR, NULL, ad7746_start_gain_calib, CIN1);
> +static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
> +		       S_IWUSR, NULL, ad7746_start_gain_calib, CIN2);
> +static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
> +		       S_IWUSR, NULL, ad7746_start_gain_calib, VIN);
> +
> +static ssize_t ad7746_show_cap_filter_rate_setup(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +
> +	return sprintf(buf, "%d\n", ad7746_cap_filter_rate_table[
> +			(chip->config >> 3) & 0x7][0]);
> +}
> +
> +static ssize_t ad7746_store_cap_filter_rate_setup(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf,
> +		size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +	u8 data;
> +	int ret, i;
> +
> +	ret = kstrtou8(buf, 10, &data);
> +	if (ret < 0)
> +		return ret;
> +
> +	for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
> +		if (data >= ad7746_cap_filter_rate_table[i][0])
> +			break;
> +
> +	if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
> +		i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	chip->config &= ~AD7746_CONF_CAPFS(0x7);
> +	chip->config |= AD7746_CONF_CAPFS(i);
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return len;
> +}
> +
> +static ssize_t ad7746_show_vt_filter_rate_setup(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +
> +	return sprintf(buf, "%d\n", ad7746_vt_filter_rate_table[
> +			(chip->config >> 6) & 0x3][0]);
> +}
> +
> +static ssize_t ad7746_store_vt_filter_rate_setup(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf,
> +		size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +	u8 data;
> +	int ret, i;
> +
> +	ret = kstrtou8(buf, 10, &data);
> +	if (ret < 0)
> +		return ret;
> +
> +	for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
> +		if (data >= ad7746_vt_filter_rate_table[i][0])
> +			break;
> +
> +	if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
> +		i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	chip->config &= ~AD7746_CONF_VTFS(0x3);
> +	chip->config |= AD7746_CONF_VTFS(i);
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return len;
> +}
> +
> +static IIO_DEVICE_ATTR(in_capacitance_sampling_frequency,
> +		       S_IRUGO | S_IWUSR, ad7746_show_cap_filter_rate_setup,
> +			ad7746_store_cap_filter_rate_setup, 0);
> +
> +static IIO_DEVICE_ATTR(in_voltage_sampling_frequency,
> +		       S_IRUGO | S_IWUSR, ad7746_show_vt_filter_rate_setup,
> +		       ad7746_store_vt_filter_rate_setup, 0);
> +
> +static IIO_CONST_ATTR(in_voltage_sampling_frequency_available, "50 31 16 8");
> +static IIO_CONST_ATTR(in_capacitance_sampling_frequency_available,
> +		       "91 84 50 26 16 13 11 9");
> +
> +static struct attribute *ad7746_attributes[] = {
> +	&iio_dev_attr_in_capacitance_sampling_frequency.dev_attr.attr,
> +	&iio_dev_attr_in_voltage_sampling_frequency.dev_attr.attr,
> +	&iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
> +	&iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
> +	&iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
> +	&iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
> +	&iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
> +	&iio_const_attr_in_voltage_sampling_frequency_available.dev_attr.attr,
> +	&iio_const_attr_in_capacitance_sampling_frequency_available.
> +	dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group ad7746_attribute_group = {
> +	.attrs = ad7746_attributes,
> +};
> +
> +static int ad7746_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int val,
> +			    int val2,
> +			    long mask)
> +{
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +	int ret, reg;
> +
> +	mutex_lock(&indio_dev->mlock);
> +
> +	switch (mask) {
> +	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
> +		if (val != 1) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		val = (val2 * 1024) / 15625;
> +
> +		switch (chan->type) {
> +		case IIO_CAPACITANCE:
> +			reg = AD7746_REG_CAP_GAINH;
> +			break;
> +		case IIO_VOLTAGE:
> +			reg = AD7746_REG_VOLT_GAINH;
> +			break;
> +		default:
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		ret = i2c_smbus_write_word_data(chip->client, reg, swab16(val));
> +		if (ret < 0)
> +			goto out;
> +
> +		ret = 0;
> +		break;
> +	case (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED):
> +		if ((val < 0) | (val > 0xFFFF)) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		ret = i2c_smbus_write_word_data(chip->client,
> +				AD7746_REG_CAP_OFFH, swab16(val));
> +		if (ret < 0)
> +			goto out;
> +
> +		ret = 0;
> +		break;
> +	case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
> +		if ((val < 0) | (val > 43008000)) { /* 21pF */
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		/* CAPDAC Scale = 21pF_typ / 127
> +		 * CIN Scale = 8.192pF / 2^24
> +		 * Offset Scale = CAPDAC Scale / CIN Scale = 338646
> +		 * */
> +
> +		val /= 338646;
> +
> +		chip->capdac[chan->channel][chan->differential] = (val > 0 ?
> +			AD7746_CAPDAC_DACP(val) | AD7746_CAPDAC_DACEN : 0);
> +
> +		ret = i2c_smbus_write_byte_data(chip->client,
> +			AD7746_REG_CAPDACA,
> +			chip->capdac[chan->channel][0]);
> +		if (ret < 0)
> +			goto out;
> +		ret = i2c_smbus_write_byte_data(chip->client,
> +			AD7746_REG_CAPDACB,
> +			chip->capdac[chan->channel][1]);
> +		if (ret < 0)
> +			goto out;
> +
> +		chip->capdac_set = chan->channel;
> +
> +		ret = 0;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +out:
> +	mutex_unlock(&indio_dev->mlock);
> +	return ret;
> +}
> +static int ad7746_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan,
> +			   int *val, int *val2,
> +			   long mask)
> +{
> +	struct ad7746_chip_info *chip = iio_priv(indio_dev);
> +	int ret, delay;
> +	u8 regval, reg;
> +
> +	union {
> +		u32 d32;
> +		u8 d8[4];
> +	} data;
> +
> +	mutex_lock(&indio_dev->mlock);
> +
> +	switch (mask) {
> +	case 0:
> +		ret = ad7746_select_channel(indio_dev, chan);
> +		if (ret < 0)
> +			goto out;
> +		delay = ret;
> +
> +		regval = chip->config | AD7746_CONF_MODE_SINGLE_CONV;
> +		ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG,
> +				regval);
> +		if (ret < 0)
> +			goto out;
> +
> +		msleep(delay);
> +		/* Now read the actual register */
> +
> +		ret = i2c_smbus_read_i2c_block_data(chip->client,
> +			chan->address >> 8, 3, &data.d8[1]);
> +
> +		if (ret < 0)
> +			goto out;
> +
> +		*val = (be32_to_cpu(data.d32) & 0xFFFFFF) - 0x800000;
> +
> +		switch (chan->type) {
> +		case IIO_TEMP:
> +		/* temperature in milli degrees Celsius
> +		 * T = ((*val / 2048) - 4096) * 1000
> +		 */
> +			*val = (*val * 125) / 256;
> +			break;
> +		case IIO_VOLTAGE:
> +			if (chan->channel == 1) /* supply_raw*/
> +				*val = *val * 6;
> +				break;
> +		default:
> +			break;
> +		}
> +
> +		ret = IIO_VAL_INT;
> +		break;
> +	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
> +		switch (chan->type) {
> +		case IIO_CAPACITANCE:
> +			reg = AD7746_REG_CAP_GAINH;
> +			break;
> +		case IIO_VOLTAGE:
> +			reg = AD7746_REG_VOLT_GAINH;
> +			break;
> +		default:
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		ret = i2c_smbus_read_word_data(chip->client, reg);
> +		if (ret < 0)
> +			goto out;
> +		/* 1 + gain_val / 2^16 */
> +		*val = 1;
> +		*val2 = (15625 * swab16(ret)) / 1024;
> +
> +		ret = IIO_VAL_INT_PLUS_MICRO;
> +		break;
> +	case (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED):
> +		ret = i2c_smbus_read_word_data(chip->client,
> +					       AD7746_REG_CAP_OFFH);
> +		if (ret < 0)
> +			goto out;
> +		*val = swab16(ret);
> +
> +		ret = IIO_VAL_INT;
> +		break;
> +	case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
> +		*val = AD7746_CAPDAC_DACP(chip->capdac[chan->channel]
> +			[chan->differential]) * 338646;
> +
> +		ret = IIO_VAL_INT;
> +		break;
> +	case (1 << IIO_CHAN_INFO_SCALE_SHARED):
> +		switch (chan->type) {
> +		case IIO_CAPACITANCE:
> +			/* 8.192pf / 2^24 */
> +			*val2 = 488;
> +			*val =  0;
> +			break;
> +		case IIO_VOLTAGE:
> +			/* 1170mV / 2^23 */
> +			*val2 = 139475;
> +			*val =  0;
> +			break;
> +		default:
> +			ret =  -EINVAL;
> +			goto out;
> +		}
> +
> +		ret = IIO_VAL_INT_PLUS_NANO;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	};
> +out:
> +	mutex_unlock(&indio_dev->mlock);
> +	return ret;
> +}
> +
> +static const struct iio_info ad7746_info = {
> +	.attrs = &ad7746_attribute_group,
> +	.read_raw = &ad7746_read_raw,
> +	.write_raw = &ad7746_write_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +/*
> + * device probe and remove
> + */
> +
> +static int __devinit ad7746_probe(struct i2c_client *client,
> +		const struct i2c_device_id *id)
> +{
> +	struct ad7746_platform_data *pdata = client->dev.platform_data;
> +	struct ad7746_chip_info *chip;
> +	struct iio_dev *indio_dev;
> +	int ret = 0;
> +	unsigned char regval = 0;
> +
> +	indio_dev = iio_allocate_device(sizeof(*chip));
> +	if (indio_dev == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +	chip = iio_priv(indio_dev);
> +	/* this is only used for device removal purposes */
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	chip->client = client;
> +	chip->capdac_set = -1;
> +
> +	/* Establish that the iio_dev is a child of the i2c device */
> +	indio_dev->name = id->name;
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &ad7746_info;
> +	indio_dev->channels = ad7746_channels;
> +	if (id->driver_data == 7746)
> +		indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
> +	else
> +		indio_dev->num_channels =  ARRAY_SIZE(ad7746_channels) - 2;
> +	indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	if (pdata) {
> +		if (pdata->exca_en) {
> +			if (pdata->exca_inv_en)
> +				regval |= AD7746_EXCSETUP_NEXCA;
> +			else
> +				regval |= AD7746_EXCSETUP_EXCA;
> +		}
> +
> +		if (pdata->excb_en) {
> +			if (pdata->excb_inv_en)
> +				regval |= AD7746_EXCSETUP_NEXCB;
> +			else
> +				regval |= AD7746_EXCSETUP_EXCB;
> +		}
> +
> +		regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
> +	} else {
> +		dev_warn(&client->dev, "No platform data? using default\n");
> +		regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
> +			AD7746_EXCSETUP_EXCLVL(3);
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(chip->client,
> +					AD7746_REG_EXC_SETUP, regval);
> +	if (ret < 0)
> +		goto error_free_dev;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret)
> +		goto error_free_dev;
> +
> +	dev_info(&client->dev, "%s capacitive sensor registered\n", id->name);
> +
> +	return 0;
> +
> +error_free_dev:
> +	iio_free_device(indio_dev);
> +error_ret:
> +	return ret;
> +}
> +
> +static int __devexit ad7746_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ad7746_id[] = {
> +	{ "ad7745", 7745 },
> +	{ "ad7746", 7746 },
> +	{ "ad7747", 7747 },
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, ad7746_id);
> +
> +static struct i2c_driver ad7746_driver = {
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	},
> +	.probe = ad7746_probe,
> +	.remove = __devexit_p(ad7746_remove),
> +	.id_table = ad7746_id,
> +};
> +
> +static __init int ad7746_init(void)
> +{
> +	return i2c_add_driver(&ad7746_driver);
> +}
> +
> +static __exit void ad7746_exit(void)
> +{
> +	i2c_del_driver(&ad7746_driver);
> +}
> +
> +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
> +MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
> +MODULE_LICENSE("GPL v2");
> +
> +module_init(ad7746_init);
> +module_exit(ad7746_exit);
> diff --git a/drivers/staging/iio/adc/ad7746.h b/drivers/staging/iio/adc/ad7746.h
> new file mode 100644
> index 0000000..ea8572d
> --- /dev/null
> +++ b/drivers/staging/iio/adc/ad7746.h
> @@ -0,0 +1,29 @@
> +/*
> + * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
> + *
> + * Copyright 2011 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#ifndef IIO_CDC_AD7746_H_
> +#define IIO_CDC_AD7746_H_
> +
> +/*
> + * TODO: struct ad7746_platform_data needs to go into include/linux/iio
> + */
> +
> +#define AD7466_EXCLVL_0		0 /* +-VDD/8 */
> +#define AD7466_EXCLVL_1		1 /* +-VDD/4 */
> +#define AD7466_EXCLVL_2		2 /* +-VDD * 3/8 */
> +#define AD7466_EXCLVL_3		3 /* +-VDD/2 */
> +
> +struct ad7746_platform_data {
> +	unsigned char exclvl;	/*Excitation Voltage Level */
> +	bool exca_en;		/* enables EXCA pin as the excitation output */
> +	bool exca_inv_en;	/* enables /EXCA pin as the excitation output */
> +	bool excb_en;		/* enables EXCB pin as the excitation output */
> +	bool excb_inv_en;	/* enables /EXCB pin as the excitation output */
> +};
> +
> +#endif /* IIO_CDC_AD7746_H_ */