Re: [PATCH v5] iio: dac: Add support for the AD5592R/AD5593R ADCs/DACs

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On 28/03/16 15:30, Jonathan Cameron wrote:
> On 23/03/16 08:19, michael.hennerich@xxxxxxxxxx wrote:
>> From: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>>
>> This patch adds support for the AD5592R (spi) and AD5593R (i2c)
>> ADC/DAC/GPIO devices.
>>
>> Signed-off-by: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
>>
> A few little bits and pieces in line.  Biggest one to me is whether Linus
> Walleij is happy with the gpio chip related parts.  I'm unconvinced you
> have completely addressed his points in the earlier review - but then I wasn't
> closely following the thread so perhaps I missed a consensus being reached.
> 
> Anyhow, as it contains a gpiochip it needs an Ack from Linus or Alexandre
> before I take it.
Working backwards looks like Linus was fairly happy, but still need that
format ack I think.

Jonathan
> 
> IIO parts look pretty good to me.
> 
> Thanks,
>  
> Jonathan
>> ---
>>
>> Changes since v1:
>> 	* Fix mutex usage
>> 	* Remove unnecessary NULL pointer guards
>> 	* Add comment explaining the invalid data read
>> 	* AD5593R Remove surplus adc readback
>>
>> Changes since v2:
>> 	* Use child nodes to describe channels
>> 	* Fix probe return and driver remove path
>> 	* Move locking closer to where its used
>> 	* Remove WARN_ON but return error
>> 	* Remove OPEN DRAIN configuration option
>>
>> Changes since v3:
>> 	* Documentation: Add missing vendor prefixes in the examples
>> 	* Minor function reordering in remove() to match the reverse of probe()
>>
>> Changes since v4:
>> 	* Documentation: Add missing gpio bindings
>> 	* Kconfig: Select GPIOLIB and remove ifdefs in code
> Looks like one of these snuck through...
> 
>> 	* Remove surplus error check in ad5592r_gpio_request()
>> 	* Add comment about reset magic
>> ---
>>  .../devicetree/bindings/iio/dac/ad5592r.txt        | 152 +++++
>>  drivers/iio/dac/Kconfig                            |  27 +
>>  drivers/iio/dac/Makefile                           |   3 +
>>  drivers/iio/dac/ad5592r-base.c                     | 694 +++++++++++++++++++++
>>  drivers/iio/dac/ad5592r-base.h                     |  78 +++
>>  drivers/iio/dac/ad5592r.c                          | 164 +++++
>>  drivers/iio/dac/ad5593r.c                          | 131 ++++
>>  include/dt-bindings/iio/adi,ad5592r.h              |  16 +
>>  8 files changed, 1265 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/iio/dac/ad5592r.txt
>>  create mode 100644 drivers/iio/dac/ad5592r-base.c
>>  create mode 100644 drivers/iio/dac/ad5592r-base.h
>>  create mode 100644 drivers/iio/dac/ad5592r.c
>>  create mode 100644 drivers/iio/dac/ad5593r.c
>>  create mode 100644 include/dt-bindings/iio/adi,ad5592r.h
>>
>> diff --git a/Documentation/devicetree/bindings/iio/dac/ad5592r.txt b/Documentation/devicetree/bindings/iio/dac/ad5592r.txt
>> new file mode 100644
>> index 0000000..35f76d7
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/dac/ad5592r.txt
>> @@ -0,0 +1,152 @@
>> +Analog Devices AD5592R/AD5593R DAC/ADC device driver
>> +
>> +Required properties for the AD5592R:
>> +	- compatible: Must be "adi,ad5592r"
>> +	- reg: SPI chip select number for the device
>> +	- spi-max-frequency: Max SPI frequency to use (< 30000000)
>> +	- spi-cpol: The AD5592R requires inverse clock polarity (CPOL) mode
>> +
>> +Required properties for the AD5593R:
>> +	- compatible: Must be "adi,ad5593r"
>> +	- reg: I2C address of the device
>> +
>> +Required properties for all supported chips:
>> +	- #address-cells: Should be 1.
>> +	- #size-cells: Should be 0.
>> +	- channel nodes:
>> +	  Each child node represents one channel and has the following
>> +	  Required properties:
>> +		* reg: Pin on which this channel is connected to.
>> +		* adi,mode: Mode or function of this channel.
>> +			    Macros specifying the valid values
>> +			    can be found in <dt-bindings/iio/adi,ad5592r.h>.
>> +
>> +			    The following values are currently supported:
>> +				* CH_MODE_UNUSED (the pin is unused)
>> +				* CH_MODE_ADC (the pin is ADC input)
>> +				* CH_MODE_DAC (the pin is DAC output)
>> +				* CH_MODE_DAC_AND_ADC (the pin is DAC output
>> +					but can be monitored by an ADC)
> Really silly question.  What is the disadvantage of configuring all dac
> channels in this mode?
> Might make sense to document this here to give people writing the dt
> files a hint.
> 
>> +				* CH_MODE_GPIO (the pin is registered
>> +					with GPIOLIB)
>> +	 Optional properties:
>> +		* adi,off-state: State of this channel when unused or the
>> +				 device gets removed. Macros specifying the
>> +				 valid values can be found in
>> +				 <dt-bindings/iio/adi,ad5592r.h>.
>> +
>> +				* CH_OFFSTATE_PULLDOWN (the pin is pulled down)
>> +				* CH_OFFSTATE_OUT_LOW  (the pin is output low)
>> +				* CH_OFFSTATE_OUT_HIGH (the pin is output high)
>> +				* CH_OFFSTATE_OUT_TRISTATE (the pin is
>> +					tristated output)
>> +
>> +
>> +Optional properties:
>> +	- vref-supply: Phandle to the external reference voltage supply. This should
>> +	  only be set if there is an external reference voltage connected to the VREF
>> +	  pin. If the property is not set the internal 2.5V reference is used.
>> +	- reset-gpios : GPIO spec for the RESET pin. If specified, it will be
>> +	  asserted during driver probe.
>> +	- gpio-controller: Marks the device node as a GPIO controller.
>> +	- #gpio-cells: Should be 2. The first cell is the GPIO number and the second
>> +	  cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>.
>> +
>> +AD5592R Example:
>> +
>> +	#include <dt-bindings/iio/adi,ad5592r.h>
>> +
>> +	vref: regulator-vref {
>> +		compatible = "regulator-fixed";
>> +		regulator-name = "vref-ad559x";
>> +		regulator-min-microvolt = <3300000>;
>> +		regulator-max-microvolt = <3300000>;
>> +		regulator-always-on;
>> +	};
>> +
>> +	ad5592r@0 {
>> +		#size-cells = <0>;
>> +		#address-cells = <1>;
>> +		#gpio-cells = <2>;
>> +		compatible = "adi,ad5592r";
>> +		reg = <0>;
>> +
>> +		spi-max-frequency = <1000000>;
>> +		spi-cpol;
>> +
>> +		vref-supply = <&vref>; /* optional */
>> +		reset-gpios = <&gpio0 86 0>;  /* optional */
>> +		gpio-controller;
>> +
>> +		channel@0 {
>> +			reg = <0>;
>> +			adi,mode = <CH_MODE_DAC>;
>> +		};
>> +		channel@1 {
>> +			reg = <1>;
>> +			adi,mode = <CH_MODE_ADC>;
>> +		};
>> +		channel@2 {
>> +			reg = <2>;
>> +			adi,mode = <CH_MODE_DAC_AND_ADC>;
>> +		};
>> +		channel@3 {
>> +			reg = <3>;
>> +			adi,mode = <CH_MODE_DAC_AND_ADC>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@4 {
>> +			reg = <4>;
>> +			adi,mode = <CH_MODE_UNUSED>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@5 {
>> +			reg = <5>;
>> +			adi,mode = <CH_MODE_GPIO>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@6 {
>> +			reg = <6>;
>> +			adi,mode = <CH_MODE_GPIO>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@7 {
>> +			reg = <7>;
>> +			adi,mode = <CH_MODE_GPIO>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +	};
>> +
>> +AD5593R Example:
>> +
>> +	#include <dt-bindings/iio/adi,ad5592r.h>
>> +
>> +	ad5593r@10 {
>> +		#size-cells = <0>;
>> +		#address-cells = <1>;
>> +		#gpio-cells = <2>;
>> +		compatible = "adi,ad5593r";
>> +		reg = <0x10>;
>> +		gpio-controller;
>> +
>> +		channel@0 {
>> +			reg = <0>;
>> +			adi,mode = <CH_MODE_DAC>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@1 {
>> +			reg = <1>;
>> +			adi,mode = <CH_MODE_ADC>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@2 {
>> +			reg = <2>;
>> +			adi,mode = <CH_MODE_DAC_AND_ADC>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +		channel@6 {
>> +			reg = <6>;
>> +			adi,mode = <CH_MODE_GPIO>;
>> +			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
>> +		};
>> +	};
>> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
>> index a995139..233dfb7 100644
>> --- a/drivers/iio/dac/Kconfig
>> +++ b/drivers/iio/dac/Kconfig
>> @@ -74,6 +74,33 @@ config AD5449
>>  	  To compile this driver as a module, choose M here: the
>>  	  module will be called ad5449.
>>  
>> +config AD5592R_BASE
>> +	tristate
>> +
>> +config AD5592R
>> +	tristate "Analog Devices AD5592R ADC/DAC driver"
>> +	depends on SPI_MASTER
>> +	select GPIOLIB
>> +	select AD5592R_BASE
>> +	help
>> +	  Say yes here to build support for Analog Devices AD5592R
>> +	  Digital to Analog / Analog to Digital Converter.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called ad5592r.
>> +
>> +config AD5593R
>> +	tristate "Analog Devices AD5593R ADC/DAC driver"
>> +	depends on I2C
>> +	select GPIOLIB
>> +	select AD5592R_BASE
>> +	help
>> +	  Say yes here to build support for Analog Devices AD5593R
>> +	  Digital to Analog / Analog to Digital Converter.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called ad5593r.
>> +
>>  config AD5504
>>  	tristate "Analog Devices AD5504/AD5501 DAC SPI driver"
>>  	depends on SPI
>> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
>> index 67b4842..de28cd2 100644
>> --- a/drivers/iio/dac/Makefile
>> +++ b/drivers/iio/dac/Makefile
>> @@ -11,6 +11,9 @@ obj-$(CONFIG_AD5064) += ad5064.o
>>  obj-$(CONFIG_AD5504) += ad5504.o
>>  obj-$(CONFIG_AD5446) += ad5446.o
>>  obj-$(CONFIG_AD5449) += ad5449.o
>> +obj-$(CONFIG_AD5592R_BASE) += ad5592r-base.o
>> +obj-$(CONFIG_AD5592R) += ad5592r.o
>> +obj-$(CONFIG_AD5593R) += ad5593r.o
>>  obj-$(CONFIG_AD5755) += ad5755.o
>>  obj-$(CONFIG_AD5761) += ad5761.o
>>  obj-$(CONFIG_AD5764) += ad5764.o
>> diff --git a/drivers/iio/dac/ad5592r-base.c b/drivers/iio/dac/ad5592r-base.c
>> new file mode 100644
>> index 0000000..4019e44
>> --- /dev/null
>> +++ b/drivers/iio/dac/ad5592r-base.c
>> @@ -0,0 +1,694 @@
>> +/*
>> + * AD5592R Digital <-> Analog converters driver
>> + *
>> + * Copyright 2014-2016 Analog Devices Inc.
>> + * Author: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>> + *
>> + * Licensed under the GPL-2.
>> + */
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/delay.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/module.h>
>> +#include <linux/mutex.h>
>> +#include <linux/of.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/gpio/driver.h>
>> +#include <linux/gpio.h>
>> +#include <linux/property.h>
>> +
>> +#include <dt-bindings/iio/adi,ad5592r.h>
>> +
>> +#include "ad5592r-base.h"
>> +
>> +static int ad5592r_gpio_get(struct gpio_chip *chip, unsigned offset)
>> +{
>> +	struct ad5592r_state *st = gpiochip_get_data(chip);
>> +	int ret = 0;
>> +	u8 val;
>> +
>> +	mutex_lock(&st->gpio_lock);
>> +
>> +	if (st->gpio_out & BIT(offset))
>> +		val = st->gpio_val;
>> +	else
>> +		ret = st->ops->gpio_read(st, &val);
>> +
>> +	mutex_unlock(&st->gpio_lock);
>> +
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return !!(val & BIT(offset));
>> +}
>> +
>> +static void ad5592r_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
>> +{
>> +	struct ad5592r_state *st = gpiochip_get_data(chip);
>> +
>> +	mutex_lock(&st->gpio_lock);
>> +
>> +	if (value)
>> +		st->gpio_val |= BIT(offset);
>> +	else
>> +		st->gpio_val &= ~BIT(offset);
>> +
>> +	st->ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
>> +
>> +	mutex_unlock(&st->gpio_lock);
>> +}
>> +
>> +static int ad5592r_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
>> +{
>> +	struct ad5592r_state *st = gpiochip_get_data(chip);
>> +	int ret;
>> +
>> +	mutex_lock(&st->gpio_lock);
>> +
>> +	st->gpio_out &= ~BIT(offset);
>> +	st->gpio_in |= BIT(offset);
>> +
>> +	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
>> +	if (ret < 0)
>> +		goto err_unlock;
>> +
>> +	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
>> +
>> +err_unlock:
>> +	mutex_unlock(&st->gpio_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static int ad5592r_gpio_direction_output(struct gpio_chip *chip,
>> +					 unsigned offset, int value)
>> +{
>> +	struct ad5592r_state *st = gpiochip_get_data(chip);
>> +	int ret;
>> +
>> +	mutex_lock(&st->gpio_lock);
>> +
>> +	if (value)
>> +		st->gpio_val |= BIT(offset);
>> +	else
>> +		st->gpio_val &= ~BIT(offset);
>> +
>> +	st->gpio_in &= ~BIT(offset);
>> +	st->gpio_out |= BIT(offset);
>> +
>> +	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
>> +	if (ret < 0)
>> +		goto err_unlock;
>> +
>> +	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
>> +	if (ret < 0)
>> +		goto err_unlock;
>> +
>> +	ret = st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
>> +
>> +err_unlock:
>> +	mutex_unlock(&st->gpio_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static int ad5592r_gpio_request(struct gpio_chip *chip, unsigned offset)
>> +{
>> +	struct ad5592r_state *st = gpiochip_get_data(chip);
>> +
>> +	if (!(st->gpio_map & BIT(offset))) {
>> +		dev_err(st->dev, "GPIO %d is reserved by alternate function\n",
>> +			offset);
>> +		return -ENODEV;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5592r_gpio_init(struct ad5592r_state *st)
>> +{
>> +	if (!st->gpio_map)
>> +		return 0;
>> +
>> +	st->gpiochip.label = dev_name(st->dev);
>> +	st->gpiochip.base = -1;
>> +	st->gpiochip.ngpio = 8;
>> +	st->gpiochip.parent = st->dev;
>> +	st->gpiochip.can_sleep = true;
>> +	st->gpiochip.direction_input = ad5592r_gpio_direction_input;
>> +	st->gpiochip.direction_output = ad5592r_gpio_direction_output;
>> +	st->gpiochip.get = ad5592r_gpio_get;
>> +	st->gpiochip.set = ad5592r_gpio_set;
>> +	st->gpiochip.request = ad5592r_gpio_request;
>> +	st->gpiochip.owner = THIS_MODULE;
>> +
>> +	mutex_init(&st->gpio_lock);
>> +
>> +	return gpiochip_add_data(&st->gpiochip, st);
>> +}
>> +
>> +static void ad5592r_gpio_cleanup(struct ad5592r_state *st)
>> +{
>> +	if (st->gpio_map)
>> +		gpiochip_remove(&st->gpiochip);
>> +}
>> +
>> +static int ad5592r_reset(struct ad5592r_state *st)
>> +{
>> +	struct gpio_desc *gpio;
>> +	struct iio_dev *iio_dev = iio_priv_to_dev(st);
>> +
>> +	gpio = devm_gpiod_get_optional(st->dev, "reset", GPIOD_OUT_LOW);
>> +	if (IS_ERR(gpio))
>> +		return PTR_ERR(gpio);
>> +
>> +	if (gpio) {
>> +		udelay(1);
>> +		gpiod_set_value(gpio, 1);
>> +	} else {
>> +		mutex_lock(&iio_dev->mlock);
>> +		/* Writing this magic value resets the device */
>> +		st->ops->reg_write(st, AD5592R_REG_RESET, 0xdac);
>> +		mutex_unlock(&iio_dev->mlock);
>> +	}
>> +
>> +	udelay(250);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5592r_get_vref(struct ad5592r_state *st)
>> +{
>> +	int ret;
>> +
>> +	if (st->reg) {
>> +		ret = regulator_get_voltage(st->reg);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		return ret / 1000;
>> +	} else {
>> +		return 2500;
>> +	}
>> +}
>> +
>> +static int ad5592r_set_channel_modes(struct ad5592r_state *st)
>> +{
>> +	const struct ad5592r_rw_ops *ops = st->ops;
>> +	int ret;
>> +	unsigned i;
>> +	struct iio_dev *iio_dev = iio_priv_to_dev(st);
>> +	u8 pulldown = 0, tristate = 0, dac = 0, adc = 0;
>> +	u16 read_back;
>> +
>> +	for (i = 0; i < st->num_channels; i++) {
>> +		switch (st->channel_modes[i]) {
>> +		case CH_MODE_DAC:
>> +			dac |= BIT(i);
>> +			break;
>> +
>> +		case CH_MODE_ADC:
>> +			adc |= BIT(i);
>> +			break;
>> +
>> +		case CH_MODE_DAC_AND_ADC:
>> +			dac |= BIT(i);
>> +			adc |= BIT(i);
>> +			break;
>> +
>> +		case CH_MODE_GPIO:
>> +			st->gpio_map |= BIT(i);
>> +			st->gpio_in |= BIT(i); /* Default to input */
>> +			break;
>> +
>> +		case CH_MODE_UNUSED:
>> +			/* fall-through */
>> +		default:
>> +			switch (st->channel_offstate[i]) {
>> +			case CH_OFFSTATE_OUT_TRISTATE:
>> +				tristate |= BIT(i);
>> +				break;
>> +
>> +			case CH_OFFSTATE_OUT_LOW:
>> +				st->gpio_out |= BIT(i);
>> +				break;
>> +
>> +			case CH_OFFSTATE_OUT_HIGH:
>> +				st->gpio_out |= BIT(i);
>> +				st->gpio_val |= BIT(i);
>> +				break;
>> +
>> +			case CH_OFFSTATE_PULLDOWN:
>> +				/* fall-through */
>> +			default:
>> +				pulldown |= BIT(i);
>> +				break;
>> +			}
>> +		}
>> +	}
>> +
>> +	mutex_lock(&iio_dev->mlock);
>> +
>> +	/* Pull down unused pins to GND */
>> +	ret = ops->reg_write(st, AD5592R_REG_PULLDOWN, pulldown);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	ret = ops->reg_write(st, AD5592R_REG_TRISTATE, tristate);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	/* Configure pins that we use */
>> +	ret = ops->reg_write(st, AD5592R_REG_DAC_EN, dac);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	ret = ops->reg_write(st, AD5592R_REG_ADC_EN, adc);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	ret = ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	ret = ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	ret = ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
>> +	if (ret)
>> +		goto err_unlock;
>> +
>> +	/* Verify that we can read back at least one register */
>> +	ret = ops->reg_read(st, AD5592R_REG_ADC_EN, &read_back);
>> +	if (!ret && (read_back & 0xff) != adc)
>> +		ret = -EIO;
>> +
>> +err_unlock:
>> +	mutex_unlock(&iio_dev->mlock);
>> +	return ret;
>> +}
>> +
>> +static int ad5592r_reset_channel_modes(struct ad5592r_state *st)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(st->channel_modes); i++)
>> +		st->channel_modes[i] = CH_MODE_UNUSED;
>> +
>> +	return ad5592r_set_channel_modes(st);
>> +}
>> +
>> +static int ad5592r_write_raw(struct iio_dev *iio_dev,
>> +	struct iio_chan_spec const *chan, int val, int val2, long mask)
>> +{
>> +	struct ad5592r_state *st = iio_priv(iio_dev);
>> +	int ret;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_RAW:
>> +
>> +		if (val >= (1 << chan->scan_type.realbits) || val < 0)
>> +			return -EINVAL;
>> +
>> +		if (!chan->output)
>> +			return -EINVAL;
>> +
>> +		mutex_lock(&iio_dev->mlock);
>> +		ret = st->ops->write_dac(st, chan->channel, val);
>> +		if (!ret)
>> +			st->cached_dac[chan->channel] = val;
>> +		mutex_unlock(&iio_dev->mlock);
>> +		return ret;
>> +	case IIO_CHAN_INFO_SCALE:
>> +		if (chan->type == IIO_VOLTAGE) {
>> +			bool gain;
>> +
>> +			if (val == st->scale_avail[0][0] &&
>> +				val2 == st->scale_avail[0][1])
>> +				gain = false;
>> +			else if (val == st->scale_avail[1][0] &&
>> +				 val2 == st->scale_avail[1][1])
>> +				gain = true;
>> +			else
>> +				return -EINVAL;
>> +
>> +			mutex_lock(&iio_dev->mlock);
>> +
>> +			ret = st->ops->reg_read(st, AD5592R_REG_CTRL,
>> +						&st->cached_gp_ctrl);
>> +			if (ret < 0) {
>> +				mutex_unlock(&iio_dev->mlock);
>> +				return ret;
>> +			}
>> +
>> +			if (chan->output) {
>> +				if (gain)
>> +					st->cached_gp_ctrl |=
>> +						AD5592R_REG_CTRL_DAC_RANGE;
>> +				else
>> +					st->cached_gp_ctrl &=
>> +						~AD5592R_REG_CTRL_DAC_RANGE;
>> +			} else {
>> +				if (gain)
>> +					st->cached_gp_ctrl |=
>> +						AD5592R_REG_CTRL_ADC_RANGE;
>> +				else
>> +					st->cached_gp_ctrl &=
>> +						~AD5592R_REG_CTRL_ADC_RANGE;
>> +			}
>> +
>> +			ret = st->ops->reg_write(st, AD5592R_REG_CTRL,
>> +						 st->cached_gp_ctrl);
>> +			mutex_unlock(&iio_dev->mlock);
>> +			if (ret < 0)
>> +				return ret;
>> +
> Spot the obvious simplication between these few lines ;) It returns ret whatever
> the value of ret, so don't check it.
>> +			return ret;
>> +
>> +		}
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5592r_read_raw(struct iio_dev *iio_dev,
>> +			   struct iio_chan_spec const *chan,
>> +			   int *val, int *val2, long m)
>> +{
>> +	struct ad5592r_state *st = iio_priv(iio_dev);
>> +	u16 read_val;
>> +	int ret;
>> +
>> +	switch (m) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		mutex_lock(&iio_dev->mlock);
>> +
>> +		if (!chan->output) {
>> +			ret = st->ops->read_adc(st, chan->channel, &read_val);
>> +			if (ret)
>> +				goto unlock;
>> +
>> +			if ((read_val >> 12 & 0x7) != (chan->channel & 0x7)) {
>> +				dev_err(st->dev, "Error while reading channel %u\n",
>> +						chan->channel);
>> +				ret = -EIO;
>> +				goto unlock;
>> +			}
>> +
>> +			read_val &= GENMASK(11, 0);
>> +
>> +		} else {
>> +			read_val = st->cached_dac[chan->channel];
>> +		}
>> +
>> +		dev_dbg(st->dev, "Channel %u read: 0x%04hX\n",
>> +				chan->channel, read_val);
>> +
>> +		*val = (int) read_val;
>> +		ret = IIO_VAL_INT;
>> +		break;
>> +	case IIO_CHAN_INFO_SCALE:
>> +		*val = ad5592r_get_vref(st);
>> +
>> +		if (chan->type == IIO_TEMP) {
>> +			s64 tmp = *val * (3767897513LL / 25LL);
>> +			*val = div_s64_rem(tmp, 1000000000LL, val2);
>> +
>> +			ret = IIO_VAL_INT_PLUS_MICRO;
>> +		} else {
>> +			int mult;
>> +
>> +			mutex_lock(&iio_dev->mlock);
>> +
>> +			if (chan->output)
>> +				mult = !!(st->cached_gp_ctrl &
>> +					AD5592R_REG_CTRL_DAC_RANGE);
>> +			else
>> +				mult = !!(st->cached_gp_ctrl &
>> +					AD5592R_REG_CTRL_ADC_RANGE);
>> +
>> +			*val *= ++mult;
>> +
>> +			*val2 = chan->scan_type.realbits;
>> +			ret = IIO_VAL_FRACTIONAL_LOG2;
>> +		}
>> +		break;
>> +	case IIO_CHAN_INFO_OFFSET:
>> +		ret = ad5592r_get_vref(st);
>> +
>> +		mutex_lock(&iio_dev->mlock);
>> +
>> +		if (st->cached_gp_ctrl & AD5592R_REG_CTRL_ADC_RANGE)
>> +			*val = (-34365 * 25) / ret;
>> +		else
>> +			*val = (-75365 * 25) / ret;
>> +		ret =  IIO_VAL_INT;
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +	}
>> +
>> +unlock:
>> +	mutex_unlock(&iio_dev->mlock);
>> +	return ret;
>> +}
>> +
>> +static int ad5592r_write_raw_get_fmt(struct iio_dev *indio_dev,
>> +				 struct iio_chan_spec const *chan, long mask)
>> +{
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_SCALE:
>> +		return IIO_VAL_INT_PLUS_NANO;
>> +
>> +	default:
>> +		return IIO_VAL_INT_PLUS_MICRO;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static const struct iio_info ad5592r_info = {
>> +	.read_raw = ad5592r_read_raw,
>> +	.write_raw = ad5592r_write_raw,
>> +	.write_raw_get_fmt = ad5592r_write_raw_get_fmt,
>> +	.driver_module = THIS_MODULE,
>> +};
>> +
>> +static ssize_t ad5592r_show_scale_available(struct iio_dev *iio_dev,
>> +					   uintptr_t private,
>> +					   const struct iio_chan_spec *chan,
>> +					   char *buf)
>> +{
>> +	struct ad5592r_state *st = iio_priv(iio_dev);
>> +
>> +	return sprintf(buf, "%d.%09u %d.%09u\n",
>> +		st->scale_avail[0][0], st->scale_avail[0][1],
>> +		st->scale_avail[1][0], st->scale_avail[1][1]);
>> +}
>> +
>> +static struct iio_chan_spec_ext_info ad5592r_ext_info[] = {
>> +	{
>> +	 .name = "scale_available",
>> +	 .read = ad5592r_show_scale_available,
>> +	 .shared = true,
>> +	 },
>> +	{},
>> +};
>> +
>> +static void ad5592r_setup_channel(struct iio_dev *iio_dev,
>> +		struct iio_chan_spec *chan, bool output, unsigned id)
>> +{
>> +	chan->type = IIO_VOLTAGE;
>> +	chan->indexed = 1;
>> +	chan->output = output;
>> +	chan->channel = id;
>> +	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>> +	chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
>> +	chan->scan_type.sign = 'u';
>> +	chan->scan_type.realbits = 12;
>> +	chan->scan_type.storagebits = 16;
>> +	chan->ext_info = ad5592r_ext_info;
>> +}
>> +
>> +static int ad5592r_alloc_channels(struct ad5592r_state *st)
>> +{
>> +	unsigned i, curr_channel = 0,
>> +		 num_channels = st->num_channels;
>> +	struct iio_dev *iio_dev = iio_priv_to_dev(st);
>> +	struct iio_chan_spec *channels;
>> +	struct fwnode_handle *child;
>> +	u32 reg, tmp;
>> +	int ret;
>> +
>> +	device_for_each_child_node(st->dev, child) {
>> +		ret = fwnode_property_read_u32(child, "reg", &reg);
>> +		if (ret || reg > ARRAY_SIZE(st->channel_modes))
>> +			continue;
>> +
>> +		ret = fwnode_property_read_u32(child, "adi,mode", &tmp);
>> +		if (!ret)
>> +			st->channel_modes[reg] = tmp;
>> +
>> +		fwnode_property_read_u32(child, "adi,off-state", &tmp);
>> +		if (!ret)
>> +			st->channel_offstate[reg] = tmp;
>> +	}
>> +
>> +	channels = devm_kzalloc(st->dev,
>> +			(1 + 2 * num_channels) * sizeof(*channels), GFP_KERNEL);
>> +	if (!channels)
>> +		return -ENOMEM;
>> +
>> +	for (i = 0; i < num_channels; i++) {
>> +		switch (st->channel_modes[i]) {
>> +		case CH_MODE_DAC:
>> +			ad5592r_setup_channel(iio_dev, &channels[curr_channel],
>> +					true, i);
>> +			curr_channel++;
>> +			break;
>> +
>> +		case CH_MODE_ADC:
>> +			ad5592r_setup_channel(iio_dev, &channels[curr_channel],
>> +					false, i);
>> +			curr_channel++;
>> +			break;
>> +
>> +		case CH_MODE_DAC_AND_ADC:
>> +			ad5592r_setup_channel(iio_dev, &channels[curr_channel],
>> +					true, i);
>> +			curr_channel++;
>> +			ad5592r_setup_channel(iio_dev, &channels[curr_channel],
>> +					false, i);
>> +			curr_channel++;
>> +			break;
>> +
>> +		default:
>> +			continue;
>> +		}
>> +	}
>> +
>> +	channels[curr_channel].type = IIO_TEMP;
>> +	channels[curr_channel].channel = 8;
>> +	channels[curr_channel].info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> +				   BIT(IIO_CHAN_INFO_SCALE) |
>> +				   BIT(IIO_CHAN_INFO_OFFSET);
>> +	curr_channel++;
>> +
>> +	iio_dev->num_channels = curr_channel;
>> +	iio_dev->channels = channels;
>> +
>> +	return 0;
>> +}
>> +
>> +static void ad5592r_init_scales(struct ad5592r_state *st, int vref_mV)
>> +{
>> +	s64 tmp = (s64)vref_mV * 1000000000LL >> 12;
>> +
>> +	st->scale_avail[0][0] =
>> +		div_s64_rem(tmp, 1000000000LL, &st->scale_avail[0][1]);
>> +	st->scale_avail[1][0] =
>> +		div_s64_rem(tmp * 2, 1000000000LL, &st->scale_avail[1][1]);
>> +}
>> +
>> +int ad5592r_probe(struct device *dev, const char *name,
>> +		const struct ad5592r_rw_ops *ops)
>> +{
>> +	struct iio_dev *iio_dev;
>> +	struct ad5592r_state *st;
>> +	int ret;
>> +
>> +	iio_dev = devm_iio_device_alloc(dev, sizeof(*st));
>> +	if (!iio_dev)
>> +		return -ENOMEM;
>> +
>> +	st = iio_priv(iio_dev);
>> +	st->dev = dev;
>> +	st->ops = ops;
>> +	st->num_channels = 8;
>> +	dev_set_drvdata(dev, iio_dev);
>> +
>> +	st->reg = devm_regulator_get_optional(dev, "vref");
>> +	if (IS_ERR(st->reg)) {
>> +		if ((PTR_ERR(st->reg) != -ENODEV) && dev->of_node)
>> +			return PTR_ERR(st->reg);
>> +
>> +		st->reg = NULL;
>> +	} else {
>> +		ret = regulator_enable(st->reg);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>> +	iio_dev->dev.parent = dev;
>> +	iio_dev->name = name;
>> +	iio_dev->info = &ad5592r_info;
>> +	iio_dev->modes = INDIO_DIRECT_MODE;
>> +
>> +	ad5592r_init_scales(st, ad5592r_get_vref(st));
>> +
>> +	ret = ad5592r_reset(st);
>> +	if (ret)
>> +		goto error_disable_reg;
>> +
>> +	ret = ops->reg_write(st, AD5592R_REG_PD,
>> +		     (st->reg == NULL) ? AD5592R_REG_PD_EN_REF : 0);
>> +	if (ret)
>> +		goto error_disable_reg;
>> +
>> +	ret = ad5592r_alloc_channels(st);
>> +	if (ret)
>> +		goto error_disable_reg;
>> +
>> +	ret = ad5592r_set_channel_modes(st);
>> +	if (ret)
>> +		goto error_reset_ch_modes;
>> +
>> +	ret = iio_device_register(iio_dev);
>> +	if (ret)
>> +		goto error_reset_ch_modes;
>> +
>> +	ret = ad5592r_gpio_init(st);
>> +	if (ret)
>> +		goto error_dev_unregister;
>> +
>> +	return 0;
>> +
>> +error_dev_unregister:
>> +	iio_device_unregister(iio_dev);
>> +
>> +error_reset_ch_modes:
>> +	ad5592r_reset_channel_modes(st);
>> +
>> +error_disable_reg:
>> +	if (st->reg)
>> +		regulator_disable(st->reg);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(ad5592r_probe);
>> +
>> +int ad5592r_remove(struct device *dev)
>> +{
>> +	struct iio_dev *iio_dev = dev_get_drvdata(dev);
>> +	struct ad5592r_state *st = iio_priv(iio_dev);
>> +
>> +	iio_device_unregister(iio_dev);
>> +	ad5592r_reset_channel_modes(st);
>> +	ad5592r_gpio_cleanup(st);
>> +
>> +	if (st->reg)
>> +		regulator_disable(st->reg);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(ad5592r_remove);
>> +
>> +MODULE_AUTHOR("Paul Cercueil <paul.cercueil@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/iio/dac/ad5592r-base.h b/drivers/iio/dac/ad5592r-base.h
>> new file mode 100644
>> index 0000000..2753385
>> --- /dev/null
>> +++ b/drivers/iio/dac/ad5592r-base.h
>> @@ -0,0 +1,78 @@
>> +/*
>> + * AD5592R / AD5593R Digital <-> Analog converters driver
>> + *
>> + * Copyright 2015-2016 Analog Devices Inc.
>> + * Author: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>> + *
>> + * Licensed under the GPL-2.
>> + */
>> +
>> +#ifndef __DRIVERS_IIO_DAC_AD5592R_BASE_H__
>> +#define __DRIVERS_IIO_DAC_AD5592R_BASE_H__
>> +
>> +#include <linux/types.h>
>> +#include <linux/cache.h>
>> +#include <linux/mutex.h>
>> +#include <linux/gpio/driver.h>
>> +
>> +struct device;
>> +struct ad5592r_state;
>> +
>> +enum ad5592r_registers {
>> +	AD5592R_REG_NOOP		= 0x0,
>> +	AD5592R_REG_DAC_READBACK	= 0x1,
>> +	AD5592R_REG_ADC_SEQ		= 0x2,
>> +	AD5592R_REG_CTRL		= 0x3,
>> +	AD5592R_REG_ADC_EN		= 0x4,
>> +	AD5592R_REG_DAC_EN		= 0x5,
>> +	AD5592R_REG_PULLDOWN		= 0x6,
>> +	AD5592R_REG_LDAC		= 0x7,
>> +	AD5592R_REG_GPIO_OUT_EN		= 0x8,
>> +	AD5592R_REG_GPIO_SET		= 0x9,
>> +	AD5592R_REG_GPIO_IN_EN		= 0xA,
>> +	AD5592R_REG_PD			= 0xB,
>> +	AD5592R_REG_OPEN_DRAIN		= 0xC,
>> +	AD5592R_REG_TRISTATE		= 0xD,
>> +	AD5592R_REG_RESET		= 0xF,
>> +};
>> +
>> +#define AD5592R_REG_PD_EN_REF		BIT(9)
>> +#define AD5592R_REG_CTRL_ADC_RANGE	BIT(5)
>> +#define AD5592R_REG_CTRL_DAC_RANGE	BIT(4)
>> +
>> +struct ad5592r_rw_ops {
>> +	int (*write_dac)(struct ad5592r_state *st, unsigned chan, u16 value);
>> +	int (*read_adc)(struct ad5592r_state *st, unsigned chan, u16 *value);
>> +	int (*reg_write)(struct ad5592r_state *st, u8 reg, u16 value);
>> +	int (*reg_read)(struct ad5592r_state *st, u8 reg, u16 *value);
>> +	int (*gpio_read)(struct ad5592r_state *st, u8 *value);
>> +};
>> +
>> +struct ad5592r_state {
>> +	struct device *dev;
>> +	struct regulator *reg;
> 
> Guessing this ifdef was meant to go.
>> +#ifdef CONFIG_GPIOLIB
>> +	struct gpio_chip gpiochip;
>> +	struct mutex gpio_lock;	/* Protect cached gpio_out, gpio_val, etc. */
>> +#endif
>> +	unsigned int num_channels;
>> +	const struct ad5592r_rw_ops *ops;
>> +	int scale_avail[2][2];
>> +	u16 cached_dac[8];
>> +	u16 cached_gp_ctrl;
>> +	u8 channel_modes[8];
>> +	u8 channel_offstate[8];
>> +	u8 gpio_map;
>> +	u8 gpio_out;
>> +	u8 gpio_in;
>> +	u8 gpio_val;
>> +
>> +	__be16 spi_msg ____cacheline_aligned;
>> +	__be16 spi_msg_nop;
>> +};
>> +
>> +int ad5592r_probe(struct device *dev, const char *name,
>> +		const struct ad5592r_rw_ops *ops);
>> +int ad5592r_remove(struct device *dev);
>> +
>> +#endif /* __DRIVERS_IIO_DAC_AD5592R_BASE_H__ */
>> diff --git a/drivers/iio/dac/ad5592r.c b/drivers/iio/dac/ad5592r.c
>> new file mode 100644
>> index 0000000..0b235a2
>> --- /dev/null
>> +++ b/drivers/iio/dac/ad5592r.c
>> @@ -0,0 +1,164 @@
>> +/*
>> + * AD5592R Digital <-> Analog converters driver
>> + *
>> + * Copyright 2015-2016 Analog Devices Inc.
>> + * Author: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>> + *
>> + * Licensed under the GPL-2.
>> + */
>> +
>> +#include "ad5592r-base.h"
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/spi/spi.h>
>> +
>> +#define AD5592R_GPIO_READBACK_EN	BIT(10)
>> +#define AD5592R_LDAC_READBACK_EN	BIT(6)
>> +
>> +static int ad5592r_spi_wnop_r16(struct ad5592r_state *st, u16 *buf)
>> +{
>> +	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
>> +	struct spi_transfer t = {
>> +			.tx_buf	= &st->spi_msg_nop,
>> +			.rx_buf	= buf,
>> +			.len = 2
>> +		};
>> +
>> +	st->spi_msg_nop = 0; /* NOP */
>> +
>> +	return spi_sync_transfer(spi, &t, 1);
>> +}
>> +
>> +static int ad5592r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value)
>> +{
>> +	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
>> +
>> +	st->spi_msg = cpu_to_be16(BIT(15) | (chan << 12) | value);
>> +
>> +	return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
>> +}
>> +
>> +static int ad5592r_read_adc(struct ad5592r_state *st, unsigned chan, u16 *value)
>> +{
>> +	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
>> +	int ret;
>> +
>> +	st->spi_msg = cpu_to_be16((AD5592R_REG_ADC_SEQ << 11) | BIT(chan));
>> +
>> +	ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
>> +	if (ret)
>> +		return ret;
>> +
>> +	/*
>> +	 * Invalid data:
>> +	 * See Figure 40. Single-Channel ADC Conversion Sequence
>> +	 */
>> +	ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
>> +	if (ret)
>> +		return ret;
>> +
>> +	*value = be16_to_cpu(st->spi_msg);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5592r_reg_write(struct ad5592r_state *st, u8 reg, u16 value)
>> +{
>> +	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
>> +
>> +	st->spi_msg = cpu_to_be16((reg << 11) | value);
>> +
>> +	return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
>> +}
>> +
>> +static int ad5592r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value)
>> +{
>> +	struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
>> +	int ret;
>> +
>> +	st->spi_msg = cpu_to_be16((AD5592R_REG_LDAC << 11) |
>> +				   AD5592R_LDAC_READBACK_EN | (reg << 2));
>> +
>> +	ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
>> +	if (ret)
>> +		return ret;
>> +
>> +	*value = be16_to_cpu(st->spi_msg);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5593r_gpio_read(struct ad5592r_state *st, u8 *value)
>> +{
>> +	int ret;
>> +
>> +	ret = ad5592r_reg_write(st, AD5592R_REG_GPIO_IN_EN,
>> +				AD5592R_GPIO_READBACK_EN | st->gpio_in);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
>> +	if (ret)
>> +		return ret;
>> +
>> +	*value = (u8) be16_to_cpu(st->spi_msg);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct ad5592r_rw_ops ad5592r_rw_ops = {
>> +	.write_dac = ad5592r_write_dac,
>> +	.read_adc = ad5592r_read_adc,
>> +	.reg_write = ad5592r_reg_write,
>> +	.reg_read = ad5592r_reg_read,
>> +	.gpio_read = ad5593r_gpio_read,
>> +};
>> +
>> +static int ad5592r_spi_probe(struct spi_device *spi)
>> +{
>> +	const struct spi_device_id *id = spi_get_device_id(spi);
>> +
>> +	return ad5592r_probe(&spi->dev, id->name, &ad5592r_rw_ops);
>> +}
>> +
>> +static int ad5592r_spi_remove(struct spi_device *spi)
>> +{
>> +	return ad5592r_remove(&spi->dev);
>> +}
>> +
>> +static const struct spi_device_id ad5592r_spi_ids[] = {
>> +	{ .name = "ad5592r", },
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(spi, ad5592r_spi_ids);
>> +
>> +static const struct of_device_id ad5592r_of_match[] = {
>> +	{ .compatible = "adi,ad5592r", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, ad5592r_of_match);
>> +
>> +static struct spi_driver ad5592r_spi_driver = {
>> +	.driver = {
>> +		.name = "ad5592r",
>> +		.of_match_table = of_match_ptr(ad5592r_of_match),
>> +	},
>> +	.probe = ad5592r_spi_probe,
>> +	.remove = ad5592r_spi_remove,
>> +	.id_table = ad5592r_spi_ids,
>> +};
>> +module_spi_driver(ad5592r_spi_driver);
>> +
>> +MODULE_AUTHOR("Paul Cercueil <paul.cercueil@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/iio/dac/ad5593r.c b/drivers/iio/dac/ad5593r.c
>> new file mode 100644
>> index 0000000..dca158a
>> --- /dev/null
>> +++ b/drivers/iio/dac/ad5593r.c
>> @@ -0,0 +1,131 @@
>> +/*
>> + * AD5593R Digital <-> Analog converters driver
>> + *
>> + * Copyright 2015-2016 Analog Devices Inc.
>> + * Author: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>> + *
>> + * Licensed under the GPL-2.
>> + */
>> +
>> +#include "ad5592r-base.h"
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +
>> +#define AD5593R_MODE_CONF		(0 << 4)
>> +#define AD5593R_MODE_DAC_WRITE		(1 << 4)
>> +#define AD5593R_MODE_ADC_READBACK	(4 << 4)
>> +#define AD5593R_MODE_DAC_READBACK	(5 << 4)
>> +#define AD5593R_MODE_GPIO_READBACK	(6 << 4)
>> +#define AD5593R_MODE_REG_READBACK	(7 << 4)
>> +
>> +static int ad5593r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value)
>> +{
>> +	struct i2c_client *i2c = to_i2c_client(st->dev);
>> +
>> +	return i2c_smbus_write_word_swapped(i2c,
>> +			AD5593R_MODE_DAC_WRITE | chan, value);
>> +}
>> +
>> +static int ad5593r_read_adc(struct ad5592r_state *st, unsigned chan, u16 *value)
>> +{
>> +	struct i2c_client *i2c = to_i2c_client(st->dev);
>> +	s32 val;
>> +
>> +	val = i2c_smbus_write_word_swapped(i2c,
>> +			AD5593R_MODE_CONF | AD5592R_REG_ADC_SEQ, BIT(chan));
>> +	if (val < 0)
>> +		return (int) val;
>> +
>> +	val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_ADC_READBACK);
>> +	if (val < 0)
>> +		return (int) val;
>> +
>> +	*value = (u16) val;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5593r_reg_write(struct ad5592r_state *st, u8 reg, u16 value)
>> +{
>> +	struct i2c_client *i2c = to_i2c_client(st->dev);
>> +
>> +	return i2c_smbus_write_word_swapped(i2c,
>> +			AD5593R_MODE_CONF | reg, value);
>> +}
>> +
>> +static int ad5593r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value)
>> +{
>> +	struct i2c_client *i2c = to_i2c_client(st->dev);
>> +	s32 val;
>> +
>> +	val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_REG_READBACK | reg);
>> +	if (val < 0)
>> +		return (int) val;
>> +
>> +	*value = (u16) val;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad5593r_gpio_read(struct ad5592r_state *st, u8 *value)
>> +{
>> +	struct i2c_client *i2c = to_i2c_client(st->dev);
>> +	s32 val;
>> +
>> +	val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_GPIO_READBACK);
>> +	if (val < 0)
>> +		return (int) val;
>> +
>> +	*value = (u8) val;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct ad5592r_rw_ops ad5593r_rw_ops = {
>> +	.write_dac = ad5593r_write_dac,
>> +	.read_adc = ad5593r_read_adc,
>> +	.reg_write = ad5593r_reg_write,
>> +	.reg_read = ad5593r_reg_read,
>> +	.gpio_read = ad5593r_gpio_read,
>> +};
>> +
>> +static int ad5593r_i2c_probe(struct i2c_client *i2c,
>> +		const struct i2c_device_id *id)
>> +{
>> +	return ad5592r_probe(&i2c->dev, id->name, &ad5593r_rw_ops);
>> +}
>> +
>> +static int ad5593r_i2c_remove(struct i2c_client *i2c)
>> +{
>> +	return ad5592r_remove(&i2c->dev);
>> +}
>> +
>> +static const struct i2c_device_id ad5593r_i2c_ids[] = {
>> +	{ .name = "ad5593r", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ad5593r_i2c_ids);
>> +
>> +static const struct of_device_id ad5593r_of_match[] = {
>> +	{ .compatible = "adi,ad5593r", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, ad5593r_of_match);
>> +
>> +static struct i2c_driver ad5593r_driver = {
>> +	.driver = {
>> +		.name = "ad5593r",
>> +		.of_match_table = of_match_ptr(ad5593r_of_match),
>> +	},
>> +	.probe = ad5593r_i2c_probe,
>> +	.remove = ad5593r_i2c_remove,
>> +	.id_table = ad5593r_i2c_ids,
>> +};
>> +module_i2c_driver(ad5593r_driver);
>> +
>> +MODULE_AUTHOR("Paul Cercueil <paul.cercueil@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/dt-bindings/iio/adi,ad5592r.h b/include/dt-bindings/iio/adi,ad5592r.h
>> new file mode 100644
>> index 0000000..c48aca1
>> --- /dev/null
>> +++ b/include/dt-bindings/iio/adi,ad5592r.h
>> @@ -0,0 +1,16 @@
>> +
>> +#ifndef _DT_BINDINGS_ADI_AD5592R_H
>> +#define _DT_BINDINGS_ADI_AD5592R_H
>> +
>> +#define CH_MODE_UNUSED			0
>> +#define CH_MODE_ADC			1
>> +#define CH_MODE_DAC			2
>> +#define CH_MODE_DAC_AND_ADC		3
>> +#define CH_MODE_GPIO			8
>> +
>> +#define CH_OFFSTATE_PULLDOWN		0
>> +#define CH_OFFSTATE_OUT_LOW		1
>> +#define CH_OFFSTATE_OUT_HIGH		2
>> +#define CH_OFFSTATE_OUT_TRISTATE	3
>> +
>> +#endif /* _DT_BINDINGS_ADI_AD5592R_H */
>>
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