iio: dac: Add support for the AD5592R/AD5593R ADCs/DACs

This patch adds support for the AD5592R (spi) and AD5593R (i2c)
ADC/DAC/GPIO devices.
Signed-off-by: Paul Cercueil <paul.cercueil@analog.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/dac/ad5592r.txt

+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, since
+					there is no disadvantage this
+					this should be considered as the
+					preferred DAC mode)
+				* 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>;
+		};
+	};

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

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

drivers/iio/dac/ad5592r-base.c

+/*
+ * AD5592R Digital <-> Analog converters driver
+ *
+ * Copyright 2014-2016 Analog Devices Inc.
+ * Author: Paul Cercueil <paul.cercueil@analog.com>
+ *
+ * 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);
+
+			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@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
+MODULE_LICENSE("GPL v2");

drivers/iio/dac/ad5592r-base.h

+/*
+ * AD5592R / AD5593R Digital <-> Analog converters driver
+ *
+ * Copyright 2015-2016 Analog Devices Inc.
+ * Author: Paul Cercueil <paul.cercueil@analog.com>
+ *
+ * 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;
+	struct gpio_chip gpiochip;
+	struct mutex gpio_lock;	/* Protect cached gpio_out, gpio_val, etc. */
+	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__ */

drivers/iio/dac/ad5592r.c

+/*
+ * AD5592R Digital <-> Analog converters driver
+ *
+ * Copyright 2015-2016 Analog Devices Inc.
+ * Author: Paul Cercueil <paul.cercueil@analog.com>
+ *
+ * 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@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
+MODULE_LICENSE("GPL v2");

drivers/iio/dac/ad5593r.c

+/*
+ * AD5593R Digital <-> Analog converters driver
+ *
+ * Copyright 2015-2016 Analog Devices Inc.
+ * Author: Paul Cercueil <paul.cercueil@analog.com>
+ *
+ * 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@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
+MODULE_LICENSE("GPL v2");

include/dt-bindings/iio/adi,ad5592r.h

+
+#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 */