Add support for the Analog Devices AD5706R, a 4-channel 16-bit
current output digital-to-analog converter with SPI interface.

Features:
  - 4 independent DAC channels
  - Hardware and software LDAC trigger
  - Configurable output range
  - PWM-based LDAC control
  - Dither and toggle modes
  - Dynamically configurable SPI speed

Signed-off-by: Alexis Czezar Torreno <alexisczezar.torreno@analog.com>

---
Changes since v1:
  - Removed PWM, GPIO, clock generator, debugfs, regmap, IIO_BUFFER
  - Removed all custom ext_info sysfs attributes
  - Simplified to basic raw read/write and read-only scale
  - SPI read/write can handle multibyte registers
---
---
 drivers/iio/dac/Kconfig   |  10 +++
 drivers/iio/dac/Makefile  |   1 +
 drivers/iio/dac/ad5706r.c | 208 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 219 insertions(+)

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index db9f5c711b3df90641f017652fbbef594cc1627d..8ccbdf6dfbca8640a47bf05b4afc6b4bf90a7e26 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -178,6 +178,16 @@ config AD5624R_SPI
 	  Say yes here to build support for Analog Devices AD5624R, AD5644R and
 	  AD5664R converters (DAC). This driver uses the common SPI interface.
 
+config AD5706R
+	tristate "Analog Devices AD5706R DAC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD5706R 4-channel,
+	  16-bit current output DAC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5706r.
+
 config AD9739A
 	tristate "Analog Devices AD9739A RF DAC spi driver"
 	depends on SPI
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 2a80bbf4e80ad557da79ed916027cedff286984b..0034317984985035f7987a744899924bfd4612e3 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_AD5449) += ad5449.o
 obj-$(CONFIG_AD5592R_BASE) += ad5592r-base.o
 obj-$(CONFIG_AD5592R) += ad5592r.o
 obj-$(CONFIG_AD5593R) += ad5593r.o
+obj-$(CONFIG_AD5706R) += ad5706r.o
 obj-$(CONFIG_AD5755) += ad5755.o
 obj-$(CONFIG_AD5758) += ad5758.o
 obj-$(CONFIG_AD5761) += ad5761.o
diff --git a/drivers/iio/dac/ad5706r.c b/drivers/iio/dac/ad5706r.c
new file mode 100644
index 0000000000000000000000000000000000000000..204d29f6495da167e922e5c9c5a2c4ff5c650693
--- /dev/null
+++ b/drivers/iio/dac/ad5706r.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AD5706R 16-bit Current Output Digital to Analog Converter
+ *
+ * Copyright 2026 Analog Devices Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+/* SPI frame layout */
+#define AD5706R_RD_MASK			BIT(15)
+#define AD5706R_ADDR_MASK		GENMASK(11, 0)
+
+/* Registers */
+#define AD5706R_REG_DAC_INPUT_A_CH(x)		(0x60 + ((x) * 2))
+#define AD5706R_REG_DAC_DATA_READBACK_CH(x)	(0x68 + ((x) * 2))
+
+#define AD5706R_DAC_RESOLUTION		16
+#define AD5706R_DAC_MAX_CODE		BIT(AD5706R_DAC_RESOLUTION)  /* 65536 */
+#define AD5706R_MULTIBYTE_REG_START	0x14
+#define AD5706R_MULTIBYTE_REG_END	0x71
+#define AD5706R_SINGLE_BYTE_LEN		1
+#define AD5706R_DOUBLE_BYTE_LEN		2
+
+struct ad5706r_state {
+	struct spi_device *spi;
+	struct mutex lock; /* Protects SPI transfers */
+
+	__be32 tx_buf __aligned(ARCH_DMA_MINALIGN);
+	__be16 rx_buf;
+};
+
+static int ad5706r_reg_len(unsigned int reg)
+{
+	if (reg >= AD5706R_MULTIBYTE_REG_START && reg <= AD5706R_MULTIBYTE_REG_END)
+		return AD5706R_DOUBLE_BYTE_LEN;
+
+	return AD5706R_SINGLE_BYTE_LEN;
+}
+
+static int ad5706r_spi_write(struct ad5706r_state *st, u16 reg, u16 val)
+{
+	unsigned int num_bytes = ad5706r_reg_len(reg);
+
+	struct spi_transfer xfer = {
+		.tx_buf = &st->tx_buf,
+		.len = num_bytes + 2,
+	};
+
+	st->tx_buf = cpu_to_be32((((u32)reg) << 16) |
+			((u32)val << (16 - (num_bytes * 8))));
+
+	return spi_sync_transfer(st->spi, &xfer, 1);
+}
+
+static int ad5706r_spi_read(struct ad5706r_state *st, u16 reg, u16 *val)
+{
+	unsigned int num_bytes = ad5706r_reg_len(reg);
+	u16 cmd;
+	int ret;
+
+	struct spi_transfer xfer[] = {
+		{
+			.tx_buf = &st->tx_buf,
+			.len = 2,
+		},
+		{
+			.rx_buf = &st->rx_buf,
+			.len = num_bytes,
+		},
+	};
+
+	cmd = AD5706R_RD_MASK | (reg & AD5706R_ADDR_MASK);
+	st->tx_buf = cpu_to_be32((u32)cmd << 16);
+
+	ret = spi_sync_transfer(st->spi, xfer, ARRAY_SIZE(xfer));
+	if (ret)
+		return ret;
+
+	*val = be16_to_cpu(st->rx_buf) >> (16 - (num_bytes * 8));
+
+	return 0;
+}
+
+static int ad5706r_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct ad5706r_state *st = iio_priv(indio_dev);
+	u16 reg_val;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		scoped_guard(mutex, &st->lock) {
+			ret = ad5706r_spi_read(st, AD5706R_REG_DAC_DATA_READBACK_CH(chan->channel),
+					       &reg_val);
+
+			if (ret)
+				return ret;
+
+			*val = reg_val;
+		}
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 50;
+		*val2 = AD5706R_DAC_RESOLUTION;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+
+	return -EINVAL;
+}
+
+static int ad5706r_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int val,
+			     int val2, long mask)
+{
+	struct ad5706r_state *st = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (val < 0 || val >= AD5706R_DAC_MAX_CODE)
+			return -EINVAL;
+
+		guard(mutex)(&st->lock);
+		return ad5706r_spi_write(st,
+					 AD5706R_REG_DAC_INPUT_A_CH(chan->channel),
+					 val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ad5706r_info = {
+	.read_raw = ad5706r_read_raw,
+	.write_raw = ad5706r_write_raw,
+};
+
+#define AD5706R_CHAN(_channel) {				\
+	.type = IIO_CURRENT,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			      BIT(IIO_CHAN_INFO_SCALE),	\
+	.output = 1,						\
+	.indexed = 1,						\
+	.channel = _channel,					\
+}
+
+static const struct iio_chan_spec ad5706r_channels[] = {
+	AD5706R_CHAN(0),
+	AD5706R_CHAN(1),
+	AD5706R_CHAN(2),
+	AD5706R_CHAN(3),
+};
+
+static int ad5706r_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct ad5706r_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+
+	ret = devm_mutex_init(&spi->dev, &st->lock);
+	if (ret)
+		return ret;
+
+	indio_dev->name = "ad5706r";
+	indio_dev->info = &ad5706r_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ad5706r_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ad5706r_channels);
+
+	return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct of_device_id ad5706r_of_match[] = {
+	{ .compatible = "adi,ad5706r" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ad5706r_of_match);
+
+static const struct spi_device_id ad5706r_id[] = {
+	{ "ad5706r", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad5706r_id);
+
+static struct spi_driver ad5706r_driver = {
+	.driver = {
+		.name = "ad5706r",
+		.of_match_table = ad5706r_of_match,
+	},
+	.probe = ad5706r_probe,
+	.id_table = ad5706r_id,
+};
+module_spi_driver(ad5706r_driver);
+
+MODULE_AUTHOR("Alexis Czezar Torreno <alexisczezar.torreno@analog.com>");
+MODULE_DESCRIPTION("AD5706R 16-bit Current Output DAC driver");
+MODULE_LICENSE("GPL");

-- 
2.34.1

On Wed, Mar 11, 2026 at 08:23:18AM +0800, Alexis Czezar Torreno wrote:
> Add support for the Analog Devices AD5706R, a 4-channel 16-bit
> current output digital-to-analog converter with SPI interface.
> 
> Features:
>   - 4 independent DAC channels
>   - Hardware and software LDAC trigger
>   - Configurable output range
>   - PWM-based LDAC control
>   - Dither and toggle modes
>   - Dynamically configurable SPI speed

...

> +#include <linux/device.h>
> +#include <linux/iio/iio.h>
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>

IWYU, please.
Yet another typical issue with ADI patches. Really, talk to your senior
colleagues who are experienced kernel developers before sending it to ML.

...

> +#define AD5706R_DAC_RESOLUTION		16
> +#define AD5706R_DAC_MAX_CODE		BIT(AD5706R_DAC_RESOLUTION)  /* 65536 */

Useless comment, use the same number explicitly instead

	BIT(16)

which is much more readable.

...

> +	st->tx_buf = cpu_to_be32((((u32)reg) << 16) |
> +			((u32)val << (16 - (num_bytes * 8))));

What the heck is this?

...

> +static const struct of_device_id ad5706r_of_match[] = {
> +	{ .compatible = "adi,ad5706r" },
> +	{ },

Even inside a single file this is inconsistent, besides being third of
101 IIO	patch issues.

> +};
> +MODULE_DEVICE_TABLE(of, ad5706r_of_match);
> +
> +static const struct spi_device_id ad5706r_id[] = {
> +	{ "ad5706r", 0 },

When there is no driver data, no need to explicitly initialise it.

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(spi, ad5706r_id);

-- 
With Best Regards,
Andy Shevchenko