[PATCH v6 0/5] Add support for AD7405/ADUM770x

[PATCH v6 0/5] Add support for AD7405/ADUM770x

[Pop Ioan Daniel]

The AD7405 is a high performance, second-order, Σ-Δ modulator
that converts an analog input signal into a high speed, single-bit
LVDS data stream, with on-chip digital isolation based on Analog
Devices, Inc., iCoupler technology. The AD7405 operates from a
4.5 V to 5.5 V (VDD1) power supply and accepts a differential input
signal of ±250 mV (±320 mV full-scale). The differential input is ideally
suited to shunt voltage monitoring in high voltage applications
where galvanic isolation is required.

MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Pop Ioan Daniel (5):
  iio: adc: ad4851: ad4851_set_oversampling_ratio parameters update
  iio: backend: update iio_backend_oversampling_ratio_set
  iio: adc: adi-axi-adc: add axi_adc_oversampling_ratio_set
  dt-bindings: iio: adc: add ad7405
  iio: adc: ad7405: add ad7405 driver

 .../bindings/iio/adc/adi,ad7405.yaml          |  60 ++++
 drivers/iio/adc/Kconfig                       |  10 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/ad4851.c                      |   6 +-
 drivers/iio/adc/ad7405.c                      | 262 ++++++++++++++++++
 drivers/iio/adc/adi-axi-adc.c                 |  20 +-
 drivers/iio/industrialio-backend.c            |   3 +-
 include/linux/iio/backend.h                   |   3 +-
 8 files changed, 359 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7405.yaml
 create mode 100644 drivers/iio/adc/ad7405.c

-- 
2.34.1

[PATCH v6 1/5] iio: adc: ad4851: ad4851_set_oversampling_ratio parameters update

[Pop Ioan Daniel]

Remove chan parameter from ad4851_set_oversampling_ratio parameters
list because the parameter is not used.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
---
no changes in v6.
 drivers/iio/adc/ad4851.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ad4851.c b/drivers/iio/adc/ad4851.c
index 98ebc853db79..12f90aa3a156 100644
--- a/drivers/iio/adc/ad4851.c
+++ b/drivers/iio/adc/ad4851.c
@@ -294,7 +294,6 @@ static int ad4851_scale_fill(struct iio_dev *indio_dev)
 }
 
 static int ad4851_set_oversampling_ratio(struct iio_dev *indio_dev,
-					 const struct iio_chan_spec *chan,
 					 unsigned int osr)
 {
 	struct ad4851_state *st = iio_priv(indio_dev);
@@ -831,7 +830,7 @@ static int ad4851_write_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_CALIBBIAS:
 		return ad4851_set_calibbias(st, chan->channel, val);
 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
-		return ad4851_set_oversampling_ratio(indio_dev, chan, val);
+		return ad4851_set_oversampling_ratio(indio_dev, val);
 	default:
 		return -EINVAL;
 	}
-- 
2.34.1

[PATCH v6 2/5] iio: backend: update iio_backend_oversampling_ratio_set

[Pop Ioan Daniel]

Add chan parameter to iio_backend_oversampling_ratio_set() to allow
for contexts where the channel must be specified. Modify all
existing users.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
---
changes in v6:
 - add blank line
 drivers/iio/adc/ad4851.c           | 3 ++-
 drivers/iio/adc/adi-axi-adc.c      | 3 ++-
 drivers/iio/industrialio-backend.c | 3 ++-
 include/linux/iio/backend.h        | 3 ++-
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/ad4851.c b/drivers/iio/adc/ad4851.c
index 12f90aa3a156..f395fa9f654a 100644
--- a/drivers/iio/adc/ad4851.c
+++ b/drivers/iio/adc/ad4851.c
@@ -320,7 +320,8 @@ static int ad4851_set_oversampling_ratio(struct iio_dev *indio_dev,
 			return ret;
 	}
 
-	ret = iio_backend_oversampling_ratio_set(st->back, osr);
+	/* Channel is ignored by the backend being used here */
+	ret = iio_backend_oversampling_ratio_set(st->back, 0, osr);
 	if (ret)
 		return ret;
 
diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 4116c44197b8..9e8c30230791 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -381,7 +381,8 @@ static int axi_adc_ad485x_data_size_set(struct iio_backend *back,
 }
 
 static int axi_adc_ad485x_oversampling_ratio_set(struct iio_backend *back,
-					  unsigned int ratio)
+						 unsigned int chan,
+						 unsigned int ratio)
 {
 	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
 
diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index c1eb9ef9db08..a4e3e54fecb1 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -720,9 +720,10 @@ EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
  * 0 on success, negative error number on failure.
  */
 int iio_backend_oversampling_ratio_set(struct iio_backend *back,
+				       unsigned int chan,
 				       unsigned int ratio)
 {
-	return iio_backend_op_call(back, oversampling_ratio_set, ratio);
+	return iio_backend_op_call(back, oversampling_ratio_set, chan, ratio);
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_oversampling_ratio_set, "IIO_BACKEND");
 
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index e59d909cb659..dbf4e4a5f4b1 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -144,7 +144,7 @@ struct iio_backend_ops {
 				  enum iio_backend_interface_type *type);
 	int (*data_size_set)(struct iio_backend *back, unsigned int size);
 	int (*oversampling_ratio_set)(struct iio_backend *back,
-				      unsigned int ratio);
+				      unsigned int chan, unsigned int ratio);
 	int (*read_raw)(struct iio_backend *back,
 			struct iio_chan_spec const *chan, int *val, int *val2,
 			long mask);
@@ -209,6 +209,7 @@ int iio_backend_interface_type_get(struct iio_backend *back,
 				   enum iio_backend_interface_type *type);
 int iio_backend_data_size_set(struct iio_backend *back, unsigned int size);
 int iio_backend_oversampling_ratio_set(struct iio_backend *back,
+				       unsigned int chan,
 				       unsigned int ratio);
 int iio_backend_read_raw(struct iio_backend *back,
 			 struct iio_chan_spec const *chan, int *val, int *val2,
-- 
2.34.1

[PATCH v6 3/5] iio: adc: adi-axi-adc: add axi_adc_oversampling_ratio_set

[Pop Ioan Daniel]

Add support for setting decimation rate.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
---
 drivers/iio/adc/adi-axi-adc.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 9e8c30230791..0b8673668745 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -80,6 +80,9 @@
 #define ADI_AXI_ADC_REG_CHAN_CTRL_3(c)		(0x0418 + (c) * 0x40)
 #define   ADI_AXI_ADC_CHAN_PN_SEL_MASK		GENMASK(19, 16)
 
+#define ADI_AXI_ADC_REG_CHAN_USR_CTRL_2(c)	(0x0424 + (c) * 0x40)
+#define   ADI_AXI_ADC_CHAN_USR_CTRL_2_DEC_RATE_N_MASK		GENMASK(15, 0)
+
 /* IO Delays */
 #define ADI_AXI_ADC_REG_DELAY(l)		(0x0800 + (l) * 0x4)
 #define   AXI_ADC_DELAY_CTRL_MASK		GENMASK(4, 0)
@@ -242,6 +245,19 @@ static int axi_adc_test_pattern_set(struct iio_backend *back,
 	}
 }
 
+static int axi_adc_oversampling_ratio_set(struct iio_backend *back,
+					  unsigned int chan,
+					  unsigned int rate)
+{
+	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+
+	return regmap_update_bits(st->regmap,
+				  ADI_AXI_ADC_REG_CHAN_USR_CTRL_2(chan),
+				  ADI_AXI_ADC_CHAN_USR_CTRL_2_DEC_RATE_N_MASK,
+				  FIELD_PREP(ADI_AXI_ADC_CHAN_USR_CTRL_2_DEC_RATE_N_MASK,
+					     rate));
+}
+
 static int axi_adc_read_chan_status(struct adi_axi_adc_state *st, unsigned int chan,
 				    unsigned int *status)
 {
@@ -550,6 +566,7 @@ static const struct iio_backend_ops adi_axi_adc_ops = {
 	.test_pattern_set = axi_adc_test_pattern_set,
 	.chan_status = axi_adc_chan_status,
 	.interface_type_get = axi_adc_interface_type_get,
+	.oversampling_ratio_set = axi_adc_oversampling_ratio_set,
 	.debugfs_reg_access = iio_backend_debugfs_ptr(axi_adc_reg_access),
 	.debugfs_print_chan_status = iio_backend_debugfs_ptr(axi_adc_debugfs_print_chan_status),
 };
-- 
2.34.1

[PATCH v6 4/5] dt-bindings: iio: adc: add ad7405

[Pop Ioan Daniel]

Add devicetree bindings for ad7405/adum770x family.

Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
---
no changes in v6.
 .../bindings/iio/adc/adi,ad7405.yaml          | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7405.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7405.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7405.yaml
new file mode 100644
index 000000000000..57f097025705
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7405.yaml
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2025 Analog Devices Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7405.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7405 family
+
+maintainers:
+  - Dragos Bogdan <dragos.bogdan@analog.com>
+  - Pop Ioan Daniel <pop.ioan-daniel@analog.com>
+
+description: |
+  Analog Devices AD7405 is a high performance isolated ADC, 1-channel,
+  16-bit with a second-order Σ-Δ modulator that converts an analog input signal
+  into a high speed, single-bit data stream.
+
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad7405.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/adum7701.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/adum7702.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ADuM7703.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7405
+      - adi,adum7701
+      - adi,adum7702
+      - adi,adum7703
+
+  clocks:
+    maxItems: 1
+
+  vdd1-supply: true
+
+  vdd2-supply: true
+
+  io-backends:
+    maxItems: 1
+
+required:
+  - compatible
+  - clocks
+  - vdd1-supply
+  - vdd2-supply
+  - io-backends
+
+additionalProperties: false
+
+examples:
+  - |
+    adc {
+        compatible = "adi,ad7405";
+        clocks = <&axi_clk_gen 0>;
+        vdd1-supply = <&vdd1>;
+        vdd2-supply = <&vdd2>;
+        io-backends = <&axi_adc>;
+    };
+...
-- 
2.34.1

Re: [PATCH v6 4/5] dt-bindings: iio: adc: add ad7405

[Krzysztof Kozlowski]

On 04/06/2025 15:34, Pop Ioan Daniel wrote:
> Add devicetree bindings for ad7405/adum770x family.
> 
> Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
> ---
> no changes in v6.
So no changes but also no previous tags?

Best regards,
Krzysztof

Re: [PATCH v6 4/5] dt-bindings: iio: adc: add ad7405

[David Lechner]

On 6/4/25 8:34 AM, Pop Ioan Daniel wrote:
> Add devicetree bindings for ad7405/adum770x family.
> 
> Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
> ---
> no changes in v6.

In previous reviews, it was requested to keep the full changelog
of all versions here. This advice applies to all patches in
all series. It makes it easier for reviewers so that we don't
have to go looking at 5 different revisions on lore to remind
us what the history was.

...

> +examples:
> +  - |
> +    adc {
> +        compatible = "adi,ad7405";
> +        clocks = <&axi_clk_gen 0>;
> +        vdd1-supply = <&vdd1>;
> +        vdd2-supply = <&vdd2>;
> +        io-backends = <&axi_adc>;

Changing this one line from :

        io-backends = <&iio_backend>;

is not really a significant change, so Krzysztof's review tag should
have been kept and would have saved him some time in making additional
reviews.

> +    };
> +...

[PATCH v6 5/5] iio: adc: ad7405: add ad7405 driver

[Pop Ioan Daniel]

Add support for the AD7405/ADUM770x, a high performance isolated ADC,
1-channel, 16-bit with a second-order Σ-Δ modulator that converts an
analog input signal into a high speed, single-bit data stream.

Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
---
changes in v6:
 - update list of headers according to IFYU principle.
 - rename ad7405_dec_rates in ad7405_dec_rates_range.
 - remove struct mutex lock.
 - update read_avail function
 - add iio_device_claim_direct()
 - rename ADI drivers for consistency
 - add comment that explain why 256 decimation rate is chosen
 drivers/iio/adc/Kconfig  |  10 ++
 drivers/iio/adc/Makefile |   1 +
 drivers/iio/adc/ad7405.c | 262 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 273 insertions(+)
 create mode 100644 drivers/iio/adc/ad7405.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index ad06cf556785..43af2070e27f 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -251,6 +251,16 @@ config AD7380
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad7380.
 
+config AD7405
+	tristate "Analog Device AD7405 ADC Driver"
+	depends on IIO_BACKEND
+	help
+	  Say yes here to build support for Analog Devices AD7405, ADUM7701,
+	  ADUM7702, ADUM7703 analog to digital converters (ADC).
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad7405.
+
 config AD7476
 	tristate "Analog Devices AD7476 1-channel ADCs driver and other similar devices from AD and TI"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 07d4b832c42e..8115f30b7862 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_AD7291) += ad7291.o
 obj-$(CONFIG_AD7292) += ad7292.o
 obj-$(CONFIG_AD7298) += ad7298.o
 obj-$(CONFIG_AD7380) += ad7380.o
+obj-$(CONFIG_AD7405) += ad7405.o
 obj-$(CONFIG_AD7476) += ad7476.o
 obj-$(CONFIG_AD7606_IFACE_PARALLEL) += ad7606_par.o
 obj-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o
diff --git a/drivers/iio/adc/ad7405.c b/drivers/iio/adc/ad7405.c
new file mode 100644
index 000000000000..a5ca61ad5150
--- /dev/null
+++ b/drivers/iio/adc/ad7405.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices AD7405 driver
+ *
+ * Copyright 2025 Analog Devices Inc.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/util_macros.h>
+
+#include <linux/iio/backend.h>
+#include <linux/iio/iio.h>
+
+static const unsigned int ad7405_dec_rates_range[] = {
+	32, 1, 4096,
+};
+
+struct ad7405_chip_info {
+	const char *name;
+	struct iio_chan_spec channel;
+	const unsigned int full_scale_mv;
+};
+
+struct ad7405_state {
+	struct iio_backend *back;
+	const struct ad7405_chip_info *info;
+	unsigned int ref_frequency;
+	unsigned int dec_rate;
+};
+
+static int ad7405_set_dec_rate(struct iio_dev *indio_dev,
+			       const struct iio_chan_spec *chan,
+			       unsigned int dec_rate)
+{
+	struct ad7405_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (!iio_device_claim_direct(indio_dev))
+		return -EBUSY;
+
+	if (dec_rate > 4096 || dec_rate < 32)
+		return -EINVAL;
+
+	ret = iio_backend_oversampling_ratio_set(st->back, chan->scan_index, dec_rate);
+	if (ret)
+		return ret;
+
+	st->dec_rate = dec_rate;
+
+	iio_device_release_direct(indio_dev);
+
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int ad7405_read_raw(struct iio_dev *indio_dev,
+			   const struct iio_chan_spec *chan, int *val,
+			   int *val2, long info)
+{
+	struct ad7405_state *st = iio_priv(indio_dev);
+
+	switch (info) {
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->info->full_scale_mv;
+		*val2 = st->info->channel.scan_type.realbits - 1;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*val = st->dec_rate;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = DIV_ROUND_CLOSEST_ULL(st->ref_frequency, st->dec_rate);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = -(1 << (st->info->channel.scan_type.realbits - 1));
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad7405_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val,
+			    int val2, long info)
+{
+	switch (info) {
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		if (val < 0)
+			return -EINVAL;
+		return ad7405_set_dec_rate(indio_dev, chan, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad7405_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     const int **vals, int *type, int *length,
+			     long info)
+{
+	switch (info) {
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*vals = ad7405_dec_rates_range;
+		*type = IIO_VAL_INT;
+		return IIO_AVAIL_RANGE;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ad7405_iio_info = {
+	.read_raw = &ad7405_read_raw,
+	.write_raw = &ad7405_write_raw,
+	.read_avail = &ad7405_read_avail,
+};
+
+#define AD7405_IIO_CHANNEL {					\
+	.type = IIO_VOLTAGE,					\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |	\
+			BIT(IIO_CHAN_INFO_OFFSET),		\
+	.info_mask_shared_by_all = IIO_CHAN_INFO_SAMP_FREQ |	\
+			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),	\
+	.info_mask_shared_by_all_available =			\
+			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),	\
+	.indexed = 1,						\
+	.channel = 0,						\
+	.channel2 = 1,						\
+	.differential = 1,					\
+	.scan_index = 0,					\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = 16,					\
+		.storagebits = 16,				\
+	},							\
+}
+
+static const struct ad7405_chip_info ad7405_chip_info = {
+	.name = "ad7405",
+	.full_scale_mv = 320,
+	.channel = AD7405_IIO_CHANNEL,
+};
+
+static const struct ad7405_chip_info adum7701_chip_info = {
+	.name = "adum7701",
+	.full_scale_mv = 320,
+	.channel = AD7405_IIO_CHANNEL,
+};
+
+static const struct ad7405_chip_info adum7702_chip_info = {
+	.name = "adum7702",
+	.full_scale_mv = 64,
+	.channel = AD7405_IIO_CHANNEL,
+};
+
+static const struct ad7405_chip_info adum7703_chip_info = {
+	.name = "adum7703",
+	.full_scale_mv = 320,
+	.channel = AD7405_IIO_CHANNEL,
+};
+
+static const char * const ad7405_power_supplies[] = {
+	"vdd1",	"vdd2",
+};
+
+static int ad7405_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct iio_dev *indio_dev;
+	struct ad7405_state *st;
+	struct clk *clk;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	st->info = device_get_match_data(dev);
+	if (!st->info)
+		return dev_err_probe(dev, -EINVAL, "no chip info\n");
+
+	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad7405_power_supplies),
+					     ad7405_power_supplies);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get and enable supplies");
+
+	clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	st->ref_frequency = clk_get_rate(clk);
+	if (!st->ref_frequency)
+		return -EINVAL;
+
+	indio_dev->name = st->info->name;
+	indio_dev->channels = &st->info->channel;
+	indio_dev->num_channels = 1;
+	indio_dev->info = &ad7405_iio_info;
+
+	st->back = devm_iio_backend_get(dev, NULL);
+	if (IS_ERR(st->back))
+		return dev_err_probe(dev, PTR_ERR(st->back),
+				     "failed to get IIO backend");
+
+	ret = iio_backend_chan_enable(st->back, 0);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_backend_enable(dev, st->back);
+	if (ret)
+		return ret;
+
+	/*
+	 *Set 256 decimation rate. The default value in the AXI_ADC register
+	 *is 0, so we set the register with a decimation rate value that is
+	 *functional for all parts.
+	 */
+	ret = ad7405_set_dec_rate(indio_dev, &indio_dev->channels[0], 256);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id ad7405_of_match[] = {
+	{ .compatible = "adi,ad7405", .data = &ad7405_chip_info, },
+	{ .compatible = "adi,adum7701", .data = &adum7701_chip_info, },
+	{ .compatible = "adi,adum7702", .data = &adum7702_chip_info, },
+	{ .compatible = "adi,adum7703", .data = &adum7703_chip_info, },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad7405_of_match);
+
+static struct platform_driver ad7405_driver = {
+	.driver = {
+		.name = "ad7405",
+		.owner = THIS_MODULE,
+		.of_match_table = ad7405_of_match,
+	},
+	.probe = ad7405_probe,
+};
+module_platform_driver(ad7405_driver);
+
+MODULE_AUTHOR("Dragos Bogdan <dragos.bogdan@analog.com>");
+MODULE_AUTHOR("Pop Ioan Daniel <pop.ioan-daniel@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7405 driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("IIO_BACKEND");
-- 
2.34.1

Re: [PATCH v6 5/5] iio: adc: ad7405: add ad7405 driver

[Andy Shevchenko]

On Wed, Jun 04, 2025 at 04:34:07PM +0300, Pop Ioan Daniel wrote:
> Add support for the AD7405/ADUM770x, a high performance isolated ADC,
> 1-channel, 16-bit with a second-order Σ-Δ modulator that converts an
> analog input signal into a high speed, single-bit data stream.

Hmm...
Have you seen these?

https://lore.kernel.org/linux-iio/20250602134349.1930891-1-pop.ioan-daniel@analog.com/T/#m114842887de000752231d69bc0939445b8720382

https://lore.kernel.org/linux-iio/20250602134349.1930891-1-pop.ioan-daniel@analog.com/T/#m2d90d77cd4fb1444c0c51e006b53d82ab33c27ac

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH v6 5/5] iio: adc: ad7405: add ad7405 driver

[Ioan-daniel, Pop]

> 
> On Wed, Jun 04, 2025 at 04:34:07PM +0300, Pop Ioan Daniel wrote:
> > Add support for the AD7405/ADUM770x, a high performance isolated ADC,
> > 1-channel, 16-bit with a second-order Σ-Δ modulator that converts an
> > analog input signal into a high speed, single-bit data stream.
> 
> Hmm...
> Have you seen these?

Hi! 
Just a question for my clarification. 
Except for comment from David Lechner, what should I do in the
next patch that is different from this patch regarding your requests?
...

Re: [PATCH v6 5/5] iio: adc: ad7405: add ad7405 driver

[Andy Shevchenko]

On Thu, Jun 05, 2025 at 01:42:50PM +0000, Ioan-daniel, Pop wrote:
> 
> > On Wed, Jun 04, 2025 at 04:34:07PM +0300, Pop Ioan Daniel wrote:
> > > Add support for the AD7405/ADUM770x, a high performance isolated ADC,
> > > 1-channel, 16-bit with a second-order Σ-Δ modulator that converts an
> > > analog input signal into a high speed, single-bit data stream.
> > 
> > Hmm...
> > Have you seen these?
> 
> Just a question for my clarification. 
> Except for comment from David Lechner, what should I do in the
> next patch that is different from this patch regarding your requests?

I believe those are generic advice, use them in any code you submit.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v6 5/5] iio: adc: ad7405: add ad7405 driver

[David Lechner]

On 6/4/25 8:34 AM, Pop Ioan Daniel wrote:
> Add support for the AD7405/ADUM770x, a high performance isolated ADC,
> 1-channel, 16-bit with a second-order Σ-Δ modulator that converts an
> analog input signal into a high speed, single-bit data stream.
> 
> Signed-off-by: Pop Ioan Daniel <pop.ioan-daniel@analog.com>
> ---

...

> diff --git a/drivers/iio/adc/ad7405.c b/drivers/iio/adc/ad7405.c
> new file mode 100644
> index 000000000000..a5ca61ad5150
> --- /dev/null
> +++ b/drivers/iio/adc/ad7405.c
> @@ -0,0 +1,262 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Analog Devices AD7405 driver
> + *
> + * Copyright 2025 Analog Devices Inc.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/kernel.h>

Maybe it wasn't clear in previous reviews, but we like to avoid including
kernel.h because it includes too much, so should be replaced with ofher
more specific headers.

> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/util_macros.h>
> +

...

> +
> +static int ad7405_set_dec_rate(struct iio_dev *indio_dev,
> +			       const struct iio_chan_spec *chan,
> +			       unsigned int dec_rate)
> +{
> +	struct ad7405_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	if (!iio_device_claim_direct(indio_dev))
> +		return -EBUSY;
> +
> +	if (dec_rate > 4096 || dec_rate < 32)
> +		return -EINVAL;
> +
> +	ret = iio_backend_oversampling_ratio_set(st->back, chan->scan_index, dec_rate);
> +	if (ret)
> +		return ret;
> +
> +	st->dec_rate = dec_rate;
> +
> +	iio_device_release_direct(indio_dev);

iio_device_release_direct() needs to always be called before returning
after iio_backend_oversampling_ratio_set() is called. So this function
needs some reordering.

It should look like:

	if (!iio_device_claim_direct(indio_dev))
		return -EBUSY;

	ret = iio_backend_oversampling_ratio_set(st->back, chan->scan_index, dec_rate);
	iio_device_release_direct(indio_dev);

With everything else before or after that.

Or move the claim/realease to ad7405_write_raw() so that the entire call
to ad7405_set_dec_rate() is syncronized.

> +
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +

...

> +static int ad7405_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct iio_dev *indio_dev;
> +	struct ad7405_state *st;
> +	struct clk *clk;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +
> +	st->info = device_get_match_data(dev);
> +	if (!st->info)
> +		return dev_err_probe(dev, -EINVAL, "no chip info\n");
> +
> +	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad7405_power_supplies),
> +					     ad7405_power_supplies);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to get and enable supplies");
> +
> +	clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	st->ref_frequency = clk_get_rate(clk);
> +	if (!st->ref_frequency)
> +		return -EINVAL;
> +
> +	indio_dev->name = st->info->name;
> +	indio_dev->channels = &st->info->channel;
> +	indio_dev->num_channels = 1;
> +	indio_dev->info = &ad7405_iio_info;
> +
> +	st->back = devm_iio_backend_get(dev, NULL);
> +	if (IS_ERR(st->back))
> +		return dev_err_probe(dev, PTR_ERR(st->back),
> +				     "failed to get IIO backend");
> +
> +	ret = iio_backend_chan_enable(st->back, 0);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_backend_enable(dev, st->back);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 *Set 256 decimation rate. The default value in the AXI_ADC register

Add space after * to match IIO comment style.

> +	 *is 0, so we set the register with a decimation rate value that is
> +	 *functional for all parts.
> +	 */
> +	ret = ad7405_set_dec_rate(indio_dev, &indio_dev->channels[0], 256);
> +	if (ret)
> +		return ret;
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}