[PATCH v12 0/9] Add support for AD485x DAS Family

[PATCH v12 0/9] Add support for AD485x DAS Family

[Antoniu Miclaus]

Add support for AD485X fully buffered, 8-channel simultaneous sampling,
16/20-bit, 1 MSPS data acquisition system (DAS) with differential, wide
common-mode range inputs.

Most of the review comments which make sense in v9 were addressed. Some of them
might have been ommitted, especially those that are a matter of preference.
Since we reached v10, I tried to cover everything that was pointed out until now.

Antoniu Miclaus (9):
  iio: backend: add API for interface get
  iio: backend: add support for data size set
  iio: backend: add API for oversampling
  iio: adc: adi-axi-adc: add interface type
  dt-bindings: iio: adc: add ad485x axi variant
  iio: adc: adi-axi-adc: set data format
  iio: adc: adi-axi-adc: add oversampling
  dt-bindings: iio: adc: add ad4851
  iio: adc: ad4851: add ad485x driver

 .../bindings/iio/adc/adi,ad4851.yaml          |  153 ++
 .../bindings/iio/adc/adi,axi-adc.yaml         |    2 +
 drivers/iio/adc/Kconfig                       |   14 +
 drivers/iio/adc/Makefile                      |    1 +
 drivers/iio/adc/ad4851.c                      | 1316 +++++++++++++++++
 drivers/iio/adc/adi-axi-adc.c                 |  146 +-
 drivers/iio/industrialio-backend.c            |   60 +
 include/linux/iio/backend.h                   |   19 +
 8 files changed, 1702 insertions(+), 9 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad4851.yaml
 create mode 100644 drivers/iio/adc/ad4851.c

-- 
2.48.1

[PATCH v12 1/9] iio: backend: add API for interface get

[Antoniu Miclaus]

Add backend support for obtaining the interface type used.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v12.
 drivers/iio/industrialio-backend.c | 24 ++++++++++++++++++++++++
 include/linux/iio/backend.h        | 11 +++++++++++
 2 files changed, 35 insertions(+)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index 363281272035..8bf3d570da1b 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -636,6 +636,30 @@ ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private,
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_ext_info_set, "IIO_BACKEND");
 
+/**
+ * iio_backend_interface_type_get - get the interface type used.
+ * @back: Backend device
+ * @type: Interface type
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_interface_type_get(struct iio_backend *back,
+				   enum iio_backend_interface_type *type)
+{
+	int ret;
+
+	ret = iio_backend_op_call(back, interface_type_get, type);
+	if (ret)
+		return ret;
+
+	if (*type >= IIO_BACKEND_INTERFACE_MAX)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_interface_type_get, "IIO_BACKEND");
+
 /**
  * iio_backend_extend_chan_spec - Extend an IIO channel
  * @back: Backend device
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index 10be00f3b120..a0ea6c29d7ba 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -70,6 +70,12 @@ enum iio_backend_sample_trigger {
 	IIO_BACKEND_SAMPLE_TRIGGER_MAX
 };
 
+enum iio_backend_interface_type {
+	IIO_BACKEND_INTERFACE_SERIAL_LVDS,
+	IIO_BACKEND_INTERFACE_SERIAL_CMOS,
+	IIO_BACKEND_INTERFACE_MAX
+};
+
 /**
  * struct iio_backend_ops - operations structure for an iio_backend
  * @enable: Enable backend.
@@ -88,6 +94,7 @@ enum iio_backend_sample_trigger {
  * @extend_chan_spec: Extend an IIO channel.
  * @ext_info_set: Extended info setter.
  * @ext_info_get: Extended info getter.
+ * @interface_type_get: Interface type.
  * @read_raw: Read a channel attribute from a backend device
  * @debugfs_print_chan_status: Print channel status into a buffer.
  * @debugfs_reg_access: Read or write register value of backend.
@@ -128,6 +135,8 @@ struct iio_backend_ops {
 			    const char *buf, size_t len);
 	int (*ext_info_get)(struct iio_backend *back, uintptr_t private,
 			    const struct iio_chan_spec *chan, char *buf);
+	int (*interface_type_get)(struct iio_backend *back,
+				  enum iio_backend_interface_type *type);
 	int (*read_raw)(struct iio_backend *back,
 			struct iio_chan_spec const *chan, int *val, int *val2,
 			long mask);
@@ -186,6 +195,8 @@ ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private,
 				 const char *buf, size_t len);
 ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
 				 const struct iio_chan_spec *chan, char *buf);
+int iio_backend_interface_type_get(struct iio_backend *back,
+				   enum iio_backend_interface_type *type);
 int iio_backend_read_raw(struct iio_backend *back,
 			 struct iio_chan_spec const *chan, int *val, int *val2,
 			 long mask);
-- 
2.48.1

[PATCH v12 2/9] iio: backend: add support for data size set

[Antoniu Miclaus]

Add backend support for setting the data size used.
This setting can be adjusted within the IP cores interfacing devices.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v12.
 drivers/iio/industrialio-backend.c | 21 +++++++++++++++++++++
 include/linux/iio/backend.h        |  3 +++
 2 files changed, 24 insertions(+)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index 8bf3d570da1b..2088afa7a55c 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -660,6 +660,27 @@ int iio_backend_interface_type_get(struct iio_backend *back,
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_interface_type_get, "IIO_BACKEND");
 
+/**
+ * iio_backend_data_size_set - set the data width/size in the data bus.
+ * @back: Backend device
+ * @size: Size in bits
+ *
+ * Some frontend devices can dynamically control the word/data size on the
+ * interface/data bus. Hence, the backend device needs to be aware of it so
+ * data can be correctly transferred.
+ *
+ * Return:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_size_set(struct iio_backend *back, unsigned int size)
+{
+	if (!size)
+		return -EINVAL;
+
+	return iio_backend_op_call(back, data_size_set, size);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
+
 /**
  * iio_backend_extend_chan_spec - Extend an IIO channel
  * @back: Backend device
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index a0ea6c29d7ba..9ae861a21472 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -95,6 +95,7 @@ enum iio_backend_interface_type {
  * @ext_info_set: Extended info setter.
  * @ext_info_get: Extended info getter.
  * @interface_type_get: Interface type.
+ * @data_size_set: Data size.
  * @read_raw: Read a channel attribute from a backend device
  * @debugfs_print_chan_status: Print channel status into a buffer.
  * @debugfs_reg_access: Read or write register value of backend.
@@ -137,6 +138,7 @@ struct iio_backend_ops {
 			    const struct iio_chan_spec *chan, char *buf);
 	int (*interface_type_get)(struct iio_backend *back,
 				  enum iio_backend_interface_type *type);
+	int (*data_size_set)(struct iio_backend *back, unsigned int size);
 	int (*read_raw)(struct iio_backend *back,
 			struct iio_chan_spec const *chan, int *val, int *val2,
 			long mask);
@@ -197,6 +199,7 @@ ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
 				 const struct iio_chan_spec *chan, char *buf);
 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_read_raw(struct iio_backend *back,
 			 struct iio_chan_spec const *chan, int *val, int *val2,
 			 long mask);
-- 
2.48.1

[PATCH v12 3/9] iio: backend: add API for oversampling

[Antoniu Miclaus]

Add backend support for setting oversampling ratio.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v12.
 drivers/iio/industrialio-backend.c | 15 +++++++++++++++
 include/linux/iio/backend.h        |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index 2088afa7a55c..d4ad36f54090 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -681,6 +681,21 @@ int iio_backend_data_size_set(struct iio_backend *back, unsigned int size)
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
 
+/**
+ * iio_backend_oversampling_ratio_set - set the oversampling ratio
+ * @back: Backend device
+ * @ratio: The oversampling ratio - value 1 corresponds to no oversampling.
+ *
+ * Return:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_oversampling_ratio_set(struct iio_backend *back,
+				       unsigned int ratio)
+{
+	return iio_backend_op_call(back, oversampling_ratio_set, ratio);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_oversampling_ratio_set, "IIO_BACKEND");
+
 /**
  * iio_backend_extend_chan_spec - Extend an IIO channel
  * @back: Backend device
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index 9ae861a21472..e45b7dfbec35 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -96,6 +96,7 @@ enum iio_backend_interface_type {
  * @ext_info_get: Extended info getter.
  * @interface_type_get: Interface type.
  * @data_size_set: Data size.
+ * @oversampling_ratio_set: Set Oversampling ratio.
  * @read_raw: Read a channel attribute from a backend device
  * @debugfs_print_chan_status: Print channel status into a buffer.
  * @debugfs_reg_access: Read or write register value of backend.
@@ -139,6 +140,8 @@ struct iio_backend_ops {
 	int (*interface_type_get)(struct iio_backend *back,
 				  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);
 	int (*read_raw)(struct iio_backend *back,
 			struct iio_chan_spec const *chan, int *val, int *val2,
 			long mask);
@@ -200,6 +203,8 @@ ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
 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 ratio);
 int iio_backend_read_raw(struct iio_backend *back,
 			 struct iio_chan_spec const *chan, int *val, int *val2,
 			 long mask);
-- 
2.48.1

[PATCH v12 4/9] iio: adc: adi-axi-adc: add interface type

[Antoniu Miclaus]

Add support for getting the interface (CMOS or LVDS) used by the AXI ADC
IP.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v12.
 drivers/iio/adc/adi-axi-adc.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index c7357601f0f8..d2e1dc63775c 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -39,6 +39,9 @@
 #define   ADI_AXI_REG_RSTN_MMCM_RSTN		BIT(1)
 #define   ADI_AXI_REG_RSTN_RSTN			BIT(0)
 
+#define ADI_AXI_ADC_REG_CONFIG			0x000c
+#define   ADI_AXI_ADC_REG_CONFIG_CMOS_OR_LVDS_N	BIT(7)
+
 #define ADI_AXI_ADC_REG_CTRL			0x0044
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
 
@@ -290,6 +293,25 @@ static int axi_adc_chan_disable(struct iio_backend *back, unsigned int chan)
 				 ADI_AXI_REG_CHAN_CTRL_ENABLE);
 }
 
+static int axi_adc_interface_type_get(struct iio_backend *back,
+				      enum iio_backend_interface_type *type)
+{
+	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(st->regmap, ADI_AXI_ADC_REG_CONFIG, &val);
+	if (ret)
+		return ret;
+
+	if (val & ADI_AXI_ADC_REG_CONFIG_CMOS_OR_LVDS_N)
+		*type = IIO_BACKEND_INTERFACE_SERIAL_CMOS;
+	else
+		*type = IIO_BACKEND_INTERFACE_SERIAL_LVDS;
+
+	return 0;
+}
+
 static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
 						 struct iio_dev *indio_dev)
 {
@@ -337,6 +359,7 @@ static const struct iio_backend_ops adi_axi_adc_ops = {
 	.iodelay_set = axi_adc_iodelays_set,
 	.test_pattern_set = axi_adc_test_pattern_set,
 	.chan_status = axi_adc_chan_status,
+	.interface_type_get = axi_adc_interface_type_get,
 	.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),
 };
-- 
2.48.1

[PATCH v12 5/9] dt-bindings: iio: adc: add ad485x axi variant

[Antoniu Miclaus]

Add a new compatible and related bindings for the fpga-based
AD485x AXI IP core, a variant of the generic AXI ADC IP.

The AXI AD485x IP is a very similar HDL (fpga) variant of the
generic AXI ADC IP, intended to control ad485x familiy.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
 Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml b/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
index e1f450b80db2..f1b470f74069 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
@@ -19,11 +19,13 @@ description: |
   memory via DMA.
 
   https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
+  https://analogdevicesinc.github.io/hdl/library/axi_ad485x/index.html
 
 properties:
   compatible:
     enum:
       - adi,axi-adc-10.0.a
+      - adi,axi-ad485x
 
   reg:
     maxItems: 1
-- 
2.48.1

Re: [PATCH v12 5/9] dt-bindings: iio: adc: add ad485x axi variant

[Jonathan Cameron]

On Fri, 7 Feb 2025 16:09:14 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add a new compatible and related bindings for the fpga-based
> AD485x AXI IP core, a variant of the generic AXI ADC IP.
> 
> The AXI AD485x IP is a very similar HDL (fpga) variant of the
> generic AXI ADC IP, intended to control ad485x familiy.

Hmm. Should we name this after a specific part? Very unlikely
the wildcard will go wrong here because of how specific this
binding is anyway but we should perhaps stick to normal rules
of no wild cards.

> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
>  Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml b/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
> index e1f450b80db2..f1b470f74069 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
> @@ -19,11 +19,13 @@ description: |
>    memory via DMA.
>  
>    https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
> +  https://analogdevicesinc.github.io/hdl/library/axi_ad485x/index.html
>  
>  properties:
>    compatible:
>      enum:
>        - adi,axi-adc-10.0.a
> +      - adi,axi-ad485x
>  
>    reg:
>      maxItems: 1

Re: [PATCH v12 5/9] dt-bindings: iio: adc: add ad485x axi variant

[Krzysztof Kozlowski]

On Sat, Feb 08, 2025 at 04:20:58PM +0000, Jonathan Cameron wrote:
> On Fri, 7 Feb 2025 16:09:14 +0200
> Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:
> 
> > Add a new compatible and related bindings for the fpga-based
> > AD485x AXI IP core, a variant of the generic AXI ADC IP.
> > 
> > The AXI AD485x IP is a very similar HDL (fpga) variant of the
> > generic AXI ADC IP, intended to control ad485x familiy.
> 
> Hmm. Should we name this after a specific part? Very unlikely
> the wildcard will go wrong here because of how specific this
> binding is anyway but we should perhaps stick to normal rules
> of no wild cards.

I am pretty sure we had this discussion about this or other block
already and we reached some sort of concensus... which is undocumented
in commit msg, so we are doomed to repeat the discussion.

Best regards,
Krzysztof

Re: [PATCH v12 5/9] dt-bindings: iio: adc: add ad485x axi variant

[Jonathan Cameron]

On Tue, 11 Feb 2025 09:16:31 +0100
Krzysztof Kozlowski <krzk@kernel.org> wrote:

> On Sat, Feb 08, 2025 at 04:20:58PM +0000, Jonathan Cameron wrote:
> > On Fri, 7 Feb 2025 16:09:14 +0200
> > Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:
> >   
> > > Add a new compatible and related bindings for the fpga-based
> > > AD485x AXI IP core, a variant of the generic AXI ADC IP.
> > > 
> > > The AXI AD485x IP is a very similar HDL (fpga) variant of the
> > > generic AXI ADC IP, intended to control ad485x familiy.  
> > 
> > Hmm. Should we name this after a specific part? Very unlikely
> > the wildcard will go wrong here because of how specific this
> > binding is anyway but we should perhaps stick to normal rules
> > of no wild cards.  
> 
> I am pretty sure we had this discussion about this or other block
> already and we reached some sort of concensus... which is undocumented
> in commit msg, so we are doomed to repeat the discussion.
> 
Having just seen similar the axi-ad7606x support. I think the key bit
I was missing here is that ADI has published the firmware under the
name with wild card. If they shoot themselves in the foot in future
then fair enough.  I'm fine with the wild card though a statement
in the commit to make me notice that detail would have been great!

Jonathan

> Best regards,
> Krzysztof
> 

[PATCH v12 6/9] iio: adc: adi-axi-adc: set data format

[Antoniu Miclaus]

Add support for selecting the data format within the AXI ADC ip.

Add separate complatible string for the custom AD485X IP and implement
the necessary changes.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
changes in v12:
 - add separate compatible for ad485x AXI IP core.
 drivers/iio/adc/adi-axi-adc.c | 99 +++++++++++++++++++++++++++++++----
 1 file changed, 90 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index d2e1dc63775c..272d82c6e887 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -45,6 +45,12 @@
 #define ADI_AXI_ADC_REG_CTRL			0x0044
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
 
+#define ADI_AXI_ADC_REG_CNTRL_3			0x004c
+#define   AD485X_CNTRL_3_PACKET_FORMAT_MSK	GENMASK(1, 0)
+#define   AD485X_PACKET_FORMAT_20BIT		0x0
+#define   AD485X_PACKET_FORMAT_24BIT		0x1
+#define   AD485X_PACKET_FORMAT_32BIT		0x2
+
 #define ADI_AXI_ADC_REG_DRP_STATUS		0x0074
 #define   ADI_AXI_ADC_DRP_LOCKED		BIT(17)
 
@@ -83,11 +89,17 @@
 	 ADI_AXI_REG_CHAN_CTRL_FMT_EN |		\
 	 ADI_AXI_REG_CHAN_CTRL_ENABLE)
 
+struct axi_adc_info {
+	unsigned int version;
+	const struct iio_backend_info *backend_info;
+};
+
 struct adi_axi_adc_state {
 	struct regmap *regmap;
 	struct device *dev;
 	/* lock to protect multiple accesses to the device registers */
 	struct mutex lock;
+	const struct axi_adc_info *info;
 };
 
 static int axi_adc_enable(struct iio_backend *back)
@@ -312,6 +324,45 @@ static int axi_adc_interface_type_get(struct iio_backend *back,
 	return 0;
 }
 
+static int axi_adc_data_size_set(struct iio_backend *back, unsigned int size)
+{
+	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+	unsigned int val;
+
+	switch (size) {
+	/*
+	 * There are two different variants of the AXI AD485X IP block, a 16-bit
+	 * and a 20-bit variant.
+	 * The 0x0 value (AD485X_PACKET_FORMAT_20BIT) is corresponding also to
+	 * the 16-bit variant of the IP block.
+	 */
+	case 16:
+	case 20:
+		val = AD485X_PACKET_FORMAT_20BIT;
+		break;
+	case 24:
+		val = AD485X_PACKET_FORMAT_24BIT;
+		break;
+	/*
+	 * The 0x2 (AD485X_PACKET_FORMAT_32BIT) corresponds only to the 20-bit
+	 * variant of the IP block. Setting this value properly is ensured by
+	 * the upper layers of the drivers calling the axi-adc functions.
+	 * Also, for 16-bit IP block, the 0x2 (AD485X_PACKET_FORMAT_32BIT)
+	 * value is handled as maximum size available which is 24-bit for this
+	 * configuration.
+	 */
+	case 32:
+		val = AD485X_PACKET_FORMAT_32BIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return regmap_update_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+				  AD485X_CNTRL_3_PACKET_FORMAT_MSK,
+				  FIELD_PREP(AD485X_CNTRL_3_PACKET_FORMAT_MSK, val));
+}
+
 static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
 						 struct iio_dev *indio_dev)
 {
@@ -364,14 +415,35 @@ static const struct iio_backend_ops adi_axi_adc_ops = {
 	.debugfs_print_chan_status = iio_backend_debugfs_ptr(axi_adc_debugfs_print_chan_status),
 };
 
+static const struct iio_backend_ops adi_ad485x_ops = {
+	.enable = axi_adc_enable,
+	.disable = axi_adc_disable,
+	.data_format_set = axi_adc_data_format_set,
+	.chan_enable = axi_adc_chan_enable,
+	.chan_disable = axi_adc_chan_disable,
+	.request_buffer = axi_adc_request_buffer,
+	.free_buffer = axi_adc_free_buffer,
+	.data_sample_trigger = axi_adc_data_sample_trigger,
+	.iodelay_set = axi_adc_iodelays_set,
+	.chan_status = axi_adc_chan_status,
+	.interface_type_get = axi_adc_interface_type_get,
+	.data_size_set = axi_adc_data_size_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),
+};
+
 static const struct iio_backend_info adi_axi_adc_generic = {
 	.name = "axi-adc",
 	.ops = &adi_axi_adc_ops,
 };
 
+static const struct iio_backend_info axi_ad485x = {
+	.name = "axi-ad485x",
+	.ops = &adi_ad485x_ops,
+};
+
 static int adi_axi_adc_probe(struct platform_device *pdev)
 {
-	const unsigned int *expected_ver;
 	struct adi_axi_adc_state *st;
 	void __iomem *base;
 	unsigned int ver;
@@ -393,8 +465,8 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(st->regmap),
 				     "failed to init register map\n");
 
-	expected_ver = device_get_match_data(&pdev->dev);
-	if (!expected_ver)
+	st->info = device_get_match_data(&pdev->dev);
+	if (!st->info)
 		return -ENODEV;
 
 	clk = devm_clk_get_enabled(&pdev->dev, NULL);
@@ -414,19 +486,19 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	if (ADI_AXI_PCORE_VER_MAJOR(ver) != ADI_AXI_PCORE_VER_MAJOR(*expected_ver)) {
+	if (ADI_AXI_PCORE_VER_MAJOR(ver) != ADI_AXI_PCORE_VER_MAJOR(st->info->version)) {
 		dev_err(&pdev->dev,
 			"Major version mismatch. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
-			ADI_AXI_PCORE_VER_MAJOR(*expected_ver),
-			ADI_AXI_PCORE_VER_MINOR(*expected_ver),
-			ADI_AXI_PCORE_VER_PATCH(*expected_ver),
+			ADI_AXI_PCORE_VER_MAJOR(st->info->version),
+			ADI_AXI_PCORE_VER_MINOR(st->info->version),
+			ADI_AXI_PCORE_VER_PATCH(st->info->version),
 			ADI_AXI_PCORE_VER_MAJOR(ver),
 			ADI_AXI_PCORE_VER_MINOR(ver),
 			ADI_AXI_PCORE_VER_PATCH(ver));
 		return -ENODEV;
 	}
 
-	ret = devm_iio_backend_register(&pdev->dev, &adi_axi_adc_generic, st);
+	ret = devm_iio_backend_register(&pdev->dev,  st->info->backend_info, st);
 	if (ret)
 		return dev_err_probe(&pdev->dev, ret,
 				     "failed to register iio backend\n");
@@ -439,11 +511,20 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static unsigned int adi_axi_adc_10_0_a_info = ADI_AXI_PCORE_VER(10, 0, 'a');
+static const struct axi_adc_info adi_axi_adc_10_0_a_info = {
+	.version = ADI_AXI_PCORE_VER(10, 0, 'a'),
+	.backend_info = &adi_axi_adc_generic,
+};
+
+static const struct axi_adc_info adi_axi_ad485x = {
+	.version = ADI_AXI_PCORE_VER(10, 0, 'a'),
+	.backend_info = &axi_ad485x,
+};
 
 /* Match table for of_platform binding */
 static const struct of_device_id adi_axi_adc_of_match[] = {
 	{ .compatible = "adi,axi-adc-10.0.a", .data = &adi_axi_adc_10_0_a_info },
+	{ .compatible = "adi,axi-ad485x", .data = &adi_axi_ad485x },
 	{ /* end of list */ }
 };
 MODULE_DEVICE_TABLE(of, adi_axi_adc_of_match);
-- 
2.48.1

Re: [PATCH v12 6/9] iio: adc: adi-axi-adc: set data format

[David Lechner]

On 2/7/25 8:09 AM, Antoniu Miclaus wrote:
> Add support for selecting the data format within the AXI ADC ip.
> 
> Add separate complatible string for the custom AD485X IP and implement
> the necessary changes.
> 
> Reviewed-by: Nuno Sa <nuno.sa@analog.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---

...

> @@ -312,6 +324,45 @@ static int axi_adc_interface_type_get(struct iio_backend *back,
>  	return 0;
>  }
>  
> +static int axi_adc_data_size_set(struct iio_backend *back, unsigned int size)

This function only applies to AD485X so would be nice to have _ad485x_ in the
function name.

Re: [PATCH v12 6/9] iio: adc: adi-axi-adc: set data format

[Jonathan Cameron]

On Fri, 7 Feb 2025 16:09:15 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add support for selecting the data format within the AXI ADC ip.
> 
> Add separate complatible string for the custom AD485X IP and implement
> the necessary changes.
> 
> Reviewed-by: Nuno Sa <nuno.sa@analog.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
> changes in v12:
>  - add separate compatible for ad485x AXI IP core.
>  drivers/iio/adc/adi-axi-adc.c | 99 +++++++++++++++++++++++++++++++----
>  1 file changed, 90 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
> index d2e1dc63775c..272d82c6e887 100644
> --- a/drivers/iio/adc/adi-axi-adc.c
> +++ b/drivers/iio/adc/adi-axi-adc.c
> @@ -45,6 +45,12 @@
>  #define ADI_AXI_ADC_REG_CTRL			0x0044
>  #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
>  
> +#define ADI_AXI_ADC_REG_CNTRL_3			0x004c
> +#define   AD485X_CNTRL_3_PACKET_FORMAT_MSK	GENMASK(1, 0)
Sorry I missed this until now, but normal IIO thing is no wild cards
in naming (been bitten too often!)

So I'd like to see these named after a specific part.

Re: [PATCH v12 6/9] iio: adc: adi-axi-adc: set data format

[Jonathan Cameron]

On Sat, 8 Feb 2025 16:22:09 +0000
Jonathan Cameron <jic23@kernel.org> wrote:

> On Fri, 7 Feb 2025 16:09:15 +0200
> Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:
> 
> > Add support for selecting the data format within the AXI ADC ip.
> > 
> > Add separate complatible string for the custom AD485X IP and implement
> > the necessary changes.
> > 
> > Reviewed-by: Nuno Sa <nuno.sa@analog.com>
> > Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> > ---
> > changes in v12:
> >  - add separate compatible for ad485x AXI IP core.
> >  drivers/iio/adc/adi-axi-adc.c | 99 +++++++++++++++++++++++++++++++----
> >  1 file changed, 90 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
> > index d2e1dc63775c..272d82c6e887 100644
> > --- a/drivers/iio/adc/adi-axi-adc.c
> > +++ b/drivers/iio/adc/adi-axi-adc.c
> > @@ -45,6 +45,12 @@
> >  #define ADI_AXI_ADC_REG_CTRL			0x0044
> >  #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
> >  
> > +#define ADI_AXI_ADC_REG_CNTRL_3			0x004c
> > +#define   AD485X_CNTRL_3_PACKET_FORMAT_MSK	GENMASK(1, 0)  
> Sorry I missed this until now, but normal IIO thing is no wild cards
> in naming (been bitten too often!)
> 
> So I'd like to see these named after a specific part.
Having realized this is named after the IP naming (which
indeed uses the wild card), maybe we could
prefix with AXI_ perhaps to make that association more obvious?


> 
> 
> 
> 

[PATCH v12 7/9] iio: adc: adi-axi-adc: add oversampling

[Antoniu Miclaus]

Add support for enabling/disabling oversampling.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v12.
 drivers/iio/adc/adi-axi-adc.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 272d82c6e887..872ff51e08a7 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -46,6 +46,7 @@
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
 
 #define ADI_AXI_ADC_REG_CNTRL_3			0x004c
+#define   AD485X_CNTRL_3_OS_EN_MSK		BIT(2)
 #define   AD485X_CNTRL_3_PACKET_FORMAT_MSK	GENMASK(1, 0)
 #define   AD485X_PACKET_FORMAT_20BIT		0x0
 #define   AD485X_PACKET_FORMAT_24BIT		0x1
@@ -363,6 +364,28 @@ static int axi_adc_data_size_set(struct iio_backend *back, unsigned int size)
 				  FIELD_PREP(AD485X_CNTRL_3_PACKET_FORMAT_MSK, val));
 }
 
+static int axi_adc_oversampling_ratio_set(struct iio_backend *back,
+					  unsigned int ratio)
+{
+	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+
+	/* The current state of the function enables or disables the
+	 * oversampling in REG_CNTRL_3 register. A ratio equal to 1 implies no
+	 * oversampling, while a value greater than 1 implies oversampling being
+	 * enabled.
+	 */
+	switch (ratio) {
+	case 0:
+		return -EINVAL;
+	case 1:
+		return regmap_clear_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+					 AD485X_CNTRL_3_OS_EN_MSK);
+	default:
+		return regmap_set_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+				       AD485X_CNTRL_3_OS_EN_MSK);
+	}
+}
+
 static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
 						 struct iio_dev *indio_dev)
 {
@@ -428,6 +451,7 @@ static const struct iio_backend_ops adi_ad485x_ops = {
 	.chan_status = axi_adc_chan_status,
 	.interface_type_get = axi_adc_interface_type_get,
 	.data_size_set = axi_adc_data_size_set,
+	.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),
 };
-- 
2.48.1

Re: [PATCH v12 7/9] iio: adc: adi-axi-adc: add oversampling

[Jonathan Cameron]

On Fri, 7 Feb 2025 16:09:16 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add support for enabling/disabling oversampling.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
> no changes in v12.
>  drivers/iio/adc/adi-axi-adc.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
> index 272d82c6e887..872ff51e08a7 100644
> --- a/drivers/iio/adc/adi-axi-adc.c
> +++ b/drivers/iio/adc/adi-axi-adc.c
> @@ -46,6 +46,7 @@
>  #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
>  
>  #define ADI_AXI_ADC_REG_CNTRL_3			0x004c
> +#define   AD485X_CNTRL_3_OS_EN_MSK		BIT(2)
>  #define   AD485X_CNTRL_3_PACKET_FORMAT_MSK	GENMASK(1, 0)
>  #define   AD485X_PACKET_FORMAT_20BIT		0x0
>  #define   AD485X_PACKET_FORMAT_24BIT		0x1
> @@ -363,6 +364,28 @@ static int axi_adc_data_size_set(struct iio_backend *back, unsigned int size)
>  				  FIELD_PREP(AD485X_CNTRL_3_PACKET_FORMAT_MSK, val));
>  }
>  
> +static int axi_adc_oversampling_ratio_set(struct iio_backend *back,

Same thing David pointed out in previous patch applies here.
axi_adc_ad4851_oversampling_ration_set() or something like that.


> +					  unsigned int ratio)
> +{
> +	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
> +
> +	/* The current state of the function enables or disables the
> +	 * oversampling in REG_CNTRL_3 register. A ratio equal to 1 implies no
> +	 * oversampling, while a value greater than 1 implies oversampling being
> +	 * enabled.
> +	 */
> +	switch (ratio) {
> +	case 0:
> +		return -EINVAL;
> +	case 1:
> +		return regmap_clear_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
> +					 AD485X_CNTRL_3_OS_EN_MSK);
> +	default:
> +		return regmap_set_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
> +				       AD485X_CNTRL_3_OS_EN_MSK);
> +	}
> +}
> +
>  static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
>  						 struct iio_dev *indio_dev)
>  {
> @@ -428,6 +451,7 @@ static const struct iio_backend_ops adi_ad485x_ops = {
>  	.chan_status = axi_adc_chan_status,
>  	.interface_type_get = axi_adc_interface_type_get,
>  	.data_size_set = axi_adc_data_size_set,
> +	.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),
>  };

[PATCH v12 8/9] dt-bindings: iio: adc: add ad4851

[Antoniu Miclaus]

Add devicetree bindings for ad485x family.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v12.
 .../bindings/iio/adc/adi,ad4851.yaml          | 153 ++++++++++++++++++
 1 file changed, 153 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad4851.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4851.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4851.yaml
new file mode 100644
index 000000000000..c6676d91b4e6
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4851.yaml
@@ -0,0 +1,153 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2024 Analog Devices Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad4851.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD485X family
+
+maintainers:
+  - Sergiu Cuciurean <sergiu.cuciurean@analog.com>
+  - Dragos Bogdan <dragos.bogdan@analog.com>
+  - Antoniu Miclaus <antoniu.miclaus@analog.com>
+
+description: |
+  Analog Devices AD485X fully buffered, 8-channel simultaneous sampling,
+  16/20-bit, 1 MSPS data acquisition system (DAS) with differential, wide
+  common-mode range inputs.
+
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad4855.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad4856.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad4857.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad4858.pdf
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    enum:
+      - adi,ad4851
+      - adi,ad4852
+      - adi,ad4853
+      - adi,ad4854
+      - adi,ad4855
+      - adi,ad4856
+      - adi,ad4857
+      - adi,ad4858
+      - adi,ad4858i
+
+  reg:
+    maxItems: 1
+
+  vcc-supply: true
+
+  vee-supply: true
+
+  vdd-supply: true
+
+  vddh-supply: true
+
+  vddl-supply: true
+
+  vio-supply: true
+
+  vrefbuf-supply: true
+
+  vrefio-supply: true
+
+  pwms:
+    description: PWM connected to the CNV pin.
+    maxItems: 1
+
+  io-backends:
+    maxItems: 1
+
+  pd-gpios:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 25000000
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^channel(@[0-7])?$":
+    $ref: adc.yaml
+    type: object
+    description: Represents the channels which are connected to the ADC.
+
+    properties:
+      reg:
+        description:
+          The channel number, as specified in the datasheet (from 0 to 7).
+        minimum: 0
+        maximum: 7
+
+      diff-channels:
+        description:
+          Each channel can be configured as a bipolar differential channel.
+          The ADC uses the same positive and negative inputs for this.
+          This property must be specified as 'reg' (or the channel number) for
+          both positive and negative inputs (i.e. diff-channels = <reg reg>).
+          Since the configuration is bipolar differential, the 'bipolar'
+          property is required.
+        items:
+          minimum: 0
+          maximum: 7
+
+      bipolar: true
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - vcc-supply
+  - vee-supply
+  - vdd-supply
+  - vio-supply
+  - pwms
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0{
+            #address-cells = <1>;
+            #size-cells = <0>;
+            compatible = "adi,ad4858";
+            reg = <0>;
+            spi-max-frequency = <10000000>;
+            vcc-supply = <&vcc>;
+            vdd-supply = <&vdd>;
+            vee-supply = <&vee>;
+            vddh-supply = <&vddh>;
+            vddl-supply = <&vddl>;
+            vio-supply = <&vio>;
+            pwms = <&pwm_gen 0 0>;
+            io-backends = <&iio_backend>;
+
+            channel@0 {
+              reg = <0>;
+              diff-channels = <0 0>;
+              bipolar;
+            };
+
+            channel@1 {
+              reg = <1>;
+            };
+        };
+    };
+...
-- 
2.48.1

[PATCH v12 9/9] iio: adc: ad4851: add ad485x driver

[Antoniu Miclaus]

Add support for the AD485X a fully buffered, 8-channel simultaneous
sampling, 16/20-bit, 1 MSPS data acquisition system (DAS) with
differential, wide common-mode range inputs.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
changes in v12.
 - drop trailing comma.
 - rework parse_channels_common function as suggested in prev review.
 - check ret first, reg after.
 - use fwnode_property_read_bool instead of fwnode_property_present for
   consistency.
 drivers/iio/adc/Kconfig  |   14 +
 drivers/iio/adc/Makefile |    1 +
 drivers/iio/adc/ad4851.c | 1316 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 1331 insertions(+)
 create mode 100644 drivers/iio/adc/ad4851.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 849c90203071..afd83fddda76 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -61,6 +61,20 @@ config AD4695
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad4695.
 
+config AD4851
+	tristate "Analog Device AD4851 DAS Driver"
+	depends on SPI
+	depends on PWM
+	select REGMAP_SPI
+	select IIO_BACKEND
+	help
+	  Say yes here to build support for Analog Devices AD4851, AD4852,
+	  AD4853, AD4854, AD4855, AD4856, AD4857, AD4858, AD4858I high speed
+	  data acquisition system (DAS).
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad4851.
+
 config AD7091R
 	tristate
 
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ee19afba62b7..e4d8ba12f841 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
 obj-$(CONFIG_AD4000) += ad4000.o
 obj-$(CONFIG_AD4130) += ad4130.o
 obj-$(CONFIG_AD4695) += ad4695.o
+obj-$(CONFIG_AD4851) += ad4851.o
 obj-$(CONFIG_AD7091R) += ad7091r-base.o
 obj-$(CONFIG_AD7091R5) += ad7091r5.o
 obj-$(CONFIG_AD7091R8) += ad7091r8.o
diff --git a/drivers/iio/adc/ad4851.c b/drivers/iio/adc/ad4851.c
new file mode 100644
index 000000000000..01cc88ecad52
--- /dev/null
+++ b/drivers/iio/adc/ad4851.c
@@ -0,0 +1,1316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices AD4851 DAS driver
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/minmax.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <linux/unaligned.h>
+#include <linux/units.h>
+
+#include <linux/iio/backend.h>
+#include <linux/iio/iio.h>
+
+#define AD4851_REG_INTERFACE_CONFIG_A	0x00
+#define AD4851_REG_INTERFACE_CONFIG_B	0x01
+#define AD4851_REG_PRODUCT_ID_L		0x04
+#define AD4851_REG_PRODUCT_ID_H		0x05
+#define AD4851_REG_DEVICE_CTRL		0x25
+#define AD4851_REG_PACKET		0x26
+#define AD4851_REG_OVERSAMPLE		0x27
+
+#define AD4851_REG_CH_CONFIG_BASE	0x2A
+#define AD4851_REG_CHX_SOFTSPAN(ch)	((0x12 * (ch)) + AD4851_REG_CH_CONFIG_BASE)
+#define AD4851_REG_CHX_OFFSET(ch)	(AD4851_REG_CHX_SOFTSPAN(ch) + 0x01)
+#define AD4851_REG_CHX_OFFSET_LSB(ch)	AD4851_REG_CHX_OFFSET(ch)
+#define AD4851_REG_CHX_OFFSET_MID(ch)	(AD4851_REG_CHX_OFFSET_LSB(ch) + 0x01)
+#define AD4851_REG_CHX_OFFSET_MSB(ch)	(AD4851_REG_CHX_OFFSET_MID(ch) + 0x01)
+#define AD4851_REG_CHX_GAIN(ch)		(AD4851_REG_CHX_OFFSET(ch) + 0x03)
+#define AD4851_REG_CHX_GAIN_LSB(ch)	AD4851_REG_CHX_GAIN(ch)
+#define AD4851_REG_CHX_GAIN_MSB(ch)	(AD4851_REG_CHX_GAIN(ch) + 0x01)
+#define AD4851_REG_CHX_PHASE(ch)	(AD4851_REG_CHX_GAIN(ch) + 0x02)
+#define AD4851_REG_CHX_PHASE_LSB(ch)	AD4851_REG_CHX_PHASE(ch)
+#define AD4851_REG_CHX_PHASE_MSB(ch)	(AD4851_REG_CHX_PHASE_LSB(ch) + 0x01)
+
+#define AD4851_REG_TESTPAT_0(c)		(0x38 + (c) * 0x12)
+#define AD4851_REG_TESTPAT_1(c)		(0x39 + (c) * 0x12)
+#define AD4851_REG_TESTPAT_2(c)		(0x3A + (c) * 0x12)
+#define AD4851_REG_TESTPAT_3(c)		(0x3B + (c) * 0x12)
+
+#define AD4851_SW_RESET			(BIT(7) | BIT(0))
+#define AD4851_SDO_ENABLE		BIT(4)
+#define AD4851_SINGLE_INSTRUCTION	BIT(7)
+#define AD4851_REFBUF			BIT(2)
+#define AD4851_REFSEL			BIT(1)
+#define AD4851_ECHO_CLOCK_MODE		BIT(0)
+
+#define AD4851_PACKET_FORMAT_0		0
+#define AD4851_PACKET_FORMAT_1		1
+#define AD4851_PACKET_FORMAT_MASK	GENMASK(1, 0)
+
+#define AD4851_OS_EN_MSK		BIT(7)
+#define AD4851_OS_RATIO_MSK		GENMASK(3, 0)
+
+#define AD4851_TEST_PAT			BIT(2)
+
+#define AD4858_PACKET_SIZE_20		0
+#define AD4858_PACKET_SIZE_24		1
+#define AD4858_PACKET_SIZE_32		2
+
+#define AD4857_PACKET_SIZE_16		0
+#define AD4857_PACKET_SIZE_24		1
+
+#define AD4851_TESTPAT_0_DEFAULT	0x2A
+#define AD4851_TESTPAT_1_DEFAULT	0x3C
+#define AD4851_TESTPAT_2_DEFAULT	0xCE
+#define AD4851_TESTPAT_3_DEFAULT(c)	(0x0A + (0x10 * (c)))
+
+#define AD4851_SOFTSPAN_0V_2V5		0
+#define AD4851_SOFTSPAN_N2V5_2V5	1
+#define AD4851_SOFTSPAN_0V_5V		2
+#define AD4851_SOFTSPAN_N5V_5V		3
+#define AD4851_SOFTSPAN_0V_6V25		4
+#define AD4851_SOFTSPAN_N6V25_6V25	5
+#define AD4851_SOFTSPAN_0V_10V		6
+#define AD4851_SOFTSPAN_N10V_10V	7
+#define AD4851_SOFTSPAN_0V_12V5		8
+#define AD4851_SOFTSPAN_N12V5_12V5	9
+#define AD4851_SOFTSPAN_0V_20V		10
+#define AD4851_SOFTSPAN_N20V_20V	11
+#define AD4851_SOFTSPAN_0V_25V		12
+#define AD4851_SOFTSPAN_N25V_25V	13
+#define AD4851_SOFTSPAN_0V_40V		14
+#define AD4851_SOFTSPAN_N40V_40V	15
+
+#define AD4851_MAX_LANES		8
+#define AD4851_MAX_IODELAY		32
+
+#define AD4851_T_CNVH_NS		40
+#define AD4851_T_CNVH_NS_MARGIN		10
+
+#define AD4841_MAX_SCALE_AVAIL		8
+
+#define AD4851_MAX_CH_NR		8
+#define AD4851_CH_START			0
+
+struct ad4851_scale {
+	unsigned int scale_val;
+	u8 reg_val;
+};
+
+static const struct ad4851_scale ad4851_scale_table_unipolar[] = {
+	{ 2500, 0x0 },
+	{ 5000, 0x2 },
+	{ 6250, 0x4 },
+	{ 10000, 0x6 },
+	{ 12500, 0x8 },
+	{ 20000, 0xA },
+	{ 25000, 0xC },
+	{ 40000, 0xE },
+};
+
+static const struct ad4851_scale ad4851_scale_table_bipolar[] = {
+	{ 5000, 0x1 },
+	{ 10000, 0x3 },
+	{ 12500, 0x5 },
+	{ 20000, 0x7 },
+	{ 25000, 0x9 },
+	{ 40000, 0xB },
+	{ 50000, 0xD },
+	{ 80000, 0xF },
+};
+
+static const unsigned int ad4851_scale_avail_unipolar[] = {
+	2500,
+	5000,
+	6250,
+	10000,
+	12500,
+	20000,
+	25000,
+	40000,
+};
+
+static const unsigned int ad4851_scale_avail_bipolar[] = {
+	5000,
+	10000,
+	12500,
+	20000,
+	25000,
+	40000,
+	50000,
+	80000,
+};
+
+struct ad4851_chip_info {
+	const char *name;
+	unsigned int product_id;
+	int num_scales;
+	unsigned long max_sample_rate_hz;
+	unsigned int resolution;
+	unsigned int max_channels;
+	int (*parse_channels)(struct iio_dev *indio_dev);
+};
+
+enum {
+	AD4851_SCAN_TYPE_NORMAL,
+	AD4851_SCAN_TYPE_RESOLUTION_BOOST,
+};
+
+struct ad4851_state {
+	struct spi_device *spi;
+	struct pwm_device *cnv;
+	struct iio_backend *back;
+	/*
+	 * Synchronize access to members the of driver state, and ensure
+	 * atomicity of consecutive regmap operations.
+	 */
+	struct mutex lock;
+	struct regmap *regmap;
+	const struct ad4851_chip_info *info;
+	struct gpio_desc *pd_gpio;
+	bool resolution_boost_enabled;
+	unsigned long cnv_trigger_rate_hz;
+	unsigned int osr;
+	bool vrefbuf_en;
+	bool vrefio_en;
+	bool bipolar_ch[AD4851_MAX_CH_NR];
+	unsigned int scales_unipolar[AD4841_MAX_SCALE_AVAIL][2];
+	unsigned int scales_bipolar[AD4841_MAX_SCALE_AVAIL][2];
+};
+
+static int ad4851_reg_access(struct iio_dev *indio_dev,
+			     unsigned int reg,
+			     unsigned int writeval,
+			     unsigned int *readval)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+
+	if (readval)
+		return regmap_read(st->regmap, reg, readval);
+
+	return regmap_write(st->regmap, reg, writeval);
+}
+
+static int ad4851_set_sampling_freq(struct ad4851_state *st, unsigned int freq)
+{
+	struct pwm_state cnv_state = {
+		.duty_cycle = AD4851_T_CNVH_NS + AD4851_T_CNVH_NS_MARGIN,
+		.enabled = true,
+	};
+	int ret;
+
+	freq = clamp(freq, 1, st->info->max_sample_rate_hz);
+
+	cnv_state.period = DIV_ROUND_UP_ULL(NSEC_PER_SEC, freq);
+
+	ret = pwm_apply_might_sleep(st->cnv, &cnv_state);
+	if (ret)
+		return ret;
+
+	st->cnv_trigger_rate_hz = freq;
+
+	return 0;
+}
+
+static const int ad4851_oversampling_ratios[] = {
+	1, 2, 4, 8, 16,	32, 64, 128,
+	256, 512, 1024, 2048, 4096, 8192, 16384, 32768,
+	65536,
+};
+
+static int ad4851_osr_to_regval(unsigned int ratio)
+{
+	int i;
+
+	for (i = 1; i < ARRAY_SIZE(ad4851_oversampling_ratios); i++)
+		if (ratio == ad4851_oversampling_ratios[i])
+			return i - 1;
+
+	return -EINVAL;
+}
+
+static int __ad4851_get_scale(struct iio_dev *indio_dev, int scale_tbl,
+			      unsigned int *val, unsigned int *val2)
+{
+	const struct iio_scan_type *scan_type;
+	unsigned int tmp;
+
+	scan_type = iio_get_current_scan_type(indio_dev, &indio_dev->channels[0]);
+	if (IS_ERR(scan_type))
+		return PTR_ERR(scan_type);
+
+	tmp = ((u64)scale_tbl * MICRO) >> scan_type->realbits;
+	*val = tmp / MICRO;
+	*val2 = tmp % MICRO;
+
+	return 0;
+}
+
+static int ad4851_scale_fill(struct iio_dev *indio_dev)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	unsigned int i, val1, val2;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(ad4851_scale_avail_unipolar); i++) {
+		ret = __ad4851_get_scale(indio_dev,
+					 ad4851_scale_avail_unipolar[i],
+					 &val1, &val2);
+		if (ret)
+			return ret;
+
+		st->scales_unipolar[i][0] = val1;
+		st->scales_unipolar[i][1] = val2;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ad4851_scale_avail_bipolar); i++) {
+		ret = __ad4851_get_scale(indio_dev,
+					 ad4851_scale_avail_bipolar[i],
+					 &val1, &val2);
+		if (ret)
+			return ret;
+
+		st->scales_bipolar[i][0] = val1;
+		st->scales_bipolar[i][1] = val2;
+	}
+
+	return 0;
+}
+
+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);
+	int val, ret;
+
+	guard(mutex)(&st->lock);
+
+	if (osr == 1) {
+		ret = regmap_clear_bits(st->regmap, AD4851_REG_OVERSAMPLE,
+					AD4851_OS_EN_MSK);
+		if (ret)
+			return ret;
+	} else {
+		val = ad4851_osr_to_regval(osr);
+		if (val < 0)
+			return -EINVAL;
+
+		ret = regmap_update_bits(st->regmap, AD4851_REG_OVERSAMPLE,
+					 AD4851_OS_EN_MSK |
+					 AD4851_OS_RATIO_MSK,
+					 FIELD_PREP(AD4851_OS_EN_MSK, 1) |
+					 FIELD_PREP(AD4851_OS_RATIO_MSK, val));
+		if (ret)
+			return ret;
+	}
+
+	ret = iio_backend_oversampling_ratio_set(st->back, osr);
+	if (ret)
+		return ret;
+
+	switch (st->info->resolution) {
+	case 20:
+		switch (osr) {
+		case 0:
+			return -EINVAL;
+		case 1:
+			val = 20;
+			break;
+		default:
+			val = 24;
+			break;
+		}
+		break;
+	case 16:
+		val = 16;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = iio_backend_data_size_set(st->back, val);
+	if (ret)
+		return ret;
+
+	if (osr == 1 || st->info->resolution == 16) {
+		ret = regmap_clear_bits(st->regmap, AD4851_REG_PACKET,
+					AD4851_PACKET_FORMAT_MASK);
+		if (ret)
+			return ret;
+
+		st->resolution_boost_enabled = false;
+	} else {
+		ret = regmap_update_bits(st->regmap, AD4851_REG_PACKET,
+					 AD4851_PACKET_FORMAT_MASK,
+					 FIELD_PREP(AD4851_PACKET_FORMAT_MASK, 1));
+		if (ret)
+			return ret;
+
+		st->resolution_boost_enabled = true;
+	}
+
+	if (st->osr != osr) {
+		ret = ad4851_scale_fill(indio_dev);
+		if (ret)
+			return ret;
+
+		st->osr = osr;
+	}
+
+	return 0;
+}
+
+static int ad4851_get_oversampling_ratio(struct ad4851_state *st, unsigned int *val)
+{
+	unsigned int osr;
+	int ret;
+
+	guard(mutex)(&st->lock);
+
+	ret = regmap_read(st->regmap, AD4851_REG_OVERSAMPLE, &osr);
+	if (ret)
+		return ret;
+
+	if (!FIELD_GET(AD4851_OS_EN_MSK, osr))
+		*val = 1;
+	else
+		*val = ad4851_oversampling_ratios[FIELD_GET(AD4851_OS_RATIO_MSK, osr) + 1];
+
+	st->osr = *val;
+
+	return IIO_VAL_INT;
+}
+
+static void ad4851_pwm_disable(void *data)
+{
+	pwm_disable(data);
+}
+
+static int ad4851_setup(struct ad4851_state *st)
+{
+	unsigned int product_id;
+	int ret;
+
+	if (st->pd_gpio) {
+		/* To initiate a global reset, bring the PD pin high twice */
+		gpiod_set_value(st->pd_gpio, 1);
+		fsleep(1);
+		gpiod_set_value(st->pd_gpio, 0);
+		fsleep(1);
+		gpiod_set_value(st->pd_gpio, 1);
+		fsleep(1);
+		gpiod_set_value(st->pd_gpio, 0);
+		fsleep(1000);
+	} else {
+		ret = regmap_set_bits(st->regmap, AD4851_REG_INTERFACE_CONFIG_A,
+				      AD4851_SW_RESET);
+		if (ret)
+			return ret;
+	}
+
+	if (st->vrefbuf_en) {
+		ret = regmap_set_bits(st->regmap, AD4851_REG_DEVICE_CTRL,
+				      AD4851_REFBUF);
+		if (ret)
+			return ret;
+	}
+
+	if (st->vrefio_en) {
+		ret = regmap_set_bits(st->regmap, AD4851_REG_DEVICE_CTRL,
+				      AD4851_REFSEL);
+		if (ret)
+			return ret;
+	}
+
+	ret = regmap_write(st->regmap, AD4851_REG_INTERFACE_CONFIG_B,
+			   AD4851_SINGLE_INSTRUCTION);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(st->regmap, AD4851_REG_INTERFACE_CONFIG_A,
+			   AD4851_SDO_ENABLE);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->regmap, AD4851_REG_PRODUCT_ID_L, &product_id);
+	if (ret)
+		return ret;
+
+	if (product_id != st->info->product_id)
+		dev_info(&st->spi->dev, "Unknown product ID: 0x%02X\n",
+			 product_id);
+
+	ret = regmap_set_bits(st->regmap, AD4851_REG_DEVICE_CTRL,
+			      AD4851_ECHO_CLOCK_MODE);
+	if (ret)
+		return ret;
+
+	return regmap_write(st->regmap, AD4851_REG_PACKET, 0);
+}
+
+/*
+ * Find the longest consecutive sequence of false values from field
+ * and return starting index.
+ */
+static int ad4851_find_opt(const unsigned long *field, unsigned int start,
+			   unsigned int nbits, unsigned int *val)
+{
+	unsigned int bit = start, end, start_cnt, cnt = 0;
+
+	for_each_clear_bitrange_from(bit, end, field, start + nbits) {
+		if (end - bit > cnt) {
+			cnt = end - bit;
+			start_cnt = bit - start;
+		}
+	}
+
+	if (!cnt)
+		return -ENOENT;
+
+	*val = start_cnt;
+
+	return cnt;
+}
+
+static int ad4851_calibrate(struct iio_dev *indio_dev)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	unsigned int opt_delay, num_lanes, delay, i, s, c;
+	enum iio_backend_interface_type interface_type;
+	DECLARE_BITMAP(pn_status, AD4851_MAX_LANES * AD4851_MAX_IODELAY);
+	bool status;
+	int ret;
+
+	ret = iio_backend_interface_type_get(st->back, &interface_type);
+	if (ret)
+		return ret;
+
+	switch (interface_type) {
+	case IIO_BACKEND_INTERFACE_SERIAL_CMOS:
+		num_lanes = indio_dev->num_channels;
+		break;
+	case IIO_BACKEND_INTERFACE_SERIAL_LVDS:
+		num_lanes = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (st->info->resolution == 16) {
+		ret = iio_backend_data_size_set(st->back, 24);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(st->regmap, AD4851_REG_PACKET,
+				   AD4851_TEST_PAT | AD4857_PACKET_SIZE_24);
+		if (ret)
+			return ret;
+	} else {
+		ret = iio_backend_data_size_set(st->back, 32);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(st->regmap, AD4851_REG_PACKET,
+				   AD4851_TEST_PAT | AD4858_PACKET_SIZE_32);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < indio_dev->num_channels; i++) {
+		ret = regmap_write(st->regmap, AD4851_REG_TESTPAT_0(i),
+				   AD4851_TESTPAT_0_DEFAULT);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(st->regmap, AD4851_REG_TESTPAT_1(i),
+				   AD4851_TESTPAT_1_DEFAULT);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(st->regmap, AD4851_REG_TESTPAT_2(i),
+				   AD4851_TESTPAT_2_DEFAULT);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(st->regmap, AD4851_REG_TESTPAT_3(i),
+				   AD4851_TESTPAT_3_DEFAULT(i));
+		if (ret)
+			return ret;
+
+		ret = iio_backend_chan_enable(st->back,
+					      indio_dev->channels[i].channel);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < num_lanes; i++) {
+		for (delay = 0; delay < AD4851_MAX_IODELAY; delay++) {
+			ret = iio_backend_iodelay_set(st->back, i, delay);
+			if (ret)
+				return ret;
+
+			ret = iio_backend_chan_status(st->back, i, &status);
+			if (ret)
+				return ret;
+
+			__assign_bit(i * AD4851_MAX_IODELAY + delay, pn_status,
+				     status);
+		}
+	}
+
+	for (i = 0; i < num_lanes; i++) {
+		c = ad4851_find_opt(pn_status, i * AD4851_MAX_IODELAY,
+				    AD4851_MAX_IODELAY, &s);
+		if (c < 0)
+			return c;
+
+		opt_delay = s + c / 2;
+		ret = iio_backend_iodelay_set(st->back, i, opt_delay);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < indio_dev->num_channels; i++) {
+		ret = iio_backend_chan_disable(st->back, i);
+		if (ret)
+			return ret;
+	}
+
+	ret = iio_backend_data_size_set(st->back, 20);
+	if (ret)
+		return ret;
+
+	return regmap_write(st->regmap, AD4851_REG_PACKET, 0);
+}
+
+static int ad4851_get_calibscale(struct ad4851_state *st, int ch, int *val, int *val2)
+{
+	unsigned int reg_val;
+	int gain;
+	int ret;
+
+	guard(mutex)(&st->lock);
+
+	ret = regmap_read(st->regmap, AD4851_REG_CHX_GAIN_MSB(ch), &reg_val);
+	if (ret)
+		return ret;
+
+	gain = reg_val << 8;
+
+	ret = regmap_read(st->regmap, AD4851_REG_CHX_GAIN_LSB(ch), &reg_val);
+	if (ret)
+		return ret;
+
+	gain |= reg_val;
+
+	*val = gain;
+	*val2 = 15;
+
+	return IIO_VAL_FRACTIONAL_LOG2;
+}
+
+static int ad4851_set_calibscale(struct ad4851_state *st, int ch, int val,
+				 int val2)
+{
+	u64 gain;
+	u8 buf[2];
+	int ret;
+
+	if (val < 0 || val2 < 0)
+		return -EINVAL;
+
+	gain = val * MICRO + val2;
+	gain = DIV_U64_ROUND_CLOSEST(gain * 32768, MICRO);
+
+	put_unaligned_be16(gain, buf);
+
+	guard(mutex)(&st->lock);
+
+	ret = regmap_write(st->regmap, AD4851_REG_CHX_GAIN_MSB(ch), buf[0]);
+	if (ret)
+		return ret;
+
+	return regmap_write(st->regmap, AD4851_REG_CHX_GAIN_LSB(ch), buf[1]);
+}
+
+static int ad4851_get_calibbias(struct ad4851_state *st, int ch, int *val)
+{
+	unsigned int lsb, mid, msb;
+	int ret;
+
+	guard(mutex)(&st->lock);
+	/*
+	 * After testing, the bulk_write operations doesn't work as expected
+	 * here since the cs needs to be raised after each byte transaction.
+	 */
+	ret = regmap_read(st->regmap, AD4851_REG_CHX_OFFSET_MSB(ch), &msb);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->regmap, AD4851_REG_CHX_OFFSET_MID(ch), &mid);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->regmap, AD4851_REG_CHX_OFFSET_LSB(ch), &lsb);
+	if (ret)
+		return ret;
+
+	if (st->info->resolution == 16) {
+		*val = msb << 8;
+		*val |= mid;
+		*val = sign_extend32(*val, 15);
+	} else {
+		*val = msb << 12;
+		*val |= mid << 4;
+		*val |= lsb >> 4;
+		*val = sign_extend32(*val, 19);
+	}
+
+	return IIO_VAL_INT;
+}
+
+static int ad4851_set_calibbias(struct ad4851_state *st, int ch, int val)
+{
+	u8 buf[3];
+	int ret;
+
+	if (val < 0)
+		return -EINVAL;
+
+	if (st->info->resolution == 16)
+		put_unaligned_be16(val, buf);
+	else
+		put_unaligned_be24(val << 4, buf);
+
+	guard(mutex)(&st->lock);
+	/*
+	 * After testing, the bulk_write operations doesn't work as expected
+	 * here since the cs needs to be raised after each byte transaction.
+	 */
+	ret = regmap_write(st->regmap, AD4851_REG_CHX_OFFSET_LSB(ch), buf[2]);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(st->regmap, AD4851_REG_CHX_OFFSET_MID(ch), buf[1]);
+	if (ret)
+		return ret;
+
+	return regmap_write(st->regmap, AD4851_REG_CHX_OFFSET_MSB(ch), buf[0]);
+}
+
+static int ad4851_set_scale(struct iio_dev *indio_dev,
+			    const struct iio_chan_spec *chan, int val, int val2)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	unsigned int scale_val[2];
+	unsigned int i;
+	const struct ad4851_scale *scale_table;
+	size_t table_size;
+	int ret;
+
+	if (st->bipolar_ch[chan->channel]) {
+		scale_table = ad4851_scale_table_bipolar;
+		table_size = ARRAY_SIZE(ad4851_scale_table_bipolar);
+	} else {
+		scale_table = ad4851_scale_table_unipolar;
+		table_size = ARRAY_SIZE(ad4851_scale_table_unipolar);
+	}
+
+	for (i = 0; i < table_size; i++) {
+		ret = __ad4851_get_scale(indio_dev, scale_table[i].scale_val,
+					 &scale_val[0], &scale_val[1]);
+		if (ret)
+			return ret;
+
+		if (scale_val[0] != val || scale_val[1] != val2)
+			continue;
+
+		return regmap_write(st->regmap,
+				    AD4851_REG_CHX_SOFTSPAN(chan->channel),
+				    scale_table[i].reg_val);
+	}
+
+	return -EINVAL;
+}
+
+static int ad4851_get_scale(struct iio_dev *indio_dev,
+			    const struct iio_chan_spec *chan, int *val,
+			    int *val2)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	const struct ad4851_scale *scale_table;
+	size_t table_size;
+	u32 softspan_val;
+	int i, ret;
+
+	if (st->bipolar_ch[chan->channel]) {
+		scale_table = ad4851_scale_table_bipolar;
+		table_size = ARRAY_SIZE(ad4851_scale_table_bipolar);
+	} else {
+		scale_table = ad4851_scale_table_unipolar;
+		table_size = ARRAY_SIZE(ad4851_scale_table_unipolar);
+	}
+
+	ret = regmap_read(st->regmap, AD4851_REG_CHX_SOFTSPAN(chan->channel),
+			  &softspan_val);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < table_size; i++) {
+		if (softspan_val == scale_table[i].reg_val)
+			break;
+	}
+
+	if (i == table_size)
+		return -EIO;
+
+	ret = __ad4851_get_scale(indio_dev, scale_table[i].scale_val, val,
+				 val2);
+	if (ret)
+		return ret;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ad4851_read_raw(struct iio_dev *indio_dev,
+			   const struct iio_chan_spec *chan,
+			   int *val, int *val2, long info)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+
+	switch (info) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = st->cnv_trigger_rate_hz;
+		*val2 = st->osr;
+		return IIO_VAL_FRACTIONAL;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		return ad4851_get_calibscale(st, chan->channel, val, val2);
+	case IIO_CHAN_INFO_SCALE:
+		return ad4851_get_scale(indio_dev, chan, val, val2);
+	case IIO_CHAN_INFO_CALIBBIAS:
+		return ad4851_get_calibbias(st, chan->channel, val);
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		return ad4851_get_oversampling_ratio(st, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad4851_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long info)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+
+	switch (info) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (val < 0 || val2 < 0)
+			return -EINVAL;
+		return ad4851_set_sampling_freq(st, val * st->osr + val2 * st->osr / MICRO);
+	case IIO_CHAN_INFO_SCALE:
+		return ad4851_set_scale(indio_dev, chan, val, val2);
+	case IIO_CHAN_INFO_CALIBSCALE:
+		return ad4851_set_calibscale(st, chan->channel, val, val2);
+	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);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad4851_update_scan_mode(struct iio_dev *indio_dev,
+				   const unsigned long *scan_mask)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	unsigned int c;
+	int ret;
+
+	for (c = 0; c < indio_dev->num_channels; c++) {
+		if (test_bit(c, scan_mask))
+			ret = iio_backend_chan_enable(st->back, c);
+		else
+			ret = iio_backend_chan_disable(st->back, c);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ad4851_read_avail(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     const int **vals, int *type, int *length,
+			     long mask)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		if (st->bipolar_ch[chan->channel]) {
+			*vals = (const int *)st->scales_bipolar;
+			*type = IIO_VAL_INT_PLUS_MICRO;
+			/* Values are stored in a 2D matrix */
+			*length = ARRAY_SIZE(ad4851_scale_avail_bipolar) * 2;
+		} else {
+			*vals = (const int *)st->scales_unipolar;
+			*type = IIO_VAL_INT_PLUS_MICRO;
+			/* Values are stored in a 2D matrix */
+			*length = ARRAY_SIZE(ad4851_scale_avail_unipolar) * 2;
+		}
+		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*vals = ad4851_oversampling_ratios;
+		*length = ARRAY_SIZE(ad4851_oversampling_ratios);
+		*type = IIO_VAL_INT;
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_scan_type ad4851_scan_type_20_u[] = {
+	[AD4851_SCAN_TYPE_NORMAL] = {
+		.sign = 'u',
+		.realbits = 20,
+		.storagebits = 32,
+	},
+	[AD4851_SCAN_TYPE_RESOLUTION_BOOST] = {
+		.sign = 'u',
+		.realbits = 24,
+		.storagebits = 32,
+	},
+};
+
+static const struct iio_scan_type ad4851_scan_type_20_b[] = {
+	[AD4851_SCAN_TYPE_NORMAL] = {
+		.sign = 's',
+		.realbits = 20,
+		.storagebits = 32,
+	},
+	[AD4851_SCAN_TYPE_RESOLUTION_BOOST] = {
+		.sign = 's',
+		.realbits = 24,
+		.storagebits = 32,
+	},
+};
+
+static int ad4851_get_current_scan_type(const struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+
+	return st->resolution_boost_enabled ? AD4851_SCAN_TYPE_RESOLUTION_BOOST
+					    : AD4851_SCAN_TYPE_NORMAL;
+}
+
+#define AD4851_IIO_CHANNEL							\
+	.type = IIO_VOLTAGE,							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_CALIBSCALE) |			\
+		BIT(IIO_CHAN_INFO_CALIBBIAS) |					\
+		BIT(IIO_CHAN_INFO_SCALE),					\
+	.info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE),		\
+	.info_mask_shared_by_all = BIT(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
+
+/*
+ * In case of AD4858_IIO_CHANNEL the scan_type is handled dynamically during the
+ * parse_channels function.
+ */
+#define AD4858_IIO_CHANNEL							\
+{										\
+	AD4851_IIO_CHANNEL							\
+}
+
+#define AD4857_IIO_CHANNEL							\
+{										\
+	AD4851_IIO_CHANNEL,							\
+	.scan_type = {								\
+		.sign = 'u',							\
+		.realbits = 16,							\
+		.storagebits = 16,						\
+	},									\
+}
+
+static int ad4851_parse_channels_common(struct iio_dev *indio_dev,
+					struct iio_chan_spec **chans,
+					const struct iio_chan_spec ad4851_chan)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	struct device *dev = &st->spi->dev;
+	struct iio_chan_spec *channels, *chan_start;
+	unsigned int num_channels, reg;
+	unsigned int index = 0;
+	int ret;
+
+	num_channels = device_get_child_node_count(dev);
+	if (num_channels > AD4851_MAX_CH_NR)
+		return dev_err_probe(dev, -EINVAL, "Too many channels: %u\n",
+				     num_channels);
+
+	channels = devm_kcalloc(dev, num_channels, sizeof(*channels), GFP_KERNEL);
+	if (!channels)
+		return -ENOMEM;
+
+	chan_start = channels;
+
+	device_for_each_child_node_scoped(dev, child) {
+		ret = fwnode_property_read_u32(child, "reg", &reg);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Missing channel number\n");
+		if (reg >= AD4851_MAX_CH_NR)
+			return dev_err_probe(dev, ret,
+					     "Invalid channel number\n");
+		*channels = ad4851_chan;
+		channels->scan_index = index++;
+		channels->channel = reg;
+
+		if (fwnode_property_present(child, "diff-channels")) {
+			channels->channel2 = reg + st->info->max_channels;
+			channels->differential = 1;
+		}
+
+		st->bipolar_ch[reg] = fwnode_property_read_bool(child, "bipolar");
+
+		if (st->bipolar_ch[reg]) {
+			channels->scan_type.sign = 's';
+		} else {
+			ret = regmap_write(st->regmap, AD4851_REG_CHX_SOFTSPAN(reg),
+					   AD4851_SOFTSPAN_0V_40V);
+			if (ret)
+				return ret;
+		}
+
+		channels++;
+	}
+
+	*chans = chan_start;
+
+	return num_channels;
+}
+
+static int ad4857_parse_channels(struct iio_dev *indio_dev)
+{
+	struct iio_chan_spec *ad4851_channels;
+	const struct iio_chan_spec ad4851_chan = AD4857_IIO_CHANNEL;
+	int ret;
+
+	ret = ad4851_parse_channels_common(indio_dev, &ad4851_channels,
+					   ad4851_chan);
+	if (ret < 0)
+		return ret;
+
+	indio_dev->channels = ad4851_channels;
+	indio_dev->num_channels = ret;
+
+	return 0;
+}
+
+static int ad4858_parse_channels(struct iio_dev *indio_dev)
+{
+	struct ad4851_state *st = iio_priv(indio_dev);
+	struct device *dev = &st->spi->dev;
+	struct iio_chan_spec *ad4851_channels;
+	const struct iio_chan_spec ad4851_chan = AD4858_IIO_CHANNEL;
+	int ret;
+
+	ret = ad4851_parse_channels_common(indio_dev, &ad4851_channels,
+					   ad4851_chan);
+	if (ret < 0)
+		return ret;
+
+	device_for_each_child_node_scoped(dev, child) {
+		ad4851_channels->has_ext_scan_type = 1;
+		if (fwnode_property_read_bool(child, "bipolar")) {
+			ad4851_channels->ext_scan_type = ad4851_scan_type_20_b;
+			ad4851_channels->num_ext_scan_type = ARRAY_SIZE(ad4851_scan_type_20_b);
+
+		} else {
+			ad4851_channels->ext_scan_type = ad4851_scan_type_20_u;
+			ad4851_channels->num_ext_scan_type = ARRAY_SIZE(ad4851_scan_type_20_u);
+		}
+		ad4851_channels++;
+	}
+
+	indio_dev->channels = ad4851_channels;
+	indio_dev->num_channels = ret;
+
+	return 0;
+}
+
+/*
+ * parse_channels() function handles the rest of the channel related attributes
+ * that are usually are stored in the chip info structure.
+ */
+static const struct ad4851_chip_info ad4851_info = {
+	.name = "ad4851",
+	.product_id = 0x67,
+	.max_sample_rate_hz = 250 * KILO,
+	.resolution = 16,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4857_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4852_info = {
+	.name = "ad4852",
+	.product_id = 0x66,
+	.max_sample_rate_hz = 250 * KILO,
+	.resolution = 20,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4858_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4853_info = {
+	.name = "ad4853",
+	.product_id = 0x65,
+	.max_sample_rate_hz = 1 * MEGA,
+	.resolution = 16,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4857_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4854_info = {
+	.name = "ad4854",
+	.product_id = 0x64,
+	.max_sample_rate_hz = 1 * MEGA,
+	.resolution = 20,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4858_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4855_info = {
+	.name = "ad4855",
+	.product_id = 0x63,
+	.max_sample_rate_hz = 250 * KILO,
+	.resolution = 16,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4857_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4856_info = {
+	.name = "ad4856",
+	.product_id = 0x62,
+	.max_sample_rate_hz = 250 * KILO,
+	.resolution = 20,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4858_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4857_info = {
+	.name = "ad4857",
+	.product_id = 0x61,
+	.max_sample_rate_hz = 1 * MEGA,
+	.resolution = 16,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4857_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4858_info = {
+	.name = "ad4858",
+	.product_id = 0x60,
+	.max_sample_rate_hz = 1 * MEGA,
+	.resolution = 20,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4858_parse_channels,
+};
+
+static const struct ad4851_chip_info ad4858i_info = {
+	.name = "ad4858i",
+	.product_id = 0x6F,
+	.max_sample_rate_hz = 1 * MEGA,
+	.resolution = 20,
+	.max_channels = AD4851_MAX_CH_NR,
+	.parse_channels = ad4858_parse_channels,
+};
+
+static const struct iio_info ad4851_iio_info = {
+	.debugfs_reg_access = ad4851_reg_access,
+	.read_raw = ad4851_read_raw,
+	.write_raw = ad4851_write_raw,
+	.update_scan_mode = ad4851_update_scan_mode,
+	.get_current_scan_type = ad4851_get_current_scan_type,
+	.read_avail = ad4851_read_avail,
+};
+
+static const struct regmap_config regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.read_flag_mask = BIT(7),
+};
+
+static const char * const ad4851_power_supplies[] = {
+	"vcc",	"vdd", "vee", "vio",
+};
+
+static int ad4851_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct device *dev = &spi->dev;
+	struct ad4851_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+
+	ret = devm_mutex_init(dev, &st->lock);
+	if (ret)
+		return ret;
+
+	ret = devm_regulator_bulk_get_enable(dev,
+					     ARRAY_SIZE(ad4851_power_supplies),
+					     ad4851_power_supplies);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to get and enable supplies\n");
+
+	ret = devm_regulator_get_enable_optional(dev, "vddh");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable vddh voltage\n");
+
+	ret = devm_regulator_get_enable_optional(dev, "vddl");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable vddl voltage\n");
+
+	ret = devm_regulator_get_enable_optional(dev, "vrefbuf");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable vrefbuf voltage\n");
+
+	st->vrefbuf_en = ret != -ENODEV;
+
+	ret = devm_regulator_get_enable_optional(dev, "vrefio");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable vrefio voltage\n");
+
+	st->vrefio_en = ret != -ENODEV;
+
+	st->pd_gpio = devm_gpiod_get_optional(dev, "pd", GPIOD_OUT_LOW);
+	if (IS_ERR(st->pd_gpio))
+		return dev_err_probe(dev, PTR_ERR(st->pd_gpio),
+				     "Error on requesting pd GPIO\n");
+
+	st->cnv = devm_pwm_get(dev, NULL);
+	if (IS_ERR(st->cnv))
+		return dev_err_probe(dev, PTR_ERR(st->cnv),
+				     "Error on requesting pwm\n");
+
+	st->info = spi_get_device_match_data(spi);
+	if (!st->info)
+		return -ENODEV;
+
+	st->regmap = devm_regmap_init_spi(spi, &regmap_config);
+	if (IS_ERR(st->regmap))
+		return PTR_ERR(st->regmap);
+
+	ret = ad4851_set_sampling_freq(st, HZ_PER_MHZ);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(&st->spi->dev, ad4851_pwm_disable,
+				       st->cnv);
+	if (ret)
+		return ret;
+
+	ret = ad4851_setup(st);
+	if (ret)
+		return ret;
+
+	indio_dev->name = st->info->name;
+	indio_dev->info = &ad4851_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = st->info->parse_channels(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = ad4851_scale_fill(indio_dev);
+	if (ret)
+		return ret;
+
+	st->back = devm_iio_backend_get(dev, NULL);
+	if (IS_ERR(st->back))
+		return PTR_ERR(st->back);
+
+	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;
+
+	ret = ad4851_calibrate(indio_dev);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id ad4851_of_match[] = {
+	{ .compatible = "adi,ad4851", .data = &ad4851_info, },
+	{ .compatible = "adi,ad4852", .data = &ad4852_info, },
+	{ .compatible = "adi,ad4853", .data = &ad4853_info, },
+	{ .compatible = "adi,ad4854", .data = &ad4854_info, },
+	{ .compatible = "adi,ad4855", .data = &ad4855_info, },
+	{ .compatible = "adi,ad4856", .data = &ad4856_info, },
+	{ .compatible = "adi,ad4857", .data = &ad4857_info, },
+	{ .compatible = "adi,ad4858", .data = &ad4858_info, },
+	{ .compatible = "adi,ad4858i", .data = &ad4858i_info, },
+	{ }
+};
+
+static const struct spi_device_id ad4851_spi_id[] = {
+	{ "ad4851", (kernel_ulong_t)&ad4851_info },
+	{ "ad4852", (kernel_ulong_t)&ad4852_info },
+	{ "ad4853", (kernel_ulong_t)&ad4853_info },
+	{ "ad4854", (kernel_ulong_t)&ad4854_info },
+	{ "ad4855", (kernel_ulong_t)&ad4855_info },
+	{ "ad4856", (kernel_ulong_t)&ad4856_info },
+	{ "ad4857", (kernel_ulong_t)&ad4857_info },
+	{ "ad4858", (kernel_ulong_t)&ad4858_info },
+	{ "ad4858i", (kernel_ulong_t)&ad4858i_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad4851_spi_id);
+
+static struct spi_driver ad4851_driver = {
+	.probe = ad4851_probe,
+	.driver = {
+		.name = "ad4851",
+		.of_match_table = ad4851_of_match,
+	},
+	.id_table = ad4851_spi_id,
+};
+module_spi_driver(ad4851_driver);
+
+MODULE_AUTHOR("Sergiu Cuciurean <sergiu.cuciurean@analog.com>");
+MODULE_AUTHOR("Dragos Bogdan <dragos.bogdan@analog.com>");
+MODULE_AUTHOR("Antoniu Miclaus <antoniu.miclaus@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD4851 DAS driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("IIO_BACKEND");
-- 
2.48.1

Re: [PATCH v12 9/9] iio: adc: ad4851: add ad485x driver

[David Lechner]

On 2/7/25 8:09 AM, Antoniu Miclaus wrote:
> Add support for the AD485X a fully buffered, 8-channel simultaneous
> sampling, 16/20-bit, 1 MSPS data acquisition system (DAS) with
> differential, wide common-mode range inputs.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---

...

> +static int ad4851_parse_channels_common(struct iio_dev *indio_dev,
> +					struct iio_chan_spec **chans,
> +					const struct iio_chan_spec ad4851_chan)
> +{
> +	struct ad4851_state *st = iio_priv(indio_dev);
> +	struct device *dev = &st->spi->dev;
> +	struct iio_chan_spec *channels, *chan_start;
> +	unsigned int num_channels, reg;
> +	unsigned int index = 0;
> +	int ret;
> +
> +	num_channels = device_get_child_node_count(dev);
> +	if (num_channels > AD4851_MAX_CH_NR)
> +		return dev_err_probe(dev, -EINVAL, "Too many channels: %u\n",
> +				     num_channels);
> +
> +	channels = devm_kcalloc(dev, num_channels, sizeof(*channels), GFP_KERNEL);
> +	if (!channels)
> +		return -ENOMEM;
> +
> +	chan_start = channels;
> +
> +	device_for_each_child_node_scoped(dev, child) {
> +		ret = fwnode_property_read_u32(child, "reg", &reg);
> +		if (ret)
> +			return dev_err_probe(dev, ret,
> +					     "Missing channel number\n");
> +		if (reg >= AD4851_MAX_CH_NR)
> +			return dev_err_probe(dev, ret,

ret will be == 0 here, so need to replace with -EINVAL.

> +					     "Invalid channel number\n");

Re: [PATCH v12 9/9] iio: adc: ad4851: add ad485x driver

[Jonathan Cameron]

On Fri, 7 Feb 2025 16:09:18 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add support for the AD485X a fully buffered, 8-channel simultaneous
> sampling, 16/20-bit, 1 MSPS data acquisition system (DAS) with
> differential, wide common-mode range inputs.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Hi Antoniu

One really trivial comment to add from me.

Jonathan

> diff --git a/drivers/iio/adc/ad4851.c b/drivers/iio/adc/ad4851.c
> new file mode 100644
> index 000000000000..01cc88ecad52
> --- /dev/null
> +++ b/drivers/iio/adc/ad4851.c
> @@ -0,0 +1,1316 @@


> +
> +static int ad4858_parse_channels(struct iio_dev *indio_dev)
> +{
> +	struct ad4851_state *st = iio_priv(indio_dev);
> +	struct device *dev = &st->spi->dev;
> +	struct iio_chan_spec *ad4851_channels;
> +	const struct iio_chan_spec ad4851_chan = AD4858_IIO_CHANNEL;
> +	int ret;
> +
> +	ret = ad4851_parse_channels_common(indio_dev, &ad4851_channels,
> +					   ad4851_chan);
> +	if (ret < 0)
> +		return ret;
> +
> +	device_for_each_child_node_scoped(dev, child) {
> +		ad4851_channels->has_ext_scan_type = 1;
> +		if (fwnode_property_read_bool(child, "bipolar")) {
> +			ad4851_channels->ext_scan_type = ad4851_scan_type_20_b;
> +			ad4851_channels->num_ext_scan_type = ARRAY_SIZE(ad4851_scan_type_20_b);
> +

Trivial but this blank line doesn't add anything useful and looks a bit odd!

> +		} else {
> +			ad4851_channels->ext_scan_type = ad4851_scan_type_20_u;
> +			ad4851_channels->num_ext_scan_type = ARRAY_SIZE(ad4851_scan_type_20_u);
> +		}
> +		ad4851_channels++;
> +	}
> +
> +	indio_dev->channels = ad4851_channels;
> +	indio_dev->num_channels = ret;
> +
> +	return 0;
> +}