[PATCH v6 1/2] iio: adc: ad799x: Implement selecting external reference voltage input on AD7991, AD7995 and AD7999.

[PATCH v6 1/2] iio: adc: ad799x: Implement selecting external reference voltage input on AD7991, AD7995 and AD7999.

[Florian Boor]

Make use of the AD7991_REF_SEL bit and support using the external
reference voltage if 'vref-supply' is present. Use VCC voltage supply
as reference if no extra reference is supplied.

Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de>
---

Changes in v6:
- Minor documentation change (label and contact info)

Changes in v5:
- Correct errors in documentation found by
  'make DT_CHECKER_FLAGS=-m dt_binding_check'
  + Reduce title length
  + Move information to description
  + Add I²C bits to example

Changes in v4:
- Check devm_regulator_get_optional() return value and
  handle values other from -ENODEV separately.
- Update documentation description

Changes in v3:
- Do not create dummy reference regulator, check for vref presence where needed.
- Use VCC as reference if no extra reference voltage is provided
- Add interrupt information to documentation

Changes in v2:
- Check if a provided external vref regulator is provided.
- Drop unused setting
- Add ad79xx documentation (second patch)


 drivers/iio/adc/ad799x.c | 68 ++++++++++++++++++++++++++++++----------
 1 file changed, 51 insertions(+), 17 deletions(-)

diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c
index 18bf8386d50a..b67b3076d76e 100644
--- a/drivers/iio/adc/ad799x.c
+++ b/drivers/iio/adc/ad799x.c
@@ -299,7 +299,11 @@ static int ad799x_read_raw(struct iio_dev *indio_dev,
 			GENMASK(chan->scan_type.realbits - 1, 0);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
-		ret = regulator_get_voltage(st->vref);
+		if (st->vref)
+			ret = regulator_get_voltage(st->vref);
+		else
+			ret = regulator_get_voltage(st->reg);
+		
 		if (ret < 0)
 			return ret;
 		*val = ret / 1000;
@@ -770,6 +774,7 @@ static int ad799x_probe(struct i2c_client *client,
 				   const struct i2c_device_id *id)
 {
 	int ret;
+	int extra_config = 0;
 	struct ad799x_state *st;
 	struct iio_dev *indio_dev;
 	const struct ad799x_chip_info *chip_info =
@@ -797,14 +802,36 @@ static int ad799x_probe(struct i2c_client *client,
 	ret = regulator_enable(st->reg);
 	if (ret)
 		return ret;
-	st->vref = devm_regulator_get(&client->dev, "vref");
+		
+	/* check if an external reference is supplied */
+	st->vref = devm_regulator_get_optional(&client->dev, "vref");
+
 	if (IS_ERR(st->vref)) {
-		ret = PTR_ERR(st->vref);
-		goto error_disable_reg;
+		if (PTR_ERR(st->vref) == -ENODEV) {
+			st->vref = NULL;
+			dev_info(&client->dev, "Using VCC reference voltage\n");
+		} else {
+			ret = PTR_ERR(st->vref);
+			goto error_disable_reg;
+		}
+	}
+		
+	if (st->vref) {
+		/* 
+		 * Use external reference voltage if supported by hardware.
+		 * This is optional if voltage / regulator present, use VCC otherwise.
+		 */
+		if ((st->id == ad7991) || (st->id == ad7995) || (st->id == ad7999)) {
+			dev_info(&client->dev, "Using external reference voltage\n");
+			extra_config |= AD7991_REF_SEL;
+			ret = regulator_enable(st->vref);
+			if (ret)
+				goto error_disable_reg;
+		} else {
+			st->vref = NULL;
+			dev_warn(&client->dev, "Supplied reference not supported\n");
+		}
 	}
-	ret = regulator_enable(st->vref);
-	if (ret)
-		goto error_disable_reg;
 
 	st->client = client;
 
@@ -815,7 +842,7 @@ static int ad799x_probe(struct i2c_client *client,
 	indio_dev->channels = st->chip_config->channel;
 	indio_dev->num_channels = chip_info->num_channels;
 
-	ret = ad799x_update_config(st, st->chip_config->default_config);
+	ret = ad799x_update_config(st, st->chip_config->default_config | extra_config);
 	if (ret)
 		goto error_disable_vref;
 
@@ -845,7 +872,8 @@ static int ad799x_probe(struct i2c_client *client,
 error_cleanup_ring:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_disable_vref:
-	regulator_disable(st->vref);
+	if (st->vref) 
+		regulator_disable(st->vref);
 error_disable_reg:
 	regulator_disable(st->reg);
 
@@ -860,7 +888,8 @@ static int ad799x_remove(struct i2c_client *client)
 	iio_device_unregister(indio_dev);
 
 	iio_triggered_buffer_cleanup(indio_dev);
-	regulator_disable(st->vref);
+	if (st->vref) 
+		regulator_disable(st->vref);
 	regulator_disable(st->reg);
 	kfree(st->rx_buf);
 
@@ -872,7 +901,8 @@ static int __maybe_unused ad799x_suspend(struct device *dev)
 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
 	struct ad799x_state *st = iio_priv(indio_dev);
 
-	regulator_disable(st->vref);
+	if (st->vref) 
+		regulator_disable(st->vref);
 	regulator_disable(st->reg);
 
 	return 0;
@@ -889,17 +919,21 @@ static int __maybe_unused ad799x_resume(struct device *dev)
 		dev_err(dev, "Unable to enable vcc regulator\n");
 		return ret;
 	}
-	ret = regulator_enable(st->vref);
-	if (ret) {
-		regulator_disable(st->reg);
-		dev_err(dev, "Unable to enable vref regulator\n");
-		return ret;
+
+	if (st->vref) {
+		ret = regulator_enable(st->vref);
+		if (ret) {
+			regulator_disable(st->reg);
+			dev_err(dev, "Unable to enable vref regulator\n");
+			return ret;
+		}
 	}
 
 	/* resync config */
 	ret = ad799x_update_config(st, st->config);
 	if (ret) {
-		regulator_disable(st->vref);
+		if (st->vref) 
+			regulator_disable(st->vref);
 		regulator_disable(st->reg);
 		return ret;
 	}
-- 
2.30.2

[PATCH v6 2/2] dt-bindings: iio: ad779x: Add binding document

[Florian Boor]

New binding documentation for AD799x series of I²C ADC ICs.

Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de>
---

Changes in v6:
- Minor documentation change (label and contact info)

Changes in v5:
- Correct errors in documentation found by
  'make DT_CHECKER_FLAGS=-m dt_binding_check'
  + Reduce title length
  + Move information to description
  + Add I²C bits to example

 .../bindings/iio/adc/adi,ad799x.yaml          | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml
new file mode 100644
index 000000000000..29641ce7175b
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad799x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD799x analog to digital converters
+
+maintainers:
+  - Michael Hennerich <Michael.Hennerich@analog.com>
+
+description: |
+    Support for Analog Devices AD7991, AD7992, AD7993, AD7994, AD7995, AD7997, AD7998,
+    AD7999 and similar analog to digital converters.
+    Specifications on the converters can be found at:
+    AD7991, AD7995, AD7999:
+      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7991_7995_7999.pdf
+    AD7992:
+      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7992.pdf
+    AD7993, AD7994:
+      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7993_7994.pdf
+    AD7997, AD7998:
+      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7997_7998.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7991
+      - adi,ad7992
+      - adi,ad7993
+      - adi,ad7994
+      - adi,ad7995
+      - adi,ad7997
+      - adi,ad7998
+      - adi,ad7999
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  vcc-supply:
+    description:
+      ADC power supply
+
+  vref-supply:
+    description:
+      ADC reference voltage supply, optional for AD7991, AD7995 and AD7999
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+       adc1: adc@28 {
+               reg = <0x28>;
+               compatible = "adi,ad7991";
+               interrupts = <13 2>;
+               interrupt-parent = <&gpio6>;
+
+               vcc-supply = <&vcc_3v3>;
+               vref-supply = <&adc_vref>;
+        };
+    };
+...
-- 
2.30.2

Re: [PATCH v6 2/2] dt-bindings: iio: ad779x: Add binding document

[Jonathan Cameron]

On Thu, 30 Sep 2021 12:42:49 +0200
Florian Boor <florian.boor@kernelconcepts.de> wrote:

> New binding documentation for AD799x series of I²C ADC ICs.
> 
> Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de>

Rob gave a tag on v5 subject to some changes I assume you've made in here.
Please make sure to pick those up as they won't get picked up across versions
by the b4 which I'm using to grab patches from lore.kernel.org.

Patches look fine to me, but I'll leave them on list a day or two to see if anyone
else has feedback.

Thanks,

Jonathan


> ---
> 
> Changes in v6:
> - Minor documentation change (label and contact info)
> 
> Changes in v5:
> - Correct errors in documentation found by
>   'make DT_CHECKER_FLAGS=-m dt_binding_check'
>   + Reduce title length
>   + Move information to description
>   + Add I²C bits to example
> 
>  .../bindings/iio/adc/adi,ad799x.yaml          | 73 +++++++++++++++++++
>  1 file changed, 73 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml
> new file mode 100644
> index 000000000000..29641ce7175b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml
> @@ -0,0 +1,73 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/adi,ad799x.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices AD799x analog to digital converters
> +
> +maintainers:
> +  - Michael Hennerich <Michael.Hennerich@analog.com>
> +
> +description: |
> +    Support for Analog Devices AD7991, AD7992, AD7993, AD7994, AD7995, AD7997, AD7998,
> +    AD7999 and similar analog to digital converters.
> +    Specifications on the converters can be found at:
> +    AD7991, AD7995, AD7999:
> +      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7991_7995_7999.pdf
> +    AD7992:
> +      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7992.pdf
> +    AD7993, AD7994:
> +      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7993_7994.pdf
> +    AD7997, AD7998:
> +      https://www.analog.com/media/en/technical-documentation/data-sheets/AD7997_7998.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ad7991
> +      - adi,ad7992
> +      - adi,ad7993
> +      - adi,ad7994
> +      - adi,ad7995
> +      - adi,ad7997
> +      - adi,ad7998
> +      - adi,ad7999
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  vcc-supply:
> +    description:
> +      ADC power supply
> +
> +  vref-supply:
> +    description:
> +      ADC reference voltage supply, optional for AD7991, AD7995 and AD7999
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +       adc1: adc@28 {
> +               reg = <0x28>;
> +               compatible = "adi,ad7991";
> +               interrupts = <13 2>;
> +               interrupt-parent = <&gpio6>;
> +
> +               vcc-supply = <&vcc_3v3>;
> +               vref-supply = <&adc_vref>;
> +        };
> +    };
> +...

Re: [PATCH v6 2/2] dt-bindings: iio: ad779x: Add binding document

[Rob Herring]

On Thu, 30 Sep 2021 12:42:49 +0200, Florian Boor wrote:
> New binding documentation for AD799x series of I²C ADC ICs.
> 
> Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de>
> ---
> 
> Changes in v6:
> - Minor documentation change (label and contact info)
> 
> Changes in v5:
> - Correct errors in documentation found by
>   'make DT_CHECKER_FLAGS=-m dt_binding_check'
>   + Reduce title length
>   + Move information to description
>   + Add I²C bits to example
> 
>  .../bindings/iio/adc/adi,ad799x.yaml          | 73 +++++++++++++++++++
>  1 file changed, 73 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad799x.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v6 1/2] iio: adc: ad799x: Implement selecting external reference voltage input on AD7991, AD7995 and AD7999.

[Jonathan Cameron]

On Thu, 30 Sep 2021 12:42:48 +0200
Florian Boor <florian.boor@kernelconcepts.de> wrote:

> Make use of the AD7991_REF_SEL bit and support using the external
> reference voltage if 'vref-supply' is present. Use VCC voltage supply
> as reference if no extra reference is supplied.
> 
> Signed-off-by: Florian Boor <florian.boor@kernelconcepts.de>

Hi Florian,

Applied, but there were are whole bunch of trailing white space issues in here
that I manually fixed up.

Please run checkpatch.pl over future patches

Applied to the togreg branch of iio.git and pushed out as testing to
see what 0-day makes of it.

Thanks,

Jonathan
> ---
> 
> Changes in v6:
> - Minor documentation change (label and contact info)
> 
> Changes in v5:
> - Correct errors in documentation found by
>   'make DT_CHECKER_FLAGS=-m dt_binding_check'
>   + Reduce title length
>   + Move information to description
>   + Add I²C bits to example
> 
> Changes in v4:
> - Check devm_regulator_get_optional() return value and
>   handle values other from -ENODEV separately.
> - Update documentation description
> 
> Changes in v3:
> - Do not create dummy reference regulator, check for vref presence where needed.
> - Use VCC as reference if no extra reference voltage is provided
> - Add interrupt information to documentation
> 
> Changes in v2:
> - Check if a provided external vref regulator is provided.
> - Drop unused setting
> - Add ad79xx documentation (second patch)
> 
> 
>  drivers/iio/adc/ad799x.c | 68 ++++++++++++++++++++++++++++++----------
>  1 file changed, 51 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c
> index 18bf8386d50a..b67b3076d76e 100644
> --- a/drivers/iio/adc/ad799x.c
> +++ b/drivers/iio/adc/ad799x.c
> @@ -299,7 +299,11 @@ static int ad799x_read_raw(struct iio_dev *indio_dev,
>  			GENMASK(chan->scan_type.realbits - 1, 0);
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_SCALE:
> -		ret = regulator_get_voltage(st->vref);
> +		if (st->vref)
> +			ret = regulator_get_voltage(st->vref);
> +		else
> +			ret = regulator_get_voltage(st->reg);
> +		
>  		if (ret < 0)
>  			return ret;
>  		*val = ret / 1000;
> @@ -770,6 +774,7 @@ static int ad799x_probe(struct i2c_client *client,
>  				   const struct i2c_device_id *id)
>  {
>  	int ret;
> +	int extra_config = 0;
>  	struct ad799x_state *st;
>  	struct iio_dev *indio_dev;
>  	const struct ad799x_chip_info *chip_info =
> @@ -797,14 +802,36 @@ static int ad799x_probe(struct i2c_client *client,
>  	ret = regulator_enable(st->reg);
>  	if (ret)
>  		return ret;
> -	st->vref = devm_regulator_get(&client->dev, "vref");
> +		
> +	/* check if an external reference is supplied */
> +	st->vref = devm_regulator_get_optional(&client->dev, "vref");
> +
>  	if (IS_ERR(st->vref)) {
> -		ret = PTR_ERR(st->vref);
> -		goto error_disable_reg;
> +		if (PTR_ERR(st->vref) == -ENODEV) {
> +			st->vref = NULL;
> +			dev_info(&client->dev, "Using VCC reference voltage\n");
> +		} else {
> +			ret = PTR_ERR(st->vref);
> +			goto error_disable_reg;
> +		}
> +	}
> +		
> +	if (st->vref) {
> +		/* 
> +		 * Use external reference voltage if supported by hardware.
> +		 * This is optional if voltage / regulator present, use VCC otherwise.
> +		 */
> +		if ((st->id == ad7991) || (st->id == ad7995) || (st->id == ad7999)) {
> +			dev_info(&client->dev, "Using external reference voltage\n");
> +			extra_config |= AD7991_REF_SEL;
> +			ret = regulator_enable(st->vref);
> +			if (ret)
> +				goto error_disable_reg;
> +		} else {
> +			st->vref = NULL;
> +			dev_warn(&client->dev, "Supplied reference not supported\n");
> +		}
>  	}
> -	ret = regulator_enable(st->vref);
> -	if (ret)
> -		goto error_disable_reg;
>  
>  	st->client = client;
>  
> @@ -815,7 +842,7 @@ static int ad799x_probe(struct i2c_client *client,
>  	indio_dev->channels = st->chip_config->channel;
>  	indio_dev->num_channels = chip_info->num_channels;
>  
> -	ret = ad799x_update_config(st, st->chip_config->default_config);
> +	ret = ad799x_update_config(st, st->chip_config->default_config | extra_config);
>  	if (ret)
>  		goto error_disable_vref;
>  
> @@ -845,7 +872,8 @@ static int ad799x_probe(struct i2c_client *client,
>  error_cleanup_ring:
>  	iio_triggered_buffer_cleanup(indio_dev);
>  error_disable_vref:
> -	regulator_disable(st->vref);
> +	if (st->vref) 
> +		regulator_disable(st->vref);
>  error_disable_reg:
>  	regulator_disable(st->reg);
>  
> @@ -860,7 +888,8 @@ static int ad799x_remove(struct i2c_client *client)
>  	iio_device_unregister(indio_dev);
>  
>  	iio_triggered_buffer_cleanup(indio_dev);
> -	regulator_disable(st->vref);
> +	if (st->vref) 
> +		regulator_disable(st->vref);
>  	regulator_disable(st->reg);
>  	kfree(st->rx_buf);
>  
> @@ -872,7 +901,8 @@ static int __maybe_unused ad799x_suspend(struct device *dev)
>  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>  	struct ad799x_state *st = iio_priv(indio_dev);
>  
> -	regulator_disable(st->vref);
> +	if (st->vref) 
> +		regulator_disable(st->vref);
>  	regulator_disable(st->reg);
>  
>  	return 0;
> @@ -889,17 +919,21 @@ static int __maybe_unused ad799x_resume(struct device *dev)
>  		dev_err(dev, "Unable to enable vcc regulator\n");
>  		return ret;
>  	}
> -	ret = regulator_enable(st->vref);
> -	if (ret) {
> -		regulator_disable(st->reg);
> -		dev_err(dev, "Unable to enable vref regulator\n");
> -		return ret;
> +
> +	if (st->vref) {
> +		ret = regulator_enable(st->vref);
> +		if (ret) {
> +			regulator_disable(st->reg);
> +			dev_err(dev, "Unable to enable vref regulator\n");
> +			return ret;
> +		}
>  	}
>  
>  	/* resync config */
>  	ret = ad799x_update_config(st, st->config);
>  	if (ret) {
> -		regulator_disable(st->vref);
> +		if (st->vref) 
> +			regulator_disable(st->vref);
>  		regulator_disable(st->reg);
>  		return ret;
>  	}