diff mbox series

[v2,3/3] dt-bindings: iio: Add ltc2688 documentation

Message ID 20220115092705.491-4-nuno.sa@analog.com (mailing list archive)
State Changes Requested
Headers show
Series Add support for LTC2688 | expand

Commit Message

Nuno Sá Jan. 15, 2022, 9:27 a.m. UTC
Document the LTC2688 devicetree properties.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 .../bindings/iio/dac/adi,ltc2688.yaml         | 147 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 148 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml

Comments

Jonathan Cameron Jan. 16, 2022, 12:01 p.m. UTC | #1
On Sat, 15 Jan 2022 10:27:05 +0100
Nuno Sá <nuno.sa@analog.com> wrote:

> Document the LTC2688 devicetree properties.
> 
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Hi Nuno,

A few minor comments inline.  I've reviewed this first so might
find answers to some of them when reading the driver code.

Thanks,

Jonathan

> ---
>  .../bindings/iio/dac/adi,ltc2688.yaml         | 147 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 148 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> new file mode 100644
> index 000000000000..ecd0943fb813
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> @@ -0,0 +1,147 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/dac/adi,ltc2688.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC2688 DAC
> +
> +maintainers:
> +  - Nuno Sá <nuno.sa@analog.com>
> +
> +description: |
> +  Analog Devices LTC2688 16 channel, 16 bit, +-15V DAC
> +  https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2688.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ltc2688
> +
> +  reg:
> +    maxItems: 1
> +
> +  vcc-supply:
> +    description: Analog Supply Voltage Input.
> +
> +  iovcc-supply:
> +    description: Digital Input/Output Supply Voltage.
> +
> +  vref-supply:
> +    description:
> +      Reference Input/Output. The voltage at the REF pin sets the full-scale
> +      range of all channels. By default, the internal reference is routed to
> +      this pin.

Perhaps "If not provided the internal reference is used and also provided on the
VREF pin".

> +
> +  clr-gpios:
> +    description:
> +      If specified, it will be asserted during driver probe. As the line is
> +      active low, it should be marked GPIO_ACTIVE_LOW.
> +    maxItems: 1
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +patternProperties:
> +  "^channel@([0-9]|1[0-5])$":
> +    type: object
> +
> +    properties:
> +      reg:
> +        description: The channel number representing the DAC output channel.
> +        maximum: 15
> +
> +      adi,toggle-mode:
> +        description:
> +          Set the channel as a toggle enabled channel. Toggle operation enables
> +          fast switching of a DAC output between two different DAC codes without
> +          any SPI transaction. It will result in a different ABI for the
> +          channel.

The ABI bit is a linux specific part so shouldn't be in the binding.  Just leave
it unsaid.

> +        type: boolean
> +
> +      adi,output-range-microvolt:
> +        description: Specify the channel output full scale range.
> +        oneOf:
> +          - items:
> +              - const: 0
> +              - enum: [5000000, 10000000]
> +          - items:
> +              - const: -5000000
> +              - const: 5000000
> +          - items:
> +              - const: -10000000
> +              - const: 10000000
> +          - items:
> +              - const: -15000000
> +              - const: 15000000

Not necessarily a thing to do now, but this is common enough we should
make it a standard DAC channel property.

> +
> +      adi,overrange:
> +        description: Enable 5% overrange over the selected full scale range.
> +        type: boolean
> +
> +      clocks:
> +        maxItems: 1
> +
> +      adi,toggle-dither-input:
> +        description:
> +          Selects the TGPx pin to be associated with this channel. This setting
> +          only makes sense for toggle or dither enabled channels. If
> +          @adi,toggle-mode is not set and this property is given, the channel is
> +          assumed to be a dither capable channel. Note that multiple channels
> +          can be mapped to the same pin. If this setting is given, the
> +          respective @clock must also be provided. Mappings between this and
> +          clocks

That's not clear, mapping between this an input pin is probably more accurate?

> +            0 - TGP1
> +            1 - TGP2
> +            2 - TGP3
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        enum: [0, 1, 2]
> +
> +    dependencies:
> +      adi,toggle-dither-input: [ clocks ]
> +
> +    required:
> +      - reg
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +
> +    spi {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +          ltc2688: ltc2688@0 {
> +                  compatible = "adi,ltc2688";
> +                  reg = <0>;
> +
> +                  vcc-supply = <&vcc>;
> +                  iovcc-supply = <&vcc>;
> +                  vref-supply = <&vref>;
> +
> +                  #address-cells = <1>;
> +                  #size-cells = <0>;
> +                  channel@0 {
> +                          reg = <0>;
> +                          adi,toggle-mode;

Can do this without adi,toggle-dither-input?

> +                          adi,overrange;
> +                  };
> +
> +                  channel@1 {
> +                          reg = <1>;
> +                          adi,output-range-microvolt = <0 10000000>;
> +
> +                          clocks = <&clock_tgp3>;
> +                          adi,toggle-dither-input = <2>;
> +                  };
> +          };
> +    };
> +
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 16a7fd7f98ee..137d4ed992cf 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11188,6 +11188,7 @@ L:	linux-iio@vger.kernel.org
>  S:	Supported
>  W:	http://ez.analog.com/community/linux-device-drivers
>  F:	Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688
> +F:	Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
>  F:	drivers/iio/dac/ltc2688.c
>  
>  LTC2947 HARDWARE MONITOR DRIVER
Nuno Sá Jan. 16, 2022, 4:18 p.m. UTC | #2
> -----Original Message-----
> From: Jonathan Cameron <jic23@kernel.org>
> Sent: Sunday, January 16, 2022 1:02 PM
> To: Sa, Nuno <Nuno.Sa@analog.com>
> Cc: linux-iio@vger.kernel.org; devicetree@vger.kernel.org; Rob
> Herring <robh+dt@kernel.org>; Lars-Peter Clausen
> <lars@metafoo.de>; Hennerich, Michael
> <Michael.Hennerich@analog.com>
> Subject: Re: [PATCH v2 3/3] dt-bindings: iio: Add ltc2688
> documentation
> 
> [External]
> 
> On Sat, 15 Jan 2022 10:27:05 +0100
> Nuno Sá <nuno.sa@analog.com> wrote:
> 
> > Document the LTC2688 devicetree properties.
> >
> > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> Hi Nuno,
> 
> A few minor comments inline.  I've reviewed this first so might
> find answers to some of them when reading the driver code.
> 
> Thanks,
> 
> Jonathan
> 
> > ---
> >  .../bindings/iio/dac/adi,ltc2688.yaml         | 147
> ++++++++++++++++++
> >  MAINTAINERS                                   |   1 +
> >  2 files changed, 148 insertions(+)
> >  create mode 100644
> Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> >
> > diff --git
> a/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> > new file mode 100644
> > index 000000000000..ecd0943fb813
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> > @@ -0,0 +1,147 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id:
> https://urldefense.com/v3/__http://devicetree.org/schemas/iio/dac/
> adi,ltc2688.yaml*__;Iw!!A3Ni8CS0y2Y!qhcjFFDY939hv3Lo2iT1fAIbSObt
> YscKoXjAnLgWZRNG6_WE2WXgZ8AdE4FUwg$
> > +$schema:
> https://urldefense.com/v3/__http://devicetree.org/meta-
> schemas/core.yaml*__;Iw!!A3Ni8CS0y2Y!qhcjFFDY939hv3Lo2iT1fAIbS
> ObtYscKoXjAnLgWZRNG6_WE2WXgZ8BOzIvN9g$
> > +
> > +title: Analog Devices LTC2688 DAC
> > +
> > +maintainers:
> > +  - Nuno Sá <nuno.sa@analog.com>
> > +
> > +description: |
> > +  Analog Devices LTC2688 16 channel, 16 bit, +-15V DAC
> > +  https://www.analog.com/media/en/technical-
> documentation/data-sheets/ltc2688.pdf
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - adi,ltc2688
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  vcc-supply:
> > +    description: Analog Supply Voltage Input.
> > +
> > +  iovcc-supply:
> > +    description: Digital Input/Output Supply Voltage.
> > +
> > +  vref-supply:
> > +    description:
> > +      Reference Input/Output. The voltage at the REF pin sets the full-
> scale
> > +      range of all channels. By default, the internal reference is routed
> to
> > +      this pin.
> 
> Perhaps "If not provided the internal reference is used and also
> provided on the
> VREF pin".

Sure...

> > +
> > +  clr-gpios:
> > +    description:
> > +      If specified, it will be asserted during driver probe. As the line is
> > +      active low, it should be marked GPIO_ACTIVE_LOW.
> > +    maxItems: 1
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +patternProperties:
> > +  "^channel@([0-9]|1[0-5])$":
> > +    type: object
> > +
> > +    properties:
> > +      reg:
> > +        description: The channel number representing the DAC output
> channel.
> > +        maximum: 15
> > +
> > +      adi,toggle-mode:
> > +        description:
> > +          Set the channel as a toggle enabled channel. Toggle operation
> enables
> > +          fast switching of a DAC output between two different DAC
> codes without
> > +          any SPI transaction. It will result in a different ABI for the
> > +          channel.
> 
> The ABI bit is a linux specific part so shouldn't be in the binding.  Just
> leave
> it unsaid.

Makes sense...
> > +        type: boolean
> > +
> > +      adi,output-range-microvolt:
> > +        description: Specify the channel output full scale range.
> > +        oneOf:
> > +          - items:
> > +              - const: 0
> > +              - enum: [5000000, 10000000]
> > +          - items:
> > +              - const: -5000000
> > +              - const: 5000000
> > +          - items:
> > +              - const: -10000000
> > +              - const: 10000000
> > +          - items:
> > +              - const: -15000000
> > +              - const: 15000000
> 
> Not necessarily a thing to do now, but this is common enough we
> should
> make it a standard DAC channel property.
> 
> > +
> > +      adi,overrange:
> > +        description: Enable 5% overrange over the selected full scale
> range.
> > +        type: boolean
> > +
> > +      clocks:
> > +        maxItems: 1
> > +
> > +      adi,toggle-dither-input:
> > +        description:
> > +          Selects the TGPx pin to be associated with this channel. This
> setting
> > +          only makes sense for toggle or dither enabled channels. If
> > +          @adi,toggle-mode is not set and this property is given, the
> channel is
> > +          assumed to be a dither capable channel. Note that multiple
> channels
> > +          can be mapped to the same pin. If this setting is given, the
> > +          respective @clock must also be provided. Mappings between
> this and
> > +          clocks
> 
> That's not clear, mapping between this an input pin is probably more
> accurate?

Yeah, you're right. When I added this, I had the clock-names properties with 
these exact names. So, in the first version it was more acceptable but since
I removed clock-names, this is not clear anymore...

> > +            0 - TGP1
> > +            1 - TGP2
> > +            2 - TGP3
> > +        $ref: /schemas/types.yaml#/definitions/uint32
> > +        enum: [0, 1, 2]
> > +
> > +    dependencies:
> > +      adi,toggle-dither-input: [ clocks ]
> > +
> > +    required:
> > +      - reg
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +
> > +    spi {
> > +          #address-cells = <1>;
> > +          #size-cells = <0>;
> > +          ltc2688: ltc2688@0 {
> > +                  compatible = "adi,ltc2688";
> > +                  reg = <0>;
> > +
> > +                  vcc-supply = <&vcc>;
> > +                  iovcc-supply = <&vcc>;
> > +                  vref-supply = <&vref>;
> > +
> > +                  #address-cells = <1>;
> > +                  #size-cells = <0>;
> > +                  channel@0 {
> > +                          reg = <0>;
> > +                          adi,toggle-mode;
> 
> Can do this without adi,toggle-dither-input?

Yes, In this case it will assume SW toggle and expose the _symbol
interface...

- Nuno Sá
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
new file mode 100644
index 000000000000..ecd0943fb813
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
@@ -0,0 +1,147 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/dac/adi,ltc2688.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices LTC2688 DAC
+
+maintainers:
+  - Nuno Sá <nuno.sa@analog.com>
+
+description: |
+  Analog Devices LTC2688 16 channel, 16 bit, +-15V DAC
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2688.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ltc2688
+
+  reg:
+    maxItems: 1
+
+  vcc-supply:
+    description: Analog Supply Voltage Input.
+
+  iovcc-supply:
+    description: Digital Input/Output Supply Voltage.
+
+  vref-supply:
+    description:
+      Reference Input/Output. The voltage at the REF pin sets the full-scale
+      range of all channels. By default, the internal reference is routed to
+      this pin.
+
+  clr-gpios:
+    description:
+      If specified, it will be asserted during driver probe. As the line is
+      active low, it should be marked GPIO_ACTIVE_LOW.
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^channel@([0-9]|1[0-5])$":
+    type: object
+
+    properties:
+      reg:
+        description: The channel number representing the DAC output channel.
+        maximum: 15
+
+      adi,toggle-mode:
+        description:
+          Set the channel as a toggle enabled channel. Toggle operation enables
+          fast switching of a DAC output between two different DAC codes without
+          any SPI transaction. It will result in a different ABI for the
+          channel.
+        type: boolean
+
+      adi,output-range-microvolt:
+        description: Specify the channel output full scale range.
+        oneOf:
+          - items:
+              - const: 0
+              - enum: [5000000, 10000000]
+          - items:
+              - const: -5000000
+              - const: 5000000
+          - items:
+              - const: -10000000
+              - const: 10000000
+          - items:
+              - const: -15000000
+              - const: 15000000
+
+      adi,overrange:
+        description: Enable 5% overrange over the selected full scale range.
+        type: boolean
+
+      clocks:
+        maxItems: 1
+
+      adi,toggle-dither-input:
+        description:
+          Selects the TGPx pin to be associated with this channel. This setting
+          only makes sense for toggle or dither enabled channels. If
+          @adi,toggle-mode is not set and this property is given, the channel is
+          assumed to be a dither capable channel. Note that multiple channels
+          can be mapped to the same pin. If this setting is given, the
+          respective @clock must also be provided. Mappings between this and
+          clocks
+            0 - TGP1
+            1 - TGP2
+            2 - TGP3
+        $ref: /schemas/types.yaml#/definitions/uint32
+        enum: [0, 1, 2]
+
+    dependencies:
+      adi,toggle-dither-input: [ clocks ]
+
+    required:
+      - reg
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+
+    spi {
+          #address-cells = <1>;
+          #size-cells = <0>;
+          ltc2688: ltc2688@0 {
+                  compatible = "adi,ltc2688";
+                  reg = <0>;
+
+                  vcc-supply = <&vcc>;
+                  iovcc-supply = <&vcc>;
+                  vref-supply = <&vref>;
+
+                  #address-cells = <1>;
+                  #size-cells = <0>;
+                  channel@0 {
+                          reg = <0>;
+                          adi,toggle-mode;
+                          adi,overrange;
+                  };
+
+                  channel@1 {
+                          reg = <1>;
+                          adi,output-range-microvolt = <0 10000000>;
+
+                          clocks = <&clock_tgp3>;
+                          adi,toggle-dither-input = <2>;
+                  };
+          };
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 16a7fd7f98ee..137d4ed992cf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11188,6 +11188,7 @@  L:	linux-iio@vger.kernel.org
 S:	Supported
 W:	http://ez.analog.com/community/linux-device-drivers
 F:	Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688
+F:	Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
 F:	drivers/iio/dac/ltc2688.c
 
 LTC2947 HARDWARE MONITOR DRIVER