diff mbox series

[1/2] dt-bindings: iio: spi-dac: Add driver for SPI shift register DACs

Message ID 20231213090910.25410-1-mike.looijmans@topic.nl
State New
Headers
Series [1/2] dt-bindings: iio: spi-dac: Add driver for SPI shift register DACs |

Commit Message

Mike Looijmans Dec. 13, 2023, 9:09 a.m. UTC 
  Add a driver for generic serial shift register DACs like TI DAC714.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>

---

 .../devicetree/bindings/iio/dac/spidac.yaml   | 69 +++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/spidac.yaml

Comments

Rob Herring Dec. 13, 2023, 10:34 a.m. UTC | #1 
On Wed, 13 Dec 2023 10:09:09 +0100, Mike Looijmans wrote:
> Add a driver for generic serial shift register DACs like TI DAC714.
> 
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> 
> ---
> 
>  .../devicetree/bindings/iio/dac/spidac.yaml   | 69 +++++++++++++++++++
>  1 file changed, 69 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/spidac.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:
./Documentation/devicetree/bindings/iio/dac/spidac.yaml:44:8: [warning] wrong indentation: expected 6 but found 7 (indentation)

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/iio/dac/spidac.example.dtb: /example-0/spi/dac@1: failed to match any schema with compatible: ['spidac']

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20231213090910.25410-1-mike.looijmans@topic.nl

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.
Rob Herring Dec. 13, 2023, 2:53 p.m. UTC | #2 
On Wed, Dec 13, 2023 at 10:09:09AM +0100, Mike Looijmans wrote:
> Add a driver for generic serial shift register DACs like TI DAC714.

This is not a driver.

> 
> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> 
> ---
> 
>  .../devicetree/bindings/iio/dac/spidac.yaml   | 69 +++++++++++++++++++
>  1 file changed, 69 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/spidac.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/spidac.yaml b/Documentation/devicetree/bindings/iio/dac/spidac.yaml
> new file mode 100644
> index 000000000000..be98da728594
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/spidac.yaml
> @@ -0,0 +1,69 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/dac/spidac.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic "shift register" SPI DAC
> +
> +description:
> +  Supports simple SPI "shift register" DACs, like TI's DAC714. These DACs have
> +  no control registers or commands, they just use a clock and serial data to
> +  shift in a raw DAC value. Multiple DACs can be daisy-chained together.
> +
> +maintainers:
> +  - Mike Looijmans <mike.looijmans@topic.nl>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - spi-dac
> +      - ti,dac714

Why does TI chip need a specific compatible and others don't?

Are power supplies on these chips the same?

> +
> +  reg:
> +    maxItems: 1
> +
> +  ldac-gpios:
> +    description:
> +      LDAC pin to be used as a hardware trigger to update the DAC outputs. Not
> +      needed when the DACs use the chip select to update their output.
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description:
> +      Optional reset pin that resets all DACs.
> +    maxItems: 1
> +
> +  num-channels:
> +    description:
> +      Number of channels (usually the number of DAC chips in series)

usually? What other possible option is there? If something else, how is 
the driver going to distinguish that?

default: 1

> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  bits-per-channel:

Perhaps 'channel-bits' as -bits is a standard unit suffix.

> +    description:
> +       Number of bits for each DAC output.
> +    $ref: /schemas/types.yaml#/definitions/uint32

Constraints? I assume all DACs are much less than 2^32 bits. default?

> +
> +required:
> +  - compatible
> +  - reg

Don't you always need to know how many bits?

> +
> +allOf:
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        dac@1 {
> +            compatible = "spidac";
> +            reg = <0x1>;
> +            ldac-gpios = <&gpio 42 GPIO_ACTIVE_LOW>;
> +        };
> +    };
> +...
> -- 
> 2.34.1
> 
> 
> Met vriendelijke groet / kind regards,
> 
> Mike Looijmans
> System Expert
> 
> 
> TOPIC Embedded Products B.V.
> Materiaalweg 4, 5681 RJ Best
> The Netherlands
> 
> T: +31 (0) 499 33 69 69
> E: mike.looijmans@topic.nl
> W: www.topic.nl
> 
> Please consider the environment before printing this e-mail
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/iio/dac/spidac.yaml b/Documentation/devicetree/bindings/iio/dac/spidac.yaml
new file mode 100644
index 000000000000..be98da728594
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/spidac.yaml
@@ -0,0 +1,69 @@ 
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/dac/spidac.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic "shift register" SPI DAC
+
+description:
+  Supports simple SPI "shift register" DACs, like TI's DAC714. These DACs have
+  no control registers or commands, they just use a clock and serial data to
+  shift in a raw DAC value. Multiple DACs can be daisy-chained together.
+
+maintainers:
+  - Mike Looijmans <mike.looijmans@topic.nl>
+
+properties:
+  compatible:
+    enum:
+      - spi-dac
+      - ti,dac714
+
+  reg:
+    maxItems: 1
+
+  ldac-gpios:
+    description:
+      LDAC pin to be used as a hardware trigger to update the DAC outputs. Not
+      needed when the DACs use the chip select to update their output.
+    maxItems: 1
+
+  reset-gpios:
+    description:
+      Optional reset pin that resets all DACs.
+    maxItems: 1
+
+  num-channels:
+    description:
+      Number of channels (usually the number of DAC chips in series)
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  bits-per-channel:
+    description:
+       Number of bits for each DAC output.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        dac@1 {
+            compatible = "spidac";
+            reg = <0x1>;
+            ldac-gpios = <&gpio 42 GPIO_ACTIVE_LOW>;
+        };
+    };
+...