[PATCH v3 3/3] dt-bindings: misc: servo-pwm: Add new bindings for servo-pwm

[PATCH v3 3/3] dt-bindings: misc: servo-pwm: Add new bindings for servo-pwm

[Angelo Compagnucci]

This binding describes the binding for controlling servo motors through
pwm.

Signed-off-by: Angelo Compagnucci <angelo@amarulasolutions.com>
---
v2:
* Converted old txt to yaml
v3:
* Fixed errors rised by make dt_binding_check 

 .../devicetree/bindings/misc/servo-pwm.yaml   | 57 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 58 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/servo-pwm.yaml

diff --git a/Documentation/devicetree/bindings/misc/servo-pwm.yaml b/Documentation/devicetree/bindings/misc/servo-pwm.yaml
new file mode 100644
index 000000000000..73e81b939daf
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/servo-pwm.yaml
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/misc/servo-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Servo motor connected to PWM
+
+maintainers:
+  - Angelo Compagnucci <angelo@amarulasolutions.com>
+
+description:
+  Each servo is represented as a servo-pwm device.
+  The 20ms period is the accepted standard and so most of the motors
+  support it, while the positioning min/max duty cycle or the motor
+  degrees aperture vary lot between manufacturers.
+  The most common type of servo (SG90) has 180 degrees of movement
+  and moves between 0.5ms and 2.5ms duty cycle.
+
+properties:
+  compatible:
+    const: servo-pwm
+
+  pwms:
+    maxItems: 1
+
+  pwm-names: true
+
+  degrees:
+    description:
+      How many degrees the motor can move.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  duty-min:
+    description:
+      Duty cycle for position the motor at 0 degrees.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  duty-max:
+    description:
+      Duty cycle for positioning the motor at "degrees" angle.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+additionalProperties: false
+
+examples:
+  - |
+
+    servo: servo@0 {
+      compatible = "servo-pwm";
+      pwms = <&pwm 0 20000000 0>;
+      degrees = <180>;
+      duty-min = <500000>;
+      duty-max = <2500000>;
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 356daea0861d..8f41daee62fc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8742,6 +8742,7 @@ M:	"Angelo Compagnucci" <angelo@amarulasolutions.com>
 L:	linux-pwm@vger.kernel.org
 S:	Maintained
 F:	Documentation/ABI/testing/sysfs-driver-servo-pwm
+F:	Documentation/devicetree/bindings/misc/servo-pwm.yaml
 F:	drivers/misc/servo-pwm.c
 
 GENERIC RESISTIVE TOUCHSCREEN ADC DRIVER
-- 
2.34.1

Re: [PATCH v3 3/3] dt-bindings: misc: servo-pwm: Add new bindings for servo-pwm

[Rob Herring]

On Fri, 17 Feb 2023 17:10:37 +0100, Angelo Compagnucci wrote:
> This binding describes the binding for controlling servo motors through
> pwm.
> 
> Signed-off-by: Angelo Compagnucci <angelo@amarulasolutions.com>
> ---
> v2:
> * Converted old txt to yaml
> v3:
> * Fixed errors rised by make dt_binding_check
> 
>  .../devicetree/bindings/misc/servo-pwm.yaml   | 57 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/misc/servo-pwm.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:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/misc/servo-pwm.example.dts:19.24-25.11: Warning (unit_address_vs_reg): /example-0/servo@0: node has a unit name, but no reg or ranges property

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20230217161038.3130053-3-angelo@amarulasolutions.com

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.

Re: [PATCH v3 3/3] dt-bindings: misc: servo-pwm: Add new bindings for servo-pwm

[Krzysztof Kozlowski]

On 17/02/2023 17:10, Angelo Compagnucci wrote:
> This binding describes the binding for controlling servo motors through
> pwm.
> 
> Signed-off-by: Angelo Compagnucci <angelo@amarulasolutions.com>
> ---
> v2:
> * Converted old txt to yaml
> v3:
> * Fixed errors rised by make dt_binding_check 

Still fails the tests.

Does not look like you tested the bindings. Please run `make
dt_binding_check` (see
Documentation/devicetree/bindings/writing-schema.rst for instructions).

> 
>  .../devicetree/bindings/misc/servo-pwm.yaml   | 57 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 58 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/misc/servo-pwm.yaml
> 
> diff --git a/Documentation/devicetree/bindings/misc/servo-pwm.yaml b/Documentation/devicetree/bindings/misc/servo-pwm.yaml
> new file mode 100644
> index 000000000000..73e81b939daf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/misc/servo-pwm.yaml
> @@ -0,0 +1,57 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/misc/servo-pwm.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Servo motor connected to PWM
> +
> +maintainers:
> +  - Angelo Compagnucci <angelo@amarulasolutions.com>
> +
> +description:
> +  Each servo is represented as a servo-pwm device.
> +  The 20ms period is the accepted standard and so most of the motors
> +  support it, while the positioning min/max duty cycle or the motor
> +  degrees aperture vary lot between manufacturers.
> +  The most common type of servo (SG90) has 180 degrees of movement
> +  and moves between 0.5ms and 2.5ms duty cycle.
> +
> +properties:
> +  compatible:
> +    const: servo-pwm
> +
> +  pwms:
> +    maxItems: 1
> +
> +  pwm-names: true

You got later feedback from Rob for v2, so this needs changes.

> +
> +  degrees:
> +    description:
> +      How many degrees the motor can move.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  duty-min:
> +    description:
> +      Duty cycle for position the motor at 0 degrees.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  duty-max:
> +    description:
> +      Duty cycle for positioning the motor at "degrees" angle.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +

Drop blank line.

Krzysztof