On Sat, Dec 17, 2022 at 09:04:23PM +0000, Corentin Labbe wrote:
> Converts hwmon/gpio-fan.txt to YAML
s/YAML/DT schema\./
>
> Signed-off-by: Corentin Labbe <clabbe@xxxxxxxxxxxx>
> ---
> Changes since v1:
> - Keeped only one example and simplified it
>
> .../devicetree/bindings/hwmon/gpio-fan.txt | 41 -------------
> .../devicetree/bindings/hwmon/gpio-fan.yaml | 59 +++++++++++++++++++
> 2 files changed, 59 insertions(+), 41 deletions(-)
> delete mode 100644 Documentation/devicetree/bindings/hwmon/gpio-fan.txt
> create mode 100644 Documentation/devicetree/bindings/hwmon/gpio-fan.yaml
>
> diff --git a/Documentation/devicetree/bindings/hwmon/gpio-fan.txt b/Documentation/devicetree/bindings/hwmon/gpio-fan.txt
> deleted file mode 100644
> index f4cfa350f6a1..000000000000
> --- a/Documentation/devicetree/bindings/hwmon/gpio-fan.txt
> +++ /dev/null
> @@ -1,41 +0,0 @@
> -Bindings for fan connected to GPIO lines
> -
> -Required properties:
> -- compatible : "gpio-fan"
> -
> -Optional properties:
> -- gpios: Specifies the pins that map to bits in the control value,
> - ordered MSB-->LSB.
> -- gpio-fan,speed-map: A mapping of possible fan RPM speeds and the
> - control value that should be set to achieve them. This array
> - must have the RPM values in ascending order.
> -- alarm-gpios: This pin going active indicates something is wrong with
> - the fan, and a udev event will be fired.
> -- #cooling-cells: If used as a cooling device, must be <2>
> - Also see:
> - Documentation/devicetree/bindings/thermal/thermal-cooling-devices.yaml
> - min and max states are derived from the speed-map of the fan.
> -
> -Note: At least one the "gpios" or "alarm-gpios" properties must be set.
> -
> -Examples:
> -
> - gpio_fan {
> - compatible = "gpio-fan";
> - gpios = <&gpio1 14 1
> - &gpio1 13 1>;
> - gpio-fan,speed-map = <0 0
> - 3000 1
> - 6000 2>;
> - alarm-gpios = <&gpio1 15 1>;
> - };
> - gpio_fan_cool: gpio_fan {
> - compatible = "gpio-fan";
> - gpios = <&gpio2 14 1
> - &gpio2 13 1>;
> - gpio-fan,speed-map = <0 0>,
> - <3000 1>,
> - <6000 2>;
> - alarm-gpios = <&gpio2 15 1>;
> - #cooling-cells = <2>; /* min followed by max */
> - };
> diff --git a/Documentation/devicetree/bindings/hwmon/gpio-fan.yaml b/Documentation/devicetree/bindings/hwmon/gpio-fan.yaml
> new file mode 100644
> index 000000000000..c522072c0d07
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/gpio-fan.yaml
> @@ -0,0 +1,59 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/gpio-fan.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Bindings for fan connected to GPIO lines
Drop 'Bindings for'. Really, just 'GPIO controlled Fan' is good.
> +
> +maintainers:
> + - OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS <devicetree@xxxxxxxxxxxxxxx>
Should be a person. You can put me.
> +
> +properties:
> + compatible:
> + const: gpio-fan
> +
> + gpios:
> + $ref: /schemas/types.yaml#/definitions/phandle-array
Already has a type. Perhaps 'maxItems: N' where N is 'should be enough'.
I'd guess 4 is more than enough. Any sane design would go with a PWM
controlled fan if that much control is needed.
> + description: Specifies the pins that map to bits in the control value,
> + ordered MSB-->LSB.
> +
> + gpio-fan,speed-map:
> + $ref: /schemas/types.yaml#/definitions/uint32-matrix
> + description: A mapping of possible fan RPM speeds and the
> + control value that should be set to achieve them. This array
> + must have the RPM values in ascending order.
Needs some constraints and the entries can be better described:
minItems: 2 (I would assume there is no point in 1 entry?)
maxItems: N
items:
items:
- description: Speed in RPM
- description: GPIO Control value
> +
> + alarm-gpios:
> + $ref: /schemas/types.yaml#/definitions/phandle-array
Drop.
maxItems: 1
> + description: This pin going active indicates something is wrong with
> + the fan, and a udev event will be fired.
'udev event' is way outside the scope of a binding.
> +
> + "#cooling-cells":
> + const: 2
> + description: If used as a cooling device, must be <2>
If not used as a cooling device can be any number of cells?
Don't repeat constraints in free form text.
> + Also see Documentation/devicetree/bindings/thermal/thermal-cooling-devices.yaml
No need to reference schema for common properties.
> + min and max states are derived from the speed-map of the fan.
This IS unique to this binding, so it should stay.
> +
> +anyOf:
> + - required:
> + - gpios
> + - required:
> + - alarm-gpios
> +
> +additionalProperties: False
> +
> +examples:
> + - |
> + #include <dt-bindings/interrupt-controller/irq.h>
> + #include <dt-bindings/clock/cortina,gemini-clock.h>
> + #include <dt-bindings/reset/cortina,gemini-reset.h>
> + #include <dt-bindings/gpio/gpio.h>
> + gpio_fan {
> + compatible = "gpio-fan";
> + gpios = <&gpio1 8 GPIO_ACTIVE_HIGH>;
> + gpio-fan,speed-map = <0 0>,
> + <3000 1>,
> + <6000 2>;
How does a single GPIO encode 3 states?
> + alarm-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH>;
> + };
> --
> 2.37.4
>
>
