[PATCH v4 1/3] dt-bindings: hwmon: fan: Add fan binding to schema

[Ban Feng]

Hi Zev,

This patch was suggested by reviewer and I cherry-pick from below link:
https://patchwork.kernel.org/project/linux-hwmon/patch/20240221104025.1306227-2-billy_tsai@aspeedtech.com/

Because I don't know the rule about the patch with cherry-pick, maybe
we should discuss it there?

Thanks,
Ban

On Tue, Mar 5, 2024 at 8:22 AM Zev Weiss <zev at bewilderbeest.net> wrote:
>
> On Mon, Feb 26, 2024 at 04:56:04PM PST, baneric926 at gmail.com wrote:
> >From: Naresh Solanki <naresh.solanki at 9elements.com>
> >
> >Add common fan properties bindings to a schema.
> >
> >Bindings for fan controllers can reference the common schema for the
> >fan
> >
> >child nodes:
> >
> >  patternProperties:
> >    "^fan@[0-2]":
> >      type: object
> >      $ref: fan-common.yaml#
> >      unevaluatedProperties: false
> >
> >Reviewed-by: Rob Herring <robh at kernel.org>
> >Signed-off-by: Naresh Solanki <naresh.solanki at 9elements.com>
> >Signed-off-by: Billy Tsai <billy_tsai at aspeedtech.com>
> >Signed-off-by: Ban Feng <kcfeng0 at nuvoton.com>
> >---
> > .../devicetree/bindings/hwmon/fan-common.yaml | 78 +++++++++++++++++++
> > 1 file changed, 78 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/hwmon/fan-common.yaml
> >
> >diff --git a/Documentation/devicetree/bindings/hwmon/fan-common.yaml b/Documentation/devicetree/bindings/hwmon/fan-common.yaml
> >new file mode 100644
> >index 000000000000..15c591c74545
> >--- /dev/null
> >+++ b/Documentation/devicetree/bindings/hwmon/fan-common.yaml
> >@@ -0,0 +1,78 @@
> >+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> >+%YAML 1.2
> >+---
> >+$id: http://devicetree.org/schemas/hwmon/fan-common.yaml#
> >+$schema: http://devicetree.org/meta-schemas/core.yaml#
> >+
> >+title: Common Fan Properties
> >+
> >+maintainers:
> >+  - Naresh Solanki <naresh.solanki at 9elements.com>
> >+  - Billy Tsai <billy_tsai at aspeedtech.com>
> >+
> >+properties:
> >+  max-rpm:
> >+    description:
> >+      Max RPM supported by fan.
> >+    $ref: /schemas/types.yaml#/definitions/uint32
> >+    maximum: 100000
> >+
> >+  min-rpm:
> >+    description:
> >+      Min RPM supported by fan.
> >+    $ref: /schemas/types.yaml#/definitions/uint32
> >+    maximum: 1000
>
> I can't say with certainty that it's not, but are we sure 1000 is low
> enough?  Looking at just what I've got on hand, an 80mm fan I have will
> run steadily at about 1500RPM, and I'd assume larger ones (e.g. 120mm)
> could potentially go significantly lower...
>
> >+
> >+  pulses-per-revolution:
> >+    description:
> >+      The number of pulse from fan sensor per revolution.
> >+    $ref: /schemas/types.yaml#/definitions/uint32
> >+    maximum: 4
>
> Might we want 'default: 2' here?
>
> >+
> >+  tach-div:
> >+    description:
> >+      Divisor for the tach sampling clock, which determines the sensitivity of the tach pin.
> >+    $ref: /schemas/types.yaml#/definitions/uint32
> >+
> >+  target-rpm:
> >+    description:
> >+      The default desired fan speed in RPM.
> >+    $ref: /schemas/types.yaml#/definitions/uint32
> >+
> >+  fan-driving-mode:
> >+    description:
> >+      Select the driving mode of the fan.(DC, PWM and so on)
>
> Nit: could use a space before the parenthetical.
>
> >+    $ref: /schemas/types.yaml#/definitions/string
> >+    enum: [ dc, pwm ]
> >+
> >+  pwms:
> >+    description:
> >+      PWM provider.
> >+    maxItems: 1
> >+
> >+  "#cooling-cells":
> >+    const: 2
> >+
> >+  cooling-levels:
> >+    description:
> >+      The control value which correspond to thermal cooling states.
> >+    $ref: /schemas/types.yaml#/definitions/uint32-array
> >+
> >+  tach-ch:
> >+    description:
> >+      The tach channel used for the fan.
> >+    $ref: /schemas/types.yaml#/definitions/uint8-array
>
> Nit: s/channel/channels/ given that it's an array?
>
> >+
> >+  label:
> >+    description:
> >+      Optional fan label
> >+
> >+  fan-supply:
> >+    description:
> >+      Power supply for fan.
> >+
> >+  reg:
> >+    maxItems: 1
> >+
> >+additionalProperties: true
> >+
> >--
> >2.34.1
> >
> >