diff mbox series

[v2,1/2] dt-bindings: hwmon: pwm-fan: Document start from stopped state properties

Message ID 20241106021559.175105-1-marex@denx.de (mailing list archive)
State Superseded
Headers show
Series [v2,1/2] dt-bindings: hwmon: pwm-fan: Document start from stopped state properties | expand

Commit Message

Marek Vasut Nov. 6, 2024, 2:14 a.m. UTC
Delta AFC0612DB-F00 fan has to be set to at least 30% PWM duty cycle
to spin up from a stopped state, and can be afterward throttled down to
lower PWM duty cycle. Introduce support for operating such fans which
need to start at higher PWM duty cycle first and can slow down next.

Document two new DT properties, "fan-stop-to-start-percent" and
"fan-stop-to-start-usec". The former describes the minimum percent
of fan RPM at which it will surely spin up from stopped state. This
value can be found in the fan datasheet and can be converted to PWM
duty cycle easily. The "fan-stop-to-start-usec" describes the minimum
time in microseconds for which the fan has to be set to stopped state
start RPM for the fan to surely spin up.

Signed-off-by: Marek Vasut <marex@denx.de>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-hwmon@vger.kernel.org
---
V2: - Rename fan-dead-stop-start-percent to fan-stop-to-start-percent
    - Rename fan-dead-stop-start-usec to fan-stop-to-start-us
---
 Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Rob Herring (Arm) Nov. 6, 2024, 3:33 a.m. UTC | #1
On Wed, 06 Nov 2024 03:14:36 +0100, Marek Vasut wrote:
> Delta AFC0612DB-F00 fan has to be set to at least 30% PWM duty cycle
> to spin up from a stopped state, and can be afterward throttled down to
> lower PWM duty cycle. Introduce support for operating such fans which
> need to start at higher PWM duty cycle first and can slow down next.
> 
> Document two new DT properties, "fan-stop-to-start-percent" and
> "fan-stop-to-start-usec". The former describes the minimum percent
> of fan RPM at which it will surely spin up from stopped state. This
> value can be found in the fan datasheet and can be converted to PWM
> duty cycle easily. The "fan-stop-to-start-usec" describes the minimum
> time in microseconds for which the fan has to be set to stopped state
> start RPM for the fan to surely spin up.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Jean Delvare <jdelvare@suse.com>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-hwmon@vger.kernel.org
> ---
> V2: - Rename fan-dead-stop-start-percent to fan-stop-to-start-percent
>     - Rename fan-dead-stop-start-usec to fan-stop-to-start-us
> ---
>  Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml: properties:fan-stop-to-start-us: '$ref' should not be valid under {'const': '$ref'}
	hint: Standard unit suffix properties don't need a type $ref
	from schema $id: http://devicetree.org/meta-schemas/core.yaml#

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20241106021559.175105-1-marex@denx.de

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.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
index 4e5abf7580cc6..f4911e3fdb5b5 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
@@ -31,6 +31,17 @@  properties:
       it must be self resetting edge interrupts.
     maxItems: 1
 
+  fan-stop-to-start-percent:
+    description:
+      Minimum fan RPM in percent to start when stopped.
+    minimum: 0
+    maximum: 100
+
+  fan-stop-to-start-us:
+    description:
+      Time to wait in microseconds after start when stopped.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
   pulses-per-revolution:
     description:
       Define the number of pulses per fan revolution for each tachometer