On 7/8/25 5:50 PM, Rob Herring wrote:
On Mon, Jun 30, 2025 at 12:02:08AM +0200, Marek Vasut wrote:
Document fan-shutdown-percent property, used to describe fan RPM in percent
set during shutdown. This is used to keep the fan running at fixed RPM after
the kernel shut down, which is useful on hardware that does keep heating
itself even after the kernel did shut down, for example from some sort of
management core.
This sounds more like "don't ever let the fan go below this RPM" or
"don't ever turn off the fan". IOW, it is more than just shutdown.
This property is literally only used during/after shutdown , this does
not limit or affect fan RPM during runtime in any way.
Also, sorry for the late reply.
diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
index 8b4ed5ee962f..a84cc3a4cfdc 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
@@ -31,6 +31,15 @@ properties:
it must be self resetting edge interrupts.
maxItems: 1
+ fan-shutdown-percent:
+ description:
+ Fan RPM in percent set during shutdown. This is used to keep the fan
+ running at fixed RPM after the kernel shut down, which is useful on
+ hardware that does keep heating itself even after the kernel did shut
+ down, for example from some sort of management core.
+ minimum: 0
+ maximum: 100
+
fan-stop-to-start-percent:
description:
Minimum fan RPM in percent to start when stopped.
--
2.47.2
--
Best regards,
Marek Vasut
