Document new retain-state-shutdown property.
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Billy Tsai <billy_tsai@aspeedtech.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
index 4e5abf7580cc..86a069969e29 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml
@@ -40,6 +40,10 @@ properties:
maximum: 4
default: 2
+ retain-state-shutdown:
+ description: Retain the state of the PWM on shutdown.
+ $ref: /schemas/types.yaml#/definitions/flag
+
pwms:
description: The PWM that is used to control the fan.
maxItems: 1
--
2.34.1On Sat, Oct 26, 2024 at 05:05:35PM +0900, Akinobu Mita wrote: > Document new retain-state-shutdown property. > > Cc: Jean Delvare <jdelvare@suse.com> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: Rob Herring <robh@kernel.org> > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org> > Cc: Conor Dooley <conor+dt@kernel.org> > Cc: Billy Tsai <billy_tsai@aspeedtech.com> > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> > --- > Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > index 4e5abf7580cc..86a069969e29 100644 > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > @@ -40,6 +40,10 @@ properties: > maximum: 4 > default: 2 > > + retain-state-shutdown: > + description: Retain the state of the PWM on shutdown. You described the desired Linux feature or behavior, not the actual hardware. The bindings are about the latter, so instead you need to rephrase the property and its description to match actual hardware capabilities/features/configuration etc. Best regards, Krzysztof
2024年10月28日(月) 5:38 Krzysztof Kozlowski <krzk@kernel.org>: > > On Sat, Oct 26, 2024 at 05:05:35PM +0900, Akinobu Mita wrote: > > Document new retain-state-shutdown property. > > > > Cc: Jean Delvare <jdelvare@suse.com> > > Cc: Guenter Roeck <linux@roeck-us.net> > > Cc: Rob Herring <robh@kernel.org> > > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org> > > Cc: Conor Dooley <conor+dt@kernel.org> > > Cc: Billy Tsai <billy_tsai@aspeedtech.com> > > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> > > --- > > Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > > index 4e5abf7580cc..86a069969e29 100644 > > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > > @@ -40,6 +40,10 @@ properties: > > maximum: 4 > > default: 2 > > > > + retain-state-shutdown: > > + description: Retain the state of the PWM on shutdown. > > You described the desired Linux feature or behavior, not the actual > hardware. The bindings are about the latter, so instead you need to > rephrase the property and its description to match actual hardware > capabilities/features/configuration etc. Is this description okay? (Reused the description of retain-state-shutdown in leds-gpio.yaml) description: Retain the state of the PWM on shutdown. Useful in BMC systems, for example, when the BMC is rebooted while the host remains up, the fan will not stop.
On 28/10/2024 13:42, Akinobu Mita wrote: > 2024年10月28日(月) 5:38 Krzysztof Kozlowski <krzk@kernel.org>: >> >> On Sat, Oct 26, 2024 at 05:05:35PM +0900, Akinobu Mita wrote: >>> Document new retain-state-shutdown property. >>> >>> Cc: Jean Delvare <jdelvare@suse.com> >>> Cc: Guenter Roeck <linux@roeck-us.net> >>> Cc: Rob Herring <robh@kernel.org> >>> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org> >>> Cc: Conor Dooley <conor+dt@kernel.org> >>> Cc: Billy Tsai <billy_tsai@aspeedtech.com> >>> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> >>> --- >>> Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml >>> index 4e5abf7580cc..86a069969e29 100644 >>> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml >>> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml >>> @@ -40,6 +40,10 @@ properties: >>> maximum: 4 >>> default: 2 >>> >>> + retain-state-shutdown: >>> + description: Retain the state of the PWM on shutdown. >> >> You described the desired Linux feature or behavior, not the actual >> hardware. The bindings are about the latter, so instead you need to >> rephrase the property and its description to match actual hardware >> capabilities/features/configuration etc. > > Is this description okay? > (Reused the description of retain-state-shutdown in leds-gpio.yaml) > > description: > Retain the state of the PWM on shutdown. Useful in BMC systems, for > example, when the BMC is rebooted while the host remains up, the fan > will not stop. Nothing improved in the property. You still say what the system should do. This is user-space choice, not DT. Best regards, Krzysztof
2024年10月28日(月) 23:22 Krzysztof Kozlowski <krzk@kernel.org>: > > On 28/10/2024 13:42, Akinobu Mita wrote: > > 2024年10月28日(月) 5:38 Krzysztof Kozlowski <krzk@kernel.org>: > >> > >> On Sat, Oct 26, 2024 at 05:05:35PM +0900, Akinobu Mita wrote: > >>> Document new retain-state-shutdown property. > >>> > >>> Cc: Jean Delvare <jdelvare@suse.com> > >>> Cc: Guenter Roeck <linux@roeck-us.net> > >>> Cc: Rob Herring <robh@kernel.org> > >>> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org> > >>> Cc: Conor Dooley <conor+dt@kernel.org> > >>> Cc: Billy Tsai <billy_tsai@aspeedtech.com> > >>> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> > >>> --- > >>> Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 4 ++++ > >>> 1 file changed, 4 insertions(+) > >>> > >>> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > >>> index 4e5abf7580cc..86a069969e29 100644 > >>> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > >>> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > >>> @@ -40,6 +40,10 @@ properties: > >>> maximum: 4 > >>> default: 2 > >>> > >>> + retain-state-shutdown: > >>> + description: Retain the state of the PWM on shutdown. > >> > >> You described the desired Linux feature or behavior, not the actual > >> hardware. The bindings are about the latter, so instead you need to > >> rephrase the property and its description to match actual hardware > >> capabilities/features/configuration etc. > > > > Is this description okay? > > (Reused the description of retain-state-shutdown in leds-gpio.yaml) > > > > description: > > Retain the state of the PWM on shutdown. Useful in BMC systems, for > > example, when the BMC is rebooted while the host remains up, the fan > > will not stop. > > Nothing improved in the property. You still say what the system should > do. This is user-space choice, not DT. It seems better to implement it as a device attribute.
On 28/10/2024 15:57, Akinobu Mita wrote: >>>> >>>> You described the desired Linux feature or behavior, not the actual >>>> hardware. The bindings are about the latter, so instead you need to >>>> rephrase the property and its description to match actual hardware >>>> capabilities/features/configuration etc. >>> >>> Is this description okay? >>> (Reused the description of retain-state-shutdown in leds-gpio.yaml) >>> >>> description: >>> Retain the state of the PWM on shutdown. Useful in BMC systems, for >>> example, when the BMC is rebooted while the host remains up, the fan >>> will not stop. >> >> Nothing improved in the property. You still say what the system should >> do. This is user-space choice, not DT. > > It seems better to implement it as a device attribute. I don't know about that. To repeat: if you say what system is supposed to be doing, it is a policy. Describe the hardware and its configuration and maybe this would be suitable for DT. Best regards, Krzysztof
2024年10月31日(木) 0:18 Krzysztof Kozlowski <krzk@kernel.org>: > > On 28/10/2024 15:57, Akinobu Mita wrote: > >>>> > >>>> You described the desired Linux feature or behavior, not the actual > >>>> hardware. The bindings are about the latter, so instead you need to > >>>> rephrase the property and its description to match actual hardware > >>>> capabilities/features/configuration etc. > >>> > >>> Is this description okay? > >>> (Reused the description of retain-state-shutdown in leds-gpio.yaml) > >>> > >>> description: > >>> Retain the state of the PWM on shutdown. Useful in BMC systems, for > >>> example, when the BMC is rebooted while the host remains up, the fan > >>> will not stop. > >> > >> Nothing improved in the property. You still say what the system should > >> do. This is user-space choice, not DT. > > > > It seems better to implement it as a device attribute. > > I don't know about that. To repeat: if you say what system is supposed > to be doing, it is a policy. Describe the hardware and its configuration > and maybe this would be suitable for DT. Billy, could you please write a proper description for this property? I'm not the right person for this.
© 2016 - 2024 Red Hat, Inc.