Re: [PATCH net 1/2] dt: ar803x: Document disable-hibernation property

Krzysztof Kozlowski
2022-08-12T11:25:56Z

On 12/08/2022 12:02, Wei Fang wrote:
>
>
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>> Sent: 2022年8月12日 15:28
>> To: Wei Fang <wei.fang@nxp.com>; andrew@lunn.ch; hkallweit1@gmail.com;
>> linux@armlinux.org.uk; davem@davemloft.net; edumazet@google.com;
>> kuba@kernel.org; pabeni@redhat.com; robh+dt@kernel.org;
>> krzysztof.kozlowski+dt@linaro.org; f.fainelli@gmail.com;
>> netdev@vger.kernel.org; devicetree@vger.kernel.org;
>> linux-kernel@vger.kernel.org
>> Subject: Re: [PATCH net 1/2] dt: ar803x: Document disable-hibernation
>> property
>>
>> On 12/08/2022 17:50, wei.fang@nxp.com wrote:
>>> From: Wei Fang <wei.fang@nxp.com>
>>>
>>
>> Please use subject prefix matching subsystem.
>>
> Ok, I'll add the subject prefix.
>
>>> The hibernation mode of Atheros AR803x PHYs is default enabled.
>>> When the cable is unplugged, the PHY will enter hibernation mode and
>>> the PHY clock does down. For some MACs, it needs the clock to support
>>> it's logic. For instance, stmmac needs the PHY inputs clock is present
>>> for software reset completion. Therefore, It is reasonable to add a DT
>>> property to disable hibernation mode.
>>>
>>> Signed-off-by: Wei Fang <wei.fang@nxp.com>
>>> ---
>>> Documentation/devicetree/bindings/net/qca,ar803x.yaml | 6 ++++++
>>> 1 file changed, 6 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/qca,ar803x.yaml
>>> b/Documentation/devicetree/bindings/net/qca,ar803x.yaml
>>> index b3d4013b7ca6..d08431d79b83 100644
>>> --- a/Documentation/devicetree/bindings/net/qca,ar803x.yaml
>>> +++ b/Documentation/devicetree/bindings/net/qca,ar803x.yaml
>>> @@ -40,6 +40,12 @@ properties:
>>> Only supported on the AR8031.
>>> type: boolean
>>>
>>> + qca,disable-hibernation:
>>> + description: |
>>> + If set, the PHY will not enter hibernation mode when the cable is
>>> + unplugged.
>>
>> Wrong indentation. Did you test the bindings?
>>
> Sorry, I just checked the patch and forgot to check the dt-bindings.
>
>> Unfortunately the property describes driver behavior not hardware, so it is not
>> suitable for DT. Instead describe the hardware
>> characteristics/features/bugs/constraints. Not driver behavior. Both in property
>> name and property description.
>>
> Thanks for your review and feedback. Actually, the hibernation mode is a feature of hardware, I will modify the property name and description to be more in line with the requirements of the DT property.

hibernation is a feature, but 'disable-hibernation' is not. DTS
describes the hardware, not policy or driver bejhvior. Why disabling
hibernation is a property of hardware? How you described, it's not,
therefore either property is not for DT or it has to be phrased
correctly to describe the hardware.

Best regards,
Krzysztof