On 16/02/2023 11:41, Claudiu.Beznea@xxxxxxxxxxxxx wrote: > On 16.02.2023 12:18, Krzysztof Kozlowski wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >> >> On 16/02/2023 11:15, Claudiu.Beznea@xxxxxxxxxxxxx wrote: >>> On 16.02.2023 12:04, Krzysztof Kozlowski wrote: >>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>>> >>>> On 14/02/2023 17:14, Claudiu Beznea wrote: >>>>> Add microchip,startup-delay-us binding to let PDMC users to specify >>>>> startup delay. >>>>> >>>>> Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx> >>>>> --- >>>>> .../devicetree/bindings/sound/microchip,sama7g5-pdmc.yaml | 6 ++++++ >>>>> 1 file changed, 6 insertions(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/sound/microchip,sama7g5-pdmc.yaml b/Documentation/devicetree/bindings/sound/microchip,sama7g5-pdmc.yaml >>>>> index c4cf1e5ab84b..9b40268537cb 100644 >>>>> --- a/Documentation/devicetree/bindings/sound/microchip,sama7g5-pdmc.yaml >>>>> +++ b/Documentation/devicetree/bindings/sound/microchip,sama7g5-pdmc.yaml >>>>> @@ -67,6 +67,12 @@ properties: >>>>> maxItems: 4 >>>>> uniqueItems: true >>>>> >>>>> + microchip,startup-delay-us: >>>>> + description: | >>>>> + Specifies the delay in microseconds that needs to be applied after >>>>> + enabling the PDMC microphones to avoid unwanted noise due to microphones >>>>> + not being ready. >>>> >>>> Is this some hardware delay? Or OS? If OS, why Linux specific delay is >>>> put into DT? >>> >>> It's the delay used in software workaround that IP needs to filter noises. >> >> Then this sounds like OS? Linux related properties usually do not belong >> to DT. >> >>> The IP is not fully featured to do this kind of filtering on its own thus >>> this software workaround. This delay may depend on used microphones thus >>> for different kind of setups (PDMC + different microphones) I introduced >>> this in DT. >> >> I understand your driver needs delay and I am not questioning this. I am >> questioning why this is suitable for DT? > > Because that delay may depend on the microphones that are used with PDMC. > Different boards may come with different microphones, thus the default > delay may not fit to fully filter the noise. Due to this I chose to add it > in DT. Ah, ok, that's good explanation. Thank you. Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> Best regards, Krzysztof