Messages in this thread | | | Date | Tue, 18 Apr 2023 11:42:58 +0200 | Subject | Re: [PATCH 1/2] dt-bindings: phy: imx8mq-usb: add phy tuning properties | From | Johannes Zink <> |
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Hi Rob, hi Krzysztof,
On 4/12/23 16:32, Johannes Zink wrote: > Hi Rob, > > On 4/12/23 15:39, Rob Herring wrote: >> On Tue, Apr 11, 2023 at 04:22:37PM +0200, Johannes Zink wrote: >>> Hi Krzystof, >>> >>> thank you for your explanations. As I'm still quite new to writing >>> bindings, I still have some questions: >>> >>> On Fri, 2023-04-07 at 11:03 +0200, Krzysztof Kozlowski wrote: >>>> On 05/04/2023 14:14, Johannes Zink wrote: >>>>> Hi Krysztof, >>>>> >>>>> thanks for your review, please find my questions below. >>>>> >>>>> On Wed, 2023-04-05 at 13:51 +0200, Krzysztof Kozlowski wrote: >>>>>> [snip] >>>>>>> A phandle to the regulator for USB VBUS. >>>>>>> + fsl,phy-tx-vref-tune: >>>>>>> + description: >>>>>>> + HS DC Voltage level adjustment >>>>>> >>>>>> "Level" in what units? >>>>>> >>>>> >>>>> The datasheet just shows percent, ranging from -6 to +24%, in 2% >>>>> increments. What unit would you suggest? >>>> >>>> percent >>>> https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml >>> >>> I am still a bit confused how to use this properly. How can I restrict >>> the values to multiples of 2 in order to avoid illegal values? >>> >>> At the moment the only thing I could come up with is something like >>> >>> fsl,phy-tx-vref-tune-percent: >>> description: | >>> Adjusts the high-speed DC level voltage >>> $ref: /schemas/types.yaml#/definitions/int32 >> >> Note that with standard unit suffixes, you don't need a type. >> >>> minimum: -6 >>> maximum: 24 >>> default: 0 >>> >>> Does something like this work? I am not quite sure if I am on the right >>> track here, especially as this requires a signed int, of which I have >>> not seen many examples so far. >> >> We'd have to change the type for -percent to signed. That's possible, >> but for vendor specific properties there's not much advantage to use >> standard units instead of just using the register values directly. >> > > I don't have any objections to that, this is pretty much what I sent in > my v1 patch <20230405112118.1256151-2-j.zink@pengutronix.de>, but > Krzysztof requested to change the vendor specific properties to use > property-units. > > Would something along the lines of the st,trim-hs-current on > Documentation/devicetree/bindings/phy/phy-stm32-usbphyc.yaml be > acceptable (i.e. use an enum and annotate the meaning of the values in > the description)? > > I will, nevertheless, try to make the descriptions a bit more verbose in > my v2 (wherever the datasheet gives me proper informations), as > Krzysztof requested.
gentle ping - any opinions on this? Shall I just send a V2 along the lines of the phy-stm32-usbphy.c?
Best regards Johannes
> > Best regards > Johannes > >> Rob >> >
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