Re: [PATCH 0/6] usb: dwc3: Calculate REFCLKPER et. al. from reference clock

[Sean Anderson]

Hi Thinh,

On 1/18/22 2:46 PM, Thinh Nguyen wrote:
> Hi Sean,
>
> Baruch Siach wrote:
> > Hi Sean, Thinh,
> >
> > On Fri, Jan 14 2022, Sean Anderson wrote:
> > > This is a rework of patches 3-5 of [1]. It attempts to correctly program
> > > REFCLKPER and REFCLK_FLADJ based on the reference clock frequency. Since
> > > we no longer need a special property duplicating this configuration,
> > > snps,ref-clock-period-ns is deprecated.
> > >
> > > Please test this! Patches 3/4 in this series have the effect of
> > > programming REFCLKPER and REFCLK_FLADJ on boards which already configure
> > > the "ref" clock. I have build tested, but not much else.
> > >
> > > [1] https://urldefense.com/v3/__https://lore.kernel.org/linux-usb/20220114044230.2677283-1-robert.hancock@xxxxxxxxxx/__;!!A4F2R9G_pg!M3zKxDZC9a_etqzXo7GSEMTHRWfc1wR_84wwM4-fShiA35CsGcxcTEffHPbprbdC4d2R$
> >
> > Thinh, you suggested the dedicated DT property for the reference clock:
> >
> >   https://urldefense.com/v3/__https://lore.kernel.org/all/d5acb192-80b9-36f7-43f5-81f21c4e6ba0@xxxxxxxxxxxx/__;!!A4F2R9G_pg!M3zKxDZC9a_etqzXo7GSEMTHRWfc1wR_84wwM4-fShiA35CsGcxcTEffHPbprbpOFmvX$
> >
> > Can you comment on this series?
>
> Unless there's a good way to pass this information for PCI devices, my
> opinion hasn't changed. (Btw, I don't think creating a dummy clock
> provider and its dummy ops is a good solution as seems to complicate and
> bloat the PCI glue drivers).

Can you explain your situation a bit more? I'm not sure how you can
access a device tree property but not add a fixed-rate clock.

--Sean