Re: [PATCH v3 28/29] media: ov2680: Add link-freq and pixel-rate controls

[Andy Shevchenko <andy@kernel.org>]

On Tue, Jul 04, 2023 at 01:19:28PM +0100, Dave Stevenson wrote:
> On Tue, 4 Jul 2023 at 12:32, Hans de Goede <hdegoede@redhat.com> wrote:
> > On 7/4/23 13:29, Hans de Goede wrote:
> > > On 7/4/23 13:23, Dave Stevenson wrote:

...

> > > So my question is do we make the link-frequency control
> > > return 331.2 MHz or 330 MHz when a 19.2 MHz xvclk is used ?
> > >
> > > 330 MHz is what will be requested in the link-frequency
> > > device property. 331.2 MHz will be what is actually used.
> > >
> > > (the 24MHz xvclk scenario results in an exact link-freq of
> > > 330MHz)
> 
> OK, that wasn't clear from the earlier discussion.
> 
> > I just realized that since both the xvclk frequency and the
> > link-frequency property will both come from the same ACPI
> > glue we could fix this be actually putting  331.2 MHz
> > in the property and making the driver accept this as valid
> > when a 19.2 MHz xvclk is used.
> >
> > That would make the property and the actually achieved
> > link-frequency be in sync again. So this is probably the
> > best way to handle this.
> >
> > Does this solution work for everyone ?
> 
> Yes, asking for the right thing sounds like a good solution.

+1 here.

> It's the same route as I went for with imx258 in [1]. There 24MHz
> results in a slightly different link freq to the existing 19.2MHz
> configuration.

-- 
With Best Regards,
Andy Shevchenko