Re: [PATCH v3 1/6] dt-bindings: opp: Introduce opp-peak-KBps and opp-avg-KBps bindings

Saravana Kannan
2019-07-22T23:41:32Z

On Mon, Jul 22, 2019 at 4:35 PM Rob Herring <robh@kernel.org> wrote:
>
> On Tue, Jul 16, 2019 at 11:58:08AM -0700, Saravana Kannan wrote:
> > On Tue, Jul 16, 2019 at 10:25 AM Sibi Sankar <sibis@codeaurora.org> wrote:
> > >
> > > Hey Saravana,
> > >
> > > https://patchwork.kernel.org/patch/10850815/
> > > There was already a discussion ^^ on how bandwidth bindings were to be
> > > named.
> >
> > Yes, I'm aware of that series. That series is trying to define a BW
> > mapping for an existing frequency OPP table. This patch is NOT about
> > adding a mapping to an existing table. This patch is about adding the
> > notion of BW OPP tables where BW is the "key" instead of "frequency".
> >
> > So let's not mixed up these two series.
>
> Maybe different reasons, but in the end we'd end up with 2 bandwidth
> properties. We need to sort out how they'd overlap/coexist.

Oh, I totally agree! My point is that the other mapping isn't the
right approach because it doesn't handle a whole swath of use cases.
The one I'm proposing can act as a super set of the other (as in, can
handle that use case too).

> The same comment in that series about defining a standard unit suffix
> also applies to this one.

I thought I read that whole series and I don't remember reading about
the unit suffix. But I'll take a closer look. I've chosen to keep the
DT units at least as "high of a resolution" as what the APIs accept
today. The APIs take KB/s. So I make sure DT can capture KB/s
differences. If we all agree that KB/s is "too accurate" then I think
we should change everything to MB/s.

-Saravana