[PATCH] clk: sunxi: Accept a greater rate when setting a parent clock
maxime.ripard at free-electrons.com
Thu Apr 14 12:31:32 PDT 2016
On Thu, Apr 14, 2016 at 08:14:28PM +0200, Jean-Francois Moine wrote:
> On Thu, 14 Apr 2016 19:24:00 +0200
> Maxime Ripard <maxime.ripard at free-electrons.com> wrote:
> > > >> That being said, we had a similar discussion for SPI around a month
> > > >> ago where we wanted a rate strictly lower than the requested one. I
> > > >> guess it's time to add a flag to tell how you want to round.
> > > >
> > > > You are right, I just removed half of the constraint, but I still wonder
> > > > why does this sequence introduced by the commit 862b728387aef3a37
> > > > (clk: sunxi: factors: automatic reparenting support) do
> > > > "provide the fastest rate <= rate"
> > > > instead of
> > > > "provide the closest rate" ?
> > > >
> > > > Emilio?
> > >
> > > Overclocking components is usually not a good default in my opinion. I
> > > don't recall at the moment if there was some other justification apart
> > > from playing it safe.
> > Yeah, I'd agree, it should be the exception rather than the norm. In
> > some cases that are very timings sensitive (audio or video), we
> > probably want to enforce something as close as possible to the
> > expected rate, even if it trips above the rate.
> > For all the other, I'd prefer to keep the current behaviour.
> OK, then, as I have no solution for this clock, there will be no audio
> 44.1KHz from the H3...
You have not read me. I already suggested in the quote above to add a
flag to tell how we should round the clock rate, the default remaining
to round it down.
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
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