Re: [PATCH v3 02/23] gcc-sdm845: Add rates to the GP clocks

Dmitry Baryshkov
2024-06-19T06:32:02Z

On Tue, Jun 18, 2024 at 09:11:58PM GMT, Konrad Dybcio wrote:
>
>
> On 6/18/24 20:55, Dmitry Baryshkov wrote:
> > On Tue, Jun 18, 2024 at 08:50:52PM GMT, Konrad Dybcio wrote:
> > >
> > >
> > > On 6/18/24 19:50, Dmitry Baryshkov wrote:
> > > > On Tue, Jun 18, 2024 at 04:59:36PM GMT, Dzmitry Sankouski wrote:
> > > > > sdm845 has "General Purpose" clocks that can be muxed to
> > > > > SoC pins.
> > > > >
> > > > > Those clocks may be used as e.g. PWM sources for external peripherals.
> > > > > Add more frequencies to the table for those clocks so it's possible
> > > > > for arbitrary peripherals to make use of them.
> > > > >
> > > > > See also: bf8bb8eaccf(clk: qcom: gcc-msm8916: Add rates to the GP clocks)
> > > >
> > > > Each time I look at the table attached to the GP CLK, I feel that it's
> > > > plain wrong. In the end the GPCLK can in theory have arbitrary value
> > > > depending on the usecase.
> > > >
> > > > Bjorn, Konrad, maybe we should add special clk_ops for GP CLK which
> > > > allow more flexibility than a default clk_rcg2_ops?
> > >
> > > If we can somehow get max m/n/d values for all possible parents, sure
> >
> > Calculate them at runtime?
>
> We'd be calculating the mnd values for a frequency that's either equal or
> reasonably close to the one requested. My worry is that we somehow need
> to get the maximum values they can take (unless they're well-known)

One of the options might be to force devices to use
assigned-clock-parent to set GP CLK sorource and pwm-clk as an actual
device using the clock.

--
With best wishes
Dmitry