Re: [PATCH] clk: stm32h7: Add stm32h743 clock driver

[Gabriel Fernandez]

Hi Stephen

Sorry for delay i was on sick live

On 04/07/2017 09:51 PM, Stephen Boyd wrote:
> On 04/06, Gabriel Fernandez wrote:
> > On 04/06/2017 12:32 AM, Stephen Boyd wrote:
> > > On 03/15, gabriel.fernandez@xxxxxx wrote:
> > > > diff --git a/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
> > > > new file mode 100644
> > > > index 0000000..9d4b587
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
> > > > @@ -0,0 +1,152 @@
> > > > +
> > > > +	rcc: rcc@58024400 {
> > > > +		#reset-cells = <1>;
> > > > +		#clock-cells = <2>
> > > > +		compatible = "st,stm32h743-rcc", "st,stm32-rcc";
> > > > +		reg = <0x58024400 0x400>;
> > > > +		clocks = <&clk_hse>, <&clk_lse>, <&clk_i2s_ckin>;
> > > > +
> > > > +		st,syscfg = <&pwrcfg>;
> > > > +
> > > > +		#address-cells = <1>;
> > > > +		#size-cells = <0>;
> > > > +
> > > > +		vco1@58024430 {
> > > > +			#clock-cells = <0>;
> > > > +			compatible = "stm32,pll";
> > > > +			reg = <0>;
> > > reg is super confusing and doesn't match unit address.
> > ok i fixed it in the v2
> >
> > > > +		};
> > > Why? Shouldn't we know this from the compatible string how many
> > > PLLs there are and where they're located? Export the PLLs through
> > > rcc node's clock-cells?
> > Because i need to offer the possibility to change the PLL VCO
> > frequencies at the start-up of this driver clock.
> > The VCO algorithm needs a division factor, a multiplication factor
> > and a fractional factor.
> > Lot's of solution are possible for one frequency and it's nightmare
> > to satisfy the 3 output dividers of the PLL.
> Sure, but do we need to configure that on a per-board basis or a
> per-SoC basis? If it's just some configuration, I wonder why we
> don't put that into the driver and base it off some compatible
> string that includes the SoC the device is for.
I prefer to let in first, the responsibility of the boot loader to 
change VCO parameters.
Then i propose a new version without DT configuration of PLL's
are you ok for that ?

best regards

Gabriel



To simply