Re: [v1 1/2] clk: qcom: gdsc: Use the default transition delay for GDSCs

From: Stephen Boyd
Date: Thu Feb 17 2022 - 18:24:54 EST


Quoting Bjorn Andersson (2022-02-10 11:32:03)
> On Thu 10 Feb 01:28 CST 2022, Stephen Boyd wrote:
>
> > I'd prefer we invert the logic so that we don't need to litter this flag
> > all over the place. I recall that the wait values were incorrect a long
> > time ago on early gdsc using designs but hopefully they've been fixed
> > now and we can simply use the default power on reset (POR) values.
>
> Are you suggesting that we make it the default to not update the values
> and then provide means to specify it where needed?

Sure!

>
> I like that suggestion.
>
> But as mentioned in my reply yesterday, GPU_CX on several platforms
> needs a different CLK_DIS_WAIT_VAL - and not the same value.
>
> Are these values ever 0? Or could we simply add the three numbers to
> struct gdsc and have 0 denote "use hw default"?

I don't think they're ever set to zero. That would most likely just
break things because they need a few clk cycles to wait between
transitioning states. Otherwise the GDSC gets stuck and the clks don't
work.