On Thu, 1 Jul 2021 at 21:26, Bjorn Andersson <bjorn.andersson@xxxxxxxxxx> wrote: > > On Thu 01 Jul 11:58 CDT 2021, Ulf Hansson wrote: > > > On Thu, 1 Jul 2021 at 18:39, Dmitry Baryshkov > > <dmitry.baryshkov@xxxxxxxxxx> wrote: > > > > > > On Thu, 1 Jul 2021 at 19:17, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > > > > > > > On Wed, 30 Jun 2021 at 15:31, Dmitry Baryshkov > > > > <dmitry.baryshkov@xxxxxxxxxx> wrote: > > > > > > > > > > On sm8250 dispcc requires MMCX power domain to be powered up before > > > > > clock controller's registers become available. For now sm8250 was using > > > > > external regulator driven by the power domain to describe this > > > > > relationship. Switch into specifying power-domain and required opp-state > > > > > directly. > > > > > > > > > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> > > > > > --- > > > > > .../bindings/clock/qcom,dispcc-sm8x50.yaml | 19 +++++++++++++++++++ > > > > > 1 file changed, 19 insertions(+) > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/clock/qcom,dispcc-sm8x50.yaml b/Documentation/devicetree/bindings/clock/qcom,dispcc-sm8x50.yaml > > > > > index 0cdf53f41f84..48d86fb34fa7 100644 > > > > > --- a/Documentation/devicetree/bindings/clock/qcom,dispcc-sm8x50.yaml > > > > > +++ b/Documentation/devicetree/bindings/clock/qcom,dispcc-sm8x50.yaml > > > > > @@ -55,6 +55,16 @@ properties: > > > > > reg: > > > > > maxItems: 1 > > > > > > > > > > + power-domains: > > > > > + description: > > > > > + A phandle and PM domain specifier for the MMCX power domain. > > > > > + maxItems: 1 > > > > > + > > > > > > > > Should you perhaps state that this is a parent domain? Or it isn't? > > > > > > > > Related to this and because this is a power domain provider, you > > > > should probably reference the common power-domain bindings somewhere > > > > here. Along the lines of this: > > > > > > > > - $ref: power-domain.yaml# > > > > > > > > As an example, you could have a look at > > > > Documentation/devicetree/bindings/power/pd-samsung.yaml. > > > > > > I'll take a look. > > > > > > > > > > > > + required-opps: > > > > > + description: > > > > > + Performance state to use for MMCX to enable register access. > > > > > + maxItems: 1 > > > > > > > > According to the previous discussions, I was under the assumption that > > > > this property belongs to a consumer node rather than in the provider > > > > node, no? > > > > > > It is both a consumer and a provider. It consumes SM8250_MMCX from > > > rpmhpd and provides MMSC_GDSC. > > > > That sounds a bit weird to me. > > > > dispcc is a hardware block powered by MMCX, so it is a consumer of it > and needs to control MMCX. Right, that sounds reasonable. > > > In my view and per the common power domain bindings (as pointed to > > above): If a power domain provider is a consumer of another power > > domain, that per definition means that there is a parent domain > > specified. > > > > And in addition to needing MMCX to access the dispcc, the exposed > power-domain "MDSS_GDSC" is powered by the same MMCX and as such > MDSS_GDSC should be a subdomain of MMCX. What do you mean by "exposed"? It sounds like you are saying that "MDSS_GDSC" is an artificial power domain, no? If that's the case, more exactly, why is it like this? My apologies if I bother you with details, but as a maintainer of genpd, it is very useful to me to have the complete picture. > > > But what I was trying to say yesterday is that the power-domain property > should be sufficient and that we shouldn't need to drive MMCX to a > particular performance_state in order to access the registers. > > Then as clients make votes on clock rates that requires higher > performance_state, they would describe this in their opp-tables etc. > > > But without any performance_state requests, pd->corner will in > rpmhpd_power_on() be 0 and as such powering on the power-domain won't > actually do anything. Similarly dev_pm_genpd_set_performance_state(dev, > 0) on an active power-domain from rpmhpd will turn it off. Yes, I noticed the patches you posted. Thanks for helping out here! > > > So the reason why Dmitry is adding the required-opps to the binding is > to get rpmhpd to actually tell the hardware to turn on the power domain. > And I don't think this is in accordance with the framework's > expectations. I agree! > > Regards, > Bjorn Kind regards Uffe
