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. > 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. 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. 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. Regards, Bjorn
