linux-kernel - Re: [PATCH 0/7] OPP/pmdomain: Assign required

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Date: Sat, 22 Jun 2024 14:18:05 +0200
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Ulf Hansson <ulf.hansson@...aro.org>, Viresh Kumar <vireshk@...nel.org>,
 Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>
Cc: Bjorn Andersson <andersson@...nel.org>, Nikunj Kela <nkela@...cinc.com>,
 Prasad Sodagudi <psodagud@...cinc.com>,
 Thierry Reding <thierry.reding@...il.com>,
 Jonathan Hunter <jonathanh@...dia.com>, linux-pm@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/7] OPP/pmdomain: Assign required_devs for required OPPs
 through genpd

On 19.06.2024 4:08 PM, Ulf Hansson wrote:
> Through dev_pm_opp_set_config() the _opp_attach_genpd() allows consumer
> drivers to hook up a device to its PM domains. This works for both a single
> and multiple PM domains. Their corresponding virtual devices that are
> created by genpd during attach, are later being assigned as the
> required_devs for the corresponding required OPPs.
> 
> In principle this works fine, but there are some problems. Especially as
> the index for a "required-opps" may not necessarily need to match the index
> for the "power-domain" in DT, in which case things gets screwed up.

So, is this series essentially tackling a problem like this:

pdp_A: power-domain-provider@...aaa {
	[...]

	opp-table {
		pdp_A_opp0: opp-0 {
			opp-level = <0>;
		};
	};
};

pdp_B: power-domain-provider@...bbbb {
	[...]

	opp-table {
		pdp_B_opp0: opp-0 {
			opp-level = <0>;
		};
	};
};

nice-device@...cccc {
	[...]

	power-domains = <&pdp_A>,
			<&pdp_B>;
	// order doesn't match /\
	required-opps = <&pdp_B_opp0>,
			<&pdp_A_opp0>;
};


?

Konrad