linux-kernel - Re: [PATCH V3 1/9] PM / OPP: Reword binding supporting multiple regulators per device

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Date:   Thu, 10 Nov 2016 23:39:40 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Mark Brown <broonie@...nel.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, nm@...com,
        sboyd@...eaurora.org, Viresh Kumar <vireshk@...nel.org>,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>, robh@...nel.org,
        d-gerlach@...com, devicetree@...r.kernel.org
Subject: Re: [PATCH V3 1/9] PM / OPP: Reword binding supporting multiple
 regulators per device

On 10-11-16, 16:36, Mark Brown wrote:
> On Thu, Nov 10, 2016 at 09:34:40AM +0530, Viresh Kumar wrote:
> > On 09-11-16, 14:58, Mark Brown wrote:
> > > On Wed, Oct 26, 2016 at 12:02:56PM +0530, Viresh Kumar wrote:
> 
> > > > +  Entries for multiple regulators shall be provided in the same field separated
> > > > +  by angular brackets <>. The OPP binding doesn't provide any provisions to
> > > > +  relate the values to their power supplies or the order in which the supplies
> > > > +  need to be configured.
> 
> > > I don't understand how this works.  If we have an unordered list of
> > > values to set for regulators how will we make sense of them?
> 
> > The platform driver is responsible to identify the order and pass it on to the
> > OPP core. And the platform driver needs to have that hard coded.
> 
> That *really* should be in the binding.

Okay, how do you suggest doing that? Will a property like supply-names
in the OPP table be fine? Like this:

@@ -369,13 +378,16 @@ Example 4: Handling multiple regulators
                        compatible = "arm,cortex-a7";
                        ...
 
-                       cpu-supply = <&cpu_supply0>, <&cpu_supply1>, <&cpu_supply2>;
+                       vcc0-supply = <&cpu_supply0>;
+                       vcc1-supply = <&cpu_supply1>;
+                       vcc2-supply = <&cpu_supply2>;
                        operating-points-v2 = <&cpu0_opp_table>;
                };
        };
 
        cpu0_opp_table: opp_table0 {
                compatible = "operating-points-v2";
+               supply-names = "vcc0", "vcc1", "vcc2";
                opp-shared;

-- 
viresh