linux-kernel - Re: [PATCH v2 2/2] regulator: tps65910: Allow supply references to the same chip

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Message-ID: <20170613202217.nj23xkahpz3jc4h5@qmqm.qmqm.pl>
Date:   Tue, 13 Jun 2017 22:22:17 +0200
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Tony Lindgren <tony@...mide.com>,
        Liam Girdwood <lgirdwood@...il.com>, j-keerthy@...com,
        linux-omap@...r.kernel.org
Subject: Re: [PATCH v2 2/2] regulator: tps65910: Allow supply references to
 the same chip

On Tue, Jun 13, 2017 at 06:46:28PM +0100, Mark Brown wrote:
> On Tue, Jun 13, 2017 at 04:41:58PM +0200, Michał Mirosław wrote:
> > This allows for (acyclic) references from tps6591x supplies to
> > its outputs.
> This is clearly not something that should be open coded in individual
> drivers, aside from the code duplication it is obviously possible to
> have two different chips supplying each other which this wouldn't help
> at all.  Is this happening for you with current kernels, we have a few
> mechanisms for deferring bindings of supplies which should help here.

What mechanisms would that be? What I observed is that whenever
a regulator's supply is not available but described in device-tree,
the whole device's registration is deferred.

The device-tree I'm working on contains:

pmic: tps65911@2d { 
    compatible = "ti,tps65911"; 
    reg = <0x2d>; 
    ...
    vcc3-supply = <&vio_reg>; // ldo6, ldo7, ldo8
    ...
    regulators {
        vio_reg: vio {
            regulator-min-microvolt = <1800000>;
            regulator-max-microvolt = <1800000>;
            regulator-always-on;
        };
        ...
    }
}

Best Regards,
Michał Mirosław