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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

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