linux-kernel - Re: [PATCH 2/3] ARM: DTS: imx6q-logicpd: Reduce inrush current on start

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]

Message-ID: <CAHCN7x+DKh8bR17C90o-zKKnFqWe_Yz5EM68xEiSY0W6ufNARA@mail.gmail.com>
Date:   Wed, 20 Mar 2019 08:41:27 -0500
From:   Adam Ford <aford173@...il.com>
To:     Shawn Guo <shawnguo@...nel.org>
Cc:     arm-soc <linux-arm-kernel@...ts.infradead.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] ARM: DTS: imx6q-logicpd: Reduce inrush current on start

On Wed, Mar 20, 2019 at 7:45 AM Shawn Guo <shawnguo@...nel.org> wrote:
>
> On Wed, Mar 06, 2019 at 08:04:00AM -0600, Adam Ford wrote:
> > The main 3.3V regulator sources a series of additional regulators.
> > This patch adds a small delay, so when the 3.3V regulator comes
> > on it delays a bit before the subsequent regulators can come on.
> > This reduces the inrush current a bit on the external DC power
> > supply.
> >
> > Fixes: 1c207f911fe9 ("ARM: dts: imx: Add support for Logic PD
> > i.MX6QD EVM")
>
> Same comment as patch #1.

The sourcing regulator occasionally cuts out because the inrush is so
high.  I would argue that preventing a hardware issue like that would
be a 'fix' and if it helps, I could add that to the description.

>
> >
> > Signed-off-by: Adam Ford <aford173@...il.com>
>
> To match the convention, the 'DTS' in subject prefix should be
> lowercase.

I will fix in V2.

>
> Shawn

adam
>
> >
> > diff --git a/arch/arm/boot/dts/imx6-logicpd-baseboard.dtsi b/arch/arm/boot/dts/imx6-logicpd-baseboard.dtsi
> > index fb01fa6e4224..e31b6923cb72 100644
> > --- a/arch/arm/boot/dts/imx6-logicpd-baseboard.dtsi
> > +++ b/arch/arm/boot/dts/imx6-logicpd-baseboard.dtsi
> > @@ -99,6 +99,7 @@
> >               regulator-min-microvolt = <3300000>;
> >               regulator-max-microvolt = <3300000>;
> >               gpio = <&gpio1 26 GPIO_ACTIVE_HIGH>;
> > +             startup-delay-us = <70000>;
> >               enable-active-high;
> >               regulator-always-on;
> >       };
> > --
> > 2.17.1
> >