diff mbox series

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

Message ID 20190306140402.17122-2-aford173@gmail.com (mailing list archive)
State Mainlined, archived
Commit dbb58e291cd47e594b64293bd91a4ce40626513c
Headers show
Series [1/3] ARM: dts: imx6q-logicpd: Shutdown LCD regulator during suspend | expand

Commit Message

Adam Ford March 6, 2019, 2:04 p.m. UTC
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")

Signed-off-by: Adam Ford <aford173@gmail.com>

Comments

Shawn Guo March 20, 2019, 12:44 p.m. UTC | #1
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.

> 
> Signed-off-by: Adam Ford <aford173@gmail.com>

To match the convention, the 'DTS' in subject prefix should be
lowercase.

Shawn

> 
> 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
>
Adam Ford March 20, 2019, 1:41 p.m. UTC | #2
On Wed, Mar 20, 2019 at 7:45 AM Shawn Guo <shawnguo@kernel.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@gmail.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
> >
Shawn Guo March 20, 2019, 2:57 p.m. UTC | #3
On Wed, Mar 20, 2019 at 08:41:27AM -0500, Adam Ford wrote:
> On Wed, Mar 20, 2019 at 7:45 AM Shawn Guo <shawnguo@kernel.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.

Yes, if you would like to get it in as a fix, please elaborate the real
world issue it fixes.

Shawn
diff mbox series

Patch

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;
 	};