arm64: dts: imx8mp-verdin: board regulators: add always-on

[PATCH] arm64: dts: imx8mp-verdin: board regulators: add always-on

Posted by Max Krummenacher 3 years, 7 months ago

From: Max Krummenacher <max.krummenacher@toradex.com>

These regulators are switched on by HW during power up and can not
be influenced by SW.
Set the always-on property.

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>

---

 arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
index 557cfef8f049..76cc89296150 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
@@ -62,6 +62,7 @@ button-wakeup {
 	/* Carrier Board Supplies */
 	reg_1p8v: regulator-1p8v {
 		compatible = "regulator-fixed";
+		regulator-always-on;
 		regulator-max-microvolt = <1800000>;
 		regulator-min-microvolt = <1800000>;
 		regulator-name = "+V1.8_SW";
@@ -69,6 +70,7 @@ reg_1p8v: regulator-1p8v {
 
 	reg_3p3v: regulator-3p3v {
 		compatible = "regulator-fixed";
+		regulator-always-on;
 		regulator-max-microvolt = <3300000>;
 		regulator-min-microvolt = <3300000>;
 		regulator-name = "+V3.3_SW";
@@ -76,6 +78,7 @@ reg_3p3v: regulator-3p3v {
 
 	reg_5p0v: regulator-5p0v {
 		compatible = "regulator-fixed";
+		regulator-always-on;
 		regulator-max-microvolt = <5000000>;
 		regulator-min-microvolt = <5000000>;
 		regulator-name = "+V5_SW";
-- 
2.35.3

Re: [PATCH] arm64: dts: imx8mp-verdin: board regulators: add always-on

Posted by Laurent Pinchart 3 years, 7 months ago

Hi Max,

(CC'ing Mark and Liam)

Thank you for the patch.

On Thu, Sep 01, 2022 at 01:04:22PM +0200, Max Krummenacher wrote:
> From: Max Krummenacher <max.krummenacher@toradex.com>
> 
> These regulators are switched on by HW during power up and can not
> be influenced by SW.
> Set the always-on property.

Is this needed ? When a fixed regulator has no control GPIO or clock, as
is the case here, I would expect the driver and/or regulator core to
understand that it's always on, as the alternative is always-off, which
is pointless :-) Mark, Liam, what do you think ?

> Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
> 
> ---
> 
>  arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
> index 557cfef8f049..76cc89296150 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi
> @@ -62,6 +62,7 @@ button-wakeup {
>  	/* Carrier Board Supplies */
>  	reg_1p8v: regulator-1p8v {
>  		compatible = "regulator-fixed";
> +		regulator-always-on;
>  		regulator-max-microvolt = <1800000>;
>  		regulator-min-microvolt = <1800000>;
>  		regulator-name = "+V1.8_SW";
> @@ -69,6 +70,7 @@ reg_1p8v: regulator-1p8v {
>  
>  	reg_3p3v: regulator-3p3v {
>  		compatible = "regulator-fixed";
> +		regulator-always-on;
>  		regulator-max-microvolt = <3300000>;
>  		regulator-min-microvolt = <3300000>;
>  		regulator-name = "+V3.3_SW";
> @@ -76,6 +78,7 @@ reg_3p3v: regulator-3p3v {
>  
>  	reg_5p0v: regulator-5p0v {
>  		compatible = "regulator-fixed";
> +		regulator-always-on;
>  		regulator-max-microvolt = <5000000>;
>  		regulator-min-microvolt = <5000000>;
>  		regulator-name = "+V5_SW";

-- 
Regards,

Laurent Pinchart

Re: [PATCH] arm64: dts: imx8mp-verdin: board regulators: add always-on

Posted by Mark Brown 3 years, 7 months ago

On Thu, Sep 01, 2022 at 09:29:13PM +0300, Laurent Pinchart wrote:
> On Thu, Sep 01, 2022 at 01:04:22PM +0200, Max Krummenacher wrote:
> > From: Max Krummenacher <max.krummenacher@toradex.com>

> > These regulators are switched on by HW during power up and can not
> > be influenced by SW.
> > Set the always-on property.
> 
> Is this needed ? When a fixed regulator has no control GPIO or clock, as
> is the case here, I would expect the driver and/or regulator core to
> understand that it's always on, as the alternative is always-off, which
> is pointless :-) Mark, Liam, what do you think ?

If there's no physical control setting always-on does nothing.

Re: [PATCH] arm64: dts: imx8mp-verdin: board regulators: add always-on

Posted by Francesco Dolcini 3 years, 7 months ago

On Thu, Sep 01, 2022 at 07:44:43PM +0100, Mark Brown wrote:
> On Thu, Sep 01, 2022 at 09:29:13PM +0300, Laurent Pinchart wrote:
> > On Thu, Sep 01, 2022 at 01:04:22PM +0200, Max Krummenacher wrote:
> > > From: Max Krummenacher <max.krummenacher@toradex.com>
> 
> > > These regulators are switched on by HW during power up and can not
> > > be influenced by SW.
> > > Set the always-on property.
> > 
> > Is this needed ? When a fixed regulator has no control GPIO or clock, as
> > is the case here, I would expect the driver and/or regulator core to
> > understand that it's always on, as the alternative is always-off, which
> > is pointless :-) Mark, Liam, what do you think ?
> 
> If there's no physical control setting always-on does nothing.

The patch was posted because of a warning on trying to disable an unused
regulator.

However this was changed with
  261f06315cf7 ("regulator: Flag uncontrollable regulators as always_on").

Max was testing with a kernel without this patch in and forgot to verify
on latest upstream kernel.

Just disregard this.

Francesco