Voltage and current regulator: usage of 'regulators' parent node in device tree

Voltage and current regulator: usage of 'regulators' parent node in device tree

[embedded (VIVAVIS AG)]

I see a lot of Device trees wrapping the regulator nodes within a parent node
like this

regulators {
    compatible = "simple-bus";
    #address-cells = <1>;
    #size-cells = <0>;
    reg_p3v3: regulator@0 {
        compatible = "regulator-fixed";
        [...]
        regulator-always-on;
    };
    [...]

Contrary to that, patches exist removing the 'regulators' node, because the 'simple-bus'
doesn't really exist in hardware. Unfortunately, the documentation is unclear about
wrapping regulator nodes like shown above.

Should I avoid the parent 'regulators' node and why?

Is the given naming schema in fixed-regulator.yaml best practice to follow?

    reg_xyz: regulator-xyz {
      compatible = "regulator-fixed";
      regulator-name = "xyz";

Thank you for clarification.

Carsten Stelling

AW: Voltage and current regulator: usage of 'regulators' parent node in device tree

[embedded (VIVAVIS AG)]

Hi,

> I see a lot of Device trees wrapping the regulator nodes within a parent node
> like this
>
> regulators {
>    compatible = "simple-bus";
>    #address-cells = <1>;
>    #size-cells = <0>;
>    reg_p3v3: regulator@0 {
>        compatible = "regulator-fixed";
>        [...]
>        regulator-always-on;
>    };
>    [...]
>
> Contrary to that, patches exist removing the 'regulators' node, because the 'simple-bus'
> doesn't really exist in hardware. Unfortunately, the documentation is unclear about
> wrapping regulator nodes like shown above.
>
> Should I avoid the parent 'regulators' node and why?
>
> Is the given naming schema in fixed-regulator.yaml best practice to follow?
>
>    reg_xyz: regulator-xyz {
>      compatible = "regulator-fixed";
>      regulator-name = "xyz";
>
> Thank you for clarification.
>
> Carsten Stelling

Possibly, the wrong list or recipients?
Any thoughts on this topic?

Thank you for your help.

Carsten

Re: Voltage and current regulator: usage of 'regulators' parent node in device tree

[Rob Herring]

On Mon, Aug 23, 2021 at 7:59 AM embedded (VIVAVIS AG)
<embedded-dQ8pE230Wp9BDgjK7y7TUQ@public.gmane.org> wrote:
>
> Dear maintainer,
>
> I see a lot of Device trees wrapping the regulator nodes within a parent node
> like this
>
> regulators {
>     compatible = "simple-bus";
>     #address-cells = <1>;
>     #size-cells = <0>;
>     reg_p3v3: regulator@0 {
>         compatible = "regulator-fixed";
>         [...]
>         regulator-always-on;
>     };
>     [...]
>
> Contrary to that, patches exist removing the 'regulators' node, because the 'simple-bus'
> doesn't really exist in hardware. Unfortunately, the documentation is unclear about
> wrapping regulator nodes like shown above.
>
> Should I avoid the parent 'regulators' node and why?

Yes and no. Yes, in the above case as there is no bus nor grouping of
fixed regulators. For a MFD that includes regulators, then a child
'regulators' node is appropriate. To put it another way, if you have a
schema defining a 'regulators' node, then it probably is appropriate.

> Is the given naming schema in fixed-regulator.yaml best practice to follow?
>
>     reg_xyz: regulator-xyz {
>       compatible = "regulator-fixed";
>       regulator-name = "xyz";

Yes, pretty much.

Rob

Voltage and current regulator: usage of 'regulators' parent node in device tree

[embedded (VIVAVIS AG)]

Dear maintainer,

I see a lot of Device trees wrapping the regulator nodes within a parent node
like this

regulators {
    compatible = "simple-bus";
    #address-cells = <1>;
    #size-cells = <0>;
    reg_p3v3: regulator@0 {
        compatible = "regulator-fixed";
        [...]
        regulator-always-on;
    };
    [...]

Contrary to that, patches exist removing the 'regulators' node, because the 'simple-bus'
doesn't really exist in hardware. Unfortunately, the documentation is unclear about
wrapping regulator nodes like shown above.

Should I avoid the parent 'regulators' node and why?

Is the given naming schema in fixed-regulator.yaml best practice to follow?

    reg_xyz: regulator-xyz {
      compatible = "regulator-fixed";
      regulator-name = "xyz";

Thank you for clarification.

Carsten Stelling

Re: Voltage and current regulator: usage of 'regulators' parent node in device tree

[Mark Brown]

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On Wed, Jul 07, 2021 at 01:09:25PM +0000, embedded (VIVAVIS AG) wrote:

> Should I avoid the parent 'regulators' node?

You should ask the DT maintainers, I don't really mind either way TBH.
My understanding was to avoid the parent node but can't remember why or
if it was important.

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Voltage and current regulator: usage of 'regulators' parent node in device tree

[embedded (VIVAVIS AG)]

I see a lot of Devicetrees wrapping the regulator nodes within a parent node
like this

regulators {
    compatible = "simple-bus";
    #address-cells = <1>;
    #size-cells = <0>;
    reg_p3v3: regulator@0 {
        compatible = "regulator-fixed";
        [...]
        regulator-always-on;
    };
    [...]

Contrary to that, patches exist removing the 'regulators' node, because the 'simple-bus'
doesn't really exist in hardware. Unfortunately, the documentation is unclear about
wrapping regulator nodes like shown above.

Should I avoid the parent 'regulators' node?

Is the given naming schema in fixed-regulator.yaml best practice to follow?

    reg_xyz: regulator-xyz {
      compatible = "regulator-fixed";
      regulator-name = "xyz";

Thank you for clarification.

Carsten Stelling