| Message ID | 20220504065252.6955-2-zev@bewilderbeest.net |
|---|---|
| State | New |
| Headers | show |
| Series | regulator: core: Add support for external outputs | expand |
On Tue, May 03, 2022 at 11:52:48PM -0700, Zev Weiss wrote: > This describes an external output supplied by a regulator, such as a > power outlet on a power distribution unit (PDU). OK, so this is that represnetation of the connection - which raises the question about why the regulator needs a property? > +description: | > + This describes an external output supplied by a regulator, such as > + a power outlet on a power distribution unit (PDU). > + > +properties: > + compatible: > + const: reg-external-output > + > + vout-supply: > + description: > + Phandle of the regulator supplying the output, which should have > + the regulator-external-output property. > + > +required: I think at a minimum anything like this would need some sort of representation of how the output physically appears so that people can work out how outputs are mapped to the hardware they see. However we already have a subsystem for external connectors - extcon. Perhaps this should be a regulator client in the extcon API? It's common for connectors to include some sort of power provision so it seems like this would fit right in.
On Wed, May 04, 2022 at 05:55:53AM PDT, Mark Brown wrote: >On Tue, May 03, 2022 at 11:52:48PM -0700, Zev Weiss wrote: >> This describes an external output supplied by a regulator, such as a >> power outlet on a power distribution unit (PDU). > >OK, so this is that represnetation of the connection - which raises the >question about why the regulator needs a property? > >> +description: | >> + This describes an external output supplied by a regulator, such as >> + a power outlet on a power distribution unit (PDU). >> + >> +properties: >> + compatible: >> + const: reg-external-output >> + >> + vout-supply: >> + description: >> + Phandle of the regulator supplying the output, which should have >> + the regulator-external-output property. >> + >> +required: > >I think at a minimum anything like this would need some sort of >representation of how the output physically appears so that people can >work out how outputs are mapped to the hardware they see. I don't quite understand what you're describing here -- could you elaborate on what you mean by "how the output physically appears", and what that might look like in a DT binding? >However we >already have a subsystem for external connectors - extcon. Perhaps this >should be a regulator client in the extcon API? It's common for >connectors to include some sort of power provision so it seems like this >would fit right in. Interesting -- I wasn't previously aware of the extcon subsystem, thanks for the pointer. However, after looking at it a bit, I'm not sure I see how it'd be applicable here, since it looks like it's built to handle hardware that's at least sophisticated enough for software to tell whether or not something's plugged in, which isn't the case here. The connector is just a ground pin and +12VDC pin, no presence-detection mechanism or anything else. Outside of the regulator itself there's really no "device" there for software to talk to or otherwise interact with at all. Thanks, Zev
On Wed, May 04, 2022 at 01:33:58PM -0700, Zev Weiss wrote: > On Wed, May 04, 2022 at 05:55:53AM PDT, Mark Brown wrote: > > I think at a minimum anything like this would need some sort of > > representation of how the output physically appears so that people can > > work out how outputs are mapped to the hardware they see. > I don't quite understand what you're describing here -- could you elaborate > on what you mean by "how the output physically appears", and what that might > look like in a DT binding? For example if the output comes out on a socket then that socket should be described. > > However we > > already have a subsystem for external connectors - extcon. Perhaps this > > should be a regulator client in the extcon API? It's common for > > connectors to include some sort of power provision so it seems like this > > would fit right in. > Interesting -- I wasn't previously aware of the extcon subsystem, thanks for > the pointer. However, after looking at it a bit, I'm not sure I see how > it'd be applicable here, since it looks like it's built to handle hardware > that's at least sophisticated enough for software to tell whether or not > something's plugged in, which isn't the case here. The connector is just a > ground pin and +12VDC pin, no presence-detection mechanism or anything else. > Outside of the regulator itself there's really no "device" there for > software to talk to or otherwise interact with at all. Sure, but there's no reason why it can't scale down to something simpler. It's easier to support something simpler than have to extend to support something more complicated.
[Adding extcon maintainers...] On Wed, May 04, 2022 at 01:49:12PM PDT, Mark Brown wrote: >On Wed, May 04, 2022 at 01:33:58PM -0700, Zev Weiss wrote: >> On Wed, May 04, 2022 at 05:55:53AM PDT, Mark Brown wrote: > >> > I think at a minimum anything like this would need some sort of >> > representation of how the output physically appears so that people can >> > work out how outputs are mapped to the hardware they see. > >> I don't quite understand what you're describing here -- could you elaborate >> on what you mean by "how the output physically appears", and what that might >> look like in a DT binding? > >For example if the output comes out on a socket then that socket should >be described. > Okay -- in the case of an Open19 power shelf like the ahe-50dc, there are 50 instances of this, 48 of which are in four ganged connectors each with 12 pairs of pins, but two of which have their own dedicated little individual sockets. The connectors are physically different, but they're all identical as far as software is concerned, so I'm not clear on why it would need to be expressed in any DT properties or the like. Or did you just mean explanatory free-form text in the description field? >> > However we >> > already have a subsystem for external connectors - extcon. Perhaps this >> > should be a regulator client in the extcon API? It's common for >> > connectors to include some sort of power provision so it seems like this >> > would fit right in. > >> Interesting -- I wasn't previously aware of the extcon subsystem, thanks for >> the pointer. However, after looking at it a bit, I'm not sure I see how >> it'd be applicable here, since it looks like it's built to handle hardware >> that's at least sophisticated enough for software to tell whether or not >> something's plugged in, which isn't the case here. The connector is just a >> ground pin and +12VDC pin, no presence-detection mechanism or anything else. >> Outside of the regulator itself there's really no "device" there for >> software to talk to or otherwise interact with at all. > >Sure, but there's no reason why it can't scale down to something >simpler. It's easier to support something simpler than have to extend >to support something more complicated. Alright, so would you suggest creating something like drivers/extcon/extcon-regulator-output.c, and just having its extcon functionality be something of a stub for now? Thanks, Zev
On Wed, May 04, 2022 at 02:35:08PM -0700, Zev Weiss wrote: > On Wed, May 04, 2022 at 01:49:12PM PDT, Mark Brown wrote: > > For example if the output comes out on a socket then that socket should > > be described. > Okay -- in the case of an Open19 power shelf like the ahe-50dc, there are 50 > instances of this, 48 of which are in four ganged connectors each with 12 > pairs of pins, but two of which have their own dedicated little individual > sockets. The connectors are physically different, but they're all identical > as far as software is concerned, so I'm not clear on why it would need to be > expressed in any DT properties or the like. Or did you just mean > explanatory free-form text in the description field? Explanatory description would be one example of something that should be described, yes - if there is control for switching the supplies on and off the user is going to need to be able to figure out which software control corresponds to which physical connection. Other devices may have more things that need autoamtion (eg, jack detection). > > Sure, but there's no reason why it can't scale down to something > > simpler. It's easier to support something simpler than have to extend > > to support something more complicated. > Alright, so would you suggest creating something like > drivers/extcon/extcon-regulator-output.c, and just having its extcon > functionality be something of a stub for now? I'm not super familiar with extcon but that seems plausible.
diff --git a/Documentation/devicetree/bindings/regulator/reg-external-output.yaml b/Documentation/devicetree/bindings/regulator/reg-external-output.yaml new file mode 100644 index 000000000000..c00bee5bd9f2 --- /dev/null +++ b/Documentation/devicetree/bindings/regulator/reg-external-output.yaml @@ -0,0 +1,37 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- + +$id: http://devicetree.org/schemas/regulator/reg-external-output.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Regulator external output + +maintainers: + - Zev Weiss <zev@bewilderbeest.net> + +description: | + This describes an external output supplied by a regulator, such as + a power outlet on a power distribution unit (PDU). + +properties: + compatible: + const: reg-external-output + + vout-supply: + description: + Phandle of the regulator supplying the output, which should have + the regulator-external-output property. + +required: + - compatible + - vout-supply + +additionalProperties: false + +examples: + - | + output { + compatible = "reg-external-output"; + vout-supply = <&output_reg>; + };
This describes an external output supplied by a regulator, such as a power outlet on a power distribution unit (PDU). Signed-off-by: Zev Weiss <zev@bewilderbeest.net> --- .../regulator/reg-external-output.yaml | 37 +++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 Documentation/devicetree/bindings/regulator/reg-external-output.yaml