[PATCH 1/6] dt-bindings: power: supply: sgm41542: document sgm41542

[Chris Morgan]

On Tue, Apr 28, 2026 at 05:09:49PM +0200, Krzysztof Kozlowski wrote:
> On 28/04/2026 16:09, Chris Morgan wrote:
> > On Tue, Apr 28, 2026 at 09:47:00AM +0200, Krzysztof Kozlowski wrote:
> >> On Mon, Apr 27, 2026 at 12:09:09PM -0500, Chris Morgan wrote:
> >>> From: Chris Morgan <macromorgan at hotmail.com>
> >>>
> >>> Document the SG Micro sgm41542 battery charger/boost converter.
> >>>
> >>> Signed-off-by: Chris Morgan <macromorgan at hotmail.com>
> >>> ---
> >>>  .../supply/sgmicro,sgm41542-charger.yaml      | 99 +++++++++++++++++++
> >>>  1 file changed, 99 insertions(+)
> >>>  create mode 100644 Documentation/devicetree/bindings/power/supply/sgmicro,sgm41542-charger.yaml
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/power/supply/sgmicro,sgm41542-charger.yaml b/Documentation/devicetree/bindings/power/supply/sgmicro,sgm41542-charger.yaml
> >>> new file mode 100644
> >>> index 000000000000..3e5041e5b551
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/power/supply/sgmicro,sgm41542-charger.yaml
> >>
> >> Filename must match compatible.
> > 
> > Acknowledged.
> > 
> >>
> >>> @@ -0,0 +1,99 @@
> >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>> +%YAML 1.2
> >>> +---
> >>> +$id: http://devicetree.org/schemas/power/supply/sgmicro,sgm41542-charger.yaml#
> >>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >>> +
> >>> +title: SGM41542 Battery Charger
> >>> +
> >>> +description: |
> >>
> >> Do not need '|' unless you need to preserve formatting.
> >>
> > 
> > Will fix.
> > 
> >>> +  The SGMicro SGM41542 is a single cell battery charger/boost controller.
> >>> +
> >>> +maintainers:
> >>> +  - Chris Morgan <macromorgan at hotmail.com>
> >>> +  - Xu Shengfei <xsf at rock-chips.com>
> >>> +
> >>> +properties:
> >>> +  compatible:
> >>> +    const: sgmicro,sgm41542
> >>> +
> >>> +  input-current-limit-microamp:
> >>
> >> Missing vendor prefix.
> >>
> > 
> > This *appears* to be a standard value (perhaps not formally, but in use by
> > enough devices to suggest a defacto standard), which is why I did not use
> > the vendor prefix here. Do I need to add that for this one?
> 
> I know, I found these other properties but I think they were just coming
> from old schema.
> 
> If it is really a common property, then should be defined in a common
> schema and this did not happen.

Would now be a good time to add it to the power-supply.yaml document?
It looks like this value is used by about 10 other devices.

Thank you,
Chris

> 
> > 
> >>> +    description:
> >>> +      Optional value to clamp the maximum input current limit to for
> >>> +      the device. If omitted, the default value for the hardware will
> >>> +      be used (2400000).
> >>> +    minimum: 100000
> >>> +    maximum: 3800000
> >>> +
> >>> +  input-voltage-limit-microvolt:
> >>> +    description:
> >>> +      Optional value to clamp the maximum input voltage limit to for
> >>> +      the device. If omitted, the default value for the hardware will
> >>> +      be used (4500000).
> >>> +    minimum: 3900000
> >>> +    maximum: 12000000
> >>> +
> >>> +  interrupts:
> >>> +    maxItems: 1
> >>> +
> >>> +  monitored-battery:
> >>
> >> You miss definition of this property. I guess this is power supply, so
> >> reference proper schema for power supplies. Look at other bindings to
> >> for some example code.
> > 
> > I'll look at this some more, I might have a few more questions. But I will
> > make the changes requested.
> > 
> >>
> >>> +    description: |
> >>> +        A phandle to a monitored battery node. Values for the following
> >>> +        are used by the driver and if not present will result in default
> >>> +        values being applied:
> >>> +        constant-charge-current-max-microamp
> >>> +        constant-charge-voltage-max-microvolt
> >>> +        charge-term-current-microamp
> >>> +        precharge-current-microamp
> >>> +
> >>> +  reg:
> >>> +    maxItems: 1
> >>> +
> >>> +  regulators:
> >>
> >> No need for regulators node, just define here otg-vbus directly. But
> >> honestly, your example is incomplete or you defined something implied by
> >> the compatible. If you have a fixed 5V regulator, what is the point of
> >> defining it in the DT?
> > 
> > The regulator can be adjusted within a range around 5V, and is referenced
> > by the USB subsystem. Should I still omit it from the device tree or instead
> > define the min and max values?
> 
> If it can be adjusted then it's fine, can stay.
> 
> 
> Best regards,
> Krzysztof