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

[Krzysztof Kozlowski <krzk@kernel.org>]

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@hotmail.com>
>>>
>>> Document the SG Micro sgm41542 battery charger/boost converter.
>>>
>>> Signed-off-by: Chris Morgan <macromorgan@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@hotmail.com>
>>> +  - Xu Shengfei <xsf@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.

> 
>>> +    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

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