Re: [PATCH 1/5] dt-bindings: connector: add fixed-batteries property

Krzysztof Kozlowski
2025-03-16T16:49:55Z

On 15/03/2025 01:56, Amit Sunil Dhamne wrote:
> Hi Krzysztof,
>
> On 3/13/25 1:48 AM, Krzysztof Kozlowski wrote:
>> On Wed, Mar 12, 2025 at 04:42:01PM -0700, Amit Sunil Dhamne wrote:
>>> Add a new "fixed-batteries" DT property to connector class. This
>>> property is populated with nodes associated with battery type power
>>> supplies powering the USB PD connector. This is needed by the Type-C
>>> Port Manager (TCPM) to query psy properties which are used to feed
>> What is "psy" in terms of bindings?
> In terms of bindings this should be a phandle to a device that
> owns/manages the battery (whose driver will eventually call
> devm_power_supply_register to register the battery). This could be a

So a charger? Please rephrain from putting Linux names into the bindings
description.

> fuel-guage ("sprd,sc2731-fgu", say), charger ("ti,bq24190") or a
> platform device ("cw2015") containing "monitored-battery" property to
> manage the simple battery.

>>> Battery_Status & Battery_Capacity AMS.
>>>
>>> Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
>>> ---
>>> Documentation/devicetree/bindings/connector/usb-connector.yaml | 8 ++++++++
>>> Documentation/devicetree/bindings/usb/maxim,max33359.yaml | 1 +
>>> 2 files changed, 9 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
>>> index 11e40d225b9f3a0d0aeea7bf764f1c00a719d615..5e15bc060f5a2cfce842f83de738f1e8bae3ce2d 100644
>>> --- a/Documentation/devicetree/bindings/connector/usb-connector.yaml
>>> +++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
>>> @@ -300,6 +300,14 @@ properties:
>>> $ref: /schemas/types.yaml#/definitions/uint8-array
>>> maxItems: 4
>>>
>>> + fixed-batteries:
>>> + description: Contains references to nodes associated with battery type power
>>> + supplies powering the USB PD device. These batteries are fixed type and
>> What is a "battery type power supply"? If you just link here batteries,
>> then we have type for it - monitored-battery - but I doubt connector has
>> direct connection to the battery.
> Regarding "nodes associated with battery type power supplies", I meant
> something like a fuel guage or a charger OR platform device with
> "monitored-battery" that will manage the battery lifecycle. If I use
> monitored-battery for this, I will be restricted to only querying 1
> simple battery. Also, I don't mean PD connector device to be a fuel
> guage or charger that manages a specific battery. It should just be able
> to query any FG/Chg for the battery status to relay that info to the
> connector's port partner.
>
> The intent of the patchset & this change is for the USB Type C protocol
> manager module (that consumes these bindings) to be able to get info

The intent should be rather to accurately describe hardware and maybe
that's the problem - you focus how to bend it for your drivers.

Best regards,
Krzysztof