On Mon Feb 19, 2024 at 2:35 PM CET, AngeloGioacchino Del Regno wrote: > >> vbus is always supplied by something, as otherwise USB won't work - whether this > >> is an always-on regulator or a passthrough from external supply this doesn't really > >> matter - you should model a regulator-fixed that provides the 5V VBUS line. > > > > I don't think this is correct, though. Think of an on-board USB > > hub. There only D+/D- are connected (and maybe the USB3.2 SerDes > > lanes). Or have a look at the M.2 pinout. There is no Vbus. > > > > Yes but the MediaTek MTU3 and/or controllers do have it ;-) .. and .. > >> For example: > >> vbus_fixed: regulator-vbus { > >> compatible = "regulator-fixed"; > >> regulator-name = "usb-vbus"; > >> regulator-always-on; > >> regulator-boot-on; > >> regulator-min-microvolt = <5000000>; > >> regulator-max-microvolt = <5000000>; > >> }; > > > > As mentioned above, I don't think this will make sense in my case. > > >> P.S.: If the rail has a different name, please use that different name. Obviously > >> that requires you to have schematics at hand, and I don't know if you do: if you > >> don't, then that regulator-vbus name is just fine. > > > > I do have the schematics. > > In that case, you should model the power tree with the fixed power lines, > check mt8195-cherry (and/or cherry-tomato) and radxa-nio-12l; even though > those are technically "doing nothing", this is device tree, so it should > provide a description of the hardware ... and the board does have fixed > power lines. > It has at least one: DC-IN (typec, barrel jack or whatever, the board needs > power, doesn't it?!). Mh, maybe I don't get it. But within the hardware there is simply no Vbus. Thus I'd argue it doesn't make sense to have a vbus-supply property. Besides, the mediatek,mtu3.yaml binding lists it as deprecated anyway and it should rather be on the connector. There, it makes perfectly sense (at least if it's a USB connector). Thus in my case, the xhci for the front port has a vbus-supply property (but it should rather have a connector node, as I've just learned). But the internal port which connects to the USB hub shouldn't have one. +-----+ +-----+ +------+ | |<--Dp/Dn-->| |<------Dp/Dn----->| USB | | SoC | | | | Conn | | | | | +-----+ | | +-----+ | USB | | PWR |--Vbus->| | | Hub | | SW | +------+ | | +-----+ | | ^ | | | PRTPWR | |-----' +-----+ "PWR SW" is a power switch, the input (+5V) isn't shown here. The power will be enabled by the USB Hub. -michael
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