On Mon, 6 Nov 2023 21:39:42 +0100 Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> wrote: > On 06/11/2023 19:57, Hugo Villeneuve wrote: > > From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> > > > > The following warning is shown when probing device: > > > > pca953x 1-0020: supply vcc not found, using dummy regulator > > > > Add fixed 3.3v regulator as vcc supply to silence the warning. > > > > This is not really a warning. It's perfectly fine to use dummy > regulator. Adding such fixed supply has sense in following cases: > 1. Bindings require the supply, > 2. This is in fact exactly that supply (verified on schematics). > > Best regards, > Krzysztof Hi Krzysztof, this is case #2, but looking more closely at the carrier board (symphony) schematics, it is not exactly the "reg_3v3_fixed" supply I mentioned in the patch, as "reg_3v3_fixed" is located on the SOM and only powers SOM components. However, "reg_3v3_fixed", which is an always-on regulator (no software enable control), is used as the enable input to a mosfet switch (Q2) on the carrier board to generate the 3.3V (label BASE_PER_3V3 on the schematics) used by all peripherals on that carrier board. I guess I could then define a new "always-on" regulator labeled as, for example, base_per_3v3, and then assign the pca953x vcc-supply property to it? Hugo.
