On Fri, May 21, 2021 at 03:20:23PM +0200, Thierry Reding wrote: > On Wed, May 19, 2021 at 02:39:46PM +0800, Chunfeng Yun wrote: > > Vbus is already an optional supply, if the vbus-supply is not > > provided in DTS, will use a dummy regulator, > > That statement is not entirely correct. The dummy regulator is > substituted only if the supply is in fact not optional. The idea behind > that is to allow DTS files that don't specify all required regulators to > get away with it, based on the assumption that the supply is one of > those always-on supplies that are often not described in DTS. > > > the warning log is as below: > > "supply vbus not found, using dummy regulator" > > And the reason why we get that warning is to point out that the DTS has > a bug and that it should be fixed (by adding a proper regulator to take > the place of the dummy). > > > This reverts commit 4ddf1ac79e5f082451cd549283d2eb7559ab6ca9. > > But if you read the description of that commit, the purpose of that > patch was in fact to make the supply completely optional in the case > where we already have the VBUS supply specified for the USB port that > the connector is parented to. > > So in that case the DTS doesn't have the bug because the VBUS supply is > already specified for the USB port and therefore it doesn't have to be > specified in the USB connector again. In fact, specifying it twice can > lead to a situation where the USB port may not be able to switch the > VBUS supply on or off because the setting might conflict with that of > the USB connector. > > So unless there's a real reason why this is needed, I don't think this > should be applied. I've dropped this from my tree now, thanks. greg k-h
