13.11.2020 20:28, Mark Brown пишет: > On Fri, Nov 13, 2020 at 08:13:49PM +0300, Dmitry Osipenko wrote: >> 13.11.2020 19:15, Mark Brown пишет: > >>> My point here is that the driver shouldn't be checking for a dummy >>> regulator, the driver should be checking the features that are provided >>> to it by the regulator and handling those. > >> I understand yours point, but then we need dummy regulator to provide >> all the features, and currently it does the opposite. > > As could any other regulator? Yes >>> It doesn't matter if this is >>> a dummy regulator or an actual regulator with limited features, the >>> effect is the same and the handling should be the same. If the driver >>> is doing anything to handle dummy regulators explicitly as dummy >>> regulators it is doing it wrong. > >> It matters because dummy regulator errors out all checks and changes >> other than enable/disable, instead of accepting them. If we could add an >> option for dummy regulator to succeed all the checks and accept all the >> values, then it could become more usable. > > I'm a bit confused here TBH - I'm not sure I see a substantial > difference between a consumer detecting that it can't set any voltages > at all and the handling for an optional regulator. Either way if it's > going to carry on and assume that whatever voltage is there works for > everything it boils down to setting a flag saying to skip the set > voltage operation. I think you are too focused on the specific > implementation you currently have here. > > We obviously can't just accept voltage change operations when we've no > idea what the current voltage of the device is. > >>> To repeat you should *only* be using regulator_get_optional() in the >>> case where the supply may be physically absent which is not the case >>> here. >> >> Alright, but then we either need to improve regulator core to make dummy >> regulator a bit more usable, or continue to work around it in drivers. >> What should we do? > > As I keep saying the consumer driver should be enumerating the voltages > it can set, if it can't find any and wants to continue then it can just > skip setting voltages later on. If only some are unavailable then it > probably wants to eliminate those specific OPPs instead. I'm seeing a dummy regulator as a helper for consumer drivers which removes burden of handling an absent (optional) regulator. Is this a correct understanding of a dummy regulator? Older DTBs don't have a regulator and we want to keep them working. This is equal to a physically absent regulator and in this case it's an optional regulator, IMO. Consumer drivers definitely should check voltages, but this should be done only for a physical regulator.
