On Wed, Jun 10, 2020 at 11:16 AM Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote: > When working with RTCs, there is one issue though: boolean properties > are not working well because there is no way to express the 3 different > conditions: > 1/ the capacitor is present, set the register > 2/ the capacitor is absent, clear the register > 3/ the device tree didn't have this property until not and the register > may have been set or cleared using another mean, don't touch it. > > As your patch is written, it only handles 1 and 3 which is probably the > safest option but then we will never have a way to clear it from the > driver. I'd say that this is not an issue but it is also something we > will never be able to change without breaking some setups. I agree. I could implement this as an enumerated string option which accepts 'yes' or 'no'. Those would cover cases 1 and 2, and the absence of the property would be case 3. I looked through the bindings that exist and didn't see any examples of properties configured this way, but I think it would be understandable to users.