On Thu, Mar 14, 2019 at 11:37 PM Jerome Brunet <jbrunet@xxxxxxxxxxxx> wrote: > Now the slightly annoying part :( > The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property > 'drive-strength' is expressed in mA. > > 1) Rounding down the value, we could be requesting a 0mA drive strength. > That would look weird. > 2) Rounding up, we can't distinguish between 2.5mA and 3mA > > To solve this issue in this in this v1, we chose to document that, on Amlogic, > drive-strength is expressed in uA instead of mA. > It works well and there is no impact on the other platforms but I'm not sure this > is really OK with the DT rules ? I want the DT people to say what they think about this. > Linus, if this is not OK with you, here are 2 other options we are > considering. We would be very interested to get your opinion on the matter: > > 1) instead the generic 'drive-strength' property, we could add an amlogic > specific property, 'amlogic,drive-strength'. It would be expressed in uA > and parsed in amlogic specific code. > I think this option is kind of overkill. Expressing drive strength in uA is > not really amlogic specific so it does not make much sense, but it would > work ... > > 2) Add another generic property "drive-strength-uA". The change to do so > would be minimal and could be benefit to other platforms later on. I would go for 2). But we really need input from bindings people on this. Yours, Linus Walleij
