On 18.11.19 11:38, Vaittinen, Matti wrote: Hi, >> a) existing DT's (in the field) become incompatible with newer >> kernel versions > > This was my main concern. This of course would not mean that we could > not take this approach for new LED controller drivers - but that would > (probably) lead to dual led registration interface Maybe just a flag for that ? Perhaps the driver could also specify a list of node names for the LEDs, so led-core can do the lookup for them. >> b) existing userlands that rely on speicific LED names become >> incomatible with newer kernel versions. > > I didn't even think this far, but yes, I see... LED node name might be > reflected in user-space LED name. I won't start arguing if this is sane > or not - this is what we seem to be living with today :) Especially in embedded world, this can really make sense: applications just use a defined LED name, no matter which board it's running on. Convention over configuration. Personally, I also like to use LED subsystem as frontend for things like gpio-driven relais, etc, and assign semantically fitting names instead of "technical" ones, > I didn't invest too much of time on this yet - but at first glimpse it > seemed that at least some of the drivers did use reg - property with > fixed value to do the matching. Those could set the property name to > 'reg' and value to 'X' and leave the DT node lookup and common property > parsing to the LED core. If my patch won't get too big objection (and > if no fatal flaws are found from the idea) - then I might try and find > the time to do some follow-up patches simplifying existing LED > drivers... Sounds good :) --mtx -- Dringender Hinweis: aufgrund existenzieller Bedrohung durch "Emotet" sollten Sie *niemals* MS-Office-Dokumente via E-Mail annehmen/öffenen, selbst wenn diese von vermeintlich vertrauenswürdigen Absendern zu stammen scheinen. Andernfalls droht Totalschaden. --- Hinweis: unverschlüsselte E-Mails können leicht abgehört und manipuliert werden ! Für eine vertrauliche Kommunikation senden Sie bitte ihren GPG/PGP-Schlüssel zu. --- Enrico Weigelt, metux IT consult Free software and Linux embedded engineering info@xxxxxxxxx -- +49-151-27565287
