On Wed, Jan 6, 2021 at 4:25 PM Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> wrote: > On Wed, Jan 6, 2021 at 2:34 PM Andy Shevchenko > <andy.shevchenko@xxxxxxxxx> wrote: > > On Wed, Jan 6, 2021 at 12:09 PM Bartosz Golaszewski > > <bgolaszewski@xxxxxxxxxxxx> wrote: > > > On Wed, Jan 6, 2021 at 12:24 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: ... > > > I can do it alright. But in the context of user-space I think this > > > doesn't really change anything. DT users still can use non-unique > > > names and libgpiod still has to account for that if the API is to be > > > considered correct. Is this change really useful? > > > > IMHO it is useful and the earliest we do the better. > > I'm wondering if user-space should make this assumption too then. That > a non-unique name is either an error or signifies some special value > (N/A). My understanding that names are basically aliases to the pin numbers inside a chip, so gpiochipX:Y should == gpiochipX:$NAME Obviously we can't guarantee that if there is no uniqueness assumption made. Otherwise the idea behind naming the lines sounds controversial to me. That said, if we allow non-unique names inside one chip, then the name field is basically *informative*, which means we may not take it anyhow as a parameter to any of the tools or anything. > > > How does it affect > > > ACPI users that already define non-unique names? > > > > I suppose that in ACPI we don't have many users that do it on their > > own (for IoT Intel platforms GPIO expanders have unique names). > > Also see above. I prefer to have a bug report with a clear source of > > the issue (like a table that the user can't / won't change which > > predates the date of kernel release with a patch. > > > > +cc: to the user who lately was active in the area. > > > > Flavio, perhaps one more rule to the gpio-line-names property has to > > be added into documentation (Bart, same to DT docs?): > > - names inside one chip must be unique > > > > Once we have a proper, core yaml binding for all GPIO devices, we'll > be able to even enforce it if we agree on a set of exceptions. -- With Best Regards, Andy Shevchenko