On Wed, Jul 13, 2016 at 3:14 PM, Johan Hovold <johan@xxxxxxxxxx> wrote: > On Wed, Jul 06, 2016 at 02:34:39PM +0200, Linus Walleij wrote: >> For the purpose of picking a certain named GPIO line (see below) >> knowing this number is unnecessary. To that mechanism all gpio >> chips are equal and the instance number does not matter. > > My point was that with gpio line names (and possibly topological > information to resolve duplicates), the N number should not matter > anymore. Agreed. It doesn't, with the new ABI. Not for technical reasons, at all. > If one needs to look up a particular gpiochip based on some hardware > naming convention, why not associate a name with the chip instead of > trying to shoehorn the dynamic gpiochip range in there? With the new ABI it is possible to set a "label" for the gpiochip, currently described as "a functional name for this GPIO chip, such as a product number" and it's certainly possible to manage this name carefully for a system to look up a certain chip. [About obtaining topological information from sysfs] > And this may even be unavoidable with dynamic buses such as USB or > greybus, where you can have multiple devices associating the same name > with a pin. That's fine as long as the user-space interface allows for a > way to distinguish them (e.g. through topological information). This should work fine AFAICT. All the ABI and information is in place to deal with this. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
