[Adding Linus Walleij to Cc:] Hello, On Thu, Dec 13, 2018 at 03:03:15PM +0100, Paul Cercueil wrote: > Le jeu. 13 déc. 2018 à 10:24, Uwe Kleine-König > <u.kleine-koenig@xxxxxxxxxxxxxx> a écrit : > > On Wed, Dec 12, 2018 at 11:09:10PM +0100, Paul Cercueil wrote: > > > The PWM in the JZ4725B works the same as in the JZ4740, except that > > > it > > > only has 6 channels available instead of 8. > > > > this driver is probed only from device tree? If yes, it might be > > sensible to specify the number of PWMs there and get it from there. > > There doesn't seem to be a generic binding for that, but there are > > several drivers that could benefit from it. (This is a bigger project > > though and shouldn't stop your patch. Still more as it already got > > Thierry's ack.) > > I think there needs to be a proper guideline, as there doesn't seem to be > a consensus about this. I learned from emails with Rob and Linus (Walleij) > that I should not have in devicetree what I can deduce from the compatible > string. I understood them a bit differently. It is ok to deduce things from the compatible string. But if you define a generic property (say) "num-pwms" that is used uniformly in most bindings this is ok, too. (And then the two different devices could use the same compatible.) An upside of the generic "num-pwms" property is that the pwm core could sanity check pwm phandles before passing them to the hardware drivers. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
