On 02/07/2016 at 13:45:18 +0200, Hans de Goede wrote : > Hi, > > On 02-07-16 13:02, Maxime Ripard wrote: > > On Sat, Jul 02, 2016 at 11:32:07AM +0200, Hans de Goede wrote: > > > Hi, > > > > > > On 02-07-16 11:12, Chen-Yu Tsai wrote: > > > > Hi, > > > > > > > > On Sat, Jul 2, 2016 at 5:00 AM, Alexandre Belloni > > > > <alexandre.belloni@xxxxxxxxxxxxxxxxxx> wrote: > > > > > Document the bindings for the Allwinner LRADC. > > > > > > > > We already have Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt > > > > and I'm pretty sure Hans (CC-ed) argued that this is not a generic ADC > > > > block. > > > > > > Right, this block is used on many tablets and some dev boards to > > > provide buttons (as in the hid type) and the block is designed for > > > this purpose, giving an irq when the adc level crosses a certain > > > threshold. > > > > > > Sure it can be used in a more generic way, but that is not its > > > primary goal. > > > > We've always had a different view on this, but it's a detail :) > > > > > So any generic purpose adc driver must not break the current > > > use-case (which is already used in mainline kernel dts files > > > in plenty of cases). > > > > Yep. > > > > > I believe that the best way to deal with this is to add an > > > "allwinner,general-purpose-mode" flag to the existing binding > > > (as well as document general purpose mode in the existing > > > binding rather then in a new binding doc). > > > > > > That seems to be the right thing to do purely looking at this > > > from a dt binding pov. > > > > There's a way simpler solution: if there's no child nodes, it's meant > > to be used as an ADC, otherwise, as input. > > > > The logic will have to be a bit more complex than that, since there's > > two channels, and you could only require one for the buttons, leaving > > the other one available as an ADC. > > > > But that doesn't require any new property. > > True, if there are no button nodes, then go general-purpose will > work too. > Well, I'd still argue that we need two different compatibles because encoding the usage of an IP in its compatible string is less than ideal. -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- 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
