On Fri, Apr 28, 2017 at 4:48 PM, Chris Brandt <chris.bra...@renesas.com> wrote:
I think this was written by me, not Geert... >> DT describes hardware, not software limitations. > > Describing things is fine, but the kernel code takes the DT and then start > configuring things based on it. > > For example, on the RSK board, that line is connected to P4_14. P4_14 can be > configured as IRQ6...but IRQ6 comes out in 8 different pin choices, and I > might want to use one of those other choices, so I don't want to describe > P4_14 as an interrupt. > > If it was just describing that "pin 15 of the PHY chip is tied to pin Y19 of > the RZ/A1H", that's fine because it's hardware connection that's not going to > change. > But...the DT also defines the pin muxing...which is a software decision (do I > want to get interrupt or just manually poll or simple ignore it). > This is the part of the whole "DT is for hardware description only" that > doesn't really make sense to me. OK yeah we do hardware description AND configuration. And we never do interpreted languages. And then there is a bunch of grayzone things. For example we have a linux,input binding for connecting keypresses to certain Linux input codes. That is really grayzone, but very useful. Yours, Linus Walleij
