Hi Linus, > Linus Walleij <linus.walleij@xxxxxxxxxx> hat am 14. März 2017 um 15:39 geschrieben: > > > On Mon, Feb 27, 2017 at 7:02 PM, Stefan Wahren <stefan.wahren@xxxxxxxx> wrote: > > > on BCM2835 (Raspberry Pi) the firmware on the VideoCore and Linux on the ARM core share > > a common pin "space". Depending on the board revision the VideoCore needs to controls > > some pins, which shouldn't be claimed by Linux on the ARM. > > > > What is the right way to exclude control on Linux for those pins in order to avoid possible > > harmful operations? > > Do you want to do this statically (at boot) or dynamically (at runtime)? statically > > If you want to do it statically, at boot time: > Just add some NOOP function (i.e. a function that result in > zero register writes or anything) named "videocore-reserved" or > something to the driver in drivers/pinctrl/bcm/pinctrl-bcm2835.c, > make it applicable to the affected pins, making it possible > to create a state that will combine the function "videocore-reserved" > with these pins, resulting in them being exclusively used for > that. If you speak of a NOOP function, do you mean a "dummy" pin function which is configured by the device tree? Like extending the "brcm,function" property from the existing binding? > > Then in the videocore device tree node (I assume there is > something like such) create a pinctrl state that just take all these > pins with this dummy function. Is there a comparable example in the existing drivers? Thanks Stefan -- 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
