>> _and system GPIOs_ :-) > > Yup, firmware should set up gpios, to make initial kernel boot. > After that, kernel can and should manage GPIOs.
Sure. But only the GPIOs it _does_ need to toggle, not the ones that have to be fixed to a certain value (like everything that is described in the par_io nodes now). Devices that really _use_ some GPIO, should use some generic GPIO binding in the device tree, and the generic GPIO subsystem in the kernel. > Few examples. [some good examples of why GPIOs can be useful at runtime snipped] > At the same time I agree: doing gpio setup in the board file isn't a > great solution, just like doing it in the device tree. But hard-code > gpio setup in the firmware is much worse and short-sighted approach. It is the correct solution for 99.99% of GPIOs: every GPIO needs to either be set to some fixed configuration (and value), dictated by the board design; or at least it needs to be initialised to something that results in a stable system ;-) Segher _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
