I was able to flip the mux state on physical pin 5 (the SPI SS line) with a call to writel in drivers/pinctrl/pinctrl-baytrail.c's byt_gpio_request
That's likely not a safe thing to do, but with that, I was able to validate functionally of an SPI device that needed active-high SS. On Fri, Feb 6, 2015 at 7:59 AM, Kevin Shelton <[email protected]> wrote: > thanks, what about for a specific pin after boot? > > I am trying to change the mux state of just one of the SPI pins (so > disabling SPI LPSS Support from the LPSS & SCC configuration menu > doesn't accomplish what I'm after since it changes all of the SPI > pins). > > The end goal of what I'm trying to accomplish is to have the SS SPI > line inverted (more background in > https://bugzilla.yoctoproject.org/show_bug.cgi?id=7267) > > On Fri, Feb 6, 2015 at 2:00 AM, Holmberg, Hans <[email protected]> > wrote: >> >>>Anyone know how to set a GPIO pin mux state? >> >> Yep. It's a bit obscure, but you can enable GPIOs via the LPSS configuration >> in the BIOS: >> >> press F5 during boot >> go to System setup > South cluster configuration > LPSS & SCC configuration >> Scroll down and disable the function that is set as primary configuration >> for the PIN you wish to use as a GPIO. >> >> See http://elinux.org/Minnowboard:MinnowMax#Layout >> Example: disabling PWM1 will let you use PIN 22 as a GPIO. >> >> Best regards, >> Hans >> _______________________________________________ >> elinux-MinnowBoard mailing list >> [email protected] >> http://lists.elinux.org/mailman/listinfo/elinux-minnowboard _______________________________________________ elinux-MinnowBoard mailing list [email protected] http://lists.elinux.org/mailman/listinfo/elinux-minnowboard
