[U-Boot] Pincontroller not getting initialized on imx6 in SPL with SPL_PINCTRL and OF_CONTROL

[Adam Ford]

I am trying to remove the manual pinmuxing code from the board file.
In an effort to accomplish this, I am trying to get SPL_OF_CONTROL and
SPL_PINCTRL to let me use the device tree(s) to initialize pin muxing.

I have the following defined:

CONFIG_SPL_PINCTRL=y
CONFIG_SPL_PINCTRL_FULL=y
CONFIG_SPL_PINCTRL_GENERIC=y
CONFIG_SPL_PINMUX=y

along with
CONFIG_PINCTRL_IMX=y
CONFIG_PINCTRL_IMX6=y

I put some debugging code into the imx6 pinctrl and I can see that
U-Boot initializes it, but that same debug message doesn't appear in
SPL.

I looked through the spl build directory, and I can see the drivers
have been built, and the map file shows they exist, but for some
reason, it doesn't initalize.  If I remove the UART pin-muxing from my
board file, the text for SPL doesn't' appear at all, so it's clear
pinctrl isn't setting up the proper muxing yet.

I am trying to figure out how/where the pinctrl system gets
initialized in SPL, and I was hoping someone might have some insight.

thanks,

adam