Question regarding runtime pinctrl

["Niedermayr, BENEDIKT" <benedikt.niedermayr@xxxxxxxxxxx>]

Hello,

as the subject may indicate, I've stumbled across the use case of controlling pinmux from userspace.
Maybe bit more background:

We are currently using platforms which can be extended with different kind of IO-shields. These IO-shields are configurable (even at runtime). Reconfiguring
during runtime is generally electrically fine.
We now want to be able to configure those IO-shields by changing the pinmux configuration during runtime (after kernel boot).

Until now we are achieving that by accessing the the pinmux/pinctrl registers directly via /dev/mem. But we see at least two issues here:
>From a security aspect, accessing the /dev/mem interface is privileged (at least requires CAP_SYS_RAWIO). But this may conflict with the final application
which should run non privileged. 
The second issue is that we actually duplicate the pinmux/pinctrl kernel implementation which already.

Are there any discussions out there related to this topic? I would be surprised if I was the first one searching for a solution for this use case. 
We already have some ideas but we also want to know if anybody had a similar use case and can share any experience?  

cheers,
Benedikt