On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
[off-list ref] wrote:

- The MFD Silicon Motion SM501 is a special case. It dynamically
  spawns an I2C bus off the MFD using sm501_create_subdev().
  We use an approach to dynamically create a machine descriptor
  table and attach this to the "SM501-LOW" or "SM501-HIGH"
  gpiochip. We use chip-local offsets to grab the right lines.
  We can get rid of two local static inline helpers as part
  of this refactoring.

(...)

SM501 users: requesting Tested-by on this patch.

Paging Simtec (if it reaches anyone), Vincent Sanders,
Teddy Wang at Silicon Motion:

Does any of you have an "Anubis" board so you can test GPIO
on this board before/after this patch and see if it checks out right?

I guess it's this board:
http://www.simtec.co.uk/products/BBD20EUROA/

Does anyone know of a commercially obtainable product using
SM501 with reasonable mainline Linux support so I can test it myself?

Getting a bit desperate...

Yours,
Linus Walleij