On Wednesday, December 14, 2016 9:55:47 AM CET Arnd Bergmann wrote:

According to your introductory mail, the interface is assumed to be
a 74HC164. Should we use that ID in the compatible string?

We can always add other strings later if we want to support multiple
wire formats.

Actually, looking up 74hc164, that seems to be a gpio expander,
so maybe a more flexible way to do the same is to put a driver
for the expander into drivers/gpio/ and have the main driver
access the outputs of that using the gpiolib interface.

	Arnd