Am 30.11.2017 um 17:58 schrieb kernel@martin.sperl.org:

quoted

drivers/tty/serial/max310x.c
Documentation/devicetree/bindings/serial/maxim,max310x.txt
Look for "#ifdef CONFIG_GPIOLIB”.

This is a gpio-controller, for which this is what I would implement.

Hi,

you are mistaken about that, max310x chips are spi to uart bridges with
strong ties to rs485 which is very similar to CAN except for the missing
arbitration in hardware. Max14830 has GPIOs with clocking support, so
this chip's driver also fused the main function with secondary gpio
functions.
https://datasheets.maximintegrated.com/en/ds/MAX14830.pdf

Anyway I'm curious what is best practice for this sort of configuration.

Regards,
Patrick