Re: [RFC PATCH 0/3] GPIO support on the Etron EJ168/EJ188/EJ198 xHCI controllers

[Linus Walleij]

On Sun, Oct 4, 2020 at 8:00 PM Martin Blumenstingl
<martin.blumenstingl@xxxxxxxxxxxxxx> wrote:

> The goal of this series to add support for the GPIO controller on the
> Etron EJ168/EJ188/EJ198 controllers.

This overall is a fine driver, but have you considered the option of just
implementing the GPIO chip in drivers/usb/host/xhci-pci.c?

There are several USB serial adapters that have a GPIO chip
embedded and we just add the GPIO chip into the serial driver.
I have done the same with some networking switches. It is
perfectly fine for drivers outside of drivers/gpio to occasionally
define a minor GPIO chip if GPIO is not their primary function.

Please consider simply activating the XHCI driver and make it
instantiate a GPIO chip if it happens to be an
EJ168/EJ188/EJ198 controller.

Yours,
Linus Walleij