Re: [PATCH V5 1/1] usb:serial add Fintek F81532/534 driver

[Johan Hovold <johan@kernel.org>]

On Thu, Oct 22, 2015 at 10:25:26AM +0800, Peter Hung wrote:
> Hi Johan,
> 
> Johan Hovold 於 2015/9/14 下午 09:33 寫道:
> > On Tue, Jul 21, 2015 at 09:58:19AM +0800, Peter Hung wrote:
> 
> >>        4. RS422 Mode
> >>           1. The RTS mode is dont care.
> >>           2. Set M2/M1/M0 as 0/0/0
> >
> > I don't think all gpios should be exported for these ports if they have
> > special functions that the driver could control transparently (e.g. for
> > SER_RS485_RTS_ON_SEND).
> 
> Surely, we can hide some setting with definitely setting like
> RS232/RS485, but the settings is only apply to our evaluation board.
> 
> Some customers will use our F81532/534 with other brand transceiver IC.
> The pins setting maybe changed, so we decided to separate UART & pins
> settings and let the 3 output pins controllable for customer.
> 
> Could I preserve currently UART & pins setting mode ?

If the pins can be set independently of the mode, and in principle be
used as general purpose output-only pins, then you should use the
gpiolib interface.

However, in the last patch it did look like the gpio-implementation was
intertwined with mode selection, something which made it seem like a bad
fit.

Would you be able to separate it, and specifically, make the gpio and
mode-handling generic and not specific for your evaluation board?

Thanks,
Johan