Re: [PATCH] USB: ftdi_sio: add GPIO support

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jul 07, 2014 at 12:44:28PM +0200, Linus Walleij wrote:
> On Fri, Jun 13, 2014 at 8:31 PM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Fri, Jun 13, 2014 at 09:25:07AM +0200, Linus Walleij wrote:
> 
> >> But I also want to bring the device model into question: normally
> >> when a mother device spawns children across different subsystems
> >> we model them as MFD devices (drivers/mfd) that instantiate
> >> children for the different subsystems. So you could spawn a
> >> serial and a GPIO device from a USB-based hub device there.
> >>
> >> I do not know if that is really apropriate in this case. It seems the
> >> device is first and foremost FTDI.
> >>
> >> But it could still spawn a child platform device for the GPIO stuff
> >> so that this can live as a separate driver under drivers/gpio/gpio-ftdi.c
> >> or similar.
> >>
> >> You could then use something like:
> >>
> >> struct platform_device *gdev;
> >
> > Ick, no, it's a USB device, do not abuse the platform_device code any
> > more than it currently is (note, I HATE the platform device code,
> > someday I'll delete it entirely...  Well, I can dream...)
> 
> Haha yeah :-)
> 
> However is the MFD cell approach acceptable?

Yes it is.