Re: [PATCH v7 10/13] serial: sh-sci: Add support for RZ/T2H SCI

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Apr 14, 2025 at 07:54:12AM +0000, Thierry Bultel wrote:
> Hi Greg,
> 
> > -----Original Message-----
> > From: Greg KH <gregkh@linuxfoundation.org>
> > Sent: vendredi 11 avril 2025 16:57
> > To: Thierry Bultel <thierry.bultel.yh@bp.renesas.com>
> > Cc: thierry.bultel@linatsea.fr; linux-renesas-soc@vger.kernel.org;
> > geert@linux-m68k.org; Paul Barker <paul.barker.ct@bp.renesas.com>; Wolfram
> > Sang <wsa+renesas@sang-engineering.com>; linux-kernel@vger.kernel.org;
> > linux-serial@vger.kernel.org
> > Subject: Re: [PATCH v7 10/13] serial: sh-sci: Add support for RZ/T2H SCI
> > 
> > On Thu, Apr 03, 2025 at 11:29:12PM +0200, Thierry Bultel wrote:
> > > --- a/include/uapi/linux/serial_core.h
> > > +++ b/include/uapi/linux/serial_core.h
> > > @@ -231,6 +231,9 @@
> > >  /* Sunplus UART */
> > >  #define PORT_SUNPLUS	123
> > >
> > > +/* SH-SCI */
> > > +#define PORT_RSCI	124
> > 
> > Why do you need to tell userspace about this specific port?  Is that a
> > hard requirement that your userspace tools require?  If not, please don't
> > export this here.
> 
> This point has been discussed with Geert and Wolfram.
> We cannot use PORT_GENERIC for this IP, and adding the new type
> is just keeping consistent with the sh-sci driver.

But, why does userspace need to know this number?  And why doesn't
PORT_GENERIC work?

thanks,

greg k-h