Re: [PATCH v2] serial: sh-sci: byte allocated register support

[Yoshinori Sato <ysato@users.sourceforge.jp>]

On Thu, 09 Aug 2018 02:52:10 +0900,
Geert Uytterhoeven wrote:
> 
> Hi Sato-san,
> 
> On Mon, Jul 23, 2018 at 10:17 AM Geert Uytterhoeven
> <geert@linux-m68k.org> wrote:
> > CC gregkh, linux-serial
> >
> > On Sun, Jul 22, 2018 at 3:02 PM Yoshinori Sato
> > <ysato@users.sourceforge.jp> wrote:
> > >
> > > H8/300 SCI registers allocated byte address.
> > > It must support to the case where shift count is 0.
> > >
> > > Changes v2.
> > > more simply code.
> > >
> > > Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
> >
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> >
> > > --- a/drivers/tty/serial/sh-sci.c
> > > +++ b/drivers/tty/serial/sh-sci.c
> > > @@ -2863,10 +2863,12 @@ static int sci_init_single(struct platform_device *dev,
> > >         port->fifosize          = sci_port->params->fifosize;
> > >
> > >         if (port->type = PORT_SCI) {
> > > -               if (sci_port->reg_size >= 0x20)
> > > -                       port->regshift = 2;
> > > -               else
> > > -                       port->regshift = 1;
> > > +               /*
> > > +                * reg_size < 0x10: BYTE aligned (scale factor=1).
> > > +                * reg_size >= 0x10 and < 0x20: WORD aligned (scale factor=2).
> > > +                * reg_size >= 0x20: DWORD aligned (scale factor=4).
> > > +                */
> > > +               port->regshift = sci_port->reg_size >> 4;
> > >         }
> > >
> > >         /*
> 
> Considering the regshift issues introduced by RZ/A2 SCIF support, I think it's
> better to not rely on the reg_size value, and change the check to
> 
>        if (!dev->dev.of_node && port->type = PORT_SCI)
> 
> If/when SuperH receives DT support, SCI ports with regshift 1 or 2 instantiated
> from DT can be supported using "reg-shift = <1>" or "reg-shift = <2>" in DT.
> 
> Reference: https://www.spinics.net/lists/linux-serial/msg31573.html
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
>

OK.
Thanks.

> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds

-- 
Yosinori Sato