linux-kernel - RE: [PATCH v3 07/13] serial: sh-sci: Add RSCI_PORT

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Message-ID:
 <TY3PR01MB1134612DF9B298D9B9A3B667786D2A@TY3PR01MB11346.jpnprd01.prod.outlook.com>
Date: Sat, 22 Nov 2025 13:20:03 +0000
From: Biju Das <biju.das.jz@...renesas.com>
To: geert <geert@...ux-m68k.org>, biju.das.au <biju.das.au@...il.com>
CC: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Jiri Slaby
	<jirislaby@...nel.org>, Rob Herring <robh@...nel.org>, Krzysztof Kozlowski
	<krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, magnus.damm
	<magnus.damm@...il.com>, wsa+renesas <wsa+renesas@...g-engineering.com>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>
Subject: RE: [PATCH v3 07/13] serial: sh-sci: Add RSCI_PORT_{SCI,SCIF} port
 IDs

Hi Geert,

Thanks for the feedback.

> -----Original Message-----
> From: Geert Uytterhoeven <geert@...ux-m68k.org>
> Sent: 21 November 2025 15:15
> Subject: Re: [PATCH v3 07/13] serial: sh-sci: Add RSCI_PORT_{SCI,SCIF} port IDs
> 
> Hi Biju,
> 
> On Fri, 14 Nov 2025 at 11:52, Biju <biju.das.au@...il.com> wrote:
> > From: Biju Das <biju.das.jz@...renesas.com>
> >
> > RZ/G3E RSCI tx/rx supports both FIFO and non-FIFO mode. It has
> > 32-stage FIFO. Add RSCI_PORT_SCI port ID for non-FIFO mode and
> > RSCI_PORT_SCIF port ID for FIFO mode. Update the rx_trigger for both these modes.
> >
> > Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> 
> Thanks for your patch!
> 
> > --- a/drivers/tty/serial/sh-sci-common.h
> > +++ b/drivers/tty/serial/sh-sci-common.h
> > @@ -8,6 +8,8 @@
> >  /* Private port IDs */
> >  enum SCI_PORT_TYPE {
> >         SCI_PORT_RSCI = BIT(7) | 0,
> > +       RSCI_PORT_SCI = BIT(7) | 1,
> > +       RSCI_PORT_SCIF = BIT(7) | 2,
> 
> Oh no... Anyone who can reminder what is the difference between SCI_PORT_RSCI and RSCI_PORT_SCI?
> 
> And now some RSCI IDs use the SCI_PORT_* prefix, while others use the
> RSCI_PORT_* prefix.
> 
> So what about renaming the existing SCI_PORT_RSCI to e.g.
> RSCI_PORT_SCIF16, and adding new types RSCI_PORT_SCI and RSCI_PORT_SCIF32?


OK, will rename SCI_PORT_RSCI->RSCI_PORT_SCIF16 since it is only used in T2H.

If you agree, I am planning to change the enum values as below, when RSCI_PORT_SC{I,IF32}
is added

RSCI_PORT_SCI = BIT(7) | 0,
RSCI_PORT_SCIF16 = BIT(7) | 1,
RSCI_PORT_SCIF32 = BIT(7) | 2,


> 
> >  };
> >
> >  enum SCI_CLKS {
> > diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
> > index 78fb3b6a318b..66ab85571230 100644
> > --- a/drivers/tty/serial/sh-sci.c
> > +++ b/drivers/tty/serial/sh-sci.c
> > @@ -3326,6 +3326,9 @@ static int sci_init_single(struct platform_device *dev,
> >         case SCI_PORT_RSCI:
> >                 sci_port->rx_trigger = 15;
> 
> Hmm, why is this 15, and not 16?

I am also surprised; this has to be 16.
As there is no user, I will update as 16 in the same renaming patch.

> 
> >                 break;
> > +       case RSCI_PORT_SCIF:
> > +               sci_port->rx_trigger = 32;
> > +               break;
> >         default:
> >                 sci_port->rx_trigger = 1;
> >                 break;
> 
> Anyone, all of the rx_trigger setting for RSCI variants is futile, as rsci.c does not implement
> sci_port_ops.set_rtg() yet.

Agree, but now it is taken care by the later patch in this series.

Cheers,
Biju