linux-kernel - Re: [PATCH v3 12/13] serial: sh-sci: Add support for RZ/G3E RSCI SCIF

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Message-ID: <CAMuHMdXshthP8nrV-qP=fSv6HGCDj47x9_jQYobZTEivy15tvw@mail.gmail.com>
Date: Fri, 21 Nov 2025 15:46:29 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Biju <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>, Biju Das <biju.das.jz@...renesas.com>, 
	Wolfram Sang <wsa+renesas@...g-engineering.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>, linux-kernel@...r.kernel.org, 
	linux-serial@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH v3 12/13] serial: sh-sci: Add support for RZ/G3E RSCI SCIF

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>
>
> Add support for RZ/G3E RSCI SCIF(a.k.a FIFO mode). RSCI IP found on the
> RZ/G3E SoC is similar to RZ/T2H, but it has a 32-stage FIFO. it has 6
> clocks(5 module clocks + 1 external clock) instead of 3 clocks(2 module
> clocks + 1 external clock) on T2H and has multiple resets. Add support
> for the hardware flow control.
>
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> ---
> v2->v3:
>  * Dropped cpu_relax() from rsci_finish_console_write() and added a
>    comment.
>  * Added sci_is_rsci_fifo_type() helper for reuse in probe() and remove().

Thanks for the update!

> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -3563,6 +3563,11 @@ static struct uart_driver sci_uart_driver = {
>         .cons           = SCI_CONSOLE,
>  };
>
> +static bool sci_is_rsci_fifo_type(u8 type)
> +{
> +       return (type == SCI_PORT_RSCI || type == RSCI_PORT_SCIF);
> +}
> +
>  static void sci_remove(struct platform_device *dev)
>  {
>         struct sci_port *s = platform_get_drvdata(dev);
> @@ -3574,7 +3579,7 @@ static void sci_remove(struct platform_device *dev)
>         if (s->port.fifosize > 1)
>                 device_remove_file(&dev->dev, &dev_attr_rx_fifo_trigger);
>         if (type == PORT_SCIFA || type == PORT_SCIFB || type == PORT_HSCIF ||
> -           type == SCI_PORT_RSCI)
> +           sci_is_rsci_fifo_type(type))

I think Jiri intended[1] having a helper that covers all cases, not
just the two RSCI variants. E.g. sci_has_fifo(u8 type).

>                 device_remove_file(&dev->dev, &dev_attr_rx_fifo_timeout);
>  }
>
> @@ -3669,6 +3674,10 @@ static const struct of_device_id of_sci_match[] __maybe_unused = {
>                 .data = &of_sci_scif_rzv2h,
>         },
>  #ifdef CONFIG_SERIAL_RSCI
> +       {
> +               .compatible = "renesas,r9a09g047-rscif",
> +               .data = &of_rsci_scif_data,
> +       },
>         {
>                 .compatible = "renesas,r9a09g077-rsci",
>                 .data = &of_sci_rsci_data,
> @@ -3936,7 +3945,7 @@ static int sci_probe(struct platform_device *dev)
>                         return ret;
>         }
>         if (sp->type == PORT_SCIFA || sp->type == PORT_SCIFB ||
> -           sp->type == PORT_HSCIF || sp->type == SCI_PORT_RSCI) {
> +           sp->type == PORT_HSCIF || sci_is_rsci_fifo_type(sp->type)) {
>                 ret = device_create_file(&dev->dev, &dev_attr_rx_fifo_timeout);
>                 if (ret) {
>                         if (sp->port.fifosize > 1) {

[1] https://lore.kernel.org/all/19a08b75-13ca-45f9-884d-f96602336dfd@kernel.org

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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