linux-kernel - Re: [PATCH v3 02/13] serial: rsci: Drop rsci_clear

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Message-ID: <CAMuHMdV_zCYLTM9gwJJE9nErumC32=2qkfPQDhpDVwKHCsVpYw@mail.gmail.com>
Date: Fri, 21 Nov 2025 15:52:37 +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 02/13] serial: rsci: Drop rsci_clear_CFC()

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>
>
> Drop rsci_clear_CFC() by reusing rsci_clear_SCxSR() as the contents of
> both functions are the same.
>
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>

Thanks for your patch!

> --- a/drivers/tty/serial/rsci.c
> +++ b/drivers/tty/serial/rsci.c
> @@ -199,11 +199,6 @@ static unsigned int rsci_get_mctrl(struct uart_port *port)
>         return 0;
>  }
>
> -static void rsci_clear_CFC(struct uart_port *port, unsigned int mask)
> -{
> -       rsci_serial_out(port, CFCLR, mask);
> -}
> -

This function is indeed identical to rsci_clear_SCxSR(), so
Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

However, while the sci_port_ops method is indeed called .clear_SCxSR(),
I think it makes more sense to drop rsci_clear_SCxSR() instead, as this
function touches the CFC register...

>  static void rsci_start_tx(struct uart_port *port)
>  {
>         struct sci_port *sp = to_sci_port(port);
> @@ -275,7 +270,7 @@ static void rsci_transmit_chars(struct uart_port *port)
>                         break;
>                 }
>
> -               rsci_clear_CFC(port, CFCLR_TDREC);
> +               rsci_clear_SCxSR(port, CFCLR_TDREC);

... and it is called directly.

>                 rsci_serial_out(port, TDR, c);
>
>                 port->icount.tx++;

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