linux-kernel - Re: [PATCH 12/19] serial: sh-sci: Add support for RZ/G3E RSCI clks

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Message-Id: <20251028113742.7ad84146ecb9a2c7f2c6b4e9@hugovil.com>
Date: Tue, 28 Oct 2025 11:37:42 -0400
From: Hugo Villeneuve <hugo@...ovil.com>
To: Biju Das <biju.das.jz@...renesas.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Jiri Slaby
 <jirislaby@...nel.org>, Geert Uytterhoeven <geert+renesas@...der.be>,
 Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
 wsa+renesas <wsa+renesas@...g-engineering.com>, Claudiu Beznea
 <claudiu.beznea.uj@...renesas.com>, Nam Cao <namcao@...utronix.de>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>, biju.das.au
 <biju.das.au@...il.com>, "linux-renesas-soc@...r.kernel.org"
 <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 12/19] serial: sh-sci: Add support for RZ/G3E RSCI clks

Hi Biju,

On Tue, 28 Oct 2025 15:08:50 +0000
Biju Das <biju.das.jz@...renesas.com> wrote:

> Hi Hugo,
> 
> Thanks for the feedback.
> 
> > -----Original Message-----
> > From: Hugo Villeneuve <hugo@...ovil.com>
> > Sent: 28 October 2025 14:51
> > Subject: Re: [PATCH 12/19] serial: sh-sci: Add support for RZ/G3E RSCI clks
> > 
> > Hi Biju,
> > 
> > On Mon, 27 Oct 2025 15:45:59 +0000
> > Biju Das <biju.das.jz@...renesas.com> wrote:
> > 
> > > RZ/G3E RSCI has 5 module clocks. Add support for these clocks.
> > 
> > In "[PATCH 03/19] dt-bindings: serial: renesas,rsci: Document RZ/G3E support", you mention that
> > "...RZ/G3E has 6 clocks...", and here 5?
> 
> 5 module clocks + 1 external clock = 6 clocks.

Ok, maybe add this precision in your cover letter (and possibly
other commits) to remove any ambiguity...

> 
> I just omitted external clock here as it is available on both G3E and T2H.
> 
> Cheers,
> Biju
> 
> > 
> > 
> > > Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> > > ---
> > >  drivers/tty/serial/sh-sci-common.h |  3 +++
> > >  drivers/tty/serial/sh-sci.c        | 14 ++++++++++++++
> > >  2 files changed, 17 insertions(+)
> > >
> > > diff --git a/drivers/tty/serial/sh-sci-common.h
> > > b/drivers/tty/serial/sh-sci-common.h
> > > index ef1d94ae8b5c..f730ff9add60 100644
> > > --- a/drivers/tty/serial/sh-sci-common.h
> > > +++ b/drivers/tty/serial/sh-sci-common.h
> > > @@ -17,6 +17,9 @@ enum SCI_CLKS {
> > >  	SCI_SCK,		/* Optional External Clock */
> > >  	SCI_BRG_INT,		/* Optional BRG Internal Clock Source */
> > >  	SCI_SCIF_CLK,		/* Optional BRG External Clock Source */
> > > +	SCI_FCK_DIV64,		/* Optional Functional Clock frequency-divided by 64 */
> > > +	SCI_FCK_DIV16,		/* Optional Functional Clock frequency-divided by 16 */
> > > +	SCI_FCK_DIV4,		/* Optional Functional Clock frequency-divided by 4 */
> > 
> > I see 6 clocks here?
> > 
> > >  	SCI_NUM_CLKS
> > >  };
> > >
> > > diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
> > > index 5f5913410df9..d45bdda2b6c1 100644
> > > --- a/drivers/tty/serial/sh-sci.c
> > > +++ b/drivers/tty/serial/sh-sci.c
> > > @@ -2994,6 +2994,9 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
> > >  		[SCI_SCK] = "sck",
> > >  		[SCI_BRG_INT] = "brg_int",
> > >  		[SCI_SCIF_CLK] = "scif_clk",
> > > +		[SCI_FCK_DIV64] = "tclk_div64",
> > > +		[SCI_FCK_DIV16] = "tclk_div16",
> > > +		[SCI_FCK_DIV4] = "tclk_div4",
> > >  	};
> > >  	struct clk *clk;
> > >  	unsigned int i;
> > > @@ -3003,6 +3006,9 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
> > >  	} else if (sci_port->type == SCI_PORT_RSCI) {
> > >  		clk_names[SCI_FCK] = "operation";
> > >  		clk_names[SCI_BRG_INT] = "bus";
> > > +	} else if (sci_port->type == RSCI_PORT_SCI || sci_port->type == RSCI_PORT_SCIF) {
> > > +		clk_names[SCI_FCK] = "tclk";
> > > +		clk_names[SCI_BRG_INT] = "bus";
> > >  	}
> > >
> > >  	for (i = 0; i < SCI_NUM_CLKS; i++) { @@ -3018,6 +3024,14 @@ static
> > > int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
> > >  					     name);
> > >  		}
> > >
> > > +		if (!clk && (sci_port->type == RSCI_PORT_SCI ||
> > > +			     sci_port->type == RSCI_PORT_SCIF) &&
> > > +		    (i == SCI_FCK || i == SCI_BRG_INT || i == SCI_FCK_DIV64 ||
> > > +		     i == SCI_FCK_DIV16 || i == SCI_FCK_DIV4)) {
> > > +			return dev_err_probe(dev, -ENODEV, "failed to get %s\n",
> > > +					     name);
> > > +		}
> > > +
> > >  		if (!clk && i == SCI_FCK) {
> > >  			/*
> > >  			 * Not all SH platforms declare a clock lookup entry
> > > --
> > > 2.43.0
> > >
> > >
> > 
> > --
> > Hugo Villeneuve
> 


-- 
Hugo Villeneuve