Re: [PATCH 13/16] clk: renesas: Add CPG core wrapper for RZ/G2L SoC

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>,
	 Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>, Jiri Slaby <jirislaby@kernel.org>,
	 Philipp Zabel <p.zabel@pengutronix.de>,
	 "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	 Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	 "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
	 Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 Biju Das <biju.das.jz@bp.renesas.com>,
	Prabhakar <prabhakar.csengg@gmail.com>
Subject: Re: [PATCH 13/16] clk: renesas: Add CPG core wrapper for RZ/G2L SoC
Date: Thu, 27 May 2021 14:04:39 +0200	[thread overview]
Message-ID: <CAMuHMdXd==dM2QJN5gg0ka_7-HDQbeKZK66nmyASFJAnsVsSQA@mail.gmail.com> (raw)
In-Reply-To: <20210514192218.13022-14-prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi Prabhakar,

On Fri, May 14, 2021 at 9:24 PM Lad Prabhakar
<prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> Add CPG core wrapper for RZ/G2L family.
>
> Based on a patch in the BSP by Binh Nguyen
> <binh.nguyen.jz@renesas.com>.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>

> --- /dev/null
> +++ b/drivers/clk/renesas/renesas-rzg2l-cpg.c

> +static int rzg2l_mod_clock_endisable(struct clk_hw *hw, bool enable)
> +{
> +       struct mstp_clock *clock = to_mod_clock(hw);
> +       struct cpg_mssr_priv *priv = clock->priv;
> +       unsigned int reg = MSSR_OFF(clock->bit) * 4;

The "* 4" here makes it difficult to review the module clock tables.

E.g.

       DEF_MOD("gic",          R9A07G044_CLK_GIC600,
                               R9A07G044_CLK_P1,
                               MSSR(5, BIT(0), (BIT(0) | BIT(1)))),

The "5" means the CLK_ON_GIC600 register is at offset CLK_ON_R(5 * 4)
 = 0x514.  Removing the "* 4" means you could use
"MSSR(0x14, BIT(0), (BIT(0) | BIT(1))" instead.

Unless it has unpleasant side effects, I'd even consider putting
the full CLK_ON offset there, i.e.
"MSSR(0x514, BIT(0), (BIT(0) | BIT(1))" and change the macros like:

    #define CLK_ON_R(reg)          (reg)
    #define CLK_MON_R(reg)         (0x680 - 0x500 + (reg))

> --- /dev/null
> +++ b/drivers/clk/renesas/renesas-rzg2l-cpg.h

> +#define CLK_ON_R(reg)          (0x500 + reg)
> +#define CLK_MON_R(reg)         (0x680 + reg)
> +#define CLK_RST_R(reg)         (0x800 + reg)
> +#define CLK_MRST_R(reg)                (0x980 + reg)

The last three don't seem to be documented?

Gr{oetje,eeting}s,

                        Geert

--
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

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