netdev - Re: [PATCH 4/6] can: rcar_canfd: Add clk_postdiv to struct rcar_canfd_hw

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Message-ID: <CAMuHMdV-uG5Q6OQd+=HHTzOUuw_T4_2i6cNh5fcZCBWACcoptg@mail.gmail.com>
Date:   Mon, 24 Oct 2022 16:47:47 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     biju.das.jz@...renesas.com
Cc:     Wolfgang Grandegger <wg@...ndegger.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Vincent Mailhol <mailhol.vincent@...adoo.fr>,
        Stefan Mätje <stefan.maetje@....eu>,
        Ulrich Hecht <uli+renesas@...nd.eu>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        linux-can@...r.kernel.org, netdev@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH 4/6] can: rcar_canfd: Add clk_postdiv to struct rcar_canfd_hw_info

Hi Biju,

On Sat, Oct 22, 2022 at 1:03 PM Biju Das <biju.das.jz@...renesas.com> wrote:
> R-Car has a clock divider for CAN FD clock within the IP, whereas
> it is not available on RZ/G2L.
>
> Add clk_postdiv to struct rcar_canfd_hw_info to take care of this
> difference.
>
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>

Thanks for your patch!

> --- a/drivers/net/can/rcar/rcar_canfd.c
> +++ b/drivers/net/can/rcar/rcar_canfd.c
> @@ -528,6 +528,7 @@ struct rcar_canfd_hw_info {
>         u32 max_channels;
>         /* hardware features */
>         unsigned multi_global_irqs:1;   /* Has multiple global irqs  */
> +       unsigned clk_postdiv:1;         /* Has CAN clk post divider  */

As this is not the actual post divider, I think this should be called
has_clk_postdiv. But see below...

>  };
>
>  /* Channel priv data */

> @@ -1948,7 +1951,7 @@ static int rcar_canfd_probe(struct platform_device *pdev)
>         }
>         fcan_freq = clk_get_rate(gpriv->can_clk);
>
> -       if (gpriv->fcan == RCANFD_CANFDCLK && info->chip_id != RENESAS_RZG2L)
> +       if (gpriv->fcan == RCANFD_CANFDCLK && info->clk_postdiv)
>                 /* CANFD clock is further divided by (1/2) within the IP */
>                 fcan_freq /= 2;

If info->clk_postdiv would be the actual post divider, you could simplify to:

    if (gpriv->fcan == RCANFD_CANFDCLK)
            fcan_freq /= info->postdiv;

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