linux-kernel - Re: [PATCH v5 3/5] media: i2c: ov5645: Turn probe error into warning for xvclk frequency mismatch

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Date:   Tue, 7 Apr 2020 09:19:14 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Cc:     Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Lad Prabhakar <prabhakar.csengg@...il.com>
Subject: Re: [PATCH v5 3/5] media: i2c: ov5645: Turn probe error into warning
 for xvclk frequency mismatch

Hi Prabhakar,

On Mon, Apr 6, 2020 at 6:43 PM Lad Prabhakar
<prabhakar.mahadev-lad.rj@...renesas.com> wrote:
> PLL's on platforms might not be so accurate enough to generate the
> required clock frequency, so instead of erroring out on xvlck frequency

xvclk? (but see below)

> mismatch just warn the user and continue ahead in probe.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

Like for 2/5, what about the xvclk naming?

> --- a/drivers/media/i2c/ov5645.c
> +++ b/drivers/media/i2c/ov5645.c
> @@ -1103,11 +1103,8 @@ static int ov5645_probe(struct i2c_client *client)
>         }
>         /* external clock must be 24MHz, allow 1% tolerance */
>         xclk_freq = clk_get_rate(ov5645->xclk);
> -       if (xclk_freq < 23760000 || xclk_freq > 24240000) {
> -               dev_err(dev, "external clock frequency %u is not supported\n",
> -                       xclk_freq);
> -               return -EINVAL;
> -       }
> +       if (xclk_freq < 23760000 || xclk_freq > 24240000)
> +               dev_warn(dev, "xvclk mismatched, modes are based on 24MHz\n");

Calling it "xvclk" here will confuse the user, as the clock is named
"xclk" in DT?

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