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Date:   Mon, 6 Apr 2020 19:51:08 +0300
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Lad Prabhakar <prabhakar.csengg@gmail.com>
Subject: Re: [PATCH v5 2/5] media: i2c: ov5645: Drop reading clock-frequency
 dt-property
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Hi Prabhakar,

On Mon, Apr 06, 2020 at 05:42:38PM +0100, Lad Prabhakar wrote:
> Modes in the driver are based on xvclk frequency fixed to 24MHz, but where
> as the OV5645 sensor can support the xvclk frequency ranging from 6MHz to
> 24MHz. So instead making clock-frequency as dt-property just let the
> driver enforce the required clock frequency.

Even if some current systems where the driver is used are using 24 MHz
clock, that doesn't mean there wouldn't be systems using another frequency
that the driver does not support right now.

The driver really should not set the frequency unless it gets it from DT,
but I think the preferred means is to use assigned-clock-rates instead, and
not to involve the driver with setting the frequency.

Otherwise we'll make it impossible to support other frequencies, at least
without more or less random defaults.

-- 
Kind regards,

Sakari Ailus