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From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Fri, 21 Jan 2022 11:52:14 +0000
Message-ID: <CA+V-a8v1to4w0yw17DgbQic2nkX4s+W3ZxPEdp89=9SLxwvBMg@mail.gmail.com>
Subject: Re: [RFC PATCH v2 1/4] media: dt-bindings: media: Document RZ/G2L
 CSI-2 block
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        =?UTF-8?Q?Niklas_S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>,
        Jacopo Mondi <jacopo@jmondi.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Biju Das <biju.das.jz@bp.renesas.com>
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Hi Geert,

On Fri, Jan 21, 2022 at 9:26 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Fri, Jan 21, 2022 at 2:06 AM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> > Document the CSI-2 block which is part of CRU found in Renesas
> > RZ/G2L SoC.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Thanks for your patch!
>
> > ---
> > Hi Geert/All,
> >
> > vclk and pclk clocks are shared with CRU both CSI and CRU driver are using
> > pm_runtime. pclk clock is necessary for register access where as vclk clock
> > is only used for calculations. So would you suggest passing vclk as part of
>
> What do you mean by "calculations"?
To set the CSI2nMCT2 register bits (FRRSKW/FRRCLK), vclk clock rate is used.

> The bindings say this is the main clock?
>
That is because the RZG2L_clock_list_r02_02.xlsx mentions it as the main clock.

> > clocks (as currently implemented) or pass the vclk clock rate as a dt property.
>
> Please do not specify clock rates in DT, but always pass clock
> specifiers instead.
> The clock subsystem handles sharing of clocks just fine.
>
Agreed.

Cheers,
Prabhakar