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From:   Rob Herring <robh@kernel.org>
Date:   Mon, 16 Jul 2018 08:00:47 -0600
Message-ID: <CAL_JsqLm7bMf5PgQa0vQR4ERApzdv+wOHfayOG7GdMtDKDJdbw@mail.gmail.com>
Subject: Re: [PATCH v2 08/34] media: camss: Unify the clock names
To:     Todor Tomov <todor.tomov@linaro.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org
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On Mon, Jul 16, 2018 at 2:53 AM Todor Tomov <todor.tomov@linaro.org> wrote:
>
> Hi Rob,
>
> Thank you for review.
>
> On 11 July 2018 at 19:07, Rob Herring <robh@kernel.org> wrote:
> > On Thu, Jul 05, 2018 at 04:32:39PM +0300, Todor Tomov wrote:
> >> Unify the clock names - use names closer to the clock
> >> definitions.
> >
> > Why? You can't just change names. You are breaking an ABI.
>
> Main reason is that this change allows more logical names and
> handling in the driver when support for 8996 is added.
> To clarify by example:
> - we used to have "camss_vfe_vfe" in 8916;
> - now we will have "vfe0" in 8916 and "vfe0" and "vfe1" in 8996.
>
> To achieve this I have changed the names to match more closely
> the definitions in the clock driver, which are based on the
> documentation. Yes, I should have done this the first time...
>
> I have used to update the dt and kernel code together. Yes, the
> change breaks the ABI but does this cause difficulties in practice?

That's up to the platform maintainers to decide. As a user of these
boards, yes, it would bother me. However, camera I don't care so much
about.

In any case, the commit message should make this crystal clear and
justify why breaking compatibility is okay.

Rob