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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 9 Jan 2020 11:15:09 +0100
Message-ID: <CAK8P3a3wnn3E9DEfAoXNAurZ3Yop-Y3d_9+3mARY2v5y2B5dAw@mail.gmail.com>
Subject: Re: [PATCH] firmware: arm_scmi: Make scmi core independent of
 transport type
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Sudeep Holla <sudeep.holla@arm.com>, peng.fan@nxp.com,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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On Thu, Jan 9, 2020 at 10:34 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 09-01-20, 09:18, Arnd Bergmann wrote:
> > On Fri, Nov 29, 2019 at 10:32 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:

> > This looks odd: rather than guessing the transport type based on
> > random DT properties, I would prefer to have it determined by
> > the device compatible string, and have different drivers bind
> > to one of them each, with each driver linking against a common
> > base implementation, either as separate modules or in one file.
>
> Since there are no platforms using the scmi binding in mainline kernel
> for now, it won't be difficult to add new compatible strings. So
> should this be done like:
>
>         compatible = "arm,scmi", "arm,scmi-mailbox";
>
> or just
>         compatible = "arm,scmi-mailbox";

I would keep compatibility with the existing binding and make a plain "arm,scmi"
mean the version with the mailbox, while for new transports, I would
require them to have both the existing compatible string and a more specific
one.

        Arnd