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Subject: Re: [RFC PATCH 0/9] Add support for Microsoft Surface System
 Aggregator Module
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-serial@vger.kernel.org,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh@kernel.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>,
        =?UTF-8?Q?Bla=c5=be_Hrastnik?= <blaz@mxxn.io>,
        Dorian Stoll <dorian.stoll@tmsp.io>
References: <20200923151511.3842150-1-luzmaximilian@gmail.com>
 <CAK8P3a3Qie_CP1dA-ERqyDv=EnaQQPnNbFYrGr3ySiY4mO0=Uw@mail.gmail.com>
From:   Maximilian Luz <luzmaximilian@gmail.com>
Message-ID: <dad42dce-15d0-245a-4d91-4733e54883a0@gmail.com>
Date:   Wed, 23 Sep 2020 17:43:06 +0200
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On 9/23/20 5:30 PM, Arnd Bergmann wrote:
> On Wed, Sep 23, 2020 at 5:15 PM Maximilian Luz <luzmaximilian@gmail.com> wrote:
>>
>> Hello,
>>
>> The Surface System Aggregator Module (we'll refer to it as Surface
>> Aggregator or SAM below) is an embedded controller (EC) found on various
>> Microsoft Surface devices. Specifically, all 4th and later generation
>> Surface devices, i.e. Surface Pro 4, Surface Book 1 and later, with the
>> exception of the Surface Go series and the Surface Duo. Notably, it
>> seems like this EC can also be found on the ARM-based Surface Pro X [1].
> 
> I think this should go to drivers/platform/x86 or drivers/platform/surface/
> along with other laptop vendor specific code rather than drivers/misc/.

I initially had this under drivers/platform/x86. There are two main
reasons I changed that: First, I think it's a bit too big for
platform/x86 given that it basically introduces a new subsystem. At this
point it's really less of "a couple of odd devices here and there" and
more of a bus-type thing. Second, with the possibility of future support
for ARM devices (Pro X, Pro X 2 which is rumored to come out soon), I
thought that platform/x86 would not be a good fit.

I'd be happy to move this to platform/surface though, if that's
considered a better fit and you're okay with me adding that. Would make
sense given that there's already a platform/chrome, which, as far as I
can tell, also seems to be mainly focused on EC support.

> I'll have a look at the code myself, but I'd prefer to have the maintainers
> for the other laptop drivers review this properly.

Thanks! I'll CC them for the next version.

Regards,
Max