From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnd Bergmann <arnd@arndb.de>
Subject: Re: [RFC 2/5] i3c: Add core I3C infrastructure
Date: Mon, 31 Jul 2017 22:16:42 +0200
Message-ID: <CAK8P3a06GoMdKdn=3Cq0FUwYnjGX0oG+FQLjxfiasVDpbonWRw@mail.gmail.com>
References: <1501518290-5723-1-git-send-email-boris.brezillon@free-electrons.com>
 <1501518290-5723-3-git-send-email-boris.brezillon@free-electrons.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Return-path: <linux-doc-owner@vger.kernel.org>
In-Reply-To: <1501518290-5723-3-git-send-email-boris.brezillon@free-electrons.com>
Sender: linux-doc-owner@vger.kernel.org
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Wolfram Sang <wsa@the-dreams.de>, linux-i2c@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Przemyslaw Sroka <psroka@cadence.com>, Arkadiusz Golec <agolec@cadence.com>, Alan Douglas <adouglas@cadence.com>, Bartosz Folta <bfolta@cadence.com>, Damian Kos <dkos@cadence.com>, Alicja Jurasik-Urbaniak <alicja@cadence.com>, Jan Kotas <jank@cadence.com>, Cyprian Wronka <cwronka@cadence.com>, Alexandre Belloni <alexandre.belloni@free-electrons.com>, Thomas Petazzoni <thomas.petazzoni@free-electrons.com>, Nishanth Menon <nm@ti.com>, Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Ku
List-Id: devicetree@vger.kernel.org

On Mon, Jul 31, 2017 at 6:24 PM, Boris Brezillon
<boris.brezillon@free-electrons.com> wrote:
> Add core infrastructure to support I3C in Linux and document it.

> - I2C backward compatibility has been designed to be transparent to I2C
>   drivers and the I2C subsystem. The I3C master just registers an I2C
>   adapter which creates a new I2C bus. I'd say that, from a
>   representation PoV it's not ideal because what should appear as a
>   single I3C bus exposing I3C and I2C devices here appears as 2
>   different busses connected to each other through the parenting (the
>   I3C master is the parent of the I2C and I3C busses).
>   On the other hand, I don't see a better solution if we want something
>   that is not invasive.

Can you describe the reasons for making i3c a separate subsystem then,
rather than extending the i2c subsystem to handle both i2c devices as
before and also i3c devices and hosts?

        Arnd