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From:   Raul Rangel <rrangel@chromium.org>
Date:   Thu, 21 Nov 2019 14:49:51 -0700
Message-ID: <CAHQZ30CYQd1-ZHJeVnKi9CMeZGiRJmvfYN5PRrpN26gcEJZXOA@mail.gmail.com>
Subject: Re: [PATCH 4/4] platform/chrome: i2c: i2c-cros-ec-tunnel: Convert i2c
 tunnel to MFD Cell
To:     Guenter Roeck <groeck@google.com>
Cc:     Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Wolfram Sang <wsa@the-dreams.de>,
        Akshu Agrawal <Akshu.Agrawal@amd.com>,
        Guenter Roeck <groeck@chromium.org>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        "open list:I2C SUBSYSTEM HOST DRIVERS" <linux-i2c@vger.kernel.org>,
        Lee Jones <lee.jones@linaro.org>,
        Benson Leung <bleung@chromium.org>
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On Thu, Nov 21, 2019 at 2:40 PM Guenter Roeck <groeck@google.com> wrote:
>
> On Thu, Nov 21, 2019 at 1:11 PM Raul E Rangel <rrangel@chromium.org> wrote:
> >
> > If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> > possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> > has finished initializing and setting the drvdata. This would cause a
> > NULL pointer panic.
> >
> > Converting this driver over to an MFD solves the problem and aligns with
> > where the cros_ec is going.
> >
>
> I thought the mfd maintainer objects to the use of the mfd API outside
> drivers/mfd. Did that change recently ?

The MFD apis are only used in drivers/mfd/cros_ec_dev.c.
drivers/i2c/busses/i2c-cros-ec-tunnel.c just registers as a simple
driver.

Raul