From: Guenter Roeck <groeck@google.com>
To: Lee Jones <lee.jones@linaro.org>
Cc: Raul E Rangel <rrangel@chromium.org>,
Enric Balletbo i Serra <enric.balletbo@collabora.com>,
Wolfram Sang <wsa@the-dreams.de>,
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>,
linux-i2c@vger.kernel.org, Benson Leung <bleung@chromium.org>
Subject: Re: [PATCH 4/4] platform/chrome: i2c: i2c-cros-ec-tunnel: Convert i2c tunnel to MFD Cell
Date: Fri, 22 Nov 2019 02:42:53 -0800 [thread overview]
Message-ID: <CABXOdTf7Oo-qPSnC040Tgxhn3mCogKo=WCsxo_Kj+C+f9DOCyw@mail.gmail.com> (raw)
In-Reply-To: <20191122080319.GC3296@dell>
On Fri, Nov 22, 2019 at 12:03 AM Lee Jones <lee.jones@linaro.org> wrote:
>
> On Thu, 21 Nov 2019, Guenter Roeck 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 ?
>
> It hasn't changed, although I don't see that here?
>
Sorry, I was confused.
Guenter
> > > Signed-off-by: Raul E Rangel <rrangel@chromium.org>
> > > ---
> > > You can now see the device node lives under the mfd device.
> > >
> > > $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
> > > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> > > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> > > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
> > >
> > > drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
> > > drivers/mfd/cros_ec_dev.c | 19 +++++++++++++
> > > 2 files changed, 32 insertions(+), 23 deletions(-)
>
> --
> Lee Jones [李琼斯]
> Linaro Services Technical Lead
> Linaro.org │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2019-11-22 11:22 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-21 21:10 [PATCH 0/4] Convert cros-ec-i2c-tunnel to MFD Cell Raul E Rangel
2019-11-21 21:10 ` [PATCH 1/4] i2c: i2c-cros-ec-tunnel: Pass ACPI node to i2c adapter Raul E Rangel
2019-11-25 16:06 ` Enric Balletbo i Serra
2019-11-25 18:05 ` Raul Rangel
2020-01-31 7:48 ` Wolfram Sang
2019-11-21 21:10 ` [PATCH 2/4] i2c: i2c-cros-ec-tunnel: Fix ACPI identifier Raul E Rangel
2019-11-25 16:23 ` Enric Balletbo i Serra
2019-11-25 18:12 ` Raul Rangel
2020-01-31 7:48 ` Wolfram Sang
2019-11-21 21:10 ` [PATCH 3/4] platform/chrome: cros_ec: Pass firmware node to MFD device Raul E Rangel
2019-11-25 16:30 ` Enric Balletbo i Serra
2019-11-21 21:10 ` [PATCH 4/4] platform/chrome: i2c: i2c-cros-ec-tunnel: Convert i2c tunnel to MFD Cell Raul E Rangel
2019-11-21 21:40 ` Guenter Roeck
2019-11-21 21:49 ` Raul Rangel
2019-11-22 8:03 ` Lee Jones
2019-11-22 10:42 ` Guenter Roeck [this message]
2019-11-25 16:51 ` Enric Balletbo i Serra
2019-11-25 19:38 ` Raul Rangel
2019-12-09 13:17 ` Lee Jones
2019-12-09 14:41 ` Enric Balletbo i Serra
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