From: Arnd Bergmann <arnd@arndb.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rob Herring <robherring2@gmail.com>,
        Grant Likely <grant.likely@linaro.org>,
        Olof Johansson <olof@lixom.net>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] drivers/core/of: Add symlink to device-tree from devices with an OF node
Date: Mon, 16 Feb 2015 10:56:19 +0100
Message-ID: <2821848.vmevui3v0t@wuerfel>
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On Monday 16 February 2015 14:59:16 Benjamin Herrenschmidt wrote:
> So I've been annoyed lately with having a bunch of devices such as i2c
> eeproms (for use by VPDs, server world !) and other bits and pieces that
> I want to be able to identify from userspace, and possibly provide
> additional data about from FW.
> 
> Basically, it boils down to correlating the sysfs device with the OF
> tree device node, so that user space can use device-tree info such as
> additional "location" or "label" (or whatever else we can come up with)
> properties to identify a given device, or get some attributes of use
> about it, etc...
> 
> Now, so far, we've done that in some subsystem in a fairly ad-hoc basis
> using "devspec" properties. For example, PCI creates them if it can
> correlate the probed device with a DT node. Some powerpc specific busses
> do that too.
> 
> However, i2c doesn't and it would be nice to have something more generic
> since technically any device can have a corresponding device tree node
> these days.
> 
> This patch achieves this by adding an "of_node" symlink to devices that
> have a non-NULL dev->of_node pointer.
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

I like the idea, this seems very useful.

Acked-by: Arnd Bergmann <arnd@arndb.de>
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