From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH] drivers/core/of: Add symlink to device-tree from devices with an OF node Date: Tue, 18 Nov 2014 10:37:08 -0600 Message-ID: References: <1415342031.4925.27.camel@kernel.crashing.org> <1415342117.4925.29.camel@kernel.crashing.org> <1415596626.5769.14.camel@kernel.crashing.org> <1415841047.5124.62.camel@kernel.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <1415841047.5124.62.camel@kernel.crashing.org> Sender: linux-kernel-owner@vger.kernel.org To: Benjamin Herrenschmidt Cc: "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann , Olof Johansson , Grant Likely , Greg KH , Jeremy Kerr List-Id: devicetree@vger.kernel.org On Wed, Nov 12, 2014 at 7:10 PM, 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) > propreties 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. > > This patch adds an "of_node" symlink to devices that have a non-NULL > dev->of_node pointer, the patch is pretty trivial and seems to work just > fine for me. > > Signed-off-by: Benjamin Herrenschmidt > --- > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 20da3ad..8c7b607 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -493,6 +493,15 @@ static int device_add_attrs(struct device *dev) > goto err_remove_dev_groups; > } > > +#ifdef CONFIG_OF > + if (dev->of_node) { if (IS_ENABLED(CONFIG_OF) && dev->of_node) > + error = sysfs_create_link(&dev->kobj, &dev->of_node->kobj, > + "of_node"); > + if (error) > + dev_warn(dev, "Error %d creating of_node link\n", error); > + } > +#endif /* CONFIG_OF */ > + > return 0; > > err_remove_dev_groups: > >