From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754233AbaKSCax (ORCPT ); Tue, 18 Nov 2014 21:30:53 -0500 Received: from gate.crashing.org ([63.228.1.57]:34100 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753439AbaKSCav (ORCPT ); Tue, 18 Nov 2014 21:30:51 -0500 Message-ID: <1416364227.5704.20.camel@kernel.crashing.org> Subject: Re: [PATCH] drivers/core/of: Add symlink to device-tree from devices with an OF node From: Benjamin Herrenschmidt To: Rob Herring Cc: "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann , Olof Johansson , Grant Likely , Greg KH , Jeremy Kerr Date: Wed, 19 Nov 2014 13:30:27 +1100 In-Reply-To: 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.7-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2014-11-18 at 10:37 -0600, Rob Herring wrote: > 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) Ok, I didn't realize the of_node field existed in struct device even without CONFIG_OF (otherwise that wouldn't have compiled). Grant, Rob, do you want to take this patch (with the above fixed) or should I not bother based on the fact that the info is in uevent ? I prefer still doing the symlink but you tell me. > > + 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: > > > > > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html