From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753603AbbBQPBL (ORCPT ); Tue, 17 Feb 2015 10:01:11 -0500 Received: from mail-wi0-f180.google.com ([209.85.212.180]:48412 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751742AbbBQPBJ (ORCPT ); Tue, 17 Feb 2015 10:01:09 -0500 MIME-Version: 1.0 In-Reply-To: <1424059156.21410.38.camel@kernel.crashing.org> References: <1424059156.21410.38.camel@kernel.crashing.org> From: Rob Herring Date: Tue, 17 Feb 2015 09:00:47 -0600 Message-ID: Subject: Re: [PATCH 2/2] drivers/core/of: Add symlink to device-tree from devices with an OF node To: Benjamin Herrenschmidt , Greg Kroah-Hartman Cc: Grant Likely , Olof Johansson , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +GregKH On Sun, Feb 15, 2015 at 9:59 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) > 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. Doesn't this need sysfs documentation? > Signed-off-by: Benjamin Herrenschmidt I don't mind applying, but this is Greg's code. Rob > --- > drivers/base/core.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 97e2baf..61ef574 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -469,6 +469,7 @@ static int device_add_attrs(struct device *dev) > { > struct class *class = dev->class; > const struct device_type *type = dev->type; > + struct device_node *of_node; > int error; > > if (class) { > @@ -493,6 +494,13 @@ static int device_add_attrs(struct device *dev) > goto err_remove_dev_groups; > } > > + of_node = dev_of_node(dev); > + if (of_node) { > + error = sysfs_create_link(&dev->kobj, &of_node->kobj, "of_node"); > + if (error) > + dev_warn(dev, "Error %d creating of_node link\n", error); > + } > + > return 0; > > err_remove_dev_groups: > > >