From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755020AbbBQPJY (ORCPT ); Tue, 17 Feb 2015 10:09:24 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:60375 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752394AbbBQPJX (ORCPT ); Tue, 17 Feb 2015 10:09:23 -0500 Date: Tue, 17 Feb 2015 07:09:19 -0800 From: Greg Kroah-Hartman To: Rob Herring Cc: Benjamin Herrenschmidt , Grant Likely , Olof Johansson , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann Subject: Re: [PATCH 2/2] drivers/core/of: Add symlink to device-tree from devices with an OF node Message-ID: <20150217150919.GA18008@kroah.com> References: <1424059156.21410.38.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 17, 2015 at 09:00:47AM -0600, Rob Herring wrote: > +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? Yes it does. > > 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); > > + } You don't clean up the link when the device is removed? And why do it here and not in device_add_class_symlinks() like all other devices do? thanks, greg k-h