From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753523AbaKMBLU (ORCPT ); Wed, 12 Nov 2014 20:11:20 -0500 Received: from gate.crashing.org ([63.228.1.57]:45858 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752662AbaKMBLS (ORCPT ); Wed, 12 Nov 2014 20:11:18 -0500 Message-ID: <1415841047.5124.62.camel@kernel.crashing.org> Subject: [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: Thu, 13 Nov 2014 12:10:47 +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> 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 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) { + 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: