Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752658Ab2KKCdA (ORCPT ); Sat, 10 Nov 2012 21:33:00 -0500 Received: from mail-ob0-f174.google.com ([209.85.214.174]:39362 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752292Ab2KKCc6 (ORCPT ); Sat, 10 Nov 2012 21:32:58 -0500 Message-ID: <509F0E56.6080806@gmail.com> Date: Sat, 10 Nov 2012 20:32:54 -0600 From: Rob Herring User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121028 Thunderbird/16.0.2 MIME-Version: 1.0 To: Stepan Moskovchenko CC: Grant Likely , devicetree-discuss@lists.ozlabs.org, David Brown , Daniel Walker , Bryan Huntsman , Russell King , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC] dt/platform: Use cell-index for device naming if available References: <1352508532-19241-1-git-send-email-stepanm@codeaurora.org> In-Reply-To: <1352508532-19241-1-git-send-email-stepanm@codeaurora.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3276 Lines: 85 On 11/09/2012 06:48 PM, Stepan Moskovchenko wrote: > Use the cell-index property to construct names for platform > devices, falling back on the existing scheme of using the > device register address if cell-index is not specified. > > The cell-index property is a more useful device identifier, > especially in systems containing several numbered instances > of a particular hardware block, since it more easily > illustrates how devices relate to each other. > > Additionally, userspace software may rely on the classic > . naming scheme to access device attributes in > sysfs, without having to know the physical addresses of > that device on every platform the userspace software may > support. Using cell-index for device naming allows the > device addresses to be hidden from userspace and to be > exposed by logical device number without having to rely on > auxdata to perform name overrides. This allows userspace to > make assumptions about which sysfs nodes map to which > logical instance of a specific hardware block. > > Signed-off-by: Stepan Moskovchenko > --- > I had also considered using something like the linux,label property to allow > custom names for platform devices without resorting to auxdata, but the > cell-index approach seems more in line with what cell-index was intended for > and with what the pre-DT platform device naming scheme used to be. Please let > me know if you think there is a better way to accomplish this. > > This is just being sent out as an RFC for now. If there are no objections, I > will send this out as an official patch, along with (or combined with) a patch > to fix up the device names in things like clock tables of any affected > platforms. cell-index is basically deprecated. This has been discussed multiple times in the past. You can use auxdata if you really need to have the old name. Rob > > drivers/of/platform.c | 13 ++++++++++++- > 1 files changed, 12 insertions(+), 1 deletions(-) > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 343ad29..472e374 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -77,8 +77,9 @@ void of_device_make_bus_id(struct device *dev) > static atomic_t bus_no_reg_magic; > struct device_node *node = dev->of_node; > const u32 *reg; > + u32 cell_index; > u64 addr; > - int magic; > + int magic, ret; > > #ifdef CONFIG_PPC_DCR > /* > @@ -101,6 +102,16 @@ void of_device_make_bus_id(struct device *dev) > #endif /* CONFIG_PPC_DCR */ > > /* > + * For devices with a specified cell-index, use the traditional > + * naming scheme of . > + */ > + ret = of_property_read_u32(node, "cell-index", &cell_index); > + if (ret == 0) { > + dev_set_name(dev, "%s.%d", node->name, cell_index); > + return; > + } > + > + /* > * For MMIO, get the physical address > */ > reg = of_get_property(node, "reg", NULL); > -- > The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/