Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759629AbaJaVOL (ORCPT ); Fri, 31 Oct 2014 17:14:11 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:49074 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751388AbaJaVOI convert rfc822-to-8bit (ORCPT ); Fri, 31 Oct 2014 17:14:08 -0400 MIME-Version: 1.0 In-Reply-To: <1414709964-27284-1-git-send-email-gavidov@codeaurora.org> References: <1414709964-27284-1-git-send-email-gavidov@codeaurora.org> From: Rob Herring Date: Sat, 1 Nov 2014 05:13:45 +0800 Message-ID: Subject: Re: [PATCH 0/1] Compact interface for Device-Tree To: Gilad Avidov Cc: Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Grant Likely , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Sagar Dharia , linux-arm-msm , David Woodhouse , "Rafael J. Wysocki" , Arnd Bergmann Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 31, 2014 at 6:59 AM, Gilad Avidov wrote: > > Device-Tree compact API > ------------------------ > > Common code seen in driver’s probe reads device tree values and handling > erroneous return codes from all those of_property_read_xxx() APIs. This > common code is factored out by the of_property_map module which allows > driver’s probe to replace that (often lengthy) code with a concise table: > > struct of_prop_map map[] = { > {"i2c", &dev->id, OF_REQ, OF_ID, -1}, > {"qcom,clk-freq-out", &dev->clk_freq_out, OF_REQ, OF_U32, 0}, > {"qcom,clk-freq-in", &dev->clk_freq_in, OF_REQ, OF_U32, 0}, > {"qcom,disable-dma", &dev->disable_dma, OF_OPT, OF_BOOL, 0}, > {"qcom,master-id", &dev->mstr_id, OF_SGST, OF_U32, 0}, > {NULL, NULL, 0, 0, 0}, > }; > > Then call populate to read the values into the device’s variables: > > ret = of_prop_populate(dev, dev->of_node, map); Interesting idea. The main concern I have with this is there has been on-going discussions about how to generalize property handling across DT and ACPI to make drivers more agnostic, so I'm copying a few folks involved in that. That may be a bit orthogonal to what this is doing, but we may want some coordination here. BTW, there is little point to a 0/1 email. All this info should be in the patch either in commit msg or documentation as part of the patch. Rob > An equivalent code snippet using the traditional of_property_read_XXXX() > API. Note that the equivalent is longer and more difficult to follow and > debug: > > /* optional property */ > dev->disable_dma = of_property_read_bool(node, "qcom,disable-dma"); > > ret = of_property_read_u32(dev->node, "qcom,clk-freq-out", &dev->clk_freq_out); > if (ret) { > dev_err(dev, "error: missing 'qcom,clk-freq-out' DT property\n"); > if (!err) > err = ret; > } > > ret = of_property_read_u32(dev->node, "qcom,clk-freq-in", &dev->clk_freq_in); > if (ret) { > dev_err(dev, "error: missing 'qcom,clk-freq-in' DT property\n"); > if (!err) > err = ret; > } > > /* suggested property */ > ret = of_property_read_u32(dev->node, "qcom,master-id", &dev->mstr_id); > if (ret && !err) > err = ret; > > > ret = of_alias_get_id(dev->node, "i2c"); > if (ret < 0) { > dev_err(dev, "error: missing '"i2c"' DT property\n"); > if (!err) > err = ret; > } else { > dev->id = ret; > } > > > The Device-Tree node and alias which are read by the above code snippets: > > aliases { > i2c0 = &i2c_0; /* I2C0 controller device */ > }; > > i2c_0: i2c@78b6000 { /* BLSP1 QUP2 */ > compatible = "qcom,i2c-msm-v2"; > reg-names = "qup_phys_addr", "bam_phys_addr"; > reg = <0x78b6000 0x600>, > <0x7884000 0x23000>; > qcom,clk-freq-out = <100000>; > qcom,clk-freq-in = <19200000>; > qcom,disable-dma; > qcom,master-id = <86>; > }; > > > Gilad Avidov (1): > of_propery_map: compact interface for Device-Tree > > Documentation/devicetree/of_property_map.txt | 76 ++++++++++++++++++++++ > drivers/of/Makefile | 2 +- > drivers/of/of_property_map.c | 88 ++++++++++++++++++++++++++ > include/linux/of_property_map.h | 74 ++++++++++++++++++++++ > 4 files changed, 239 insertions(+), 1 deletion(-) > create mode 100644 Documentation/devicetree/of_property_map.txt > create mode 100644 drivers/of/of_property_map.c > create mode 100644 include/linux/of_property_map.h > > -- > The Qualcomm Innovation Center, Inc. is a member of the 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/