From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752219AbbASL2q (ORCPT ); Mon, 19 Jan 2015 06:28:46 -0500 Received: from mail-lb0-f173.google.com ([209.85.217.173]:35024 "EHLO mail-lb0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751412AbbASL21 (ORCPT ); Mon, 19 Jan 2015 06:28:27 -0500 MIME-Version: 1.0 In-Reply-To: <20150119105753.GC21553@leverpostej> References: <1421581173-28416-1-git-send-email-ricardo.ribalda@gmail.com> <1421581173-28416-5-git-send-email-ricardo.ribalda@gmail.com> <20150119105753.GC21553@leverpostej> From: Ricardo Ribalda Delgado Date: Mon, 19 Jan 2015 12:28:04 +0100 Message-ID: Subject: Re: [PATCH 4/8] gpio-mm-lantiq: Use of_propery_read_u16 To: Mark Rutland Cc: "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Linus Walleij , Alexandre Courbot , "grant.likely@linaro.org" , Rob Herring , John Crispin , "devicetree@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Mark Thanks for noticing. I have just sent the v2 of the patch. Regards! On Mon, Jan 19, 2015 at 11:57 AM, Mark Rutland wrote: > On Sun, Jan 18, 2015 at 11:39:29AM +0000, Ricardo Ribalda Delgado wrote: >> Instead of parsing manually the shadow content, use the much simpler >> helper of_property_read_u16. >> >> Cc: Linus Walleij >> Cc: Alexandre Courbot >> Cc: Grant Likely >> Cc: Rob Herring >> Cc: John Crispin >> Cc: devicetree@vger.kernel.org >> Signed-off-by: Ricardo Ribalda Delgado >> --- >> drivers/gpio/gpio-mm-lantiq.c | 6 ++---- >> 1 file changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/gpio/gpio-mm-lantiq.c b/drivers/gpio/gpio-mm-lantiq.c >> index 7d55161..b511a6b 100644 >> --- a/drivers/gpio/gpio-mm-lantiq.c >> +++ b/drivers/gpio/gpio-mm-lantiq.c >> @@ -105,7 +105,6 @@ static void ltq_mm_save_regs(struct of_mm_gpio_chip *mm_gc) >> static int ltq_mm_probe(struct platform_device *pdev) >> { >> struct ltq_mm *chip; >> - const __be32 *shadow; >> >> chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); >> if (!chip) >> @@ -117,9 +116,8 @@ static int ltq_mm_probe(struct platform_device *pdev) >> chip->mmchip.save_regs = ltq_mm_save_regs; >> >> /* store the shadow value if one was passed by the devicetree */ >> - shadow = of_get_property(pdev->dev.of_node, "lantiq,shadow", NULL); >> - if (shadow) >> - chip->shadow = be32_to_cpu(*shadow); >> + of_property_read_u16(pdev->dev.of_node, "lantiq,shadow", >> + &chip->shadow); > > The old code and new code aren't equivalent: > > The binding doesn't specify the use of /bits/ 16 <...>, nor does the > only in-tree dts use it: > > arch/mips/boot/dts/easy50712.dts: lantiq,shadow = <0xfff>; > > So in the DTB, lantiq-shadow will be stored as a be32 value. The byte > stream will look like: [00 00 0f ff]. > > The existing code reads all 4 bytes, and converts them as required, > reading the expected value of 0xfff. If you use of_property_read_u16, > this will only take the first 2 bytes, and will incorrectly read 0. > > You can instead use of_property_read_u32, which will function > equivalently to the existing code. > > Thanks, > Mark. -- Ricardo Ribalda