From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH v10 2/2] tty/serial: Add Spreadtrum sc9836-uart driver support Date: Thu, 29 Jan 2015 16:05:53 +0000 Message-ID: <20150129160553.GC26493@n2100.arm.linux.org.uk> References: <1422443324-25082-1-git-send-email-chunyan.zhang@spreadtrum.com> <1422443324-25082-3-git-send-email-chunyan.zhang@spreadtrum.com> <54CA5128.8050500@gmail.com> <54CA568E.6080306@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <54CA568E.6080306-WaGBZJeGNqdsbIuE7sb01tBPR1lH4CV8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Hurley , Thierry Reding Cc: Varka Bhadram , Chunyan Zhang , gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, gnomes-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org, heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org, andrew-g2DYL2Zd6BY@public.gmane.org, jslaby-AlSwsSmVLrQ@public.gmane.org, lanqing.liu-lxIno14LUO0EEoCn2XhGlw@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, zhang.lyra-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, zhizhou.zhang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org, geng.ren-lxIno14LUO0EEoCn2XhGlw@public.gmane.org, antonynpavlov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, orsonzhai-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, florian.vaussard-p8DiymsW2f8@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, hytszk-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, wei.qiao-lxIno14LUO0EEoCn2XhGlw@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org List-Id: linux-api@vger.kernel.org On Thu, Jan 29, 2015 at 10:49:34AM -0500, Peter Hurley wrote: > Hi Varka, > > On 01/29/2015 10:26 AM, Varka Bhadram wrote: > > This check is not required. It will be done by devm_ioremap_resource() > > I disagree. devm_ioremap_resource() interprets the NULL resource as > a bad parameter and returns -EINVAL which is then forwarded as the > return value from the probe. > > -ENODEV is the correct return value from the probe if the expected > resource is not available (either because it doesn't exist or was already > claimed by another driver). (Adding Thierry as the author of this function.) I believe devm_ioremap_resource() was explicitly designed to remove such error handling from drivers, and to give drivers a unified error response to such things as missing resources. See the comments for this function in lib/devres.c. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html