From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eddie Huang Subject: Re: [rtc-linux] [PATCH 2/2] rtc: mediatek: Add MT63xx RTC driver Date: Mon, 16 Mar 2015 17:52:09 +0800 Message-ID: <1426499529.15259.58.camel@mtksdaap41> References: <1422437276-41334-1-git-send-email-eddie.huang@mediatek.com> <1422437276-41334-3-git-send-email-eddie.huang@mediatek.com> <20150223135044.108ea32a65063a50aa36a309@linux-foundation.org> <1426242563.18291.19.camel@mtksdaap41> <20150313105742.GS24885@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150313105742.GS24885-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sascha Hauer Cc: Andrew Morton , Mark Rutland , Alessandro Zummo , srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, Pawel Moll , Ian Campbell , rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, yh.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tianping Fang , Grant Likely , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Sascha Hauer , Kumar Gala , Matthias Brugger , yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org Hi Sascha, On Fri, 2015-03-13 at 11:57 +0100, Sascha Hauer wrote: > Hi Eddie, > > On Fri, Mar 13, 2015 at 06:29:23PM +0800, Eddie Huang wrote: > > > regmap_read() and regmap_write() can return errors. There is no > > > checking for this. > > > > > > > I encounter some trouble when I add code to check return value of > > regmap_read and regmap_write. Every RTC register access through regmap, > > and there are many register read/write in this driver. If I check every > > return value, the driver will become ugly. I try to make this driver > > clean using following macro. > > > > static int __rtc_read(struct mt6397_rtc *rtc, u32 offset, u32 *data) > > { > > u32 addr = rtc->addr_base + offset; > > > > if (offset < rtc->addr_range) > > return regmap_read(rtc->regmap, addr, data); > > > > return -EINVAL; > > } > > > > #define rtc_read(ret, rtc, offset, data) \ > > ({ \ > > ret = __rtc_read(rtc, offset, data); \ > > if (ret < 0) \ > > goto rtc_exit; \ > > }) \ > > Hiding a goto (or return) in a macro is a very bad idea. > > what you can do is > > ret |= regmap_read(rtc->regmap, RTC_TC_SEC, &tm->tm_sec); > ret |= regmap_read(rtc->regmap, RTC_TC_MIN, &tm->tm_min); > > if (ret) > return -EIO; > > (Don't return ret in this case though as it might contain different > error codes orred together) > OK, I will drop macro, and check regmap_read, regmap_write return value in each function. > Another possibilty at least for contiguous registers would be > regmap_bulk_read(). > > Sascha > Contiguous registers access occurs in reading and writing time. I think Matthias's suggestion is a good way: do { ret = __mtk_rtc_read_time(rtc, &tm, &sec); if (ret < 0) goto rtc_exit; } while (sec < tm->tm_sec); Eddie -- 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