From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: [PATCH V2 01/14] clk: add helper functions clk_prepare_enable and clk_disable_unprepare Date: Fri, 11 Nov 2011 10:15:56 +0100 Message-ID: <20111111091556.GI16886@pengutronix.de> References: <1320973829-4388-1-git-send-email-richard.zhao@linaro.org> <1320973829-4388-2-git-send-email-richard.zhao@linaro.org> <20111111084950.GH16886@pengutronix.de> <20111111090546.GC14617@b20223-02.ap.freescale.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20111111090546.GC14617@b20223-02.ap.freescale.net> Sender: netdev-owner@vger.kernel.org To: Richard Zhao Cc: amit.kucheria@canonical.com, linux@arm.linux.org.uk, kernel@pengutronix.de, netdev@vger.kernel.org, linux-mmc@vger.kernel.org, ben-linux@fluff.org, eric.miao@linaro.org, linux-i2c@vger.kernel.org, linux-serial@vger.kernel.org, cjb@laptop.org, linux-arm-kernel@lists.infradead.org, alan@linux.intel.com List-Id: linux-serial@vger.kernel.org On Fri, Nov 11, 2011 at 05:05:47PM +0800, Richard Zhao wrote: > On Fri, Nov 11, 2011 at 09:49:50AM +0100, Sascha Hauer wrote: > > On Fri, Nov 11, 2011 at 09:10:16AM +0800, Richard Zhao wrote: > > > Signed-off-by: Richard Zhao > > > --- > > > include/linux/clk.h | 19 +++++++++++++++++++ > > > 1 files changed, 19 insertions(+), 0 deletions(-) > > > > > > diff --git a/include/linux/clk.h b/include/linux/clk.h > > > index 7213b52..63985f7 100644 > > > --- a/include/linux/clk.h > > > +++ b/include/linux/clk.h > > > @@ -107,6 +107,25 @@ static inline void clk_unprepare(struct clk *clk) > > > } > > > #endif > > > > > > +static inline int clk_prepare_enable(struct clk *clk) > > > +{ > > > + int ret; > > > + > > > + ret = clk_prepare(clk); > > > + if (!ret) > > > + ret = clk_enable(clk); > > > + if (ret) > > > + clk_unprepare(clk); > > > > As Baruch already pointed out this is hard to read. Also it contains a > > bug. When clk_prepare fails clk_unprepare is called afterwards. > > > > Hint: Kernel guys are not afraid of having multiple return statements > > in a function, instead they like it when something is handled early > > without having to read the rest of the function. > { > int ret; > > ret = clk_prepare(clk); > if (ret) > return ret; > ret = clk_enable(clk); > if (ret) > clk_unprepare(clk); > return ret; Yes, looks good. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |