From mboxrd@z Thu Jan 1 00:00:00 1970 From: LW@KARO-electronics.de (Lothar =?UTF-8?B?V2HDn21hbm4=?=) Date: Mon, 14 Oct 2013 10:04:58 +0200 Subject: [PATCH 01/11] usb: chipidea: Add power management support In-Reply-To: <1381570513-24927-2-git-send-email-peter.chen@freescale.com> References: <1381570513-24927-1-git-send-email-peter.chen@freescale.com> <1381570513-24927-2-git-send-email-peter.chen@freescale.com> Message-ID: <20131014100458.4f577d01@ipc1.ka-ro> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Peter Chen wrote: > This commit adds runtime and system power management support for > chipidea core. The runtime pm support is controlled by glue > layer, it can be enabled by flag CI_HDRC_SUPPORTS_RUNTIME_PM. > [...] > +#ifdef CONFIG_PM > +static int ci_controller_suspend(struct device *dev) > +{ > + struct ci_hdrc *ci = dev_get_drvdata(dev); > + > + dev_dbg(dev, "at %s\n", __func__); > + > + if (atomic_read(&ci->in_lpm)) > + return 0; > + What does this 'atomic_read()' buy you over just testing/assinging a simple integer. Note that just because the function has 'atomic' in its name the sequence: atomic_read(); ... atomic_set(); does not magically become an atomic operation. Lothar Wa?mann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstra?e 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Gesch?ftsf?hrer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info at karo-electronics.de ___________________________________________________________