From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@kernel.org (Kevin Hilman) Date: Mon, 20 Oct 2014 11:09:19 -0700 Subject: [PATCH] spi/atmel: add support for runtime PM In-Reply-To: (Wenyou Yang's message of "Mon, 20 Oct 2014 02:05:42 +0000") References: <1413424160-21180-1-git-send-email-wenyou.yang@atmel.com> <7hk33yhms4.fsf@deeprootsystems.com> <20141017135716.GS1820@sirena.org.uk> <7hd29qhj3i.fsf@deeprootsystems.com> Message-ID: <7hd29mfwa8.fsf@deeprootsystems.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org "Yang, Wenyou" writes: >> -----Original Message----- >> From: Kevin Hilman [mailto:khilman at kernel.org] >> Sent: Friday, October 17, 2014 10:22 PM >> To: Mark Brown >> Cc: Yang, Wenyou; linux-spi at vger.kernel.org; linux-kernel at vger.kernel.org; Ferre, >> Nicolas; linux-arm-kernel at lists.infradead.org >> Subject: Re: [PATCH] spi/atmel: add support for runtime PM >> >> Mark Brown writes: >> >> > On Fri, Oct 17, 2014 at 06:02:35AM -0700, Kevin Hilman wrote: >> >> Wenyou Yang writes: >> > >> >> > + if (!pm_runtime_suspended(dev)) { >> >> > + clk_disable_unprepare(as->clk); >> >> > + pinctrl_pm_select_sleep_state(dev); >> >> > + } >> > >> >> a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback >> >> does the same thing. >> > >> > Will that do the right thing when runtime PM is disabled in Kconfig? >> >> Good point. >> >> Then the way to make this cleaner, and obvious on inspection that system >> suspend/resume are doing the same thing as runtime suspend/resume is to have - >> >suspend call the runtime_suspend function. >> >> The runtime suspend/resume functions then should be wrapped in CONFIG_PM >> instead of CONFIG_PM_RUNTIME. > But if the runtime PM is disabled, __pm_runtime_idle() return -ENOSYS, > which invoked by pm_runtime_put_sync(), in spite of the runtime > suspend/resume functions wrapper, You won't be calling _put_sync(), instead you'll just directly call atmel_spi_runtime_suspend(). The goal is to make it obvious upon reading that ->suspend and ->runtime_suspend are doing exactly the same thing. Kevin