From mboxrd@z Thu Jan 1 00:00:00 1970 From: shawn.guo@linaro.org (Shawn Guo) Date: Tue, 20 Dec 2011 20:00:43 +0800 Subject: [PATCH 12/12] arm/mxs: select HAVE_CLK_PREPARE for clock In-Reply-To: <1324382443-4439-1-git-send-email-shawn.guo@linaro.org> References: <1324382443-4439-1-git-send-email-shawn.guo@linaro.org> Message-ID: <1324382443-4439-13-git-send-email-shawn.guo@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This patch adds clk_prepare/clk_unprepare for mxs clock api by renaming the existing non-atomic clk_enable/clk_disable to clk_prepare/clk_unprepare and adding a pair of dummy clk_enable/clk_disable. Then with selecting HAVE_CLK_PREPARE for mxs clock, we can fix the mutex locking warning that has been reported for a few times. Signed-off-by: Shawn Guo --- arch/arm/Kconfig | 1 + arch/arm/mach-mxs/clock.c | 31 ++++++++++++++++++++++--------- 2 files changed, 23 insertions(+), 9 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 776d76b..dc46163 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -442,6 +442,7 @@ config ARCH_MXS select ARCH_REQUIRE_GPIOLIB select CLKDEV_LOOKUP select CLKSRC_MMIO + select HAVE_CLK_PREPARE help Support for Freescale MXS-based family of processors diff --git a/arch/arm/mach-mxs/clock.c b/arch/arm/mach-mxs/clock.c index 755eec0..97a6f4a 100644 --- a/arch/arm/mach-mxs/clock.c +++ b/arch/arm/mach-mxs/clock.c @@ -74,10 +74,15 @@ static int __clk_enable(struct clk *clk) return 0; } -/* This function increments the reference count on the clock and enables the - * clock if not already enabled. The parent clock tree is recursively enabled +/* + * The clk_enable/clk_disable could be called by drivers in atomic context, + * so they should not really hold mutex. Instead, clk_prepare/clk_unprepare + * can hold a mutex, as the pair will only be called in non-atomic context. + * Before migrating to common clk framework, we can have __clk_enable and + * __clk_disable called in clk_prepare/clk_unprepare with mutex held and + * leave clk_enable/clk_disable as the dummy functions. */ -int clk_enable(struct clk *clk) +int clk_prepare(struct clk *clk) { int ret = 0; @@ -90,13 +95,9 @@ int clk_enable(struct clk *clk) return ret; } -EXPORT_SYMBOL(clk_enable); +EXPORT_SYMBOL(clk_prepare); -/* This function decrements the reference count on the clock and disables - * the clock when reference count is 0. The parent clock tree is - * recursively disabled - */ -void clk_disable(struct clk *clk) +void clk_unprepare(struct clk *clk) { if (clk == NULL || IS_ERR(clk)) return; @@ -105,6 +106,18 @@ void clk_disable(struct clk *clk) __clk_disable(clk); mutex_unlock(&clocks_mutex); } +EXPORT_SYMBOL(clk_unprepare); + +int clk_enable(struct clk *clk) +{ + return 0; +} +EXPORT_SYMBOL(clk_enable); + +void clk_disable(struct clk *clk) +{ + /* nothing to do */ +} EXPORT_SYMBOL(clk_disable); /* Retrieve the *current* clock rate. If the clock itself -- 1.7.4.1