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authorShawn Guo <shawn.guo@linaro.org>2011-12-20 09:12:34 +0100
committerShawn Guo <shawn.guo@linaro.org>2011-12-28 14:35:08 +0100
commit6abda3e129bfe4d74b5c274da7dff0e2b1488818 (patch)
treef9fd67a5c38101d9d1af3e2d858fadd4d19527cc /arch/arm/mach-mxs/clock.c
parentclk: add config option HAVE_CLK_PREPARE into Kconfig (diff)
downloadlinux-6abda3e129bfe4d74b5c274da7dff0e2b1488818.tar.xz
linux-6abda3e129bfe4d74b5c274da7dff0e2b1488818.zip
ARM: mxs: select HAVE_CLK_PREPARE for clock
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 <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mach-mxs/clock.c')
-rw-r--r--arch/arm/mach-mxs/clock.c31
1 files changed, 22 insertions, 9 deletions
diff --git a/arch/arm/mach-mxs/clock.c b/arch/arm/mach-mxs/clock.c
index 755eec0b5a89..97a6f4acc6cc 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