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Commit 6abda3e1 authored by Shawn Guo's avatar Shawn Guo
Browse files

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: default avatarShawn Guo <shawn.guo@linaro.org>
parent 5c77f560

arch/arm/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -442,6 +442,7 @@ config ARCH_MXS 
	select ARCH_REQUIRE_GPIOLIB

	select ARCH_REQUIRE_GPIOLIB

	select CLKDEV_LOOKUP

	select CLKDEV_LOOKUP

	select CLKSRC_MMIO

	select CLKSRC_MMIO

	select HAVE_CLK_PREPARE

	help

	help

	  Support for Freescale MXS-based family of processors

	  Support for Freescale MXS-based family of processors

arch/arm/mach-mxs/clock.c

+22 −9
Original line number Original line Diff line number Diff line
@@ -74,10 +74,15 @@ static int __clk_enable(struct clk *clk) 
	return 0;

	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;

	int ret = 0;
@@ -90,13 +95,9 @@ int clk_enable(struct clk *clk) 




	return ret;

	return ret;

}

}

EXPORT_SYMBOL(clk_enable);

EXPORT_SYMBOL(clk_prepare);





/* This function decrements the reference count on the clock and disables

void clk_unprepare(struct clk *clk)

 * the clock when reference count is 0. The parent clock tree is

 * recursively disabled

 */

void clk_disable(struct clk *clk)

{

{

	if (clk == NULL || IS_ERR(clk))

	if (clk == NULL || IS_ERR(clk))

		return;

		return;
@@ -105,6 +106,18 @@ void clk_disable(struct clk *clk) 
	__clk_disable(clk);

	__clk_disable(clk);

	mutex_unlock(&clocks_mutex);

	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);

EXPORT_SYMBOL(clk_disable);





/* Retrieve the *current* clock rate. If the clock itself

/* Retrieve the *current* clock rate. If the clock itself