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authorAmit Kucheria <amit.kucheria@verdurent.com>2010-05-28 11:29:09 +0300
committerSascha Hauer <s.hauer@pengutronix.de>2010-07-26 14:17:57 +0200
commit9b839ec0a880977d05ec4d25028ca4a0c3216c61 (patch)
tree261d1f3be890592d6cd229e2d4251d2b9024a1ec /arch/arm/plat-mxc/clock.c
parentc45dd814008f8842f854aa6960dfd6c610a01873 (diff)
downloadlinux-9b839ec0a880977d05ec4d25028ca4a0c3216c61.tar.bz2
arm: mxc: utilise usecount field in clock operations
This patch fixes the clock refcounting when reparenting is used. Boot-tested on imx51 babbage board. Sascha pointed out a good explanation of refcounting here: http://www.spinics.net/lists/arm-kernel/msg85879.html Signed-off-by: Amit Kucheria <amit.kucheria@canonical.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/arm/plat-mxc/clock.c')
-rw-r--r--arch/arm/plat-mxc/clock.c37
1 files changed, 25 insertions, 12 deletions
diff --git a/arch/arm/plat-mxc/clock.c b/arch/arm/plat-mxc/clock.c
index 323ff8ccc877..2ed3ab173add 100644
--- a/arch/arm/plat-mxc/clock.c
+++ b/arch/arm/plat-mxc/clock.c
@@ -52,13 +52,14 @@ static void __clk_disable(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return;
-
- __clk_disable(clk->parent);
- __clk_disable(clk->secondary);
-
WARN_ON(!clk->usecount);
- if (!(--clk->usecount) && clk->disable)
- clk->disable(clk);
+
+ if (!(--clk->usecount)) {
+ if (clk->disable)
+ clk->disable(clk);
+ __clk_disable(clk->parent);
+ __clk_disable(clk->secondary);
+ }
}
static int __clk_enable(struct clk *clk)
@@ -66,12 +67,13 @@ static int __clk_enable(struct clk *clk)
if (clk == NULL || IS_ERR(clk))
return -EINVAL;
- __clk_enable(clk->parent);
- __clk_enable(clk->secondary);
-
- if (clk->usecount++ == 0 && clk->enable)
- clk->enable(clk);
+ if (clk->usecount++ == 0) {
+ __clk_enable(clk->parent);
+ __clk_enable(clk->secondary);
+ if (clk->enable)
+ clk->enable(clk);
+ }
return 0;
}
@@ -160,17 +162,28 @@ EXPORT_SYMBOL(clk_set_rate);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
int ret = -EINVAL;
+ struct clk *old;
if (clk == NULL || IS_ERR(clk) || parent == NULL ||
IS_ERR(parent) || clk->set_parent == NULL)
return ret;
+ if (clk->usecount)
+ clk_enable(parent);
+
mutex_lock(&clocks_mutex);
ret = clk->set_parent(clk, parent);
- if (ret == 0)
+ if (ret == 0) {
+ old = clk->parent;
clk->parent = parent;
+ } else {
+ old = parent;
+ }
mutex_unlock(&clocks_mutex);
+ if (clk->usecount)
+ clk_disable(old);
+
return ret;
}
EXPORT_SYMBOL(clk_set_parent);