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Subject[PATCH] arm: mxc: utilise usecount field in clock operations
Date
clk->usecount can be used by platform code to check if a clock is active or
not.

Signed-off-by: Amit Kucheria <amit.kucheria@canonical.com>
---
arch/arm/plat-mxc/clock.c | 37 ++++++++++++++++++++++++-------------
1 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/arch/arm/plat-mxc/clock.c b/arch/arm/plat-mxc/clock.c
index 323ff8c..c791f38 100644
--- a/arch/arm/plat-mxc/clock.c
+++ b/arch/arm/plat-mxc/clock.c
@@ -50,15 +50,15 @@ static DEFINE_MUTEX(clocks_mutex);

static void __clk_disable(struct clk *clk)
{
- if (clk == NULL || IS_ERR(clk))
+ if (clk == NULL || IS_ERR(clk) || !clk->usecount)
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 +66,13 @@ 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 +161,27 @@ EXPORT_SYMBOL(clk_set_rate);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
int ret = -EINVAL;
+ struct clk *prev_parent = clk->parent;

if (clk == NULL || IS_ERR(clk) || parent == NULL ||
IS_ERR(parent) || clk->set_parent == NULL)
return ret;

+ if (clk->usecount != 0) {
+ clk_enable(parent);
+ }
+
mutex_lock(&clocks_mutex);
ret = clk->set_parent(clk, parent);
- if (ret == 0)
+ if (ret == 0) {
clk->parent = parent;
+ }
mutex_unlock(&clocks_mutex);

+ if (clk->usecount != 0) {
+ clk_disable(prev_parent);
+ }
+
return ret;
}
EXPORT_SYMBOL(clk_set_parent);
--
1.7.0.4


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