[PATCH v2 1/4] [RFC] clk: new locking scheme for reentrancy

On Wed, Aug 15, 2012 at 04:43:31PM -0700, Mike Turquette wrote:

+void __clk_unprepare(struct clk *clk, struct clk *top)
+{
 	if (clk->ops->unprepare)
 		clk->ops->unprepare(clk->hw);
 
-	__clk_unprepare(clk->parent);
+	if (clk != top)
+		__clk_unprepare(clk->parent, top);
+}

The __clk_unprepare does not match the __clk_prepare below in terms of
if we should call clk->ops->prepare/unprepare on top clock.

I have to change __clk_unprepare to something like the below to get
the series work on imx6q.

 void __clk_unprepare(struct clk *clk, struct clk *top)
 {
+       if (clk == top)
+               return;
+
        if (clk->ops->unprepare)
                clk->ops->unprepare(clk->hw);

-       if (clk != top)
-               __clk_unprepare(clk->parent, top);
+       __clk_unprepare(clk->parent, top);
 }

+int __clk_prepare(struct clk *clk, struct clk *top)
+{
+	int ret = 0;
+
+	if (clk != top) {
+		ret = __clk_prepare(clk->parent, top);
 		if (ret)
 			return ret;
 
 		if (clk->ops->prepare) {
 			ret = clk->ops->prepare(clk->hw);
 			if (ret) {
-				__clk_unprepare(clk->parent);
+				/* this is safe since clk != top */
+				__clk_unprepare(clk->parent, top);
 				return ret;
 			}
 		}
 	}
 
-	clk->prepare_count++;
-
 	return 0;
 }

-- 
Regards,
Shawn