davinci: support re-parenting a clock in the clock framework
The clk_set_parent() API is implemented to enable re-parenting
clocks in the clock tree.
This is useful in DVFS and helps by shifting clocks to an asynchronous
domain where supported by hardware
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
diff --git a/arch/arm/mach-davinci/clock.c b/arch/arm/mach-davinci/clock.c
index 09e0e1c..e7696fc 100644
--- a/arch/arm/mach-davinci/clock.c
+++ b/arch/arm/mach-davinci/clock.c
@@ -141,6 +141,33 @@
}
EXPORT_SYMBOL(clk_set_rate);
+int clk_set_parent(struct clk *clk, struct clk *parent)
+{
+ unsigned long flags;
+
+ if (clk == NULL || IS_ERR(clk))
+ return -EINVAL;
+
+ /* Cannot change parent on enabled clock */
+ if (WARN_ON(clk->usecount))
+ return -EINVAL;
+
+ mutex_lock(&clocks_mutex);
+ clk->parent = parent;
+ list_del_init(&clk->childnode);
+ list_add(&clk->childnode, &clk->parent->children);
+ mutex_unlock(&clocks_mutex);
+
+ spin_lock_irqsave(&clockfw_lock, flags);
+ if (clk->recalc)
+ clk->rate = clk->recalc(clk);
+ propagate_rate(clk);
+ spin_unlock_irqrestore(&clockfw_lock, flags);
+
+ return 0;
+}
+EXPORT_SYMBOL(clk_set_parent);
+
int clk_register(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))