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>
This commit is contained in:
Sekhar Nori 2009-08-31 15:48:04 +05:30 committed by Kevin Hilman
parent d6a61563f9
commit b82a51e8ce

View file

@ -141,6 +141,33 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
}
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))