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clk: clk_set_parent() with current parent shouldn't fail

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If a driver calls clk_set_parent(clk, parent) and parent is the
current parent of clk we shouldn't fail in any case.
Unfortunately if clk is a read-only mux we return -ENOSYS
because we think we can't change the parent, except for in this
special case where we don't actually need to change the parent at
all. Return 0 in such a situation.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
This commit is contained in:
Stephen Boyd 2015-02-02 14:11:25 -08:00
parent dfc202ead3
commit b61c43c09f
1 changed files with 6 additions and 4 deletions
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10
drivers/clk/clk.c
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@ -2055,16 +2055,18 @@ static int clk_core_set_parent(struct clk_core *clk, struct clk_core *parent)
if (!clk)
return 0;
/* verify ops for for multi-parent clks */
if ((clk->num_parents > 1) && (!clk->ops->set_parent))
return -ENOSYS;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
if (clk->parent == parent)
goto out;
/* verify ops for for multi-parent clks */
if ((clk->num_parents > 1) && (!clk->ops->set_parent)) {
ret = -ENOSYS;
goto out;
}
/* check that we are allowed to re-parent if the clock is in use */
if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
ret = -EBUSY;