Commit b61c43c0 authored by Stephen Boyd's avatar Stephen Boyd

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

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: default avatarStephen Boyd <sboyd@codeaurora.org>
Acked-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: default avatarMichael Turquette <mturquette@linaro.org>
parent dfc202ea
...@@ -2055,16 +2055,18 @@ static int clk_core_set_parent(struct clk_core *clk, struct clk_core *parent) ...@@ -2055,16 +2055,18 @@ static int clk_core_set_parent(struct clk_core *clk, struct clk_core *parent)
if (!clk) if (!clk)
return 0; 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 */ /* prevent racing with updates to the clock topology */
clk_prepare_lock(); clk_prepare_lock();
if (clk->parent == parent) if (clk->parent == parent)
goto out; 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 */ /* check that we are allowed to re-parent if the clock is in use */
if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) { if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
ret = -EBUSY; ret = -EBUSY;
......
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