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clk: clock multiplexers may register out of order 

When a clock, C is initialised any orphan clocks listing C as
a possible parent are reparented to it regardless of the
parent requested by the orphan's get_parent() operation.

This means that multiplexers registered before their parents
are reparented to the first parent subsequently declared,
regardless of the selection made by the hardware registers.

For example:
	static const char *sel[] = { "srcA", "srcB", "dummy", "srcC" };

	child = clk_register_mux(NULL, "child",  sel, ARRAY_SIZE(sel), ...);
	clk_register_fixed(NULL, "dummy", ...);
	clk_register_fixed(NULL, "srcA", ...);
	clk_register_fixed(NULL, "srcB", ...);
	clk_register_fixed(NULL, "srcC", ...);

Causes child's parent to always be "dummy".

To fix this, when an orphanned clock has a get_parent() operation,
only reparent to the clock indicated by get_parent().

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: improve $SUBJECT]
This commit is contained in:
Martin Fuzzey 2012-11-22 20:15:05 +01:00 committed by Mike Turquette
parent 45228ef322
commit 1f61e5f143
1 changed files with 9 additions and 1 deletions
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10
drivers/clk/clk.c
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@ -1298,12 +1298,20 @@ int __clk_init(struct device *dev, struct clk *clk)
* walk the list of orphan clocks and reparent any that are children of
* this clock
*/
hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node)
hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) {
if (orphan->ops->get_parent) {
i = orphan->ops->get_parent(orphan->hw);
if (!strcmp(clk->name, orphan->parent_names[i]))
__clk_reparent(orphan, clk);
continue;
}
for (i = 0; i < orphan->num_parents; i++)
if (!strcmp(clk->name, orphan->parent_names[i])) {
__clk_reparent(orphan, clk);
break;
}
}
/*
* optional platform-specific magic