Commit 1f61e5f1 authored Nov 22, 2012 by Martin Fuzzey Committed by Mike Turquette Nov 26, 2012

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]

parent 45228ef3

drivers/clk/clk.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -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