Implement clk-mux remuxing if the CLK_SET_RATE_REMUX flag is set. This
implements round_rate for clk-mux to propagate the round_rate to each
parent and to choose the best one.
Signed-off-by: James Hogan <james.ho...@imgtec.com>
---
drivers/clk/clk-mux.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
index 508c032..20b3f0b 100644
--- a/drivers/clk/clk-mux.c
+++ b/drivers/clk/clk-mux.c
@@ -82,9 +82,56 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
return 0;
}
+/* Return index of parent that provides best clock rate */
+static int clk_mux_bestparent(struct clk *clk, unsigned long rate,
+ unsigned long *best_parent_rate)
+{
+ int i, num_parents, bestparent = -1;
+ unsigned long parent_rate, best = 0;
+ struct clk *parent;
+
+ num_parents = __clk_get_num_parents(clk);
+ for (i = 0; i < num_parents; i++) {
+ parent = __clk_get_parent_by_index(clk, i);
+ if (!parent)
+ continue;
+ parent_rate = __clk_round_rate(parent, rate);
+ if (parent_rate <= rate && parent_rate > best) {
+ bestparent = i;
+ best = parent_rate;
+ *best_parent_rate = parent_rate;
+ }
+ }
+
+ return bestparent;
+}
+
+static long clk_mux_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate, u8 *best_parent)
+{
+ struct clk *clk = hw->clk;
+ unsigned long flags = __clk_get_flags(clk);
+ int parent;
+
+ /* never remux unless the flag is set */
+ if (!(flags & CLK_SET_RATE_REMUX)) {
+ if (flags & CLK_SET_RATE_PARENT)
+ return __clk_round_rate(__clk_get_parent(clk), rate);
+ else
+ return __clk_get_rate(clk);
+ }
+
+ parent = clk_mux_bestparent(clk, rate, prate);
+ if (best_parent && parent >= 0)
+ *best_parent = parent;
+
+ return *prate;
+}
+
const struct clk_ops clk_mux_ops = {
.get_parent = clk_mux_get_parent,
.set_parent = clk_mux_set_parent,
+ .round_rate = clk_mux_round_rate,
};
EXPORT_SYMBOL_GPL(clk_mux_ops);
--
1.8.1.2
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