[v2] clk: sunxi: Accept a greater rate when setting a parent clock

Commit Message

Jean-Francois Moine March 30, 2016, 5:47 p.m. UTC

The best rate of a clock may be a bit greater than the requested one.
In such a case, the rate setting from a child clock was rejected.

This patch fixes the problem searching a 'best rate' instead of
a 'fastest rate <= rate'.

Signed-off-by: Jean-Francois Moine <[e-mail]>
---
 drivers/clk/sunxi/clk-factors.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
index ddefe96..c8e2f29 100644
--- a/drivers/clk/sunxi/clk-factors.c
+++ b/drivers/clk/sunxi/clk-factors.c
@@ -95,9 +95,10 @@  static int clk_factors_determine_rate(struct clk_hw *hw,
 	struct clk_factors *factors = to_clk_factors(hw);
 	struct clk_hw *parent, *best_parent = NULL;
 	int i, num_parents;
-	unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0;
+	unsigned long parent_rate, best = 0, child_rate, best_child_rate;
+	unsigned long d_rate, best_d_rate = ~0ul;
 
-	/* find the parent that can help provide the fastest rate <= rate */
+	/* find the parent that can help provide the best rate */
 	num_parents = clk_hw_get_num_parents(hw);
 	for (i = 0; i < num_parents; i++) {
 		struct factors_request factors_req = {
@@ -116,10 +117,18 @@  static int clk_factors_determine_rate(struct clk_hw *hw,
 		factors->get_factors(&factors_req);
 		child_rate = factors_req.rate;
 
-		if (child_rate <= req->rate && child_rate > best_child_rate) {
+		if (child_rate >= req->rate)
+			d_rate = child_rate - req->rate;
+		else
+			d_rate = req->rate - child_rate;
+
+		if (d_rate < best_d_rate) {
 			best_parent = parent;
 			best = parent_rate;
 			best_child_rate = child_rate;
+			if (d_rate == 0)
+				break;
+			best_d_rate = d_rate;
 		}
 	}