clk: sunxi: factors: automatic reparenting support

[karo-tx-linux.git] / drivers / clk / sunxi / clk-factors.c

diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
index 9e232644f07edfac55e29bb2f8d69185ea214357..3806d97e529b06011c0b3018ec12ac2d7811b16d 100644 (file)
--- a/drivers/clk/sunxi/clk-factors.c
+++ b/drivers/clk/sunxi/clk-factors.c
@@ -77,6 +77,41 @@ static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate,
        return rate;
 }
 
+static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate,
+                                      unsigned long *best_parent_rate,
+                                      struct clk **best_parent_p)
+{
+       struct clk *clk = hw->clk, *parent, *best_parent = NULL;
+       int i, num_parents;
+       unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0;
+
+       /* find the parent that can help provide the fastest rate <= rate */
+       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;
+               if (__clk_get_flags(clk) & CLK_SET_RATE_PARENT)
+                       parent_rate = __clk_round_rate(parent, rate);
+               else
+                       parent_rate = __clk_get_rate(parent);
+
+               child_rate = clk_factors_round_rate(hw, rate, &parent_rate);
+
+               if (child_rate <= rate && child_rate > best_child_rate) {
+                       best_parent = parent;
+                       best = parent_rate;
+                       best_child_rate = child_rate;
+               }
+       }
+
+       if (best_parent)
+               *best_parent_p = best_parent;
+       *best_parent_rate = best;
+
+       return best_child_rate;
+}
+
 static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
                                unsigned long parent_rate)
 {
@@ -113,6 +148,7 @@ static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
 }
 
 const struct clk_ops clk_factors_ops = {
+       .determine_rate = clk_factors_determine_rate,
        .recalc_rate = clk_factors_recalc_rate,
        .round_rate = clk_factors_round_rate,
        .set_rate = clk_factors_set_rate,