target/linux/sunxi/patches-3.12/112-clk-sunxi-automatic-reparenting.patch

   1 From 679e8db359d0c1994e88f3a4a2aa0697ce001ad4 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Emilio=20L=C3=B3pez?= <emilio@elopez.com.ar>
   3 Date: Thu, 5 Sep 2013 19:52:41 -0300
   4 Subject: [PATCH] clk: sunxi: factors: automatic reparenting support
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 This commit implements .determine_rate, so that our factor clocks can be
  10 reparented when needed.
  11
  12 Signed-off-by: Emilio López <emilio@elopez.com.ar>
  13 ---
  14  drivers/clk/sunxi/clk-factors.c | 36 ++++++++++++++++++++++++++++++++++++
  15  1 file changed, 36 insertions(+)
  16
  17 diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
  18 index 9e23264..3806d97 100644
  19 --- a/drivers/clk/sunxi/clk-factors.c
  20 +++ b/drivers/clk/sunxi/clk-factors.c
  21 @@ -77,6 +77,41 @@ static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate,
  22         return rate;
  23  }
  24
  25 +static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate,
  26 +                                      unsigned long *best_parent_rate,
  27 +                                      struct clk **best_parent_p)
  28 +{
  29 +       struct clk *clk = hw->clk, *parent, *best_parent = NULL;
  30 +       int i, num_parents;
  31 +       unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0;
  32 +
  33 +       /* find the parent that can help provide the fastest rate <= rate */
  34 +       num_parents = __clk_get_num_parents(clk);
  35 +       for (i = 0; i < num_parents; i++) {
  36 +               parent = clk_get_parent_by_index(clk, i);
  37 +               if (!parent)
  38 +                       continue;
  39 +               if (__clk_get_flags(clk) & CLK_SET_RATE_PARENT)
  40 +                       parent_rate = __clk_round_rate(parent, rate);
  41 +               else
  42 +                       parent_rate = __clk_get_rate(parent);
  43 +
  44 +               child_rate = clk_factors_round_rate(hw, rate, &parent_rate);
  45 +
  46 +               if (child_rate <= rate && child_rate > best_child_rate) {
  47 +                       best_parent = parent;
  48 +                       best = parent_rate;
  49 +                       best_child_rate = child_rate;
  50 +               }
  51 +       }
  52 +
  53 +       if (best_parent)
  54 +               *best_parent_p = best_parent;
  55 +       *best_parent_rate = best;
  56 +
  57 +       return best_child_rate;
  58 +}
  59 +
  60  static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
  61                                 unsigned long parent_rate)
  62  {
  63 @@ -113,6 +148,7 @@ static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
  64  }
  65
  66  const struct clk_ops clk_factors_ops = {
  67 +       .determine_rate = clk_factors_determine_rate,
  68         .recalc_rate = clk_factors_recalc_rate,
  69         .round_rate = clk_factors_round_rate,
  70         .set_rate = clk_factors_set_rate,
  71 --
  72 1.8.5.1
  73