target/linux/ipq806x/patches-3.18/131-clk-Add-__clk_mux_determine_rate_closest.patch

   1 From 15a02c1f6dd7c2bb150c61d00ffb33f584ff2288 Mon Sep 17 00:00:00 2001
   2 From: Stephen Boyd <sboyd@codeaurora.org>
   3 Date: Mon, 19 Jan 2015 18:05:28 -0800
   4 Subject: [PATCH] clk: Add __clk_mux_determine_rate_closest
   5
   6 Some clock drivers want to find the closest rate on the input of
   7 a mux instead of a rate that's less than or equal to the desired
   8 rate. Add a generic mux function to support this.
   9
  10 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
  11 Tested-by: Kenneth Westfield <kwestfie@codeaurora.org>
  12 Signed-off-by: Michael Turquette <mturquette@linaro.org>
  13 ---
  14  drivers/clk/clk.c            | 47 +++++++++++++++++++++++++++++++++++---------
  15  include/linux/clk-provider.h |  8 +++++++-
  16  2 files changed, 45 insertions(+), 10 deletions(-)
  17
  18 --- a/drivers/clk/clk.c
  19 +++ b/drivers/clk/clk.c
  20 @@ -695,14 +695,20 @@ struct clk *__clk_lookup(const char *nam
  21         return NULL;
  22  }
  23
  24 -/*
  25 - * Helper for finding best parent to provide a given frequency. This can be used
  26 - * directly as a determine_rate callback (e.g. for a mux), or from a more
  27 - * complex clock that may combine a mux with other operations.
  28 - */
  29 -long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
  30 -                             unsigned long *best_parent_rate,
  31 -                             struct clk **best_parent_p)
  32 +static bool mux_is_better_rate(unsigned long rate, unsigned long now,
  33 +                          unsigned long best, unsigned long flags)
  34 +{
  35 +       if (flags & CLK_MUX_ROUND_CLOSEST)
  36 +               return abs(now - rate) < abs(best - rate);
  37 +
  38 +       return now <= rate && now > best;
  39 +}
  40 +
  41 +static long
  42 +clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
  43 +                            unsigned long *best_parent_rate,
  44 +                            struct clk **best_parent_p,
  45 +                            unsigned long flags)
  46  {
  47         struct clk *clk = hw->clk, *parent, *best_parent = NULL;
  48         int i, num_parents;
  49 @@ -730,7 +736,7 @@ long __clk_mux_determine_rate(struct clk
  50                         parent_rate = __clk_round_rate(parent, rate);
  51                 else
  52                         parent_rate = __clk_get_rate(parent);
  53 -               if (parent_rate <= rate && parent_rate > best) {
  54 +               if (mux_is_better_rate(rate, parent_rate, best, flags)) {
  55                         best_parent = parent;
  56                         best = parent_rate;
  57                 }
  58 @@ -743,8 +749,31 @@ out:
  59
  60         return best;
  61  }
  62 +
  63 +/*
  64 + * Helper for finding best parent to provide a given frequency. This can be used
  65 + * directly as a determine_rate callback (e.g. for a mux), or from a more
  66 + * complex clock that may combine a mux with other operations.
  67 + */
  68 +long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
  69 +                             unsigned long *best_parent_rate,
  70 +                             struct clk **best_parent_p)
  71 +{
  72 +       return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
  73 +                                           best_parent_p, 0);
  74 +}
  75  EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
  76
  77 +long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
  78 +                             unsigned long *best_parent_rate,
  79 +                             struct clk **best_parent_p)
  80 +{
  81 +       return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
  82 +                                           best_parent_p,
  83 +                                           CLK_MUX_ROUND_CLOSEST);
  84 +}
  85 +EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
  86 +
  87  /***        clk api        ***/
  88
  89  void __clk_unprepare(struct clk *clk)
  90 --- a/include/linux/clk-provider.h
  91 +++ b/include/linux/clk-provider.h
  92 @@ -382,6 +382,8 @@ struct clk *clk_register_divider_table(s
  93   *     register, and mask of mux bits are in higher 16-bit of this register.
  94   *     While setting the mux bits, higher 16-bit should also be updated to
  95   *     indicate changing mux bits.
  96 + * CLK_MUX_ROUND_CLOSEST - Use the parent rate that is closest to the desired
  97 + *     frequency.
  98   */
  99  struct clk_mux {
 100         struct clk_hw   hw;
 101 @@ -396,7 +398,8 @@ struct clk_mux {
 102  #define CLK_MUX_INDEX_ONE              BIT(0)
 103  #define CLK_MUX_INDEX_BIT              BIT(1)
 104  #define CLK_MUX_HIWORD_MASK            BIT(2)
 105 -#define CLK_MUX_READ_ONLY      BIT(3) /* mux setting cannot be changed */
 106 +#define CLK_MUX_READ_ONLY              BIT(3) /* mux can't be changed */
 107 +#define CLK_MUX_ROUND_CLOSEST          BIT(4)
 108
 109  extern const struct clk_ops clk_mux_ops;
 110  extern const struct clk_ops clk_mux_ro_ops;
 111 @@ -554,6 +557,9 @@ struct clk *__clk_lookup(const char *nam
 112  long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
 113                               unsigned long *best_parent_rate,
 114                               struct clk **best_parent_p);
 115 +long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
 116 +                             unsigned long *best_parent_rate,
 117 +                             struct clk **best_parent_p);
 118
 119  /*
 120   * FIXME clock api without lock protection