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
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.
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>
14 drivers/clk/clk.c | 47 +++++++++++++++++++++++++++++++++++---------
15 include/linux/clk-provider.h | 8 +++++++-
16 2 files changed, 45 insertions(+), 10 deletions(-)
18 --- a/drivers/clk/clk.c
19 +++ b/drivers/clk/clk.c
20 @@ -695,14 +695,20 @@ struct clk *__clk_lookup(const char *nam
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.
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)
35 + if (flags & CLK_MUX_ROUND_CLOSEST)
36 + return abs(now - rate) < abs(best - rate);
38 + return now <= rate && now > best;
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)
47 struct clk *clk = hw->clk, *parent, *best_parent = NULL;
49 @@ -730,7 +736,7 @@ long __clk_mux_determine_rate(struct clk
50 parent_rate = __clk_round_rate(parent, rate);
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)) {
58 @@ -743,8 +749,31 @@ out:
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.
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)
72 + return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
75 EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
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)
81 + return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
83 + CLK_MUX_ROUND_CLOSEST);
85 +EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
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
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)
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);
120 * FIXME clock api without lock protection