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f0948f59 SH |
1 | /* |
2 | * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * Standard functionality for the common clock API. | |
9 | */ | |
10 | #include <linux/module.h> | |
11 | #include <linux/clk-provider.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/err.h> | |
14 | ||
15 | /* | |
16 | * DOC: basic fixed multiplier and divider clock that cannot gate | |
17 | * | |
18 | * Traits of this clock: | |
19 | * prepare - clk_prepare only ensures that parents are prepared | |
20 | * enable - clk_enable only ensures that parents are enabled | |
21 | * rate - rate is fixed. clk->rate = parent->rate / div * mult | |
22 | * parent - fixed parent. No clk_set_parent support | |
23 | */ | |
24 | ||
25 | #define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw) | |
26 | ||
27 | static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, | |
28 | unsigned long parent_rate) | |
29 | { | |
30 | struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); | |
31 | ||
32 | return parent_rate * fix->mult / fix->div; | |
33 | } | |
34 | ||
35 | static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate, | |
36 | unsigned long *prate) | |
37 | { | |
38 | struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); | |
39 | ||
40 | if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) { | |
41 | unsigned long best_parent; | |
42 | ||
43 | best_parent = (rate / fix->mult) * fix->div; | |
44 | *prate = __clk_round_rate(__clk_get_parent(hw->clk), | |
45 | best_parent); | |
46 | } | |
47 | ||
48 | return (*prate / fix->div) * fix->mult; | |
49 | } | |
50 | ||
51 | static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate, | |
52 | unsigned long parent_rate) | |
53 | { | |
54 | return 0; | |
55 | } | |
56 | ||
57 | struct clk_ops clk_fixed_factor_ops = { | |
58 | .round_rate = clk_factor_round_rate, | |
59 | .set_rate = clk_factor_set_rate, | |
60 | .recalc_rate = clk_factor_recalc_rate, | |
61 | }; | |
62 | EXPORT_SYMBOL_GPL(clk_fixed_factor_ops); | |
63 | ||
64 | struct clk *clk_register_fixed_factor(struct device *dev, const char *name, | |
65 | const char *parent_name, unsigned long flags, | |
66 | unsigned int mult, unsigned int div) | |
67 | { | |
68 | struct clk_fixed_factor *fix; | |
69 | struct clk_init_data init; | |
70 | struct clk *clk; | |
71 | ||
72 | fix = kmalloc(sizeof(*fix), GFP_KERNEL); | |
73 | if (!fix) { | |
74 | pr_err("%s: could not allocate fixed factor clk\n", __func__); | |
75 | return ERR_PTR(-ENOMEM); | |
76 | } | |
77 | ||
78 | /* struct clk_fixed_factor assignments */ | |
79 | fix->mult = mult; | |
80 | fix->div = div; | |
81 | fix->hw.init = &init; | |
82 | ||
83 | init.name = name; | |
84 | init.ops = &clk_fixed_factor_ops; | |
85 | init.flags = flags; | |
86 | init.parent_names = &parent_name; | |
87 | init.num_parents = 1; | |
88 | ||
89 | clk = clk_register(dev, &fix->hw); | |
90 | ||
91 | if (IS_ERR(clk)) | |
92 | kfree(fix); | |
93 | ||
94 | return clk; | |
95 | } |