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Sascha Hauerf0948f52012-05-03 15:36:14 +05301/*
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
27static 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
35static 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
51static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
52 unsigned long parent_rate)
53{
54 return 0;
55}
56
57struct 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};
62EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
63
64struct 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;
Rajendra Nayakf7d8caa2012-06-01 14:02:47 +053085 init.flags = flags | CLK_IS_BASIC;
Sascha Hauerf0948f52012-05-03 15:36:14 +053086 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}