tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
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 unsigned long long int rate;
32
33 rate = (unsigned long long int)parent_rate * fix->mult;
34 do_div(rate, fix->div);
35 return (unsigned long)rate;
36}
37
38static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
39 unsigned long *prate)
40{
41 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
42
43 if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
44 unsigned long best_parent;
45
46 best_parent = (rate / fix->mult) * fix->div;
47 *prate = __clk_round_rate(__clk_get_parent(hw->clk),
48 best_parent);
49 }
50
51 return (*prate / fix->div) * fix->mult;
52}
53
54static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
55 unsigned long parent_rate)
56{
57 return 0;
58}
59
60struct clk_ops clk_fixed_factor_ops = {
61 .round_rate = clk_factor_round_rate,
62 .set_rate = clk_factor_set_rate,
63 .recalc_rate = clk_factor_recalc_rate,
64};
65EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
66
67struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
68 const char *parent_name, unsigned long flags,
69 unsigned int mult, unsigned int div)
70{
71 struct clk_fixed_factor *fix;
72 struct clk_init_data init;
73 struct clk *clk;
74
75 fix = kmalloc(sizeof(*fix), GFP_KERNEL);
76 if (!fix) {
77 pr_err("%s: could not allocate fixed factor clk\n", __func__);
78 return ERR_PTR(-ENOMEM);
79 }
80
81 /* struct clk_fixed_factor assignments */
82 fix->mult = mult;
83 fix->div = div;
84 fix->hw.init = &init;
85
86 init.name = name;
87 init.ops = &clk_fixed_factor_ops;
88 init.flags = flags | CLK_IS_BASIC;
89 init.parent_names = &parent_name;
90 init.num_parents = 1;
91
92 clk = clk_register(dev, &fix->hw);
93
94 if (IS_ERR(clk))
95 kfree(fix);
96
97 return clk;
98}