clk-fixed-factor.c
3.68 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
/*
* Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Standard functionality for the common clock API.
*/
#include <linux/module.h>
#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
/*
* DOC: basic fixed multiplier and divider clock that cannot gate
*
* Traits of this clock:
* prepare - clk_prepare only ensures that parents are prepared
* enable - clk_enable only ensures that parents are enabled
* rate - rate is fixed. clk->rate = parent->rate / div * mult
* parent - fixed parent. No clk_set_parent support
*/
#define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)
static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
unsigned long long int rate;
rate = (unsigned long long int)parent_rate * fix->mult;
do_div(rate, fix->div);
return (unsigned long)rate;
}
static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
unsigned long best_parent;
best_parent = (rate / fix->mult) * fix->div;
*prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
}
return (*prate / fix->div) * fix->mult;
}
static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
/*
* We must report success but we can do so unconditionally because
* clk_factor_round_rate returns values that ensure this call is a
* nop.
*/
return 0;
}
const struct clk_ops clk_fixed_factor_ops = {
.round_rate = clk_factor_round_rate,
.set_rate = clk_factor_set_rate,
.recalc_rate = clk_factor_recalc_rate,
};
EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
unsigned int mult, unsigned int div)
{
struct clk_fixed_factor *fix;
struct clk_init_data init;
struct clk *clk;
fix = kmalloc(sizeof(*fix), GFP_KERNEL);
if (!fix)
return ERR_PTR(-ENOMEM);
/* struct clk_fixed_factor assignments */
fix->mult = mult;
fix->div = div;
fix->hw.init = &init;
init.name = name;
init.ops = &clk_fixed_factor_ops;
init.flags = flags | CLK_IS_BASIC;
init.parent_names = &parent_name;
init.num_parents = 1;
clk = clk_register(dev, &fix->hw);
if (IS_ERR(clk))
kfree(fix);
return clk;
}
EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
#ifdef CONFIG_OF
/**
* of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
*/
void __init of_fixed_factor_clk_setup(struct device_node *node)
{
struct clk *clk;
const char *clk_name = node->name;
const char *parent_name;
u32 div, mult;
if (of_property_read_u32(node, "clock-div", &div)) {
pr_err("%s Fixed factor clock <%s> must have a clock-div property\n",
__func__, node->name);
return;
}
if (of_property_read_u32(node, "clock-mult", &mult)) {
pr_err("%s Fixed factor clock <%s> must have a clock-mult property\n",
__func__, node->name);
return;
}
of_property_read_string(node, "clock-output-names", &clk_name);
parent_name = of_clk_get_parent_name(node, 0);
clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
mult, div);
if (!IS_ERR(clk))
of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);
CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
of_fixed_factor_clk_setup);
#endif