clk-multiplier.c
3.34 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
/*
* Copyright (C) 2015 Maxime Ripard <maxime.ripard@free-electrons.com>
*
* 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.
*/
#include <linux/bitops.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/slab.h>
#define to_clk_multiplier(_hw) container_of(_hw, struct clk_multiplier, hw)
static unsigned long __get_mult(struct clk_multiplier *mult,
unsigned long rate,
unsigned long parent_rate)
{
if (mult->flags & CLK_MULTIPLIER_ROUND_CLOSEST)
return DIV_ROUND_CLOSEST(rate, parent_rate);
return rate / parent_rate;
}
static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_multiplier *mult = to_clk_multiplier(hw);
unsigned long val;
val = clk_readl(mult->reg) >> mult->shift;
val &= GENMASK(mult->width - 1, 0);
if (!val && mult->flags & CLK_MULTIPLIER_ZERO_BYPASS)
val = 1;
return parent_rate * val;
}
static bool __is_best_rate(unsigned long rate, unsigned long new,
unsigned long best, unsigned long flags)
{
if (flags & CLK_MULTIPLIER_ROUND_CLOSEST)
return abs(rate - new) < abs(rate - best);
return new >= rate && new < best;
}
static unsigned long __bestmult(struct clk_hw *hw, unsigned long rate,
unsigned long *best_parent_rate,
u8 width, unsigned long flags)
{
unsigned long orig_parent_rate = *best_parent_rate;
unsigned long parent_rate, current_rate, best_rate = ~0;
unsigned int i, bestmult = 0;
if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT))
return rate / *best_parent_rate;
for (i = 1; i < ((1 << width) - 1); i++) {
if (rate == orig_parent_rate * i) {
/*
* This is the best case for us if we have a
* perfect match without changing the parent
* rate.
*/
*best_parent_rate = orig_parent_rate;
return i;
}
parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
rate / i);
current_rate = parent_rate * i;
if (__is_best_rate(rate, current_rate, best_rate, flags)) {
bestmult = i;
best_rate = current_rate;
*best_parent_rate = parent_rate;
}
}
return bestmult;
}
static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct clk_multiplier *mult = to_clk_multiplier(hw);
unsigned long factor = __bestmult(hw, rate, parent_rate,
mult->width, mult->flags);
return *parent_rate * factor;
}
static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_multiplier *mult = to_clk_multiplier(hw);
unsigned long factor = __get_mult(mult, rate, parent_rate);
unsigned long flags = 0;
unsigned long val;
if (mult->lock)
spin_lock_irqsave(mult->lock, flags);
else
__acquire(mult->lock);
val = clk_readl(mult->reg);
val &= ~GENMASK(mult->width + mult->shift - 1, mult->shift);
val |= factor << mult->shift;
clk_writel(val, mult->reg);
if (mult->lock)
spin_unlock_irqrestore(mult->lock, flags);
else
__release(mult->lock);
return 0;
}
const struct clk_ops clk_multiplier_ops = {
.recalc_rate = clk_multiplier_recalc_rate,
.round_rate = clk_multiplier_round_rate,
.set_rate = clk_multiplier_set_rate,
};
EXPORT_SYMBOL_GPL(clk_multiplier_ops);