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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Chen-Yu Tsai <wens@csie.org>
*/
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include "ccu_sdm.h"
bool ccu_sdm_helper_is_enabled(struct ccu_common *common,
struct ccu_sdm_internal *sdm)
{
if (!(common->features & CCU_FEATURE_SIGMA_DELTA_MOD))
return false;
if (sdm->enable && !(readl(common->base + common->reg) & sdm->enable))
return false;
return !!(readl(common->base + sdm->tuning_reg) & sdm->tuning_enable);
}
void ccu_sdm_helper_enable(struct ccu_common *common,
struct ccu_sdm_internal *sdm,
unsigned long rate)
{
unsigned long flags;
unsigned int i;
u32 reg;
if (!(common->features & CCU_FEATURE_SIGMA_DELTA_MOD))
return;
/* Set the pattern */
for (i = 0; i < sdm->table_size; i++)
if (sdm->table[i].rate == rate)
writel(sdm->table[i].pattern,
common->base + sdm->tuning_reg);
/* Make sure SDM is enabled */
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + sdm->tuning_reg);
writel(reg | sdm->tuning_enable, common->base + sdm->tuning_reg);
spin_unlock_irqrestore(common->lock, flags);
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + common->reg);
writel(reg | sdm->enable, common->base + common->reg);
spin_unlock_irqrestore(common->lock, flags);
}
void ccu_sdm_helper_disable(struct ccu_common *common,
struct ccu_sdm_internal *sdm)
{
unsigned long flags;
u32 reg;
if (!(common->features & CCU_FEATURE_SIGMA_DELTA_MOD))
return;
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + common->reg);
writel(reg & ~sdm->enable, common->base + common->reg);
spin_unlock_irqrestore(common->lock, flags);
spin_lock_irqsave(common->lock, flags);
reg = readl(common->base + sdm->tuning_reg);
writel(reg & ~sdm->tuning_enable, common->base + sdm->tuning_reg);
spin_unlock_irqrestore(common->lock, flags);
}
/*
* Sigma delta modulation provides a way to do fractional-N frequency
* synthesis, in essence allowing the PLL to output any frequency
* within its operational range. On earlier SoCs such as the A10/A20,
* some PLLs support this. On later SoCs, all PLLs support this.
*
* The datasheets do not explain what the "wave top" and "wave bottom"
* parameters mean or do, nor how to calculate the effective output
* frequency. The only examples (and real world usage) are for the audio
* PLL to generate 24.576 and 22.5792 MHz clock rates used by the audio
* peripherals. The author lacks the underlying domain knowledge to
* pursue this.
*
* The goal and function of the following code is to support the two
* clock rates used by the audio subsystem, allowing for proper audio
* playback and capture without any pitch or speed changes.
*/
bool ccu_sdm_helper_has_rate(struct ccu_common *common,
struct ccu_sdm_internal *sdm,
unsigned long rate)
{
unsigned int i;
if (!(common->features & CCU_FEATURE_SIGMA_DELTA_MOD))
return false;
for (i = 0; i < sdm->table_size; i++)
if (sdm->table[i].rate == rate)
return true;
return false;
}
unsigned long ccu_sdm_helper_read_rate(struct ccu_common *common,
struct ccu_sdm_internal *sdm,
u32 m, u32 n)
{
unsigned int i;
u32 reg;
pr_debug("%s: Read sigma-delta modulation setting\n",
clk_hw_get_name(&common->hw));
if (!(common->features & CCU_FEATURE_SIGMA_DELTA_MOD))
return 0;
pr_debug("%s: clock is sigma-delta modulated\n",
clk_hw_get_name(&common->hw));
reg = readl(common->base + sdm->tuning_reg);
pr_debug("%s: pattern reg is 0x%x",
clk_hw_get_name(&common->hw), reg);
for (i = 0; i < sdm->table_size; i++)
if (sdm->table[i].pattern == reg &&
sdm->table[i].m == m && sdm->table[i].n == n)
return sdm->table[i].rate;
/* We can't calculate the effective clock rate, so just fail. */
return 0;
}
int ccu_sdm_helper_get_factors(struct ccu_common *common,
struct ccu_sdm_internal *sdm,
unsigned long rate,
unsigned long *m, unsigned long *n)
{
unsigned int i;
if (!(common->features & CCU_FEATURE_SIGMA_DELTA_MOD))
return -EINVAL;
for (i = 0; i < sdm->table_size; i++)
if (sdm->table[i].rate == rate) {
*m = sdm->table[i].m;
*n = sdm->table[i].n;
return 0;
}
/* nothing found */
return -EINVAL;
}
|
