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
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/*
* Copyright 2014 Google, Inc
* Author: Alexandru M Stan <amstan@chromium.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include "clk.h"
struct rockchip_mmc_clock {
struct clk_hw hw;
void __iomem *reg;
int id;
int shift;
};
#define to_mmc_clock(_hw) container_of(_hw, struct rockchip_mmc_clock, hw)
#define RK3288_MMC_CLKGEN_DIV 2
static unsigned long rockchip_mmc_recalc(struct clk_hw *hw,
unsigned long parent_rate)
{
return parent_rate / RK3288_MMC_CLKGEN_DIV;
}
#define ROCKCHIP_MMC_DELAY_SEL BIT(10)
#define ROCKCHIP_MMC_DEGREE_MASK 0x3
#define ROCKCHIP_MMC_DELAYNUM_OFFSET 2
#define ROCKCHIP_MMC_DELAYNUM_MASK (0xff << ROCKCHIP_MMC_DELAYNUM_OFFSET)
#define ROCKCHIP_MMC_INIT_STATE_RESET 0x1
#define ROCKCHIP_MMC_INIT_STATE_SHIFT 1
#define PSECS_PER_SEC 1000000000000LL
/*
* Each fine delay is between 44ps-77ps. Assume each fine delay is 60ps to
* simplify calculations. So 45degs could be anywhere between 33deg and 57.8deg.
*/
#define ROCKCHIP_MMC_DELAY_ELEMENT_PSEC 60
static int rockchip_mmc_get_phase(struct clk_hw *hw)
{
struct rockchip_mmc_clock *mmc_clock = to_mmc_clock(hw);
unsigned long rate = clk_get_rate(hw->clk);
u32 raw_value;
u16 degrees;
u32 delay_num = 0;
raw_value = readl(mmc_clock->reg) >> (mmc_clock->shift);
degrees = (raw_value & ROCKCHIP_MMC_DEGREE_MASK) * 90;
if (raw_value & ROCKCHIP_MMC_DELAY_SEL) {
/* degrees/delaynum * 10000 */
unsigned long factor = (ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10) *
36 * (rate / 1000000);
delay_num = (raw_value & ROCKCHIP_MMC_DELAYNUM_MASK);
delay_num >>= ROCKCHIP_MMC_DELAYNUM_OFFSET;
degrees += DIV_ROUND_CLOSEST(delay_num * factor, 10000);
}
return degrees % 360;
}
static int rockchip_mmc_set_phase(struct clk_hw *hw, int degrees)
{
struct rockchip_mmc_clock *mmc_clock = to_mmc_clock(hw);
unsigned long rate = clk_get_rate(hw->clk);
u8 nineties, remainder;
u8 delay_num;
u32 raw_value;
u32 delay;
nineties = degrees / 90;
remainder = (degrees % 90);
/*
* Due to the inexact nature of the "fine" delay, we might
* actually go non-monotonic. We don't go _too_ monotonic
* though, so we should be OK. Here are options of how we may
* work:
*
* Ideally we end up with:
* 1.0, 2.0, ..., 69.0, 70.0, ..., 89.0, 90.0
*
* On one extreme (if delay is actually 44ps):
* .73, 1.5, ..., 50.6, 51.3, ..., 65.3, 90.0
* The other (if delay is actually 77ps):
* 1.3, 2.6, ..., 88.6. 89.8, ..., 114.0, 90
*
* It's possible we might make a delay that is up to 25
* degrees off from what we think we're making. That's OK
* though because we should be REALLY far from any bad range.
*/
/*
* Convert to delay; do a little extra work to make sure we
* don't overflow 32-bit / 64-bit numbers.
*/
delay = 10000000; /* PSECS_PER_SEC / 10000 / 10 */
delay *= remainder;
delay = DIV_ROUND_CLOSEST(delay,
(rate / 1000) * 36 *
(ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10));
delay_num = (u8) min_t(u32, delay, 255);
raw_value = delay_num ? ROCKCHIP_MMC_DELAY_SEL : 0;
raw_value |= delay_num << ROCKCHIP_MMC_DELAYNUM_OFFSET;
raw_value |= nineties;
writel(HIWORD_UPDATE(raw_value, 0x07ff, mmc_clock->shift), mmc_clock->reg);
pr_debug("%s->set_phase(%d) delay_nums=%u reg[0x%p]=0x%03x actual_degrees=%d\n",
clk_hw_get_name(hw), degrees, delay_num,
mmc_clock->reg, raw_value>>(mmc_clock->shift),
rockchip_mmc_get_phase(hw)
);
return 0;
}
static const struct clk_ops rockchip_mmc_clk_ops = {
.recalc_rate = rockchip_mmc_recalc,
.get_phase = rockchip_mmc_get_phase,
.set_phase = rockchip_mmc_set_phase,
};
struct clk *rockchip_clk_register_mmc(const char *name,
const char *const *parent_names, u8 num_parents,
void __iomem *reg, int shift)
{
struct clk_init_data init;
struct rockchip_mmc_clock *mmc_clock;
struct clk *clk;
mmc_clock = kmalloc(sizeof(*mmc_clock), GFP_KERNEL);
if (!mmc_clock)
return ERR_PTR(-ENOMEM);
init.name = name;
init.num_parents = num_parents;
init.parent_names = parent_names;
init.ops = &rockchip_mmc_clk_ops;
mmc_clock->hw.init = &init;
mmc_clock->reg = reg;
mmc_clock->shift = shift;
/*
* Assert init_state to soft reset the CLKGEN
* for mmc tuning phase and degree
*/
if (mmc_clock->shift == ROCKCHIP_MMC_INIT_STATE_SHIFT)
writel(HIWORD_UPDATE(ROCKCHIP_MMC_INIT_STATE_RESET,
ROCKCHIP_MMC_INIT_STATE_RESET,
mmc_clock->shift), mmc_clock->reg);
clk = clk_register(NULL, &mmc_clock->hw);
if (IS_ERR(clk))
kfree(mmc_clock);
return clk;
}
|
