clk-divider.c
4.33 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
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
179
180
181
182
183
184
185
186
187
/*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/clk.h>
#include "clk.h"
#define pll_out_override(p) (BIT((p->shift - 6)))
#define div_mask(d) ((1 << (d->width)) - 1)
#define get_mul(d) (1 << d->frac_width)
#define get_max_div(d) div_mask(d)
#define PERIPH_CLK_UART_DIV_ENB BIT(24)
static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate,
unsigned long parent_rate)
{
s64 divider_ux1 = parent_rate;
u8 flags = divider->flags;
int mul;
if (!rate)
return 0;
mul = get_mul(divider);
if (!(flags & TEGRA_DIVIDER_INT))
divider_ux1 *= mul;
if (flags & TEGRA_DIVIDER_ROUND_UP)
divider_ux1 += rate - 1;
do_div(divider_ux1, rate);
if (flags & TEGRA_DIVIDER_INT)
divider_ux1 *= mul;
divider_ux1 -= mul;
if (divider_ux1 < 0)
return 0;
if (divider_ux1 > get_max_div(divider))
return get_max_div(divider);
return divider_ux1;
}
static unsigned long clk_frac_div_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
u32 reg;
int div, mul;
u64 rate = parent_rate;
reg = readl_relaxed(divider->reg) >> divider->shift;
div = reg & div_mask(divider);
mul = get_mul(divider);
div += mul;
rate *= mul;
rate += div - 1;
do_div(rate, div);
return rate;
}
static long clk_frac_div_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
int div, mul;
unsigned long output_rate = *prate;
if (!rate)
return output_rate;
div = get_div(divider, rate, output_rate);
if (div < 0)
return *prate;
mul = get_mul(divider);
return DIV_ROUND_UP(output_rate * mul, div + mul);
}
static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
int div;
unsigned long flags = 0;
u32 val;
div = get_div(divider, rate, parent_rate);
if (div < 0)
return div;
if (divider->lock)
spin_lock_irqsave(divider->lock, flags);
val = readl_relaxed(divider->reg);
val &= ~(div_mask(divider) << divider->shift);
val |= div << divider->shift;
if (divider->flags & TEGRA_DIVIDER_UART) {
if (div)
val |= PERIPH_CLK_UART_DIV_ENB;
else
val &= ~PERIPH_CLK_UART_DIV_ENB;
}
if (divider->flags & TEGRA_DIVIDER_FIXED)
val |= pll_out_override(divider);
writel_relaxed(val, divider->reg);
if (divider->lock)
spin_unlock_irqrestore(divider->lock, flags);
return 0;
}
const struct clk_ops tegra_clk_frac_div_ops = {
.recalc_rate = clk_frac_div_recalc_rate,
.set_rate = clk_frac_div_set_rate,
.round_rate = clk_frac_div_round_rate,
};
struct clk *tegra_clk_register_divider(const char *name,
const char *parent_name, void __iomem *reg,
unsigned long flags, u8 clk_divider_flags, u8 shift, u8 width,
u8 frac_width, spinlock_t *lock)
{
struct tegra_clk_frac_div *divider;
struct clk *clk;
struct clk_init_data init;
divider = kzalloc(sizeof(*divider), GFP_KERNEL);
if (!divider) {
pr_err("%s: could not allocate fractional divider clk\n",
__func__);
return ERR_PTR(-ENOMEM);
}
init.name = name;
init.ops = &tegra_clk_frac_div_ops;
init.flags = flags;
init.parent_names = parent_name ? &parent_name : NULL;
init.num_parents = parent_name ? 1 : 0;
divider->reg = reg;
divider->shift = shift;
divider->width = width;
divider->frac_width = frac_width;
divider->lock = lock;
divider->flags = clk_divider_flags;
/* Data in .init is copied by clk_register(), so stack variable OK */
divider->hw.init = &init;
clk = clk_register(NULL, ÷r->hw);
if (IS_ERR(clk))
kfree(divider);
return clk;
}