blob: 4d75b1f37e3a4b74ee4606ce33d54b8a771beb6a [file] [log] [blame]
Prashant Gaikwad8f8f4842013-01-11 13:16:20 +05301/*
2 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
16
17#include <linux/kernel.h>
18#include <linux/io.h>
19#include <linux/err.h>
20#include <linux/slab.h>
21#include <linux/clk-provider.h>
22#include <linux/clk.h>
23
24#include "clk.h"
25
26#define pll_out_override(p) (BIT((p->shift - 6)))
27#define div_mask(d) ((1 << (d->width)) - 1)
28#define get_mul(d) (1 << d->frac_width)
29#define get_max_div(d) div_mask(d)
30
31#define PERIPH_CLK_UART_DIV_ENB BIT(24)
32
33static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate,
34 unsigned long parent_rate)
35{
36 s64 divider_ux1 = parent_rate;
37 u8 flags = divider->flags;
38 int mul;
39
40 if (!rate)
41 return 0;
42
43 mul = get_mul(divider);
44
45 if (!(flags & TEGRA_DIVIDER_INT))
46 divider_ux1 *= mul;
47
48 if (flags & TEGRA_DIVIDER_ROUND_UP)
49 divider_ux1 += rate - 1;
50
51 do_div(divider_ux1, rate);
52
53 if (flags & TEGRA_DIVIDER_INT)
54 divider_ux1 *= mul;
55
56 divider_ux1 -= mul;
57
58 if (divider_ux1 < 0)
59 return 0;
60
61 if (divider_ux1 > get_max_div(divider))
62 return -EINVAL;
63
64 return divider_ux1;
65}
66
67static unsigned long clk_frac_div_recalc_rate(struct clk_hw *hw,
68 unsigned long parent_rate)
69{
70 struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
71 u32 reg;
72 int div, mul;
73 u64 rate = parent_rate;
74
75 reg = readl_relaxed(divider->reg) >> divider->shift;
76 div = reg & div_mask(divider);
77
78 mul = get_mul(divider);
79 div += mul;
80
81 rate *= mul;
82 rate += div - 1;
83 do_div(rate, div);
84
85 return rate;
86}
87
88static long clk_frac_div_round_rate(struct clk_hw *hw, unsigned long rate,
89 unsigned long *prate)
90{
91 struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
92 int div, mul;
93 unsigned long output_rate = *prate;
94
95 if (!rate)
96 return output_rate;
97
98 div = get_div(divider, rate, output_rate);
99 if (div < 0)
100 return *prate;
101
102 mul = get_mul(divider);
103
104 return DIV_ROUND_UP(output_rate * mul, div + mul);
105}
106
107static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
108 unsigned long parent_rate)
109{
110 struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
111 int div;
112 unsigned long flags = 0;
113 u32 val;
114
115 div = get_div(divider, rate, parent_rate);
116 if (div < 0)
117 return div;
118
119 if (divider->lock)
120 spin_lock_irqsave(divider->lock, flags);
121
122 val = readl_relaxed(divider->reg);
123 val &= ~(div_mask(divider) << divider->shift);
124 val |= div << divider->shift;
125
126 if (divider->flags & TEGRA_DIVIDER_UART) {
127 if (div)
128 val |= PERIPH_CLK_UART_DIV_ENB;
129 else
130 val &= ~PERIPH_CLK_UART_DIV_ENB;
131 }
132
133 if (divider->flags & TEGRA_DIVIDER_FIXED)
134 val |= pll_out_override(divider);
135
136 writel_relaxed(val, divider->reg);
137
138 if (divider->lock)
139 spin_unlock_irqrestore(divider->lock, flags);
140
141 return 0;
142}
143
144const struct clk_ops tegra_clk_frac_div_ops = {
145 .recalc_rate = clk_frac_div_recalc_rate,
146 .set_rate = clk_frac_div_set_rate,
147 .round_rate = clk_frac_div_round_rate,
148};
149
150struct clk *tegra_clk_register_divider(const char *name,
151 const char *parent_name, void __iomem *reg,
152 unsigned long flags, u8 clk_divider_flags, u8 shift, u8 width,
153 u8 frac_width, spinlock_t *lock)
154{
155 struct tegra_clk_frac_div *divider;
156 struct clk *clk;
157 struct clk_init_data init;
158
159 divider = kzalloc(sizeof(*divider), GFP_KERNEL);
160 if (!divider) {
161 pr_err("%s: could not allocate fractional divider clk\n",
162 __func__);
163 return ERR_PTR(-ENOMEM);
164 }
165
166 init.name = name;
167 init.ops = &tegra_clk_frac_div_ops;
168 init.flags = flags;
169 init.parent_names = parent_name ? &parent_name : NULL;
170 init.num_parents = parent_name ? 1 : 0;
171
172 divider->reg = reg;
173 divider->shift = shift;
174 divider->width = width;
175 divider->frac_width = frac_width;
176 divider->lock = lock;
177 divider->flags = clk_divider_flags;
178
179 /* Data in .init is copied by clk_register(), so stack variable OK */
180 divider->hw.init = &init;
181
182 clk = clk_register(NULL, &divider->hw);
183 if (IS_ERR(clk))
184 kfree(divider);
185
186 return clk;
187}