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gerrit-public.fairphone.software / kernel / msm-4.9 / a0f93b4268d903430d7e21110f10be0919daf3b2 / . / drivers / clk / mmp / clk-apbc.c
blob: d14120eaa71f4c5d5498814aeee91a46d9012283 [file] [log] [blame]
Chao Xie6b63f022012-08-20 02:55:11 +0000[diff] [blame]1/*
2 * mmp APB clock operation source file
3 *
4 * Copyright (C) 2012 Marvell
5 * Chao Xie <xiechao.mail@gmail.com>
6 *
7 * This file is licensed under the terms of the GNU General Public
8 * License version 2. This program is licensed "as is" without any
9 * warranty of any kind, whether express or implied.
10 */
11
12#include <linux/kernel.h>
13#include <linux/clk.h>
14#include <linux/io.h>
15#include <linux/err.h>
16#include <linux/delay.h>
17#include <linux/slab.h>
18
19#include "clk.h"
20
21/* Common APB clock register bit definitions */
22#define APBC_APBCLK (1 << 0) /* APB Bus Clock Enable */
23#define APBC_FNCLK (1 << 1) /* Functional Clock Enable */
24#define APBC_RST (1 << 2) /* Reset Generation */
25#define APBC_POWER (1 << 7) /* Reset Generation */
26
27#define to_clk_apbc(hw) container_of(hw, struct clk_apbc, hw)
28struct clk_apbc {
29 struct clk_hw hw;
30 void __iomem *base;
31 unsigned int delay;
32 unsigned int flags;
33 spinlock_t *lock;
34};
35
36static int clk_apbc_prepare(struct clk_hw *hw)
37{
38 struct clk_apbc *apbc = to_clk_apbc(hw);
39 unsigned int data;
40 unsigned long flags = 0;
41
42 /*
43 * It may share same register as MUX clock,
44 * and it will impact FNCLK enable. Spinlock is needed
45 */
46 if (apbc->lock)
47 spin_lock_irqsave(apbc->lock, flags);
48
49 data = readl_relaxed(apbc->base);
50 if (apbc->flags & APBC_POWER_CTRL)
51 data |= APBC_POWER;
52 data |= APBC_FNCLK;
53 writel_relaxed(data, apbc->base);
54
55 if (apbc->lock)
56 spin_unlock_irqrestore(apbc->lock, flags);
57
58 udelay(apbc->delay);
59
60 if (apbc->lock)
61 spin_lock_irqsave(apbc->lock, flags);
62
63 data = readl_relaxed(apbc->base);
64 data |= APBC_APBCLK;
65 writel_relaxed(data, apbc->base);
66
67 if (apbc->lock)
68 spin_unlock_irqrestore(apbc->lock, flags);
69
70 udelay(apbc->delay);
71
72 if (!(apbc->flags & APBC_NO_BUS_CTRL)) {
73 if (apbc->lock)
74 spin_lock_irqsave(apbc->lock, flags);
75
76 data = readl_relaxed(apbc->base);
77 data &= ~APBC_RST;
78 writel_relaxed(data, apbc->base);
79
80 if (apbc->lock)
81 spin_unlock_irqrestore(apbc->lock, flags);
82 }
83
84 return 0;
85}
86
87static void clk_apbc_unprepare(struct clk_hw *hw)
88{
89 struct clk_apbc *apbc = to_clk_apbc(hw);
90 unsigned long data;
91 unsigned long flags = 0;
92
93 if (apbc->lock)
94 spin_lock_irqsave(apbc->lock, flags);
95
96 data = readl_relaxed(apbc->base);
97 if (apbc->flags & APBC_POWER_CTRL)
98 data &= ~APBC_POWER;
99 data &= ~APBC_FNCLK;
100 writel_relaxed(data, apbc->base);
101
102 if (apbc->lock)
103 spin_unlock_irqrestore(apbc->lock, flags);
104
105 udelay(10);
106
107 if (apbc->lock)
108 spin_lock_irqsave(apbc->lock, flags);
109
110 data = readl_relaxed(apbc->base);
111 data &= ~APBC_APBCLK;
112 writel_relaxed(data, apbc->base);
113
114 if (apbc->lock)
115 spin_unlock_irqrestore(apbc->lock, flags);
116}
117
118struct clk_ops clk_apbc_ops = {
119 .prepare = clk_apbc_prepare,
120 .unprepare = clk_apbc_unprepare,
121};
122
123struct clk *mmp_clk_register_apbc(const char *name, const char *parent_name,
124 void __iomem *base, unsigned int delay,
125 unsigned int apbc_flags, spinlock_t *lock)
126{
127 struct clk_apbc *apbc;
128 struct clk *clk;
129 struct clk_init_data init;
130
131 apbc = kzalloc(sizeof(*apbc), GFP_KERNEL);
132 if (!apbc)
133 return NULL;
134
135 init.name = name;
136 init.ops = &clk_apbc_ops;
137 init.flags = CLK_SET_RATE_PARENT;
138 init.parent_names = (parent_name ? &parent_name : NULL);
139 init.num_parents = (parent_name ? 1 : 0);
140
141 apbc->base = base;
142 apbc->delay = delay;
143 apbc->flags = apbc_flags;
144 apbc->lock = lock;
145 apbc->hw.init = &init;
146
147 clk = clk_register(NULL, &apbc->hw);
148 if (IS_ERR(clk))
149 kfree(apbc);
150
151 return clk;
152}