tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * arch/arm/common/clkdev.c
3 *
4 * Copyright (C) 2008 Russell King.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Helper for the clk API to assist looking up a struct clk.
11 */
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/device.h>
15#include <linux/list.h>
16#include <linux/errno.h>
17#include <linux/err.h>
18#include <linux/string.h>
19#include <linux/mutex.h>
20
21#include <asm/clkdev.h>
22#include <mach/clkdev.h>
23
24static LIST_HEAD(clocks);
25static DEFINE_MUTEX(clocks_mutex);
26
27/*
28 * Find the correct struct clk for the device and connection ID.
29 * We do slightly fuzzy matching here:
30 * An entry with a NULL ID is assumed to be a wildcard.
31 * If an entry has a device ID, it must match
32 * If an entry has a connection ID, it must match
33 * Then we take the most specific entry - with the following
34 * order of precidence: dev+con > dev only > con only.
35 */
36static struct clk *clk_find(const char *dev_id, const char *con_id)
37{
38 struct clk_lookup *p;
39 struct clk *clk = NULL;
40 int match, best = 0;
41
42 list_for_each_entry(p, &clocks, node) {
43 match = 0;
44 if (p->dev_id) {
45 if (!dev_id || strcmp(p->dev_id, dev_id))
46 continue;
47 match += 2;
48 }
49 if (p->con_id) {
50 if (!con_id || strcmp(p->con_id, con_id))
51 continue;
52 match += 1;
53 }
54 if (match == 0)
55 continue;
56
57 if (match > best) {
58 clk = p->clk;
59 best = match;
60 }
61 }
62 return clk;
63}
64
65struct clk *clk_get_sys(const char *dev_id, const char *con_id)
66{
67 struct clk *clk;
68
69 mutex_lock(&clocks_mutex);
70 clk = clk_find(dev_id, con_id);
71 if (clk && !__clk_get(clk))
72 clk = NULL;
73 mutex_unlock(&clocks_mutex);
74
75 return clk ? clk : ERR_PTR(-ENOENT);
76}
77EXPORT_SYMBOL(clk_get_sys);
78
79struct clk *clk_get(struct device *dev, const char *con_id)
80{
81 const char *dev_id = dev ? dev_name(dev) : NULL;
82
83 return clk_get_sys(dev_id, con_id);
84}
85EXPORT_SYMBOL(clk_get);
86
87void clk_put(struct clk *clk)
88{
89 __clk_put(clk);
90}
91EXPORT_SYMBOL(clk_put);
92
93void clkdev_add(struct clk_lookup *cl)
94{
95 mutex_lock(&clocks_mutex);
96 list_add_tail(&cl->node, &clocks);
97 mutex_unlock(&clocks_mutex);
98}
99EXPORT_SYMBOL(clkdev_add);
100
101#define MAX_DEV_ID 20
102#define MAX_CON_ID 16
103
104struct clk_lookup_alloc {
105 struct clk_lookup cl;
106 char dev_id[MAX_DEV_ID];
107 char con_id[MAX_CON_ID];
108};
109
110struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
111 const char *dev_fmt, ...)
112{
113 struct clk_lookup_alloc *cla;
114
115 cla = kzalloc(sizeof(*cla), GFP_KERNEL);
116 if (!cla)
117 return NULL;
118
119 cla->cl.clk = clk;
120 if (con_id) {
121 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
122 cla->cl.con_id = cla->con_id;
123 }
124
125 if (dev_fmt) {
126 va_list ap;
127
128 va_start(ap, dev_fmt);
129 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
130 cla->cl.dev_id = cla->dev_id;
131 va_end(ap);
132 }
133
134 return &cla->cl;
135}
136EXPORT_SYMBOL(clkdev_alloc);
137
138/*
139 * clkdev_drop - remove a clock dynamically allocated
140 */
141void clkdev_drop(struct clk_lookup *cl)
142{
143 mutex_lock(&clocks_mutex);
144 list_del(&cl->node);
145 mutex_unlock(&clocks_mutex);
146 kfree(cl);
147}
148EXPORT_SYMBOL(clkdev_drop);