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   1 /*
   2  * arch/arm/mach-ns9xxx/clock.c
   3  *
   4  * Copyright (C) 2007 by Digi International Inc.
   5  * All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  */
  11 #include <linux/err.h>
  12 #include <linux/module.h>
  13 #include <linux/list.h>
  14 #include <linux/clk.h>
  15 #include <linux/string.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/semaphore.h>
  18
  19 #include "clock.h"
  20
  21 static LIST_HEAD(clocks);
  22 static DEFINE_SPINLOCK(clk_lock);
  23
  24 struct clk *clk_get(struct device *dev, const char *id)
  25 {
  26         struct clk *p, *ret = NULL, *retgen = NULL;
  27         unsigned long flags;
  28         int idno;
  29
  30         if (dev == NULL || dev->bus != &platform_bus_type)
  31                 idno = -1;
  32         else
  33                 idno = to_platform_device(dev)->id;
  34
  35         spin_lock_irqsave(&clk_lock, flags);
  36         list_for_each_entry(p, &clocks, node) {
  37                 if (strcmp(id, p->name) == 0) {
  38                         if (p->id == idno) {
  39                                 if (!try_module_get(p->owner))
  40                                         continue;
  41                                 ret = p;
  42                                 break;
  43                         } else if (p->id == -1)
  44                                 /* remember match with id == -1 in case there is
  45                                  * no clock for idno */
  46                                 retgen = p;
  47                 }
  48         }
  49
  50         if (!ret && retgen && try_module_get(retgen->owner))
  51                 ret = retgen;
  52
  53         if (ret)
  54                 ++ret->refcount;
  55
  56         spin_unlock_irqrestore(&clk_lock, flags);
  57
  58         return ret ? ret : ERR_PTR(-ENOENT);
  59 }
  60 EXPORT_SYMBOL(clk_get);
  61
  62 void clk_put(struct clk *clk)
  63 {
  64         module_put(clk->owner);
  65         --clk->refcount;
  66 }
  67 EXPORT_SYMBOL(clk_put);
  68
  69 static int clk_enable_unlocked(struct clk *clk)
  70 {
  71         int ret = 0;
  72         if (clk->parent) {
  73                 ret = clk_enable_unlocked(clk->parent);
  74                 if (ret)
  75                         return ret;
  76         }
  77
  78         if (clk->usage++ == 0 && clk->endisable)
  79                 ret = clk->endisable(clk, 1);
  80
  81         return ret;
  82 }
  83
  84 int clk_enable(struct clk *clk)
  85 {
  86         int ret;
  87         unsigned long flags;
  88
  89         spin_lock_irqsave(&clk_lock, flags);
  90
  91         ret = clk_enable_unlocked(clk);
  92
  93         spin_unlock_irqrestore(&clk_lock, flags);
  94
  95         return ret;
  96 }
  97 EXPORT_SYMBOL(clk_enable);
  98
  99 static void clk_disable_unlocked(struct clk *clk)
 100 {
 101         if (--clk->usage == 0 && clk->endisable)
 102                 clk->endisable(clk, 0);
 103
 104         if (clk->parent)
 105                 clk_disable_unlocked(clk->parent);
 106 }
 107
 108 void clk_disable(struct clk *clk)
 109 {
 110         unsigned long flags;
 111
 112         spin_lock_irqsave(&clk_lock, flags);
 113
 114         clk_disable_unlocked(clk);
 115
 116         spin_unlock_irqrestore(&clk_lock, flags);
 117 }
 118 EXPORT_SYMBOL(clk_disable);
 119
 120 unsigned long clk_get_rate(struct clk *clk)
 121 {
 122         if (clk->get_rate)
 123                 return clk->get_rate(clk);
 124
 125         if (clk->rate)
 126                 return clk->rate;
 127
 128         if (clk->parent)
 129                 return clk_get_rate(clk->parent);
 130
 131         return 0;
 132 }
 133 EXPORT_SYMBOL(clk_get_rate);
 134
 135 int clk_register(struct clk *clk)
 136 {
 137         unsigned long flags;
 138
 139         spin_lock_irqsave(&clk_lock, flags);
 140
 141         list_add(&clk->node, &clocks);
 142
 143         if (clk->parent)
 144                 ++clk->parent->refcount;
 145
 146         spin_unlock_irqrestore(&clk_lock, flags);
 147
 148         return 0;
 149 }
 150
 151 int clk_unregister(struct clk *clk)
 152 {
 153         int ret = 0;
 154         unsigned long flags;
 155
 156         spin_lock_irqsave(&clk_lock, flags);
 157
 158         if (clk->usage || clk->refcount)
 159                 ret = -EBUSY;
 160         else
 161                 list_del(&clk->node);
 162
 163         if (clk->parent)
 164                 --clk->parent->refcount;
 165
 166         spin_unlock_irqrestore(&clk_lock, flags);
 167
 168         return ret;
 169 }
 170
 171 #if defined CONFIG_DEBUG_FS
 172
 173 #include <linux/debugfs.h>
 174 #include <linux/seq_file.h>
 175
 176 static int clk_debugfs_show(struct seq_file *s, void *null)
 177 {
 178         unsigned long flags;
 179         struct clk *p;
 180
 181         spin_lock_irqsave(&clk_lock, flags);
 182
 183         list_for_each_entry(p, &clocks, node)
 184                 seq_printf(s, "%s.%d: usage=%lu refcount=%lu rate=%lu\n",
 185                                 p->name, p->id, p->usage, p->refcount,
 186                                 p->usage ? clk_get_rate(p) : 0);
 187
 188         spin_unlock_irqrestore(&clk_lock, flags);
 189
 190         return 0;
 191 }
 192
 193 static int clk_debugfs_open(struct inode *inode, struct file *file)
 194 {
 195         return single_open(file, clk_debugfs_show, NULL);
 196 }
 197
 198 static struct file_operations clk_debugfs_operations = {
 199         .open = clk_debugfs_open,
 200         .read = seq_read,
 201         .llseek = seq_lseek,
 202         .release = single_release,
 203 };
 204
 205 static int __init clk_debugfs_init(void)
 206 {
 207         struct dentry *dentry;
 208
 209         dentry = debugfs_create_file("clk", S_IFREG | S_IRUGO, NULL, NULL,
 210                         &clk_debugfs_operations);
 211         return IS_ERR(dentry) ? PTR_ERR(dentry) : 0;
 212 }
 213 subsys_initcall(clk_debugfs_init);
 214
 215 #endif /* if defined CONFIG_DEBUG_FS */