arch/arm/mach-msm/clock.c

   1 /* arch/arm/mach-msm/clock.c
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  * Copyright (c) 2007-2010, Code Aurora Forum. All rights reserved.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/list.h>
  19 #include <linux/err.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/pm_qos.h>
  22 #include <linux/mutex.h>
  23 #include <linux/clk.h>
  24 #include <linux/string.h>
  25 #include <linux/module.h>
  26 #include <linux/clkdev.h>
  27
  28 #include "clock.h"
  29
  30 static DEFINE_MUTEX(clocks_mutex);
  31 static DEFINE_SPINLOCK(clocks_lock);
  32 static LIST_HEAD(clocks);
  33
  34 /*
  35  * Standard clock functions defined in include/linux/clk.h
  36  */
  37 int clk_enable(struct clk *clk)
  38 {
  39         unsigned long flags;
  40         spin_lock_irqsave(&clocks_lock, flags);
  41         clk->count++;
  42         if (clk->count == 1)
  43                 clk->ops->enable(clk->id);
  44         spin_unlock_irqrestore(&clocks_lock, flags);
  45         return 0;
  46 }
  47 EXPORT_SYMBOL(clk_enable);
  48
  49 void clk_disable(struct clk *clk)
  50 {
  51         unsigned long flags;
  52         spin_lock_irqsave(&clocks_lock, flags);
  53         BUG_ON(clk->count == 0);
  54         clk->count--;
  55         if (clk->count == 0)
  56                 clk->ops->disable(clk->id);
  57         spin_unlock_irqrestore(&clocks_lock, flags);
  58 }
  59 EXPORT_SYMBOL(clk_disable);
  60
  61 int clk_reset(struct clk *clk, enum clk_reset_action action)
  62 {
  63         return clk->ops->reset(clk->remote_id, action);
  64 }
  65 EXPORT_SYMBOL(clk_reset);
  66
  67 unsigned long clk_get_rate(struct clk *clk)
  68 {
  69         return clk->ops->get_rate(clk->id);
  70 }
  71 EXPORT_SYMBOL(clk_get_rate);
  72
  73 int clk_set_rate(struct clk *clk, unsigned long rate)
  74 {
  75         int ret;
  76         if (clk->flags & CLKFLAG_MAX) {
  77                 ret = clk->ops->set_max_rate(clk->id, rate);
  78                 if (ret)
  79                         return ret;
  80         }
  81         if (clk->flags & CLKFLAG_MIN) {
  82                 ret = clk->ops->set_min_rate(clk->id, rate);
  83                 if (ret)
  84                         return ret;
  85         }
  86
  87         if (clk->flags & CLKFLAG_MAX || clk->flags & CLKFLAG_MIN)
  88                 return ret;
  89
  90         return clk->ops->set_rate(clk->id, rate);
  91 }
  92 EXPORT_SYMBOL(clk_set_rate);
  93
  94 long clk_round_rate(struct clk *clk, unsigned long rate)
  95 {
  96         return clk->ops->round_rate(clk->id, rate);
  97 }
  98 EXPORT_SYMBOL(clk_round_rate);
  99
 100 int clk_set_min_rate(struct clk *clk, unsigned long rate)
 101 {
 102         return clk->ops->set_min_rate(clk->id, rate);
 103 }
 104 EXPORT_SYMBOL(clk_set_min_rate);
 105
 106 int clk_set_max_rate(struct clk *clk, unsigned long rate)
 107 {
 108         return clk->ops->set_max_rate(clk->id, rate);
 109 }
 110 EXPORT_SYMBOL(clk_set_max_rate);
 111
 112 int clk_set_parent(struct clk *clk, struct clk *parent)
 113 {
 114         return -ENOSYS;
 115 }
 116 EXPORT_SYMBOL(clk_set_parent);
 117
 118 struct clk *clk_get_parent(struct clk *clk)
 119 {
 120         return ERR_PTR(-ENOSYS);
 121 }
 122 EXPORT_SYMBOL(clk_get_parent);
 123
 124 int clk_set_flags(struct clk *clk, unsigned long flags)
 125 {
 126         if (clk == NULL || IS_ERR(clk))
 127                 return -EINVAL;
 128         return clk->ops->set_flags(clk->id, flags);
 129 }
 130 EXPORT_SYMBOL(clk_set_flags);
 131
 132 /* EBI1 is the only shared clock that several clients want to vote on as of
 133  * this commit. If this changes in the future, then it might be better to
 134  * make clk_min_rate handle the voting or make ebi1_clk_set_min_rate more
 135  * generic to support different clocks.
 136  */
 137 static struct clk *ebi1_clk;
 138
 139 void __init msm_clock_init(struct clk_lookup *clock_tbl, unsigned num_clocks)
 140 {
 141         unsigned n;
 142
 143         mutex_lock(&clocks_mutex);
 144         for (n = 0; n < num_clocks; n++) {
 145                 clkdev_add(&clock_tbl[n]);
 146                 list_add_tail(&clock_tbl[n].clk->list, &clocks);
 147         }
 148         mutex_unlock(&clocks_mutex);
 149
 150         ebi1_clk = clk_get(NULL, "ebi1_clk");
 151         BUG_ON(ebi1_clk == NULL);
 152
 153 }
 154
 155 /* The bootloader and/or AMSS may have left various clocks enabled.
 156  * Disable any clocks that belong to us (CLKFLAG_AUTO_OFF) but have
 157  * not been explicitly enabled by a clk_enable() call.
 158  */
 159 static int __init clock_late_init(void)
 160 {
 161         unsigned long flags;
 162         struct clk *clk;
 163         unsigned count = 0;
 164
 165         clock_debug_init();
 166         mutex_lock(&clocks_mutex);
 167         list_for_each_entry(clk, &clocks, list) {
 168                 clock_debug_add(clk);
 169                 if (clk->flags & CLKFLAG_AUTO_OFF) {
 170                         spin_lock_irqsave(&clocks_lock, flags);
 171                         if (!clk->count) {
 172                                 count++;
 173                                 clk->ops->auto_off(clk->id);
 174                         }
 175                         spin_unlock_irqrestore(&clocks_lock, flags);
 176                 }
 177         }
 178         mutex_unlock(&clocks_mutex);
 179         pr_info("clock_late_init() disabled %d unused clocks\n", count);
 180         return 0;
 181 }
 182
 183 late_initcall(clock_late_init);
 184