arch/arm/mach-bcmring/clock.c

   1 /*****************************************************************************
   2 * Copyright 2001 - 2009 Broadcom Corporation.  All rights reserved.
   3 *
   4 * Unless you and Broadcom execute a separate written software license
   5 * agreement governing use of this software, this software is licensed to you
   6 * under the terms of the GNU General Public License version 2, available at
   7 * http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
   8 *
   9 * Notwithstanding the above, under no circumstances may you combine this
  10 * software in any way with any other Broadcom software provided under a
  11 * license other than the GPL, without Broadcom's express prior written
  12 * consent.
  13 *****************************************************************************/
  14
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/device.h>
  18 #include <linux/list.h>
  19 #include <linux/errno.h>
  20 #include <linux/err.h>
  21 #include <linux/string.h>
  22 #include <linux/clk.h>
  23 #include <linux/spinlock.h>
  24 #include <mach/csp/hw_cfg.h>
  25 #include <mach/csp/chipcHw_def.h>
  26 #include <mach/csp/chipcHw_reg.h>
  27 #include <mach/csp/chipcHw_inline.h>
  28
  29 #include <asm/clkdev.h>
  30
  31 #include "clock.h"
  32
  33 #define clk_is_primary(x)       ((x)->type & CLK_TYPE_PRIMARY)
  34 #define clk_is_pll1(x)          ((x)->type & CLK_TYPE_PLL1)
  35 #define clk_is_pll2(x)          ((x)->type & CLK_TYPE_PLL2)
  36 #define clk_is_programmable(x)  ((x)->type & CLK_TYPE_PROGRAMMABLE)
  37 #define clk_is_bypassable(x)    ((x)->type & CLK_TYPE_BYPASSABLE)
  38
  39 #define clk_is_using_xtal(x)    ((x)->mode & CLK_MODE_XTAL)
  40
  41 static DEFINE_SPINLOCK(clk_lock);
  42
  43 static void __clk_enable(struct clk *clk)
  44 {
  45         if (!clk)
  46                 return;
  47
  48         /* enable parent clock first */
  49         if (clk->parent)
  50                 __clk_enable(clk->parent);
  51
  52         if (clk->use_cnt++ == 0) {
  53                 if (clk_is_pll1(clk)) { /* PLL1 */
  54                         chipcHw_pll1Enable(clk->rate_hz, 0);
  55                 } else if (clk_is_pll2(clk)) {  /* PLL2 */
  56                         chipcHw_pll2Enable(clk->rate_hz);
  57                 } else if (clk_is_using_xtal(clk)) {    /* source is crystal */
  58                         if (!clk_is_primary(clk))
  59                                 chipcHw_bypassClockEnable(clk->csp_id);
  60                 } else {        /* source is PLL */
  61                         chipcHw_setClockEnable(clk->csp_id);
  62                 }
  63         }
  64 }
  65
  66 int clk_enable(struct clk *clk)
  67 {
  68         unsigned long flags;
  69
  70         if (!clk)
  71                 return -EINVAL;
  72
  73         spin_lock_irqsave(&clk_lock, flags);
  74         __clk_enable(clk);
  75         spin_unlock_irqrestore(&clk_lock, flags);
  76
  77         return 0;
  78 }
  79 EXPORT_SYMBOL(clk_enable);
  80
  81 static void __clk_disable(struct clk *clk)
  82 {
  83         if (!clk)
  84                 return;
  85
  86         BUG_ON(clk->use_cnt == 0);
  87
  88         if (--clk->use_cnt == 0) {
  89                 if (clk_is_pll1(clk)) { /* PLL1 */
  90                         chipcHw_pll1Disable();
  91                 } else if (clk_is_pll2(clk)) {  /* PLL2 */
  92                         chipcHw_pll2Disable();
  93                 } else if (clk_is_using_xtal(clk)) {    /* source is crystal */
  94                         if (!clk_is_primary(clk))
  95                                 chipcHw_bypassClockDisable(clk->csp_id);
  96                 } else {        /* source is PLL */
  97                         chipcHw_setClockDisable(clk->csp_id);
  98                 }
  99         }
 100
 101         if (clk->parent)
 102                 __clk_disable(clk->parent);
 103 }
 104
 105 void clk_disable(struct clk *clk)
 106 {
 107         unsigned long flags;
 108
 109         if (!clk)
 110                 return;
 111
 112         spin_lock_irqsave(&clk_lock, flags);
 113         __clk_disable(clk);
 114         spin_unlock_irqrestore(&clk_lock, flags);
 115 }
 116 EXPORT_SYMBOL(clk_disable);
 117
 118 unsigned long clk_get_rate(struct clk *clk)
 119 {
 120         if (!clk)
 121                 return 0;
 122
 123         return clk->rate_hz;
 124 }
 125 EXPORT_SYMBOL(clk_get_rate);
 126
 127 long clk_round_rate(struct clk *clk, unsigned long rate)
 128 {
 129         unsigned long flags;
 130         unsigned long actual;
 131         unsigned long rate_hz;
 132
 133         if (!clk)
 134                 return -EINVAL;
 135
 136         if (!clk_is_programmable(clk))
 137                 return -EINVAL;
 138
 139         if (clk->use_cnt)
 140                 return -EBUSY;
 141
 142         spin_lock_irqsave(&clk_lock, flags);
 143         actual = clk->parent->rate_hz;
 144         rate_hz = min(actual, rate);
 145         spin_unlock_irqrestore(&clk_lock, flags);
 146
 147         return rate_hz;
 148 }
 149 EXPORT_SYMBOL(clk_round_rate);
 150
 151 int clk_set_rate(struct clk *clk, unsigned long rate)
 152 {
 153         unsigned long flags;
 154         unsigned long actual;
 155         unsigned long rate_hz;
 156
 157         if (!clk)
 158                 return -EINVAL;
 159
 160         if (!clk_is_programmable(clk))
 161                 return -EINVAL;
 162
 163         if (clk->use_cnt)
 164                 return -EBUSY;
 165
 166         spin_lock_irqsave(&clk_lock, flags);
 167         actual = clk->parent->rate_hz;
 168         rate_hz = min(actual, rate);
 169         rate_hz = chipcHw_setClockFrequency(clk->csp_id, rate_hz);
 170         clk->rate_hz = rate_hz;
 171         spin_unlock_irqrestore(&clk_lock, flags);
 172
 173         return 0;
 174 }
 175 EXPORT_SYMBOL(clk_set_rate);
 176
 177 struct clk *clk_get_parent(struct clk *clk)
 178 {
 179         if (!clk)
 180                 return NULL;
 181
 182         return clk->parent;
 183 }
 184 EXPORT_SYMBOL(clk_get_parent);
 185
 186 int clk_set_parent(struct clk *clk, struct clk *parent)
 187 {
 188         unsigned long flags;
 189         struct clk *old_parent;
 190
 191         if (!clk || !parent)
 192                 return -EINVAL;
 193
 194         if (!clk_is_primary(parent) || !clk_is_bypassable(clk))
 195                 return -EINVAL;
 196
 197         /* if more than one user, parent is not allowed */
 198         if (clk->use_cnt > 1)
 199                 return -EBUSY;
 200
 201         if (clk->parent == parent)
 202                 return 0;
 203
 204         spin_lock_irqsave(&clk_lock, flags);
 205         old_parent = clk->parent;
 206         clk->parent = parent;
 207         if (clk_is_using_xtal(parent))
 208                 clk->mode |= CLK_MODE_XTAL;
 209         else
 210                 clk->mode &= (~CLK_MODE_XTAL);
 211
 212         /* if clock is active */
 213         if (clk->use_cnt != 0) {
 214                 clk->use_cnt--;
 215                 /* enable clock with the new parent */
 216                 __clk_enable(clk);
 217                 /* disable the old parent */
 218                 __clk_disable(old_parent);
 219         }
 220         spin_unlock_irqrestore(&clk_lock, flags);
 221
 222         return 0;
 223 }
 224 EXPORT_SYMBOL(clk_set_parent);