arch/arm/mach-versatile/clock.c

   1 /*
   2  *  linux/arch/arm/mach-versatile/clock.c
   3  *
   4  *  Copyright (C) 2004 ARM Limited.
   5  *  Written by Deep Blue Solutions Limited.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/list.h>
  14 #include <linux/errno.h>
  15 #include <linux/err.h>
  16 #include <linux/string.h>
  17
  18 #include <asm/semaphore.h>
  19 #include <asm/hardware/clock.h>
  20 #include <asm/hardware/icst307.h>
  21
  22 #include "clock.h"
  23
  24 static LIST_HEAD(clocks);
  25 static DECLARE_MUTEX(clocks_sem);
  26
  27 struct clk *clk_get(struct device *dev, const char *id)
  28 {
  29         struct clk *p, *clk = ERR_PTR(-ENOENT);
  30
  31         down(&clocks_sem);
  32         list_for_each_entry(p, &clocks, node) {
  33                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  34                         clk = p;
  35                         break;
  36                 }
  37         }
  38         up(&clocks_sem);
  39
  40         return clk;
  41 }
  42 EXPORT_SYMBOL(clk_get);
  43
  44 void clk_put(struct clk *clk)
  45 {
  46         module_put(clk->owner);
  47 }
  48 EXPORT_SYMBOL(clk_put);
  49
  50 int clk_enable(struct clk *clk)
  51 {
  52         return 0;
  53 }
  54 EXPORT_SYMBOL(clk_enable);
  55
  56 void clk_disable(struct clk *clk)
  57 {
  58 }
  59 EXPORT_SYMBOL(clk_disable);
  60
  61 int clk_use(struct clk *clk)
  62 {
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(clk_use);
  66
  67 void clk_unuse(struct clk *clk)
  68 {
  69 }
  70 EXPORT_SYMBOL(clk_unuse);
  71
  72 unsigned long clk_get_rate(struct clk *clk)
  73 {
  74         return clk->rate;
  75 }
  76 EXPORT_SYMBOL(clk_get_rate);
  77
  78 long clk_round_rate(struct clk *clk, unsigned long rate)
  79 {
  80         return rate;
  81 }
  82 EXPORT_SYMBOL(clk_round_rate);
  83
  84 int clk_set_rate(struct clk *clk, unsigned long rate)
  85 {
  86         int ret = -EIO;
  87
  88         if (clk->setvco) {
  89                 struct icst307_vco vco;
  90
  91                 vco = icst307_khz_to_vco(clk->params, rate / 1000);
  92                 clk->rate = icst307_khz(clk->params, vco) * 1000;
  93
  94                 printk("Clock %s: setting VCO reg params: S=%d R=%d V=%d\n",
  95                         clk->name, vco.s, vco.r, vco.v);
  96
  97                 clk->setvco(clk, vco);
  98                 ret = 0;
  99         }
 100         return ret;
 101 }
 102 EXPORT_SYMBOL(clk_set_rate);
 103
 104 /*
 105  * These are fixed clocks.
 106  */
 107 static struct clk kmi_clk = {
 108         .name   = "KMIREFCLK",
 109         .rate   = 24000000,
 110 };
 111
 112 static struct clk uart_clk = {
 113         .name   = "UARTCLK",
 114         .rate   = 24000000,
 115 };
 116
 117 static struct clk mmci_clk = {
 118         .name   = "MCLK",
 119         .rate   = 33000000,
 120 };
 121
 122 int clk_register(struct clk *clk)
 123 {
 124         down(&clocks_sem);
 125         list_add(&clk->node, &clocks);
 126         up(&clocks_sem);
 127         return 0;
 128 }
 129 EXPORT_SYMBOL(clk_register);
 130
 131 void clk_unregister(struct clk *clk)
 132 {
 133         down(&clocks_sem);
 134         list_del(&clk->node);
 135         up(&clocks_sem);
 136 }
 137 EXPORT_SYMBOL(clk_unregister);
 138
 139 static int __init clk_init(void)
 140 {
 141         clk_register(&kmi_clk);
 142         clk_register(&uart_clk);
 143         clk_register(&mmci_clk);
 144         return 0;
 145 }
 146 arch_initcall(clk_init);