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 #include <linux/clk.h>
  18 #include <linux/mutex.h>
  19
  20 #include <asm/hardware/icst307.h>
  21
  22 #include "clock.h"
  23
  24 static LIST_HEAD(clocks);
  25 static DEFINE_MUTEX(clocks_mutex);
  26
  27 struct clk *clk_get(struct device *dev, const char *id)
  28 {
  29         struct clk *p, *clk = ERR_PTR(-ENOENT);
  30
  31         mutex_lock(&clocks_mutex);
  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         mutex_unlock(&clocks_mutex);
  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 unsigned long clk_get_rate(struct clk *clk)
  62 {
  63         return clk->rate;
  64 }
  65 EXPORT_SYMBOL(clk_get_rate);
  66
  67 long clk_round_rate(struct clk *clk, unsigned long rate)
  68 {
  69         return rate;
  70 }
  71 EXPORT_SYMBOL(clk_round_rate);
  72
  73 int clk_set_rate(struct clk *clk, unsigned long rate)
  74 {
  75         int ret = -EIO;
  76
  77         if (clk->setvco) {
  78                 struct icst307_vco vco;
  79
  80                 vco = icst307_khz_to_vco(clk->params, rate / 1000);
  81                 clk->rate = icst307_khz(clk->params, vco) * 1000;
  82
  83                 printk("Clock %s: setting VCO reg params: S=%d R=%d V=%d\n",
  84                         clk->name, vco.s, vco.r, vco.v);
  85
  86                 clk->setvco(clk, vco);
  87                 ret = 0;
  88         }
  89         return ret;
  90 }
  91 EXPORT_SYMBOL(clk_set_rate);
  92
  93 /*
  94  * These are fixed clocks.
  95  */
  96 static struct clk kmi_clk = {
  97         .name   = "KMIREFCLK",
  98         .rate   = 24000000,
  99 };
 100
 101 static struct clk uart_clk = {
 102         .name   = "UARTCLK",
 103         .rate   = 24000000,
 104 };
 105
 106 static struct clk mmci_clk = {
 107         .name   = "MCLK",
 108         .rate   = 33000000,
 109 };
 110
 111 int clk_register(struct clk *clk)
 112 {
 113         mutex_lock(&clocks_mutex);
 114         list_add(&clk->node, &clocks);
 115         mutex_unlock(&clocks_mutex);
 116         return 0;
 117 }
 118 EXPORT_SYMBOL(clk_register);
 119
 120 void clk_unregister(struct clk *clk)
 121 {
 122         mutex_lock(&clocks_mutex);
 123         list_del(&clk->node);
 124         mutex_unlock(&clocks_mutex);
 125 }
 126 EXPORT_SYMBOL(clk_unregister);
 127
 128 static int __init clk_init(void)
 129 {
 130         clk_register(&kmi_clk);
 131         clk_register(&uart_clk);
 132         clk_register(&mmci_clk);
 133         return 0;
 134 }
 135 arch_initcall(clk_init);