arch/arm/mach-realview/clock.c

   1 /*
   2  *  linux/arch/arm/mach-realview/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/clk.h>
  17 #include <linux/mutex.h>
  18
  19 #include <asm/hardware/icst307.h>
  20
  21 #include "clock.h"
  22
  23 static LIST_HEAD(clocks);
  24 static DEFINE_MUTEX(clocks_mutex);
  25
  26 struct clk *clk_get(struct device *dev, const char *id)
  27 {
  28         struct clk *p, *clk = ERR_PTR(-ENOENT);
  29
  30         mutex_lock(&clocks_mutex);
  31         list_for_each_entry(p, &clocks, node) {
  32                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  33                         clk = p;
  34                         break;
  35                 }
  36         }
  37         mutex_unlock(&clocks_mutex);
  38
  39         return clk;
  40 }
  41 EXPORT_SYMBOL(clk_get);
  42
  43 void clk_put(struct clk *clk)
  44 {
  45         module_put(clk->owner);
  46 }
  47 EXPORT_SYMBOL(clk_put);
  48
  49 int clk_enable(struct clk *clk)
  50 {
  51         return 0;
  52 }
  53 EXPORT_SYMBOL(clk_enable);
  54
  55 void clk_disable(struct clk *clk)
  56 {
  57 }
  58 EXPORT_SYMBOL(clk_disable);
  59
  60 unsigned long clk_get_rate(struct clk *clk)
  61 {
  62         return clk->rate;
  63 }
  64 EXPORT_SYMBOL(clk_get_rate);
  65
  66 long clk_round_rate(struct clk *clk, unsigned long rate)
  67 {
  68         return rate;
  69 }
  70 EXPORT_SYMBOL(clk_round_rate);
  71
  72 int clk_set_rate(struct clk *clk, unsigned long rate)
  73 {
  74         int ret = -EIO;
  75
  76         if (clk->setvco) {
  77                 struct icst307_vco vco;
  78
  79                 vco = icst307_khz_to_vco(clk->params, rate / 1000);
  80                 clk->rate = icst307_khz(clk->params, vco) * 1000;
  81
  82                 printk("Clock %s: setting VCO reg params: S=%d R=%d V=%d\n",
  83                         clk->name, vco.s, vco.r, vco.v);
  84
  85                 clk->setvco(clk, vco);
  86                 ret = 0;
  87         }
  88         return ret;
  89 }
  90 EXPORT_SYMBOL(clk_set_rate);
  91
  92 /*
  93  * These are fixed clocks.
  94  */
  95 static struct clk kmi_clk = {
  96         .name   = "KMIREFCLK",
  97         .rate   = 24000000,
  98 };
  99
 100 static struct clk uart_clk = {
 101         .name   = "UARTCLK",
 102         .rate   = 24000000,
 103 };
 104
 105 static struct clk mmci_clk = {
 106         .name   = "MCLK",
 107         .rate   = 33000000,
 108 };
 109
 110 int clk_register(struct clk *clk)
 111 {
 112         mutex_lock(&clocks_mutex);
 113         list_add(&clk->node, &clocks);
 114         mutex_unlock(&clocks_mutex);
 115         return 0;
 116 }
 117 EXPORT_SYMBOL(clk_register);
 118
 119 void clk_unregister(struct clk *clk)
 120 {
 121         mutex_lock(&clocks_mutex);
 122         list_del(&clk->node);
 123         mutex_unlock(&clocks_mutex);
 124 }
 125 EXPORT_SYMBOL(clk_unregister);
 126
 127 static int __init clk_init(void)
 128 {
 129         clk_register(&kmi_clk);
 130         clk_register(&uart_clk);
 131         clk_register(&mmci_clk);
 132         return 0;
 133 }
 134 arch_initcall(clk_init);