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/semaphore.h>
  21 #include <asm/hardware/icst307.h>
  22
  23 #include "clock.h"
  24
  25 static LIST_HEAD(clocks);
  26 static DEFINE_MUTEX(clocks_mutex);
  27
  28 struct clk *clk_get(struct device *dev, const char *id)
  29 {
  30         struct clk *p, *clk = ERR_PTR(-ENOENT);
  31
  32         mutex_lock(&clocks_mutex);
  33         list_for_each_entry(p, &clocks, node) {
  34                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
  35                         clk = p;
  36                         break;
  37                 }
  38         }
  39         mutex_unlock(&clocks_mutex);
  40
  41         return clk;
  42 }
  43 EXPORT_SYMBOL(clk_get);
  44
  45 void clk_put(struct clk *clk)
  46 {
  47         module_put(clk->owner);
  48 }
  49 EXPORT_SYMBOL(clk_put);
  50
  51 int clk_enable(struct clk *clk)
  52 {
  53         return 0;
  54 }
  55 EXPORT_SYMBOL(clk_enable);
  56
  57 void clk_disable(struct clk *clk)
  58 {
  59 }
  60 EXPORT_SYMBOL(clk_disable);
  61
  62 unsigned long clk_get_rate(struct clk *clk)
  63 {
  64         return clk->rate;
  65 }
  66 EXPORT_SYMBOL(clk_get_rate);
  67
  68 long clk_round_rate(struct clk *clk, unsigned long rate)
  69 {
  70         return rate;
  71 }
  72 EXPORT_SYMBOL(clk_round_rate);
  73
  74 int clk_set_rate(struct clk *clk, unsigned long rate)
  75 {
  76         int ret = -EIO;
  77
  78         if (clk->setvco) {
  79                 struct icst307_vco vco;
  80
  81                 vco = icst307_khz_to_vco(clk->params, rate / 1000);
  82                 clk->rate = icst307_khz(clk->params, vco) * 1000;
  83
  84                 printk("Clock %s: setting VCO reg params: S=%d R=%d V=%d\n",
  85                         clk->name, vco.s, vco.r, vco.v);
  86
  87                 clk->setvco(clk, vco);
  88                 ret = 0;
  89         }
  90         return ret;
  91 }
  92 EXPORT_SYMBOL(clk_set_rate);
  93
  94 /*
  95  * These are fixed clocks.
  96  */
  97 static struct clk kmi_clk = {
  98         .name   = "KMIREFCLK",
  99         .rate   = 24000000,
 100 };
 101
 102 static struct clk uart_clk = {
 103         .name   = "UARTCLK",
 104         .rate   = 24000000,
 105 };
 106
 107 static struct clk mmci_clk = {
 108         .name   = "MCLK",
 109         .rate   = 33000000,
 110 };
 111
 112 int clk_register(struct clk *clk)
 113 {
 114         mutex_lock(&clocks_mutex);
 115         list_add(&clk->node, &clocks);
 116         mutex_unlock(&clocks_mutex);
 117         return 0;
 118 }
 119 EXPORT_SYMBOL(clk_register);
 120
 121 void clk_unregister(struct clk *clk)
 122 {
 123         mutex_lock(&clocks_mutex);
 124         list_del(&clk->node);
 125         mutex_unlock(&clocks_mutex);
 126 }
 127 EXPORT_SYMBOL(clk_unregister);
 128
 129 static int __init clk_init(void)
 130 {
 131         clk_register(&kmi_clk);
 132         clk_register(&uart_clk);
 133         clk_register(&mmci_clk);
 134         return 0;
 135 }
 136 arch_initcall(clk_init);