Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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);
137 
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