release/src-rt-6.x.4708/linux/linux-2.6.36/arch/arm/mach-s3c2440/s3c244x-clock.c

   1 /* linux/arch/arm/plat-s3c24xx/s3c24xx-clock.c
   2  *
   3  * Copyright (c) 2004-2008 Simtec Electronics
   4  *      http://armlinux.simtec.co.uk/
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * S3C2440/S3C2442 Common clock support
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22 */
  23
  24 #include <linux/init.h>
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/list.h>
  28 #include <linux/errno.h>
  29 #include <linux/err.h>
  30 #include <linux/device.h>
  31 #include <linux/sysdev.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/ioport.h>
  34 #include <linux/clk.h>
  35 #include <linux/io.h>
  36
  37 #include <mach/hardware.h>
  38 #include <asm/atomic.h>
  39 #include <asm/irq.h>
  40
  41 #include <mach/regs-clock.h>
  42
  43 #include <plat/clock.h>
  44 #include <plat/cpu.h>
  45
  46 static int s3c2440_setparent_armclk(struct clk *clk, struct clk *parent)
  47 {
  48         unsigned long camdivn;
  49         unsigned long dvs;
  50
  51         if (parent == &clk_f)
  52                 dvs = 0;
  53         else if (parent == &clk_h)
  54                 dvs = S3C2440_CAMDIVN_DVSEN;
  55         else
  56                 return -EINVAL;
  57
  58         clk->parent = parent;
  59
  60         camdivn  = __raw_readl(S3C2440_CAMDIVN);
  61         camdivn &= ~S3C2440_CAMDIVN_DVSEN;
  62         camdivn |= dvs;
  63         __raw_writel(camdivn, S3C2440_CAMDIVN);
  64
  65         return 0;
  66 }
  67
  68 static struct clk clk_arm = {
  69         .name           = "armclk",
  70         .id             = -1,
  71         .ops            = &(struct clk_ops) {
  72                 .set_parent     = s3c2440_setparent_armclk,
  73         },
  74 };
  75
  76 static int s3c244x_clk_add(struct sys_device *sysdev)
  77 {
  78         unsigned long camdivn = __raw_readl(S3C2440_CAMDIVN);
  79         unsigned long clkdivn;
  80         struct clk *clock_upll;
  81         int ret;
  82
  83         printk("S3C244X: Clock Support, DVS %s\n",
  84                (camdivn & S3C2440_CAMDIVN_DVSEN) ? "on" : "off");
  85
  86         clk_arm.parent = (camdivn & S3C2440_CAMDIVN_DVSEN) ? &clk_h : &clk_f;
  87
  88         ret = s3c24xx_register_clock(&clk_arm);
  89         if (ret < 0) {
  90                 printk(KERN_ERR "S3C24XX: Failed to add armclk (%d)\n", ret);
  91                 return ret;
  92         }
  93
  94         clock_upll = clk_get(NULL, "upll");
  95         if (IS_ERR(clock_upll)) {
  96                 printk(KERN_ERR "S3C244X: Failed to get upll clock\n");
  97                 return -ENOENT;
  98         }
  99
 100         /* check rate of UPLL, and if it is near 96MHz, then change
 101          * to using half the UPLL rate for the system */
 102
 103         if (clk_get_rate(clock_upll) > (94 * MHZ)) {
 104                 clk_usb_bus.rate = clk_get_rate(clock_upll) / 2;
 105
 106                 spin_lock(&clocks_lock);
 107
 108                 clkdivn = __raw_readl(S3C2410_CLKDIVN);
 109                 clkdivn |= S3C2440_CLKDIVN_UCLK;
 110                 __raw_writel(clkdivn, S3C2410_CLKDIVN);
 111
 112                 spin_unlock(&clocks_lock);
 113         }
 114
 115         return 0;
 116 }
 117
 118 static struct sysdev_driver s3c2440_clk_driver = {
 119         .add            = s3c244x_clk_add,
 120 };
 121
 122 static int s3c2440_clk_init(void)
 123 {
 124         return sysdev_driver_register(&s3c2440_sysclass, &s3c2440_clk_driver);
 125 }
 126
 127 arch_initcall(s3c2440_clk_init);
 128
 129 static struct sysdev_driver s3c2442_clk_driver = {
 130         .add            = s3c244x_clk_add,
 131 };
 132
 133 static int s3c2442_clk_init(void)
 134 {
 135         return sysdev_driver_register(&s3c2442_sysclass, &s3c2442_clk_driver);
 136 }
 137
 138 arch_initcall(s3c2442_clk_init);