arch/arm/plat-s3c24xx/s3c244x-clock.c

   1 /* linux/arch/arm/plat-s3c24xx/s3c24xx-clock.c
   2  *
   3  * Copyright (c) 2004-2005,2008 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/mutex.h>
  35 #include <linux/clk.h>
  36
  37 #include <mach/hardware.h>
  38 #include <asm/atomic.h>
  39 #include <asm/irq.h>
  40 #include <asm/io.h>
  41
  42 #include <mach/regs-clock.h>
  43
  44 #include <asm/plat-s3c24xx/clock.h>
  45 #include <asm/plat-s3c24xx/cpu.h>
  46
  47 static int s3c2440_setparent_armclk(struct clk *clk, struct clk *parent)
  48 {
  49         unsigned long camdivn;
  50         unsigned long dvs;
  51
  52         if (parent == &clk_f)
  53                 dvs = 0;
  54         else if (parent == &clk_h)
  55                 dvs = S3C2440_CAMDIVN_DVSEN;
  56         else
  57                 return -EINVAL;
  58
  59         clk->parent = parent;
  60
  61         camdivn  = __raw_readl(S3C2440_CAMDIVN);
  62         camdivn &= ~S3C2440_CAMDIVN_DVSEN;
  63         camdivn |= dvs;
  64         __raw_writel(camdivn, S3C2440_CAMDIVN);
  65
  66         return 0;
  67 }
  68
  69 static struct clk clk_arm = {
  70         .name           = "armclk",
  71         .id             = -1,
  72         .set_parent     = s3c2440_setparent_armclk,
  73 };
  74
  75 static int s3c244x_clk_add(struct sys_device *sysdev)
  76 {
  77         unsigned long camdivn = __raw_readl(S3C2440_CAMDIVN);
  78         unsigned long clkdivn;
  79         struct clk *clock_upll;
  80         int ret;
  81
  82         printk("S3C244X: Clock Support, DVS %s\n",
  83                (camdivn & S3C2440_CAMDIVN_DVSEN) ? "on" : "off");
  84
  85         clk_arm.parent = (camdivn & S3C2440_CAMDIVN_DVSEN) ? &clk_h : &clk_f;
  86
  87         ret = s3c24xx_register_clock(&clk_arm);
  88         if (ret < 0) {
  89                 printk(KERN_ERR "S3C24XX: Failed to add armclk (%d)\n", ret);
  90                 return ret;
  91         }
  92
  93         clock_upll = clk_get(NULL, "upll");
  94         if (IS_ERR(clock_upll)) {
  95                 printk(KERN_ERR "S3C244X: Failed to get upll clock\n");
  96                 return -ENOENT;
  97         }
  98
  99         /* check rate of UPLL, and if it is near 96MHz, then change
 100          * to using half the UPLL rate for the system */
 101
 102         if (clk_get_rate(clock_upll) > (94 * MHZ)) {
 103                 clk_usb_bus.rate = clk_get_rate(clock_upll) / 2;
 104
 105                 mutex_lock(&clocks_mutex);
 106
 107                 clkdivn = __raw_readl(S3C2410_CLKDIVN);
 108                 clkdivn |= S3C2440_CLKDIVN_UCLK;
 109                 __raw_writel(clkdivn, S3C2410_CLKDIVN);
 110
 111                 mutex_unlock(&clocks_mutex);
 112         }
 113
 114         return 0;
 115 }
 116
 117 static struct sysdev_driver s3c2440_clk_driver = {
 118         .add            = s3c244x_clk_add,
 119 };
 120
 121 static int s3c2440_clk_init(void)
 122 {
 123         return sysdev_driver_register(&s3c2440_sysclass, &s3c2440_clk_driver);
 124 }
 125
 126 arch_initcall(s3c2440_clk_init);
 127
 128 static struct sysdev_driver s3c2442_clk_driver = {
 129         .add            = s3c244x_clk_add,
 130 };
 131
 132 static int s3c2442_clk_init(void)
 133 {
 134         return sysdev_driver_register(&s3c2442_sysclass, &s3c2442_clk_driver);
 135 }
 136
 137 arch_initcall(s3c2442_clk_init);