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/interrupt.h>
  32 #include <linux/ioport.h>
  33 #include <linux/clk.h>
  34 #include <linux/io.h>
  35
  36 #include <mach/hardware.h>
  37 #include <linux/atomic.h>
  38 #include <asm/irq.h>
  39
  40 #include <mach/regs-clock.h>
  41
  42 #include <plat/clock.h>
  43 #include <plat/cpu.h>
  44
  45 static int s3c2440_setparent_armclk(struct clk *clk, struct clk *parent)
  46 {
  47         unsigned long camdivn;
  48         unsigned long dvs;
  49
  50         if (parent == &clk_f)
  51                 dvs = 0;
  52         else if (parent == &clk_h)
  53                 dvs = S3C2440_CAMDIVN_DVSEN;
  54         else
  55                 return -EINVAL;
  56
  57         clk->parent = parent;
  58
  59         camdivn  = __raw_readl(S3C2440_CAMDIVN);
  60         camdivn &= ~S3C2440_CAMDIVN_DVSEN;
  61         camdivn |= dvs;
  62         __raw_writel(camdivn, S3C2440_CAMDIVN);
  63
  64         return 0;
  65 }
  66
  67 static struct clk clk_arm = {
  68         .name           = "armclk",
  69         .id             = -1,
  70         .ops            = &(struct clk_ops) {
  71                 .set_parent     = s3c2440_setparent_armclk,
  72         },
  73 };
  74
  75 static int s3c244x_clk_add(struct device *dev, struct subsys_interface *sif)
  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                 spin_lock(&clocks_lock);
 106
 107                 clkdivn = __raw_readl(S3C2410_CLKDIVN);
 108                 clkdivn |= S3C2440_CLKDIVN_UCLK;
 109                 __raw_writel(clkdivn, S3C2410_CLKDIVN);
 110
 111                 spin_unlock(&clocks_lock);
 112         }
 113
 114         return 0;
 115 }
 116
 117 static struct subsys_interface s3c2440_clk_interface = {
 118         .name           = "s3c2440_clk",
 119         .subsys         = &s3c2440_subsys,
 120         .add_dev        = s3c244x_clk_add,
 121 };
 122
 123 static int s3c2440_clk_init(void)
 124 {
 125         return subsys_interface_register(&s3c2440_clk_interface);
 126 }
 127
 128 arch_initcall(s3c2440_clk_init);
 129
 130 static struct subsys_interface s3c2442_clk_interface = {
 131         .name           = "s3c2442_clk",
 132         .subsys         = &s3c2442_subsys,
 133         .add_dev        = s3c244x_clk_add,
 134 };
 135
 136 static int s3c2442_clk_init(void)
 137 {
 138         return subsys_interface_register(&s3c2442_clk_interface);
 139 }
 140
 141 arch_initcall(s3c2442_clk_init);