LXR linux/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
  46static 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
  68static struct clk clk_arm = {
  69        .name           = "armclk",
  70        .id             = -1,
  71        .ops            = &(struct clk_ops) {
  72                .set_parent     = s3c2440_setparent_armclk,
  73        },
  74};
  75
  76static 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
 118static struct sysdev_driver s3c2440_clk_driver = {
 119        .add            = s3c244x_clk_add,
 120};
 121
 122static int s3c2440_clk_init(void)
 123{
 124        return sysdev_driver_register(&s3c2440_sysclass, &s3c2440_clk_driver);
 125}
 126
 127arch_initcall(s3c2440_clk_init);
 128
 129static struct sysdev_driver s3c2442_clk_driver = {
 130        .add            = s3c244x_clk_add,
 131};
 132
 133static int s3c2442_clk_init(void)
 134{
 135        return sysdev_driver_register(&s3c2442_sysclass, &s3c2442_clk_driver);
 136}
 137
 138arch_initcall(s3c2442_clk_init);
 139