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   1 /* linux/arch/arm/mach-s3c2410/clock.c
   2  *
   3  * Copyright (c) 2006 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410,S3C2440,S3C2442 Clock control support
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22
  23 #include <linux/init.h>
  24 #include <linux/module.h>
  25 #include <linux/kernel.h>
  26 #include <linux/list.h>
  27 #include <linux/errno.h>
  28 #include <linux/err.h>
  29 #include <linux/sysdev.h>
  30 #include <linux/clk.h>
  31 #include <linux/mutex.h>
  32 #include <linux/delay.h>
  33
  34 #include <asm/hardware.h>
  35 #include <asm/io.h>
  36
  37 #include <asm/arch/regs-clock.h>
  38 #include <asm/arch/regs-gpio.h>
  39
  40 #include "clock.h"
  41 #include "cpu.h"
  42
  43 int s3c2410_clkcon_enable(struct clk *clk, int enable)
  44 {
  45         unsigned int clocks = clk->ctrlbit;
  46         unsigned long clkcon;
  47
  48         clkcon = __raw_readl(S3C2410_CLKCON);
  49
  50         if (enable)
  51                 clkcon |= clocks;
  52         else
  53                 clkcon &= ~clocks;
  54
  55         /* ensure none of the special function bits set */
  56         clkcon &= ~(S3C2410_CLKCON_IDLE|S3C2410_CLKCON_POWER);
  57
  58         __raw_writel(clkcon, S3C2410_CLKCON);
  59
  60         return 0;
  61 }
  62
  63 static int s3c2410_upll_enable(struct clk *clk, int enable)
  64 {
  65         unsigned long clkslow = __raw_readl(S3C2410_CLKSLOW);
  66         unsigned long orig = clkslow;
  67
  68         if (enable)
  69                 clkslow &= ~S3C2410_CLKSLOW_UCLK_OFF;
  70         else
  71                 clkslow |= S3C2410_CLKSLOW_UCLK_OFF;
  72
  73         __raw_writel(clkslow, S3C2410_CLKSLOW);
  74
  75         /* if we started the UPLL, then allow to settle */
  76
  77         if (enable && (orig & S3C2410_CLKSLOW_UCLK_OFF))
  78                 udelay(200);
  79
  80         return 0;
  81 }
  82
  83 /* standard clock definitions */
  84
  85 static struct clk init_clocks_disable[] = {
  86         {
  87                 .name           = "nand",
  88                 .id             = -1,
  89                 .parent         = &clk_h,
  90                 .enable         = s3c2410_clkcon_enable,
  91                 .ctrlbit        = S3C2410_CLKCON_NAND,
  92         }, {
  93                 .name           = "sdi",
  94                 .id             = -1,
  95                 .parent         = &clk_p,
  96                 .enable         = s3c2410_clkcon_enable,
  97                 .ctrlbit        = S3C2410_CLKCON_SDI,
  98         }, {
  99                 .name           = "adc",
 100                 .id             = -1,
 101                 .parent         = &clk_p,
 102                 .enable         = s3c2410_clkcon_enable,
 103                 .ctrlbit        = S3C2410_CLKCON_ADC,
 104         }, {
 105                 .name           = "i2c",
 106                 .id             = -1,
 107                 .parent         = &clk_p,
 108                 .enable         = s3c2410_clkcon_enable,
 109                 .ctrlbit        = S3C2410_CLKCON_IIC,
 110         }, {
 111                 .name           = "iis",
 112                 .id             = -1,
 113                 .parent         = &clk_p,
 114                 .enable         = s3c2410_clkcon_enable,
 115                 .ctrlbit        = S3C2410_CLKCON_IIS,
 116         }, {
 117                 .name           = "spi",
 118                 .id             = -1,
 119                 .parent         = &clk_p,
 120                 .enable         = s3c2410_clkcon_enable,
 121                 .ctrlbit        = S3C2410_CLKCON_SPI,
 122         }
 123 };
 124
 125 static struct clk init_clocks[] = {
 126         {
 127                 .name           = "lcd",
 128                 .id             = -1,
 129                 .parent         = &clk_h,
 130                 .enable         = s3c2410_clkcon_enable,
 131                 .ctrlbit        = S3C2410_CLKCON_LCDC,
 132         }, {
 133                 .name           = "gpio",
 134                 .id             = -1,
 135                 .parent         = &clk_p,
 136                 .enable         = s3c2410_clkcon_enable,
 137                 .ctrlbit        = S3C2410_CLKCON_GPIO,
 138         }, {
 139                 .name           = "usb-host",
 140                 .id             = -1,
 141                 .parent         = &clk_h,
 142                 .enable         = s3c2410_clkcon_enable,
 143                 .ctrlbit        = S3C2410_CLKCON_USBH,
 144         }, {
 145                 .name           = "usb-device",
 146                 .id             = -1,
 147                 .parent         = &clk_h,
 148                 .enable         = s3c2410_clkcon_enable,
 149                 .ctrlbit        = S3C2410_CLKCON_USBD,
 150         }, {
 151                 .name           = "timers",
 152                 .id             = -1,
 153                 .parent         = &clk_p,
 154                 .enable         = s3c2410_clkcon_enable,
 155                 .ctrlbit        = S3C2410_CLKCON_PWMT,
 156         }, {
 157                 .name           = "uart",
 158                 .id             = 0,
 159                 .parent         = &clk_p,
 160                 .enable         = s3c2410_clkcon_enable,
 161                 .ctrlbit        = S3C2410_CLKCON_UART0,
 162         }, {
 163                 .name           = "uart",
 164                 .id             = 1,
 165                 .parent         = &clk_p,
 166                 .enable         = s3c2410_clkcon_enable,
 167                 .ctrlbit        = S3C2410_CLKCON_UART1,
 168         }, {
 169                 .name           = "uart",
 170                 .id             = 2,
 171                 .parent         = &clk_p,
 172                 .enable         = s3c2410_clkcon_enable,
 173                 .ctrlbit        = S3C2410_CLKCON_UART2,
 174         }, {
 175                 .name           = "rtc",
 176                 .id             = -1,
 177                 .parent         = &clk_p,
 178                 .enable         = s3c2410_clkcon_enable,
 179                 .ctrlbit        = S3C2410_CLKCON_RTC,
 180         }, {
 181                 .name           = "watchdog",
 182                 .id             = -1,
 183                 .parent         = &clk_p,
 184                 .ctrlbit        = 0,
 185         }, {
 186                 .name           = "usb-bus-host",
 187                 .id             = -1,
 188                 .parent         = &clk_usb_bus,
 189         }, {
 190                 .name           = "usb-bus-gadget",
 191                 .id             = -1,
 192                 .parent         = &clk_usb_bus,
 193         },
 194 };
 195
 196 /* s3c2410_baseclk_add()
 197  *
 198  * Add all the clocks used by the s3c2410 or compatible CPUs
 199  * such as the S3C2440 and S3C2442.
 200  *
 201  * We cannot use a system device as we are needed before any
 202  * of the init-calls that initialise the devices are actually
 203  * done.
 204 */
 205
 206 int __init s3c2410_baseclk_add(void)
 207 {
 208         unsigned long clkslow = __raw_readl(S3C2410_CLKSLOW);
 209         unsigned long clkcon  = __raw_readl(S3C2410_CLKCON);
 210         struct clk *clkp;
 211         struct clk *xtal;
 212         int ret;
 213         int ptr;
 214
 215         clk_upll.enable = s3c2410_upll_enable;
 216
 217         if (s3c24xx_register_clock(&clk_usb_bus) < 0)
 218                 printk(KERN_ERR "failed to register usb bus clock\n");
 219
 220         /* register clocks from clock array */
 221
 222         clkp = init_clocks;
 223         for (ptr = 0; ptr < ARRAY_SIZE(init_clocks); ptr++, clkp++) {
 224                 /* ensure that we note the clock state */
 225
 226                 clkp->usage = clkcon & clkp->ctrlbit ? 1 : 0;
 227
 228                 ret = s3c24xx_register_clock(clkp);
 229                 if (ret < 0) {
 230                         printk(KERN_ERR "Failed to register clock %s (%d)\n",
 231                                clkp->name, ret);
 232                 }
 233         }
 234
 235         /* We must be careful disabling the clocks we are not intending to
 236          * be using at boot time, as subsytems such as the LCD which do
 237          * their own DMA requests to the bus can cause the system to lockup
 238          * if they where in the middle of requesting bus access.
 239          *
 240          * Disabling the LCD clock if the LCD is active is very dangerous,
 241          * and therefore the bootloader should be careful to not enable
 242          * the LCD clock if it is not needed.
 243         */
 244
 245         /* install (and disable) the clocks we do not need immediately */
 246
 247         clkp = init_clocks_disable;
 248         for (ptr = 0; ptr < ARRAY_SIZE(init_clocks_disable); ptr++, clkp++) {
 249
 250                 ret = s3c24xx_register_clock(clkp);
 251                 if (ret < 0) {
 252                         printk(KERN_ERR "Failed to register clock %s (%d)\n",
 253                                clkp->name, ret);
 254                 }
 255
 256                 s3c2410_clkcon_enable(clkp, 0);
 257         }
 258
 259         /* show the clock-slow value */
 260
 261         xtal = clk_get(NULL, "xtal");
 262
 263         printk("CLOCK: Slow mode (%ld.%ld MHz), %s, MPLL %s, UPLL %s\n",
 264                print_mhz(clk_get_rate(xtal) /
 265                          ( 2 * S3C2410_CLKSLOW_GET_SLOWVAL(clkslow))),
 266                (clkslow & S3C2410_CLKSLOW_SLOW) ? "slow" : "fast",
 267                (clkslow & S3C2410_CLKSLOW_MPLL_OFF) ? "off" : "on",
 268                (clkslow & S3C2410_CLKSLOW_UCLK_OFF) ? "off" : "on");
 269
 270         return 0;
 271 }