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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 #include <linux/serial_core.h>
  34
  35 #include <asm/mach/map.h>
  36
  37 #include <asm/hardware.h>
  38 #include <asm/io.h>
  39
  40 #include <asm/arch/regs-serial.h>
  41 #include <asm/arch/regs-clock.h>
  42 #include <asm/arch/regs-gpio.h>
  43
  44 #include <asm/plat-s3c24xx/s3c2410.h>
  45 #include <asm/plat-s3c24xx/clock.h>
  46 #include <asm/plat-s3c24xx/cpu.h>
  47
  48 int s3c2410_clkcon_enable(struct clk *clk, int enable)
  49 {
  50         unsigned int clocks = clk->ctrlbit;
  51         unsigned long clkcon;
  52
  53         clkcon = __raw_readl(S3C2410_CLKCON);
  54
  55         if (enable)
  56                 clkcon |= clocks;
  57         else
  58                 clkcon &= ~clocks;
  59
  60         /* ensure none of the special function bits set */
  61         clkcon &= ~(S3C2410_CLKCON_IDLE|S3C2410_CLKCON_POWER);
  62
  63         __raw_writel(clkcon, S3C2410_CLKCON);
  64
  65         return 0;
  66 }
  67
  68 static int s3c2410_upll_enable(struct clk *clk, int enable)
  69 {
  70         unsigned long clkslow = __raw_readl(S3C2410_CLKSLOW);
  71         unsigned long orig = clkslow;
  72
  73         if (enable)
  74                 clkslow &= ~S3C2410_CLKSLOW_UCLK_OFF;
  75         else
  76                 clkslow |= S3C2410_CLKSLOW_UCLK_OFF;
  77
  78         __raw_writel(clkslow, S3C2410_CLKSLOW);
  79
  80         /* if we started the UPLL, then allow to settle */
  81
  82         if (enable && (orig & S3C2410_CLKSLOW_UCLK_OFF))
  83                 udelay(200);
  84
  85         return 0;
  86 }
  87
  88 /* standard clock definitions */
  89
  90 static struct clk init_clocks_disable[] = {
  91         {
  92                 .name           = "nand",
  93                 .id             = -1,
  94                 .parent         = &clk_h,
  95                 .enable         = s3c2410_clkcon_enable,
  96                 .ctrlbit        = S3C2410_CLKCON_NAND,
  97         }, {
  98                 .name           = "sdi",
  99                 .id             = -1,
 100                 .parent         = &clk_p,
 101                 .enable         = s3c2410_clkcon_enable,
 102                 .ctrlbit        = S3C2410_CLKCON_SDI,
 103         }, {
 104                 .name           = "adc",
 105                 .id             = -1,
 106                 .parent         = &clk_p,
 107                 .enable         = s3c2410_clkcon_enable,
 108                 .ctrlbit        = S3C2410_CLKCON_ADC,
 109         }, {
 110                 .name           = "i2c",
 111                 .id             = -1,
 112                 .parent         = &clk_p,
 113                 .enable         = s3c2410_clkcon_enable,
 114                 .ctrlbit        = S3C2410_CLKCON_IIC,
 115         }, {
 116                 .name           = "iis",
 117                 .id             = -1,
 118                 .parent         = &clk_p,
 119                 .enable         = s3c2410_clkcon_enable,
 120                 .ctrlbit        = S3C2410_CLKCON_IIS,
 121         }, {
 122                 .name           = "spi",
 123                 .id             = -1,
 124                 .parent         = &clk_p,
 125                 .enable         = s3c2410_clkcon_enable,
 126                 .ctrlbit        = S3C2410_CLKCON_SPI,
 127         }
 128 };
 129
 130 static struct clk init_clocks[] = {
 131         {
 132                 .name           = "lcd",
 133                 .id             = -1,
 134                 .parent         = &clk_h,
 135                 .enable         = s3c2410_clkcon_enable,
 136                 .ctrlbit        = S3C2410_CLKCON_LCDC,
 137         }, {
 138                 .name           = "gpio",
 139                 .id             = -1,
 140                 .parent         = &clk_p,
 141                 .enable         = s3c2410_clkcon_enable,
 142                 .ctrlbit        = S3C2410_CLKCON_GPIO,
 143         }, {
 144                 .name           = "usb-host",
 145                 .id             = -1,
 146                 .parent         = &clk_h,
 147                 .enable         = s3c2410_clkcon_enable,
 148                 .ctrlbit        = S3C2410_CLKCON_USBH,
 149         }, {
 150                 .name           = "usb-device",
 151                 .id             = -1,
 152                 .parent         = &clk_h,
 153                 .enable         = s3c2410_clkcon_enable,
 154                 .ctrlbit        = S3C2410_CLKCON_USBD,
 155         }, {
 156                 .name           = "timers",
 157                 .id             = -1,
 158                 .parent         = &clk_p,
 159                 .enable         = s3c2410_clkcon_enable,
 160                 .ctrlbit        = S3C2410_CLKCON_PWMT,
 161         }, {
 162                 .name           = "uart",
 163                 .id             = 0,
 164                 .parent         = &clk_p,
 165                 .enable         = s3c2410_clkcon_enable,
 166                 .ctrlbit        = S3C2410_CLKCON_UART0,
 167         }, {
 168                 .name           = "uart",
 169                 .id             = 1,
 170                 .parent         = &clk_p,
 171                 .enable         = s3c2410_clkcon_enable,
 172                 .ctrlbit        = S3C2410_CLKCON_UART1,
 173         }, {
 174                 .name           = "uart",
 175                 .id             = 2,
 176                 .parent         = &clk_p,
 177                 .enable         = s3c2410_clkcon_enable,
 178                 .ctrlbit        = S3C2410_CLKCON_UART2,
 179         }, {
 180                 .name           = "rtc",
 181                 .id             = -1,
 182                 .parent         = &clk_p,
 183                 .enable         = s3c2410_clkcon_enable,
 184                 .ctrlbit        = S3C2410_CLKCON_RTC,
 185         }, {
 186                 .name           = "watchdog",
 187                 .id             = -1,
 188                 .parent         = &clk_p,
 189                 .ctrlbit        = 0,
 190         }, {
 191                 .name           = "usb-bus-host",
 192                 .id             = -1,
 193                 .parent         = &clk_usb_bus,
 194         }, {
 195                 .name           = "usb-bus-gadget",
 196                 .id             = -1,
 197                 .parent         = &clk_usb_bus,
 198         },
 199 };
 200
 201 /* s3c2410_baseclk_add()
 202  *
 203  * Add all the clocks used by the s3c2410 or compatible CPUs
 204  * such as the S3C2440 and S3C2442.
 205  *
 206  * We cannot use a system device as we are needed before any
 207  * of the init-calls that initialise the devices are actually
 208  * done.
 209 */
 210
 211 int __init s3c2410_baseclk_add(void)
 212 {
 213         unsigned long clkslow = __raw_readl(S3C2410_CLKSLOW);
 214         unsigned long clkcon  = __raw_readl(S3C2410_CLKCON);
 215         struct clk *clkp;
 216         struct clk *xtal;
 217         int ret;
 218         int ptr;
 219
 220         clk_upll.enable = s3c2410_upll_enable;
 221
 222         if (s3c24xx_register_clock(&clk_usb_bus) < 0)
 223                 printk(KERN_ERR "failed to register usb bus clock\n");
 224
 225         /* register clocks from clock array */
 226
 227         clkp = init_clocks;
 228         for (ptr = 0; ptr < ARRAY_SIZE(init_clocks); ptr++, clkp++) {
 229                 /* ensure that we note the clock state */
 230
 231                 clkp->usage = clkcon & clkp->ctrlbit ? 1 : 0;
 232
 233                 ret = s3c24xx_register_clock(clkp);
 234                 if (ret < 0) {
 235                         printk(KERN_ERR "Failed to register clock %s (%d)\n",
 236                                clkp->name, ret);
 237                 }
 238         }
 239
 240         /* We must be careful disabling the clocks we are not intending to
 241          * be using at boot time, as subsytems such as the LCD which do
 242          * their own DMA requests to the bus can cause the system to lockup
 243          * if they where in the middle of requesting bus access.
 244          *
 245          * Disabling the LCD clock if the LCD is active is very dangerous,
 246          * and therefore the bootloader should be careful to not enable
 247          * the LCD clock if it is not needed.
 248         */
 249
 250         /* install (and disable) the clocks we do not need immediately */
 251
 252         clkp = init_clocks_disable;
 253         for (ptr = 0; ptr < ARRAY_SIZE(init_clocks_disable); ptr++, clkp++) {
 254
 255                 ret = s3c24xx_register_clock(clkp);
 256                 if (ret < 0) {
 257                         printk(KERN_ERR "Failed to register clock %s (%d)\n",
 258                                clkp->name, ret);
 259                 }
 260
 261                 s3c2410_clkcon_enable(clkp, 0);
 262         }
 263
 264         /* show the clock-slow value */
 265
 266         xtal = clk_get(NULL, "xtal");
 267
 268         printk("CLOCK: Slow mode (%ld.%ld MHz), %s, MPLL %s, UPLL %s\n",
 269                print_mhz(clk_get_rate(xtal) /
 270                          ( 2 * S3C2410_CLKSLOW_GET_SLOWVAL(clkslow))),
 271                (clkslow & S3C2410_CLKSLOW_SLOW) ? "slow" : "fast",
 272                (clkslow & S3C2410_CLKSLOW_MPLL_OFF) ? "off" : "on",
 273                (clkslow & S3C2410_CLKSLOW_UCLK_OFF) ? "off" : "on");
 274
 275         return 0;
 276 }