arch/arm/mach-s3c24xx/clock-s3c2443.c

   1 /* linux/arch/arm/mach-s3c2443/clock.c
   2  *
   3  * Copyright (c) 2007, 2010 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2443 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
  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/clk.h>
  32 #include <linux/mutex.h>
  33 #include <linux/serial_core.h>
  34 #include <linux/io.h>
  35
  36 #include <asm/mach/map.h>
  37
  38 #include <mach/hardware.h>
  39
  40 #include <mach/regs-s3c2443-clock.h>
  41
  42 #include <plat/cpu-freq.h>
  43
  44 #include <plat/clock.h>
  45 #include <plat/clock-clksrc.h>
  46 #include <plat/cpu.h>
  47
  48 /* We currently have to assume that the system is running
  49  * from the XTPll input, and that all ***REFCLKs are being
  50  * fed from it, as we cannot read the state of OM[4] from
  51  * software.
  52  *
  53  * It would be possible for each board initialisation to
  54  * set the correct muxing at initialisation
  55 */
  56
  57 /* clock selections */
  58
  59 /* armdiv
  60  *
  61  * this clock is sourced from msysclk and can have a number of
  62  * divider values applied to it to then be fed into armclk.
  63  * The real clock definition is done in s3c2443-clock.c,
  64  * only the armdiv divisor table must be defined here.
  65 */
  66
  67 static unsigned int armdiv[16] = {
  68         [S3C2443_CLKDIV0_ARMDIV_1 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]      = 1,
  69         [S3C2443_CLKDIV0_ARMDIV_2 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]      = 2,
  70         [S3C2443_CLKDIV0_ARMDIV_3 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]      = 3,
  71         [S3C2443_CLKDIV0_ARMDIV_4 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]      = 4,
  72         [S3C2443_CLKDIV0_ARMDIV_6 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]      = 6,
  73         [S3C2443_CLKDIV0_ARMDIV_8 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]      = 8,
  74         [S3C2443_CLKDIV0_ARMDIV_12 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]     = 12,
  75         [S3C2443_CLKDIV0_ARMDIV_16 >> S3C2443_CLKDIV0_ARMDIV_SHIFT]     = 16,
  76 };
  77
  78 /* hsspi
  79  *
  80  * high-speed spi clock, sourced from esysclk
  81 */
  82
  83 static struct clksrc_clk clk_hsspi = {
  84         .clk    = {
  85                 .name           = "hsspi-if",
  86                 .parent         = &clk_esysclk.clk,
  87                 .ctrlbit        = S3C2443_SCLKCON_HSSPICLK,
  88                 .enable         = s3c2443_clkcon_enable_s,
  89         },
  90         .reg_div = { .reg = S3C2443_CLKDIV1, .size = 2, .shift = 4 },
  91 };
  92
  93
  94 /* clk_hsmcc_div
  95  *
  96  * this clock is sourced from epll, and is fed through a divider,
  97  * to a mux controlled by sclkcon where either it or a extclk can
  98  * be fed to the hsmmc block
  99 */
 100
 101 static struct clksrc_clk clk_hsmmc_div = {
 102         .clk    = {
 103                 .name           = "hsmmc-div",
 104                 .devname        = "s3c-sdhci.1",
 105                 .parent         = &clk_esysclk.clk,
 106         },
 107         .reg_div = { .reg = S3C2443_CLKDIV1, .size = 2, .shift = 6 },
 108 };
 109
 110 static int s3c2443_setparent_hsmmc(struct clk *clk, struct clk *parent)
 111 {
 112         unsigned long clksrc = __raw_readl(S3C2443_SCLKCON);
 113
 114         clksrc &= ~(S3C2443_SCLKCON_HSMMCCLK_EXT |
 115                     S3C2443_SCLKCON_HSMMCCLK_EPLL);
 116
 117         if (parent == &clk_epll)
 118                 clksrc |= S3C2443_SCLKCON_HSMMCCLK_EPLL;
 119         else if (parent == &clk_ext)
 120                 clksrc |= S3C2443_SCLKCON_HSMMCCLK_EXT;
 121         else
 122                 return -EINVAL;
 123
 124         if (clk->usage > 0) {
 125                 __raw_writel(clksrc, S3C2443_SCLKCON);
 126         }
 127
 128         clk->parent = parent;
 129         return 0;
 130 }
 131
 132 static int s3c2443_enable_hsmmc(struct clk *clk, int enable)
 133 {
 134         return s3c2443_setparent_hsmmc(clk, clk->parent);
 135 }
 136
 137 static struct clk clk_hsmmc = {
 138         .name           = "hsmmc-if",
 139         .devname        = "s3c-sdhci.1",
 140         .parent         = &clk_hsmmc_div.clk,
 141         .enable         = s3c2443_enable_hsmmc,
 142         .ops            = &(struct clk_ops) {
 143                 .set_parent     = s3c2443_setparent_hsmmc,
 144         },
 145 };
 146
 147 /* standard clock definitions */
 148
 149 static struct clk init_clocks_off[] = {
 150         {
 151                 .name           = "sdi",
 152                 .parent         = &clk_p,
 153                 .enable         = s3c2443_clkcon_enable_p,
 154                 .ctrlbit        = S3C2443_PCLKCON_SDI,
 155         }, {
 156                 .name           = "spi",
 157                 .devname        = "s3c2410-spi.0",
 158                 .parent         = &clk_p,
 159                 .enable         = s3c2443_clkcon_enable_p,
 160                 .ctrlbit        = S3C2443_PCLKCON_SPI1,
 161         }
 162 };
 163
 164 /* clocks to add straight away */
 165
 166 static struct clksrc_clk *clksrcs[] __initdata = {
 167         &clk_hsspi,
 168         &clk_hsmmc_div,
 169 };
 170
 171 static struct clk *clks[] __initdata = {
 172         &clk_hsmmc,
 173 };
 174
 175 static struct clk_lookup s3c2443_clk_lookup[] = {
 176         CLKDEV_INIT("s3c-sdhci.1", "mmc_busclk.2", &clk_hsmmc),
 177         CLKDEV_INIT("s3c2443-spi.0", "spi_busclk2", &clk_hsspi.clk),
 178 };
 179
 180 void __init s3c2443_init_clocks(int xtal)
 181 {
 182         unsigned long epllcon = __raw_readl(S3C2443_EPLLCON);
 183         int ptr;
 184
 185         clk_epll.rate = s3c2443_get_epll(epllcon, xtal);
 186         clk_epll.parent = &clk_epllref.clk;
 187
 188         s3c2443_common_init_clocks(xtal, s3c2443_get_mpll,
 189                                    armdiv, ARRAY_SIZE(armdiv),
 190                                    S3C2443_CLKDIV0_ARMDIV_MASK);
 191
 192         s3c24xx_register_clocks(clks, ARRAY_SIZE(clks));
 193
 194         for (ptr = 0; ptr < ARRAY_SIZE(clksrcs); ptr++)
 195                 s3c_register_clksrc(clksrcs[ptr], 1);
 196
 197         /* We must be careful disabling the clocks we are not intending to
 198          * be using at boot time, as subsystems such as the LCD which do
 199          * their own DMA requests to the bus can cause the system to lockup
 200          * if they where in the middle of requesting bus access.
 201          *
 202          * Disabling the LCD clock if the LCD is active is very dangerous,
 203          * and therefore the bootloader should be careful to not enable
 204          * the LCD clock if it is not needed.
 205         */
 206
 207         /* install (and disable) the clocks we do not need immediately */
 208
 209         s3c_register_clocks(init_clocks_off, ARRAY_SIZE(init_clocks_off));
 210         s3c_disable_clocks(init_clocks_off, ARRAY_SIZE(init_clocks_off));
 211         clkdev_add_table(s3c2443_clk_lookup, ARRAY_SIZE(s3c2443_clk_lookup));
 212 }