1 files changed, 716 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c2412/clock.c b/arch/arm/mach-s3c2412/clock.c
new file mode 100644
index 000000000000..6a8e4448770b
--- /dev/null
+++ b/arch/arm/mach-s3c2412/clock.c
@@ -0,0 +1,716 @@
+/* linux/arch/arm/mach-s3c2412/clock.c
+ *
+ * Copyright (c) 2006 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2412,S3C2413 Clock control support
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/sysdev.h>
+#include <linux/clk.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/serial_core.h>
+
+#include <asm/mach/map.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+
+#include <asm/arch/regs-serial.h>
+#include <asm/arch/regs-clock.h>
+#include <asm/arch/regs-gpio.h>
+
+#include <asm/plat-s3c24xx/s3c2412.h>
+#include <asm/plat-s3c24xx/clock.h>
+#include <asm/plat-s3c24xx/cpu.h>
+
+/* We currently have to assume that the system is running
+ * from the XTPll input, and that all ***REFCLKs are being
+ * fed from it, as we cannot read the state of OM[4] from
+ * software.
+ *
+ * It would be possible for each board initialisation to
+ * set the correct muxing at initialisation
+*/
+
+static int s3c2412_clkcon_enable(struct clk *clk, int enable)
+{
+        unsigned int clocks = clk->ctrlbit;
+        unsigned long clkcon;
+
+        clkcon = __raw_readl(S3C2410_CLKCON);
+
+        if (enable)
+                clkcon |= clocks;
+        else
+                clkcon &= ~clocks;
+
+        __raw_writel(clkcon, S3C2410_CLKCON);
+
+        return 0;
+}
+
+static int s3c2412_upll_enable(struct clk *clk, int enable)
+{
+        unsigned long upllcon = __raw_readl(S3C2410_UPLLCON);
+        unsigned long orig = upllcon;
+
+        if (!enable)
+                upllcon |= S3C2412_PLLCON_OFF;
+        else
+                upllcon &= ~S3C2412_PLLCON_OFF;
+
+        __raw_writel(upllcon, S3C2410_UPLLCON);
+
+        /* allow ~150uS for the PLL to settle and lock */
+
+        if (enable && (orig & S3C2412_PLLCON_OFF))
+                udelay(150);
+
+        return 0;
+}
+
+/* clock selections */
+
+/* CPU EXTCLK input */
+static struct clk clk_ext = {
+        .name           = "extclk",
+        .id             = -1,
+};
+
+static struct clk clk_erefclk = {
+        .name           = "erefclk",
+        .id             = -1,
+};
+
+static struct clk clk_urefclk = {
+        .name           = "urefclk",
+        .id             = -1,
+};
+
+static int s3c2412_setparent_usysclk(struct clk *clk, struct clk *parent)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+
+        if (parent == &clk_urefclk)
+                clksrc &= ~S3C2412_CLKSRC_USYSCLK_UPLL;
+        else if (parent == &clk_upll)
+                clksrc |= S3C2412_CLKSRC_USYSCLK_UPLL;
+        else
+                return -EINVAL;
+
+        clk->parent = parent;
+
+        __raw_writel(clksrc, S3C2412_CLKSRC);
+        return 0;
+}
+
+static struct clk clk_usysclk = {
+        .name           = "usysclk",
+        .id             = -1,
+        .parent         = &clk_xtal,
+        .set_parent     = s3c2412_setparent_usysclk,
+};
+
+static struct clk clk_mrefclk = {
+        .name           = "mrefclk",
+        .parent         = &clk_xtal,
+        .id             = -1,
+};
+
+static struct clk clk_mdivclk = {
+        .name           = "mdivclk",
+        .parent         = &clk_xtal,
+        .id             = -1,
+};
+
+static int s3c2412_setparent_usbsrc(struct clk *clk, struct clk *parent)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+
+        if (parent == &clk_usysclk)
+                clksrc &= ~S3C2412_CLKSRC_USBCLK_HCLK;
+        else if (parent == &clk_h)
+                clksrc |= S3C2412_CLKSRC_USBCLK_HCLK;
+        else
+                return -EINVAL;
+
+        clk->parent = parent;
+
+        __raw_writel(clksrc, S3C2412_CLKSRC);
+        return 0;
+}
+
+static unsigned long s3c2412_roundrate_usbsrc(struct clk *clk,
+                                              unsigned long rate)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        int div;
+
+        if (rate > parent_rate)
+                return parent_rate;
+
+        div = parent_rate / rate;
+        if (div > 2)
+                div = 2;
+
+        return parent_rate / div;
+}
+
+static unsigned long s3c2412_getrate_usbsrc(struct clk *clk)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long div = __raw_readl(S3C2410_CLKDIVN);
+
+        return parent_rate / ((div & S3C2412_CLKDIVN_USB48DIV) ? 2 : 1);
+}
+
+static int s3c2412_setrate_usbsrc(struct clk *clk, unsigned long rate)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long clkdivn = __raw_readl(S3C2410_CLKDIVN);
+
+        rate = s3c2412_roundrate_usbsrc(clk, rate);
+
+        if ((parent_rate / rate) == 2)
+                clkdivn |= S3C2412_CLKDIVN_USB48DIV;
+        else
+                clkdivn &= ~S3C2412_CLKDIVN_USB48DIV;
+
+        __raw_writel(clkdivn, S3C2410_CLKDIVN);
+        return 0;
+}
+
+static struct clk clk_usbsrc = {
+        .name           = "usbsrc",
+        .id             = -1,
+        .get_rate       = s3c2412_getrate_usbsrc,
+        .set_rate       = s3c2412_setrate_usbsrc,
+        .round_rate     = s3c2412_roundrate_usbsrc,
+        .set_parent     = s3c2412_setparent_usbsrc,
+};
+
+static int s3c2412_setparent_msysclk(struct clk *clk, struct clk *parent)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+
+        if (parent == &clk_mdivclk)
+                clksrc &= ~S3C2412_CLKSRC_MSYSCLK_MPLL;
+        else if (parent == &clk_upll)
+                clksrc |= S3C2412_CLKSRC_MSYSCLK_MPLL;
+        else
+                return -EINVAL;
+
+        clk->parent = parent;
+
+        __raw_writel(clksrc, S3C2412_CLKSRC);
+        return 0;
+}
+
+static struct clk clk_msysclk = {
+        .name           = "msysclk",
+        .id             = -1,
+        .set_parent     = s3c2412_setparent_msysclk,
+};
+
+/* these next clocks have an divider immediately after them,
+ * so we can register them with their divider and leave out the
+ * intermediate clock stage
+*/
+static unsigned long s3c2412_roundrate_clksrc(struct clk *clk,
+                                              unsigned long rate)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        int div;
+
+        if (rate > parent_rate)
+                return parent_rate;
+
+        /* note, we remove the +/- 1 calculations as they cancel out */
+
+        div = (rate / parent_rate);
+
+        if (div < 1)
+                div = 1;
+        else if (div > 16)
+                div = 16;
+
+        return parent_rate / div;
+}
+
+static int s3c2412_setparent_uart(struct clk *clk, struct clk *parent)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+
+        if (parent == &clk_erefclk)
+                clksrc &= ~S3C2412_CLKSRC_UARTCLK_MPLL;
+        else if (parent == &clk_mpll)
+                clksrc |= S3C2412_CLKSRC_UARTCLK_MPLL;
+        else
+                return -EINVAL;
+
+        clk->parent = parent;
+
+        __raw_writel(clksrc, S3C2412_CLKSRC);
+        return 0;
+}
+
+static unsigned long s3c2412_getrate_uart(struct clk *clk)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long div = __raw_readl(S3C2410_CLKDIVN);
+
+        div &= S3C2412_CLKDIVN_UARTDIV_MASK;
+        div >>= S3C2412_CLKDIVN_UARTDIV_SHIFT;
+
+        return parent_rate / (div + 1);
+}
+
+static int s3c2412_setrate_uart(struct clk *clk, unsigned long rate)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long clkdivn = __raw_readl(S3C2410_CLKDIVN);
+
+        rate = s3c2412_roundrate_clksrc(clk, rate);
+
+        clkdivn &= ~S3C2412_CLKDIVN_UARTDIV_MASK;
+        clkdivn |= ((parent_rate / rate) - 1) << S3C2412_CLKDIVN_UARTDIV_SHIFT;
+
+        __raw_writel(clkdivn, S3C2410_CLKDIVN);
+        return 0;
+}
+
+static struct clk clk_uart = {
+        .name           = "uartclk",
+        .id             = -1,
+        .get_rate       = s3c2412_getrate_uart,
+        .set_rate       = s3c2412_setrate_uart,
+        .set_parent     = s3c2412_setparent_uart,
+        .round_rate     = s3c2412_roundrate_clksrc,
+};
+
+static int s3c2412_setparent_i2s(struct clk *clk, struct clk *parent)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+
+        if (parent == &clk_erefclk)
+                clksrc &= ~S3C2412_CLKSRC_I2SCLK_MPLL;
+        else if (parent == &clk_mpll)
+                clksrc |= S3C2412_CLKSRC_I2SCLK_MPLL;
+        else
+                return -EINVAL;
+
+        clk->parent = parent;
+
+        __raw_writel(clksrc, S3C2412_CLKSRC);
+        return 0;
+}
+
+static unsigned long s3c2412_getrate_i2s(struct clk *clk)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long div = __raw_readl(S3C2410_CLKDIVN);
+
+        div &= S3C2412_CLKDIVN_I2SDIV_MASK;
+        div >>= S3C2412_CLKDIVN_I2SDIV_SHIFT;
+
+        return parent_rate / (div + 1);
+}
+
+static int s3c2412_setrate_i2s(struct clk *clk, unsigned long rate)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long clkdivn = __raw_readl(S3C2410_CLKDIVN);
+
+        rate = s3c2412_roundrate_clksrc(clk, rate);
+
+        clkdivn &= ~S3C2412_CLKDIVN_I2SDIV_MASK;
+        clkdivn |= ((parent_rate / rate) - 1) << S3C2412_CLKDIVN_I2SDIV_SHIFT;
+
+        __raw_writel(clkdivn, S3C2410_CLKDIVN);
+        return 0;
+}
+
+static struct clk clk_i2s = {
+        .name           = "i2sclk",
+        .id             = -1,
+        .get_rate       = s3c2412_getrate_i2s,
+        .set_rate       = s3c2412_setrate_i2s,
+        .set_parent     = s3c2412_setparent_i2s,
+        .round_rate     = s3c2412_roundrate_clksrc,
+};
+
+static int s3c2412_setparent_cam(struct clk *clk, struct clk *parent)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+
+        if (parent == &clk_usysclk)
+                clksrc &= ~S3C2412_CLKSRC_CAMCLK_HCLK;
+        else if (parent == &clk_h)
+                clksrc |= S3C2412_CLKSRC_CAMCLK_HCLK;
+        else
+                return -EINVAL;
+
+        clk->parent = parent;
+
+        __raw_writel(clksrc, S3C2412_CLKSRC);
+        return 0;
+}
+static unsigned long s3c2412_getrate_cam(struct clk *clk)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long div = __raw_readl(S3C2410_CLKDIVN);
+
+        div &= S3C2412_CLKDIVN_CAMDIV_MASK;
+        div >>= S3C2412_CLKDIVN_CAMDIV_SHIFT;
+
+        return parent_rate / (div + 1);
+}
+
+static int s3c2412_setrate_cam(struct clk *clk, unsigned long rate)
+{
+        unsigned long parent_rate = clk_get_rate(clk->parent);
+        unsigned long clkdivn = __raw_readl(S3C2410_CLKDIVN);
+
+        rate = s3c2412_roundrate_clksrc(clk, rate);
+
+        clkdivn &= ~S3C2412_CLKDIVN_CAMDIV_MASK;
+        clkdivn |= ((parent_rate / rate) - 1) << S3C2412_CLKDIVN_CAMDIV_SHIFT;
+
+        __raw_writel(clkdivn, S3C2410_CLKDIVN);
+        return 0;
+}
+
+static struct clk clk_cam = {
+        .name           = "camif-upll", /* same as 2440 name */
+        .id             = -1,
+        .get_rate       = s3c2412_getrate_cam,
+        .set_rate       = s3c2412_setrate_cam,
+        .set_parent     = s3c2412_setparent_cam,
+        .round_rate     = s3c2412_roundrate_clksrc,
+};
+
+/* standard clock definitions */
+
+static struct clk init_clocks_disable[] = {
+        {
+                .name           = "nand",
+                .id             = -1,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_NAND,
+        }, {
+                .name           = "sdi",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_SDI,
+        }, {
+                .name           = "adc",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_ADC,
+        }, {
+                .name           = "i2c",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_IIC,
+        }, {
+                .name           = "iis",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_IIS,
+        }, {
+                .name           = "spi",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_SPI,
+        }
+};
+
+static struct clk init_clocks[] = {
+        {
+                .name           = "dma",
+                .id             = 0,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_DMA0,
+        }, {
+                .name           = "dma",
+                .id             = 1,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_DMA1,
+        }, {
+                .name           = "dma",
+                .id             = 2,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_DMA2,
+        }, {
+                .name           = "dma",
+                .id             = 3,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_DMA3,
+        }, {
+                .name           = "lcd",
+                .id             = -1,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_LCDC,
+        }, {
+                .name           = "gpio",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_GPIO,
+        }, {
+                .name           = "usb-host",
+                .id             = -1,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_USBH,
+        }, {
+                .name           = "usb-device",
+                .id             = -1,
+                .parent         = &clk_h,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_USBD,
+        }, {
+                .name           = "timers",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_PWMT,
+        }, {
+                .name           = "uart",
+                .id             = 0,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_UART0,
+        }, {
+                .name           = "uart",
+                .id             = 1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_UART1,
+        }, {
+                .name           = "uart",
+                .id             = 2,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_UART2,
+        }, {
+                .name           = "rtc",
+                .id             = -1,
+                .parent         = &clk_p,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_RTC,
+        }, {
+                .name           = "watchdog",
+                .id             = -1,
+                .parent         = &clk_p,
+                .ctrlbit        = 0,
+        }, {
+                .name           = "usb-bus-gadget",
+                .id             = -1,
+                .parent         = &clk_usb_bus,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_USB_DEV48,
+        }, {
+                .name           = "usb-bus-host",
+                .id             = -1,
+                .parent         = &clk_usb_bus,
+                .enable         = s3c2412_clkcon_enable,
+                .ctrlbit        = S3C2412_CLKCON_USB_HOST48,
+        }
+};
+
+/* clocks to add where we need to check their parentage */
+
+struct clk_init {
+        struct clk      *clk;
+        unsigned int     bit;
+        struct clk      *src_0;
+        struct clk      *src_1;
+};
+
+static struct clk_init clks_src[] __initdata = {
+        {
+                .clk    = &clk_usysclk,
+                .bit    = S3C2412_CLKSRC_USBCLK_HCLK,
+                .src_0  = &clk_urefclk,
+                .src_1  = &clk_upll,
+        }, {
+                .clk    = &clk_i2s,
+                .bit    = S3C2412_CLKSRC_I2SCLK_MPLL,
+                .src_0  = &clk_erefclk,
+                .src_1  = &clk_mpll,
+        }, {
+                .clk    = &clk_cam,
+                .bit    = S3C2412_CLKSRC_CAMCLK_HCLK,
+                .src_0  = &clk_usysclk,
+                .src_1  = &clk_h,
+        }, {
+                .clk    = &clk_msysclk,
+                .bit    = S3C2412_CLKSRC_MSYSCLK_MPLL,
+                .src_0  = &clk_mdivclk,
+                .src_1  = &clk_mpll,
+        }, {
+                .clk    = &clk_uart,
+                .bit    = S3C2412_CLKSRC_UARTCLK_MPLL,
+                .src_0  = &clk_erefclk,
+                .src_1  = &clk_mpll,
+        }, {
+                .clk    = &clk_usbsrc,
+                .bit    = S3C2412_CLKSRC_USBCLK_HCLK,
+                .src_0  = &clk_usysclk,
+                .src_1  = &clk_h,
+        },
+};
+
+/* s3c2412_clk_initparents
+ *
+ * Initialise the parents for the clocks that we get at start-time
+*/
+
+static void __init s3c2412_clk_initparents(void)
+{
+        unsigned long clksrc = __raw_readl(S3C2412_CLKSRC);
+        struct clk_init *cip = clks_src;
+        struct clk *src;
+        int ptr;
+        int ret;
+
+        for (ptr = 0; ptr < ARRAY_SIZE(clks_src); ptr++, cip++) {
+                ret = s3c24xx_register_clock(cip->clk);
+                if (ret < 0) {
+                        printk(KERN_ERR "Failed to register clock %s (%d)\n",
+                               cip->clk->name, ret);
+                }
+
+                src = (clksrc & cip->bit) ? cip->src_1 : cip->src_0;
+
+                printk(KERN_INFO "%s: parent %s\n", cip->clk->name, src->name);
+                clk_set_parent(cip->clk, src);
+        }
+}
+
+/* clocks to add straight away */
+
+static struct clk *clks[] __initdata = {
+        &clk_ext,
+        &clk_usb_bus,
+        &clk_erefclk,
+        &clk_urefclk,
+        &clk_mrefclk,
+};
+
+int __init s3c2412_baseclk_add(void)
+{
+        unsigned long clkcon  = __raw_readl(S3C2410_CLKCON);
+        struct clk *clkp;
+        int ret;
+        int ptr;
+
+        clk_upll.enable = s3c2412_upll_enable;
+        clk_usb_bus.parent = &clk_usbsrc;
+        clk_usb_bus.rate = 0x0;
+
+        s3c2412_clk_initparents();
+
+        for (ptr = 0; ptr < ARRAY_SIZE(clks); ptr++) {
+                clkp = clks[ptr];
+
+                ret = s3c24xx_register_clock(clkp);
+                if (ret < 0) {
+                        printk(KERN_ERR "Failed to register clock %s (%d)\n",
+                               clkp->name, ret);
+                }
+        }
+
+        /* ensure usb bus clock is within correct rate of 48MHz */
+
+        if (clk_get_rate(&clk_usb_bus) != (48 * 1000 * 1000)) {
+                printk(KERN_INFO "Warning: USB bus clock not at 48MHz\n");
+
+                /* for the moment, let's use the UPLL, and see if we can
+                 * get 48MHz */
+
+                clk_set_parent(&clk_usysclk, &clk_upll);
+                clk_set_parent(&clk_usbsrc, &clk_usysclk);
+                clk_set_rate(&clk_usbsrc, 48*1000*1000);
+        }
+
+        printk("S3C2412: upll %s, %ld.%03ld MHz, usb-bus %ld.%03ld MHz\n",
+               (__raw_readl(S3C2410_UPLLCON) & S3C2412_PLLCON_OFF) ? "off":"on",
+               print_mhz(clk_get_rate(&clk_upll)),
+               print_mhz(clk_get_rate(&clk_usb_bus)));
+
+        /* register clocks from clock array */
+
+        clkp = init_clocks;
+        for (ptr = 0; ptr < ARRAY_SIZE(init_clocks); ptr++, clkp++) {
+                /* ensure that we note the clock state */
+
+                clkp->usage = clkcon & clkp->ctrlbit ? 1 : 0;
+
+                ret = s3c24xx_register_clock(clkp);
+                if (ret < 0) {
+                        printk(KERN_ERR "Failed to register clock %s (%d)\n",
+                               clkp->name, ret);
+                }
+        }
+
+        /* We must be careful disabling the clocks we are not intending to
+         * be using at boot time, as subsytems such as the LCD which do
+         * their own DMA requests to the bus can cause the system to lockup
+         * if they where in the middle of requesting bus access.
+         *
+         * Disabling the LCD clock if the LCD is active is very dangerous,
+         * and therefore the bootloader should be careful to not enable
+         * the LCD clock if it is not needed.
+        */
+
+        /* install (and disable) the clocks we do not need immediately */
+
+        clkp = init_clocks_disable;
+        for (ptr = 0; ptr < ARRAY_SIZE(init_clocks_disable); ptr++, clkp++) {
+
+                ret = s3c24xx_register_clock(clkp);
+                if (ret < 0) {
+                        printk(KERN_ERR "Failed to register clock %s (%d)\n",
+                               clkp->name, ret);
+                }
+
+                s3c2412_clkcon_enable(clkp, 0);
+        }
+
+        return 0;
+}