This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / arch / arm / mach-s3c2410 / s3c2412-clock.c
diff --git a/arch/arm/mach-s3c2410/s3c2412-clock.c b/arch/arm/mach-s3c2410/s3c2412-clock.c
new file mode 100644 (file)
index 0000000..c95ed3e
--- /dev/null
@@ -0,0 +1,711 @@
+/* linux/arch/arm/mach-s3c2410/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 <asm/hardware.h>
+#include <asm/io.h>
+
+#include <asm/arch/regs-clock.h>
+#include <asm/arch/regs-gpio.h>
+
+#include "clock.h"
+#include "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
+*/
+
+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;
+};
+
+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 */
+
+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;
+}