diff -Nur c3000_pre/linux/arch/arm/config.in c3000_work/linux/arch/arm/config.in
--- c3000_pre/linux/arch/arm/config.in	2004-12-03 21:22:15.000000000 +0900
+++ linux/arch/arm/config.in	2004-12-03 20:34:56.000000000 +0900
@@ -478,6 +478,9 @@
    if [ "$CONFIG_ARCH_PXA_SPITZ" = "y" ]; then
       bool 'Use clock change(cccr_change) enable (EXPERIMENTAL)' CONFIG_SL_CCCR_CHANGE
    fi
+   if [ "$CONFIG_SL_CCCR_CHANGE" = "y" ]; then
+      bool 'Core voltage change enable (EXPERIMENTAL)' CONFIG_CHANGE_CORE_VOLT
+   fi
    if [ "$CONFIG_ARCH_SHARP_SL" = "y" ]; then
       define_bool CONFIG_BATT y
    fi
diff -Nur c3000_pre/linux/arch/arm/mach-pxa/pxa27x_power.c c3000_work/linux/arch/arm/mach-pxa/pxa27x_power.c
--- c3000_pre/linux/arch/arm/mach-pxa/pxa27x_power.c	2004-11-04 14:13:54.000000000 +0900
+++ linux/arch/arm/mach-pxa/pxa27x_power.c	2004-12-03 21:02:07.000000000 +0900
@@ -324,7 +324,7 @@
   return -1;
 }
 
-#ifdef DEBUG
+#if defined(DEBUG) || defined(CONFIG_CHANGE_CORE_VOLT)
 int pwr_i2c_read( unsigned char device, unsigned char *value )
 {
   unsigned long	r;
@@ -409,8 +409,8 @@
   pwr_i2c_close();
 }
 
-#ifdef DEBUG
-static unsigned char cpu_xscale_voltage_read(void)
+#if defined(DEBUG) || defined(CONFIG_CHANGE_CORE_VOLT)
+unsigned char cpu_xscale_voltage_read(void)
 {
   unsigned char value=0xff;
   pwr_i2c_open();
@@ -419,6 +419,16 @@
   return value;
 }
 
+void cpu_xscale_voltage_write(unsigned char value)
+{
+  if (value > 0x10 )
+    return;
+  value += 0x10;
+  pwr_i2c_open();
+  pwr_i2c_write( 0x0c, value );
+  pwr_i2c_close();
+}
+
 #define CLKCFG(a)	asm("mrc p14, 0, %0, C6, C0, 0" : "=r"(a))
 static void __debug_printk(void)
 {
diff -Nur c3000_pre/linux/arch/arm/mach-pxa/sharpsl_apm.c c3000_work/linux/arch/arm/mach-pxa/sharpsl_apm.c
--- c3000_pre/linux/arch/arm/mach-pxa/sharpsl_apm.c	2004-12-03 21:22:15.000000000 +0900
+++ linux/arch/arm/mach-pxa/sharpsl_apm.c	2004-12-03 21:06:20.000000000 +0900
@@ -135,6 +135,11 @@
 struct proc_dir_entry *proc_zaurus;
 #endif
 
+#if defined(CONFIG_CHANGE_CORE_VOLT)
+extern unsigned char cpu_xscale_voltage_read(void);
+extern void cpu_xscale_voltage_write(unsigned char);
+#endif
+
 #if defined(CONFIG_SABINAL_DISCOVERY)
 #define SHARPSL_AC_LINE_STATUS (( ASIC3_GPIO_PSTS_D & AC_IN )? APM_AC_OFFLINE : APM_AC_ONLINE)
 #define BACKPACK_IN_DETECT()	( ASIC3_GPIO_PSTS_D & BACKPACK_DETECT ) /* 0: exist , 1: not in */
@@ -1022,6 +1027,44 @@
 };
 #endif
 
+#if defined(CONFIG_CHANGE_CORE_VOLT)
+static ssize_t core_volt_read_params(struct file *file, char *buf,
+				       size_t nbytes, loff_t *ppos)
+{
+        char outputbuf[32];
+	int count;
+	
+	if (*ppos>0) /* Assume reading completed in previous read*/
+	        return 0;
+	count = sprintf(outputbuf, "0x%02X\n", (unsigned int) cpu_xscale_voltage_read() );
+	count++;
+	*ppos += count;
+	if (count>nbytes)/* Assume output can be read at one time */
+	        return -EINVAL;
+	if (copy_to_user(buf, outputbuf, count+1))
+	        return -EFAULT;
+	return count;
+}
+
+static ssize_t core_volt_write_params(struct file *file, const char *buf,
+					size_t nbytes, loff_t *ppos)
+{
+        unsigned int param=0;
+    
+	sscanf(buf,"%x",&param);
+	if (param) {
+	        printk("Change Core voltage = %x.\n", param);
+		cpu_xscale_voltage_write(param);
+	}
+	return nbytes;
+}
+
+static struct file_operations proc_core_volt_params_operations = {
+        read:core_volt_read_params,
+        write:core_volt_write_params,
+};
+#endif
+
 #ifdef CONFIG_APM_CPU_IDLE
 #ifdef SHARPSL_NEW_IDLE
 static int save_icmr;
@@ -2835,6 +2878,7 @@
 	struct proc_dir_entry *lock_fcs_proc;
 	struct proc_dir_entry *power_mode_proc;
 	struct proc_dir_entry *cccr_change_proc;
+	struct proc_dir_entry *core_volt_proc;
 
 	apm_info.bios = apm_bios_info;
 	if (apm_info.bios.version == 0) {
@@ -2967,6 +3011,14 @@
 	        cccr_change_proc->proc_fops = &proc_cccr_change_params_operations;
 	}
 #endif
+
+#if defined(CONFIG_CHANGE_CORE_VOLT)
+	core_volt_proc = create_proc_entry("zaurus/CoreVolt", 0, NULL);
+	if (core_volt_proc) {
+	        core_volt_proc->proc_fops = &proc_core_volt_params_operations;
+	}
+#endif
+
 	kernel_thread(apm_thread, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD);
   	
 #if defined(CONFIG_SABINAL_DISCOVERY) || defined(CONFIG_ARCH_PXA_TOSA)