Linux/AM3354: ioremap segfault on hardware registers which are used by unknown process

Part Number: AM3354

Tool/software: Linux

I'm still trying to gain access to MCSPI0-registers on the BeagleBone Black Wireless mapped at 0x4800_0000->0x4800_0FFF

With loadable kernel module, i try to request_mem_region, and use ioremap() after. request_mem_region returns NULL, and forcing through ioremap() gives segmentation fault.

#include <linux/init.h>             // Macros used to mark up functions e.g., __init __exit
#include <linux/module.h>           // Core header for loading LKMs into the kernel
#include <linux/kernel.h>           // Contains types, macros, functions for the kernel
#include <linux/version.h>
#include <linux/ioport.h>
#include <asm/io.h>
MODULE_LICENSE("GPL");              ///< The license type -- this affects runtime behavior
MODULE_AUTHOR("Derek Molloy");      ///< The author -- visible when you use modinfo
MODULE_DESCRIPTION("A simple Linux driver for the BBB.");  ///< The description -- see modinfo
MODULE_VERSION("0.1");              ///< The version of the module
#define DRIVER_NAME     "TEST"
#define MCSPI0_START    0x48030000
#define MCSPI0_SIZE     0xFFF
static char *name =     "world";        ///< An example LKM argument -- default value is "world"
void *regs;
long unsigned int int_reg;
module_param(name, charp, S_IRUGO); ///< Param desc. charp = char ptr, S_IRUGO can be read/not changed
MODULE_PARM_DESC(name, "The name to display in /var/log/kern.log");  ///< parameter description
/** @brief The LKM initialization function
 *  The static keyword restricts the visibility of the function to within this C file. The __init
 *  macro means that for a built-in driver (not a LKM) the function is only used at initialization
 *  time and that it can be discarded and its memory freed up after that point.
 *  @return returns 0 if successful
 */
static void __exit helloBBB_exit(void){
   printk(KERN_INFO "EBB: Goodbye %s from the BBB LKM!\n", name);
}
static int request_memory(void)
{
        if (request_mem_region( MCSPI0_START,MCSPI0_SIZE, DRIVER_NAME ) == NULL)
        {
                printk(KERN_INFO "Could not reserve memory\n");
                return 1;
        } 
        return 1;
}

static int testfun(void)
{
        //printk(KERN_INFO "testRead: %d from regs!\n", (int)int_reg);
        return 0;
}


static int __init helloBBB_init(void){
        printk(KERN_INFO "EBB: Hello %s from the BBB LKM!\n", name);
        if (request_memory() != 0)
        {
        regs = ioremap(0x48030000, 0xFFF);
        int_reg = ioread8(regs);
        testfun();
        }
   return 0;
}


module_init(helloBBB_init);
module_exit(helloBBB_exit);

cat /proc/iomem | grep spi:

48030000-480303ff : /ocp/spi@48030000

Is there any way for me to shut down the process occupying hardware registers to gain access? Have I missed something?