int __init init_cyclone_clock(void)
 {
-       u64* reg;
+       u64 __iomem *reg;
        u64 base;       /* saved cyclone base address */
        u64 offset;     /* offset from pageaddr to cyclone_timer register */
        int i;
-       u32* volatile cyclone_timer;    /* Cyclone MPMC0 register */
+       u32 __iomem *cyclone_timer;     /* Cyclone MPMC0 register */
 
        if (!use_cyclone)
                return 0;
 
        /* find base address */
        offset = (CYCLONE_CBAR_ADDR);
-       reg = (u64*)ioremap_nocache(offset, sizeof(u64));
+       reg = ioremap_nocache(offset, sizeof(u64));
        if(!reg){
                printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
                                " register.\n");
 
        /* setup PMCC */
        offset = (base + CYCLONE_PMCC_OFFSET);
-       reg = (u64*)ioremap_nocache(offset, sizeof(u64));
+       reg = ioremap_nocache(offset, sizeof(u64));
        if(!reg){
                printk(KERN_ERR "Summit chipset: Could not find valid PMCC"
                                " register.\n");
 
        /* setup MPCS */
        offset = (base + CYCLONE_MPCS_OFFSET);
-       reg = (u64*)ioremap_nocache(offset, sizeof(u64));
+       reg = ioremap_nocache(offset, sizeof(u64));
        if(!reg){
                printk(KERN_ERR "Summit chipset: Could not find valid MPCS"
                                " register.\n");
 
        /* map in cyclone_timer */
        offset = (base + CYCLONE_MPMC_OFFSET);
-       cyclone_timer = (u32*)ioremap_nocache(offset, sizeof(u32));
+       cyclone_timer = ioremap_nocache(offset, sizeof(u32));
        if(!cyclone_timer){
                printk(KERN_ERR "Summit chipset: Could not find valid MPMC"
                                " register.\n");
                        printk(KERN_ERR "Summit chipset: Counter not counting!"
                                        " DISABLED\n");
                        iounmap(cyclone_timer);
-                       cyclone_timer = 0;
+                       cyclone_timer = NULL;
                        use_cyclone = 0;
                        return -ENODEV;
                }