为什么我这样点灯点不起来？

RK3328芯片手册

 #include <linux/init.h>
#include <linux/module.h>
#include <asm/io.h>
#include <linux/ioport.h>

#define GPIO2_BASE  0xFF230000
#define GPIO2_MEM_SIZE  0x00010000
#define GPIO2_DIR   (volatile unsigned long *)ioremap(GPIO2_BASE + 4, 4)
#define GPIO2_OUT   (volatile unsigned long *)ioremap(GPIO2_BASE + 0, 4)
MODULE_LICENSE("Dual BSD/GPL");
static int hello_init(void)
{
    unsigned int res;
    unsigned int set;

    printk(KERN_INFO "Hello, world\n");
    //request_mem_region(GPIO2_BASE, GPIO2_MEM_SIZE, "GPIO2_LED");

    res = __raw_readl(GPIO2_DIR);
    printk(KERN_INFO "Before set GPIO2_DIR value :%d\n", res);
    res = __raw_readl(GPIO2_OUT);
    printk(KERN_INFO "Before set GPIO2_OUT value :%d\n", res);

    //GPIO2_B7 output
    set = __raw_readl(GPIO2_DIR);
    set |= ~(1 << 23);
    set = 0;    //全out
    __raw_writel(set, GPIO2_DIR);

    //GPIO2_D2 = 1
    set = __raw_readl(GPIO2_OUT);
    set |= (1 << 23);
    set = 0xffffffff;   //全高电平
    __raw_writel(set, GPIO2_OUT);

    res = __raw_readl(GPIO2_DIR);
    printk(KERN_INFO "After set GPIO2_DIR value :%d\n", res);
    res = __raw_readl(GPIO2_OUT);
    printk(KERN_INFO "After set GPIO2_OUT value :%d\n", res);

//ERR:
    return 0;
}
static void hello_exit(void)
{
    printk(KERN_INFO "Goodbye, cruel world\n");
    //release_mem_region(GPIO2_BASE, GPIO2_MEM_SIZE);
}
module_init(hello_init);
module_exit(hello_exit);

这样写有问题吗？（实际上灯没被点亮）

https://bbs.csdn.net/topics/392233391