linux下点灯有关问题

linux下点灯问题
硬件平台：OMAP-L138
软件平台：linux-2.6.32+VMware

问题描述：
板子上有个CPLD，CPLD的逻辑关系开发商不给，只给了文档描述,如下：


我自己写了个字符驱动用来控制灯的状态：
代码如下：

C/C++ code

static int __init hello_init(void){        unsigned long led_addr;        led_addr = (unsigned long)ioremap(0x64000040,0x08);        printk("\nled_addr is 0x%x.\n",led_addr);        writel(0x00,led_addr);        iounmap(led_addr);        printk("\nhelloword:: Hello module is installed!!!!!!\n");        return 0;}

动态加载的信息如下：
root@seed:/opt# insmod first_driver_hello.ko

led_addr is 0xc4888040.

helloword:: Hello module is installed!!!!!!
root@seed:/opt# 

但是灯没有点亮，已证实硬件没有问题，请高手指点~~~

[解决办法]
不要这么直接嘛
先试试读写是否正常
先读 再写 再读，看看你的写入是否有效果
[解决办法]
随便在内核里找了段代码
if (!request_mem_region(up->port.mapbase, size, "serial")) {
ret = -EBUSY;
break;
}

if (up->port.flags & UPF_IOREMAP) {
up->port.membase = ioremap_nocache(up->port.mapbase,
size);
if (!up->port.membase) {
release_mem_region(up->port.mapbase, size);
ret = -ENOMEM;
}
}

这里你应该先request_mem_region
此外建议使用ioread8 iowrite8 这样的api
[解决办法]

C/C++ code

这个驱动，请根据你的需要进行修改。#include <linux/config.h>#include <linux/init.h>#include <linux/module.h>#include <linux/kernel.h>#include <linux/fcntl.h>#include <linux/fs.h>#include <linux/types.h>#include <linux/input.h>#include <asm/io.h>void *R_GPBCON;void *R_GPBDAT;static u32 resave_gpbcon;static u32 resave_gpbdat;static struct input_dev my_led_dev;static void iomap_gpb(void){    R_GPBCON = ioremap(0x56000010,0x4);    R_GPBDAT = ioremap(0x56000014,0x4);}static void unmap_gpb(void){    iounmap(R_GPBCON);    iounmap(R_GPBDAT);}static void init_led_reg(void){    u32 temp;    resave_gpbcon = __raw_readl(R_GPBCON);    resave_gpbdat = __raw_readl(R_GPBDAT);        temp = resave_gpbcon & (~(0xff << 10));    temp |= ((0x1 << 10) | (0x1 << 12)| \                     (0x1 << 14) | (0x1 << 16));    __raw_writel(temp,R_GPBCON);    temp = resave_gpbdat | ( 0xf << 5);    __raw_writel(temp,R_GPBDAT);    }static void resave_led_reg(void){    __raw_writel(resave_gpbcon,R_GPBCON);    __raw_writel(resave_gpbdat,R_GPBDAT);}static int my_led_event(struct input_dev *dev, \       unsigned int type, unsigned int code, int value)       {    u32 temp;            if (type != EV_LED)        return -1;    switch (code) {        case LED_NUML:             break;        default:             return -1;    }        temp = __raw_readl(R_GPBDAT);    temp &= (~(0xf << 5));    __raw_writel(temp | value,R_GPBDAT);        return 0;}static int __init my_led_init(void){    init_input_dev(&my_led_dev);        my_led_dev.evbit[0] = BIT(EV_LED);    my_led_dev.ledbit[0] = BIT(LED_NUML);    my_led_dev.event = my_led_event;    my_led_dev.name = "my_led_name";    my_led_dev.phys = "my_led_phys";    my_led_dev.id.bustype = BUS_HOST;    my_led_dev.id.vendor = 0x001f;    my_led_dev.id.product = 0x0001;    my_led_dev.id.version = 0x0100;        iomap_gpb();    init_led_reg();    input_register_device(&my_led_dev);    return 0;}static void __exit my_led_exit(void){        resave_led_reg();        unmap_gpb();            input_unregister_device(&my_led_dev);}module_init(my_led_init);module_exit(my_led_exit);下面为测试程序#include <sys/types.h>#include <unistd.h>#include <fcntl.h>#include <linux/ioctl.h>#include <linux/types.h>#include <linux/delay.h>#include <linux/input.h>#include <stdio.h>int main(void){    struct input_event my_led_event;    __s32 ret;    __s32 fb;    __u32 loop;    __u32 led_buffer[4] = {0xE,0xD,0xB,0x7};        fb = open("/dev/input/event1",O_RDWR);    if (fb < 0){        printf("open error!\n");        exit(1);    }        my_led_event.type = EV_LED;    my_led_event.code = LED_NUML;            loop = 0;    while (1){        loop &= 0x3;        my_led_event.value = *(led_buffer + loop) << 5;                ret = write(fb,&my_led_event,sizeof(struct input_event));        if (ret < 0){            printf("write error!\n");            exit(1);        }                sleep(1);        loop ++;    }    return 0;} 
  

 

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