驱动的问题

1.
Q.
[root@FriendlyARM 2.6.32.2-FriendlyARM]# rmmod hello    
rmmod: chdir(2.6.32.2): No such file or directory
到这里,问题就出现了,rmmod: chdir(2.6.32.2): No such file or directory
A.
注意这里的问题提示目录为:chdir(2.6.32.2),根据置顶帖"驱动的加载与卸载中常见问题：rmmod chdir no such file or directory 的最终解决办法"11楼wbweb的提示,于是我大胆的将开发板的/lib/modules/2.6.32.2-FriendlyARM/目录 修改为 /lib/modules/2.6.32.2/ 后,重新测试后,成功.
2.
Q.
在执行rmmod ixp4xx-ehci-hcd.ko命令的时候，出现如下oops错误：
WARNING: at drivers/base/core.c:122 device_release+0x68/0x74()
Device 'ixp4xx-ehci.0' does not have a release() function, it is broken and must be fixed.
Modules linked in: [last unloaded: ixp4xx_ehci_hcd]
[] (dump_stack+0x0/0x14) from [] (warn_slowpath+0x68/0x9c)
[] (warn_slowpath+0x0/0x9c) from [] (device_release+0x68/0x74)
 r3:bf130668 r2:c039c685
 r7:c7a0bf38 r6:c7a84bc0 r5:c03d7d9c r4:bf130644
[] (device_release+0x0/0x74) from [] (kobject_release+0x48/0x5c)
[] (kobject_release+0x0/0x5c) from [] (kref_put+0x78/0x88)
 r6:c03cac34 r5:c017ba4c r4:bf130660
[] (kref_put+0x0/0x88) from [] (kobject_put+0x48/0x58)
 r5:bf1307b0 r4:bf130644
[] (kobject_put+0x0/0x58) from [] (put_device+0x1c/0x20)
 r4:bf1305e0
[] (put_device+0x0/0x20) from [] (platform_device_put+0x1c/0x20)
[] (platform_device_put+0x0/0x20) from [] (platform_device_unregister+0x1c/0x20)
[] (platform_device_unregister+0x0/0x20) from [] (ixp4xx_ehci_cleanup+0x38/0x4c [ixp4xx_ehci_hcd])
 r4:00000000
[] (ixp4xx_ehci_cleanup+0x0/0x4c [ixp4xx_ehci_hcd]) from [] (sys_delete_module+0x20c/0x280)
[] (sys_delete_module+0x0/0x280) from [] (ret_fast_syscall+0x0/0x2c)
 r8:c0025024 r7:00000081 r6:6863695f r5:78785f65 r4:69787034
A.
这个错误发生在删除usb驱动时对设备进行unregister的时候：
platform_device_unregister(device);//device = &ixdp4xx_ehci_controller[0];
其中ixdp4xx_ehci_controller的定义如下：
static struct platform_device ixdp4xx_ehci_controller[] =  {
    /* Host controller 0 */
    {
        .name        = IXP4XX_EHCI_NAME,
        .id        = 0,
        .dev = {
            .dma_mask               = &ehci_dma_mask,
            .coherent_dma_mask      = 0xffffffff,
        },
        .resource    = ixp4xx_ehci_host0_res,
        .num_resources    = 2,
    },
｝
WARNING警告出自内核的如下代码：driver/base/core.c
static void device_release(struct kobject *kobj)
{
    struct device *dev = to_dev(kobj);

    if (dev->release)
        dev->release(dev);
    else if (dev->type && dev->type->release)
        dev->type->release(dev);
    else if (dev->class && dev->class->dev_release)
        dev->class->dev_release(dev);
    else
        WARN(1, KERN_ERR "Device '%s' does not have a release() "
            "function, it is broken and must be fixed.\n",
            dev_name(dev));
}
根据警告信息提示，我在ixdp4xx_ehci_controller［0］的.dev域下实现了一个空的release函数，解决办法如下：
static void  ixdp4xx_ehci_controller_release(struct device *dev)
{
    printk(KERN_INFO "\nixdp4xx_ehci_controller_release...");
}
static struct platform_device ixdp4xx_ehci_controller[] =  {
    /* Host controller 0 */
    {
        .name        = IXP4XX_EHCI_NAME,
        .id        = 0,
        .dev = {
            .dma_mask               = &ehci_dma_mask,
            .coherent_dma_mask      = 0xffffffff,
            .release = &ixdp4xx_ehci_controller_release
        },
        .resource    = ixp4xx_ehci_host0_res,
        .num_resources    = 2,
    },
｝
然后ok

3.
Q.
就会出现：Syntax error: word unexpected (expect ing ")")，郁闷了好久！
一直都是用ftp将s3c2440_adc_test传到开发板上，没有发现什么错误，但运行就是出错。
A.
最终确定：s3c2440_adc_test文件传输的不完整，
导致运行s3c2440_adc_test出现错误：Syntax error: word unexpected (expect ing ")")