On Thu, Aug 28, 2008 at 12:02:26AM +0530, Prasad Joshi wrote:
> Hi All,
>
> I want register the character device with sysfs and want a device file to be
> created. The function device_create() does the same, but it seems to be
> failing in my case.
>
> Here is the part of the code
>
> #define MYMAJOR 200
>
> struct mydevice {
> struct device *parent;
> struct device *this_device;
> dev_t dev;
> char name[20];
> };
>
> struct mydevice my_misc = {
> .name = "myzero",
> .parent = NULL,
> };
>
> struct class *my_class;
> struct mydevice zdev;
>
> static int __init myudev_init(void)
> {
> int err = 0;
> zdev.dev = MKDEV(MYMAJOR, 10);
Did you already register this major/minor?
> my_class = class_create (THIS_MODULE, "mymisc");
> err = PTR_ERR(my_class);
> if (IS_ERR(my_class))
> goto class_err;
>
> zdev.this_device = device_create(my_class, zdev.parent, zdev.dev, "%s",
> zdev.name);
You are passing NULL, or some garbage for the parent here, do you really
want that?
> err = PTR_ERR(zdev.this_device);
> if (IS_ERR(zdev.this_device))
> goto device_err;
>
> return 0;
> device_err:
> class_destroy(my_class);
> class_err:
> return err;
> }
>
>
> While debugging the code, I could findout that device_add() is the failing
>
> int device_add(struct device *dev)
> {
> struct device *parent = NULL;
> struct class_interface *class_intf;
> int error;
>
> dev = get_device(dev); <<<<<<<<<<<<<<<<<<< here the code is
> failing
What kernel version are you using?
thanks,
greg k-h
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