no device creation by udev

no device creation by udev

[anno79 at mailbox.org]

I have written the following lines of code

to get a char device working.

( lines with # indicate that I have tried versions of this code snippet without them)

  class_hello = class_create(THIS_MODULE, device_name);
# class_hello->devnode = &hello_devnode;
  retval = alloc_chrdev_region( &dev_file, 0, 1, device_name );
  cdev_init( &device, &file_ops );
# device.owner = THIS_MODULE;

# kobject_set_name(&device.kobj, device_name);
  cdev_add( &device, MKDEV(dev_file, 0), 1 )
  device = device_create( class_hello, NULL, MKDEV(dev_file, 0), NULL, device_name );
# kobj_device->devt = MKDEV(dev_file, 0);


Make it open / close / read / write works fine  - but look at that

$ ls /sys/class/hello/hello
power subsystem uevent

The "dev" entry is missing - and udev does not react.

Anybody knows what is else needed to make udev react?
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no device creation by udev

[Victor Rodriguez]

On Fri, Jun 24, 2016 at 11:44 AM,  <anno79@mailbox.org> wrote:
> I have written the following lines of code
>
> to get a char device working.
>
> ( lines with # indicate that I have tried versions of this code snippet
> without them)
>
>   class_hello = class_create(THIS_MODULE, device_name);
> # class_hello->devnode = &hello_devnode;
>   retval = alloc_chrdev_region( &dev_file, 0, 1, device_name );
>   cdev_init( &device, &file_ops );
> # device.owner = THIS_MODULE;
>
> # kobject_set_name(&device.kobj, device_name);
>   cdev_add( &device, MKDEV(dev_file, 0), 1 )
>   device = device_create( class_hello, NULL, MKDEV(dev_file, 0), NULL,
> device_name );
> # kobj_device->devt = MKDEV(dev_file, 0);
>
>
> Make it open / close / read / write works fine  - but look at that
>
> $ ls /sys/class/hello/hello
> power subsystem uevent
>
> The "dev" entry is missing - and udev does not react.
>
> Anybody knows what is else needed to make udev react?
>

http://www.linuxdevcenter.com/pub/a/linux/2007/07/05/devhelloworld-a-simple-introduction-to-device-drivers-under-linux.html?page=3

Did you register ?

This simple tutorial works fine for me , what kernel version are you ussing ?

Regards

Victor Rodriguez


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