From mboxrd@z Thu Jan  1 00:00:00 1970
From: vm.rod25@gmail.com (Victor Rodriguez)
Date: Fri, 1 Jul 2016 09:38:54 -0500
Subject: no device creation by udev
In-Reply-To: <1608011627.62108.1466786656948@office.mailbox.org>
References: <1608011627.62108.1466786656948@office.mailbox.org>
Message-ID: <CAK5mtexT-vaGEH72c5H8hbDdeAOC85u2Wj7LZkOboajntAdO8w@mail.gmail.com>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

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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