Adding a kobject in the device model hierarchy

Adding a kobject in the device model hierarchy

[Prabhu nath]

Dear All,

        I have written one pseudo char driver. I have initialized the device
generic structure
    with cdev_init function. This will initialize the kobject structure
embedded within struct cdev
    with appropriate ktype. If I want to add this kobject in
/sys/devices/virtual/misc/ location
    of sysfs, how is the following fields set
    * kobj->parent
    * kobj->kset
    * kobj->kset->obj.

    Also, in general how to look out for the parent kobject ? Would like to
know, if there are
      mechanisms provisioned by Linux Kernel.

    Robert: My 2 cents as I am reading the LKD(3rd edition), it would be
appropriate to add one
            example as a solution to the above problem. Generally, it has
been told as
            kobj->kset = my_kset in Page # 353.

Note: Even in LDD(3rd editon page 369). It has been mentioned that "The
kobject's kset field must be
     pointed at the kset of interest"


Thanks,
Prabhu
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Adding a kobject in the device model hierarchy

[Greg KH]

On Sat, Jan 01, 2011 at 09:58:11PM +0530, Prabhu nath wrote:
> Dear All,
> 
>         I have written one pseudo char driver. I have initialized the device
> generic structure
>     with cdev_init function. This will initialize the kobject structure
> embedded within struct cdev
>     with appropriate ktype.

But NEVER touch that kobject, it is not for your use at all.

> If I want to add this kobject in
> /sys/devices/virtual/misc/ location
>     of sysfs, how is the following fields set
>     * kobj->parent
>     * kobj->kset
>     * kobj->kset->obj.

Nope, you need your own struct device, do not use the kobject in the
cdev, again, it is NOT for use at all.  It is private to a cdev and
I need to figure out a way to make it so that you can't even see it one
day to keep people from trying to use it.

good luck,

greg k-h