CODEWITHSUNDEEP
clinuxdriver
Dimitar Penev
Dimitar Penev

Reputation: 151

Linux: My char driver creates a node in sysfs but can not clean it after reloading

I am writting a simple char driver. I create node in sysfs with device_create() and it is created properly. I get my node in /dev automatically as well. My problem is that class_distroy() and device_destroy() don't clean the /sys/devices/virtual/tdmcdev/tdm/ directory crated on init. My init and close code below

    ...
    /* Node in the /dev/  */
    tdm->dev_major = 0; //for dynamic major        

    tdm_dev = MKDEV(tdm->dev_major, 0);
    tdm->dev_major = MAJOR(tdm_dev);
    err = alloc_chrdev_region(&tdm_dev, 0, 1, "tdm"); //One node to read/write data frame
    if (err) {
            printk("can't alloc minor for /dev/tdm\n");
            return -ENODEV;
    }

    cdev_init(&(tdm->cdev), &tdm_dev_fops);
    tdm->cdev.owner = THIS_MODULE;
    err = cdev_add(&(tdm->cdev), tdm_dev, 1);
    if (err) {
            printk("cdev_add() failed for /dev/tdm\n");
            unregister_chrdev_region(tdm_dev, 1);
            return -ENODEV;
    }

    /* Node /sys/devices/virtual/tdmcdev/tdm/  */
    tdm->dev_class = class_create(THIS_MODULE, "tdmcdev");
    if (IS_ERR(device_create(tdm->dev_class, NULL, tdm_dev, NULL, "tdm"))) {
            printk("device_create() failed for the tdm device\n");
            class_destroy(tdm->dev_class);
            cdev_del(&(tdm->cdev));
            unregister_chrdev_region(tdm_dev, 1);
            return -ENOMEM;
    }
    ...

my close code 

    dev_t tdm_dev = MKDEV(tdm->dev_major, 0);

    device_destroy(tdm->dev_class, tdm_dev);
    class_destroy(tdm->dev_class);

    cdev_del(&(tdm->cdev));
    unregister_chrdev_region(tdm_dev, 1);
    ...

It is on Linux OpenWrt 3.10.49 on MIPS CPU. Anyone seeing something not in order?

Thanks. Dimitar

Upvotes: 3

Views: 703

Answers (1)

Dimitar Penev
Dimitar Penev

Reputation: 151

It appeared a stupid one. I am using dynamic major so start from value 0. I have to move tdm->dev_major = MAJOR(tdm_dev) after the alloc_chrdev_region() of course so get the proper major which I can clean afterwords

Thanks Dimitar

Upvotes: 2

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