{
        if (hw_dev == dev->hw_dev)
                return 0;
-       if (dev->hw_dev != NULL)
+       if (dev->hw_dev)
                return -EEXIST;
        dev->hw_dev = get_device(hw_dev);
        return 0;
                }
                module_put(driv->module);
        }
-       if (driv == NULL) {
+       if (!driv) {
                /*  recognize has failed if we get here */
                /*  report valid board names before returning error */
                for (driv = comedi_drivers; driv; driv = driv->next) {
                ret = -EIO;
                goto out;
        }
-       if (driv->attach == NULL) {
+       if (!driv->attach) {
                /* driver does not support manual configuration */
                dev_warn(dev->class_dev,
                         "driver '%s' does not support attach using comedi_config\n",
 
 void comedi_auto_unconfig(struct device *hardware_device)
 {
-       if (hardware_device == NULL)
+       if (!hardware_device)
                return;
        comedi_release_hardware_device(hardware_device);
 }