staging: vt6655/device_main.c: use generic power management

Drivers should not use legacy power management as they have to manage power
states and related operations, for the device, themselves. This driver was
handling them with the help of PCI helper functions like
pci_save/restore_state(), pci_enable/disable_device(), etc.

With generic PM, all essentials will be handled by the PCI core. Driver
needs to do only device-specific operations.

The driver was also using pci_enable_wake(...,..., 0) to disable wake. Use
device_wakeup_disable() instead.

Compile-tested only.
Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Link: https://lore.kernel.org/r/20200629082819.216405-5-vaibhavgupta40@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/device_main.c

@@ -1766,48 +1766,37 @@ vt6655_probe(struct pci_dev *pcid, const struct pci_device_id *ent)
 
 /*------------------------------------------------------------------*/
 
-#ifdef CONFIG_PM
-static int vt6655_suspend(struct pci_dev *pcid, pm_message_t state)
+static int __maybe_unused vt6655_suspend(struct device *dev_d)
 {
-	struct vnt_private *priv = pci_get_drvdata(pcid);
+	struct vnt_private *priv = dev_get_drvdata(dev_d);
 	unsigned long flags;
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	pci_save_state(pcid);
-
 	MACbShutdown(priv);
 
-	pci_disable_device(pcid);
-
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	pci_set_power_state(pcid, pci_choose_state(pcid, state));
-
 	return 0;
 }
 
-static int vt6655_resume(struct pci_dev *pcid)
+static int __maybe_unused vt6655_resume(struct device *dev_d)
 {
-	pci_set_power_state(pcid, PCI_D0);
-	pci_enable_wake(pcid, PCI_D0, 0);
-	pci_restore_state(pcid);
+	device_wakeup_disable(dev_d);
 
 	return 0;
 }
-#endif
 
 MODULE_DEVICE_TABLE(pci, vt6655_pci_id_table);
 
+static SIMPLE_DEV_PM_OPS(vt6655_pm_ops, vt6655_suspend, vt6655_resume);
+
 static struct pci_driver device_driver = {
 	.name = DEVICE_NAME,
 	.id_table = vt6655_pci_id_table,
 	.probe = vt6655_probe,
 	.remove = vt6655_remove,
-#ifdef CONFIG_PM
-	.suspend = vt6655_suspend,
-	.resume = vt6655_resume,
-#endif
+	.driver.pm = &vt6655_pm_ops,
 };
 
 module_pci_driver(device_driver);