sis900: use generic power management

Drivers using legacy power management .suspen()/.resume() callbacks
have to manage PCI states and device's PM states themselves. They also
need to take care of standard configuration registers.

Switch to generic power management framework using a single
"struct dev_pm_ops" variable to take the unnecessary load from the driver.
This also avoids the need for the driver to directly call most of the PCI
helper functions and device power state control functions, as through
the generic framework PCI Core takes care of the necessary operations,
and drivers are required to do only device-specific jobs.
Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sis/sis900.c

@@ -2502,11 +2502,9 @@ static void sis900_remove(struct pci_dev *pci_dev)
 	pci_release_regions(pci_dev);
 }
 
-#ifdef CONFIG_PM
-
-static int sis900_suspend(struct pci_dev *pci_dev, pm_message_t state)
+static int __maybe_unused sis900_suspend(struct device *dev)
 {
-	struct net_device *net_dev = pci_get_drvdata(pci_dev);
+	struct net_device *net_dev = dev_get_drvdata(dev);
 	struct sis900_private *sis_priv = netdev_priv(net_dev);
 	void __iomem *ioaddr = sis_priv->ioaddr;
 
@@ -2519,22 +2517,17 @@ static int sis900_suspend(struct pci_dev *pci_dev, pm_message_t state)
 	/* Stop the chip's Tx and Rx Status Machine */
 	sw32(cr, RxDIS | TxDIS | sr32(cr));
 
-	pci_set_power_state(pci_dev, PCI_D3hot);
-	pci_save_state(pci_dev);
-
 	return 0;
 }
 
-static int sis900_resume(struct pci_dev *pci_dev)
+static int __maybe_unused sis900_resume(struct device *dev)
 {
-	struct net_device *net_dev = pci_get_drvdata(pci_dev);
+	struct net_device *net_dev = dev_get_drvdata(dev);
 	struct sis900_private *sis_priv = netdev_priv(net_dev);
 	void __iomem *ioaddr = sis_priv->ioaddr;
 
 	if(!netif_running(net_dev))
 		return 0;
-	pci_restore_state(pci_dev);
-	pci_set_power_state(pci_dev, PCI_D0);
 
 	sis900_init_rxfilter(net_dev);
 
@@ -2558,17 +2551,15 @@ static int sis900_resume(struct pci_dev *pci_dev)
 
 	return 0;
 }
-#endif /* CONFIG_PM */
+
+static SIMPLE_DEV_PM_OPS(sis900_pm_ops, sis900_suspend, sis900_resume);
 
 static struct pci_driver sis900_pci_driver = {
 	.name		= SIS900_MODULE_NAME,
 	.id_table	= sis900_pci_tbl,
 	.probe		= sis900_probe,
 	.remove		= sis900_remove,
-#ifdef CONFIG_PM
-	.suspend	= sis900_suspend,
-	.resume		= sis900_resume,
-#endif /* CONFIG_PM */
+	.driver.pm	= &sis900_pm_ops,
 };
 
 static int __init sis900_init_module(void)