ipw2100: use generic power management

With legacy PM, drivers themselves were responsible for managing the
device's power states and takes care of register states.

After upgrading to the generic structure, PCI core will take care of
required tasks and drivers should do only device-specific operations.

The driver was invoking PCI helper functions like pci_save/restore_state(),
pci_enable/disable_device() and pci_set_power_state(), which is not
recommended.

Compile-tested only.
Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200629072525.156154-2-vaibhavgupta40@gmail.com

drivers/net/wireless/intel/ipw2x00/ipw2100.c

@@ -6397,10 +6397,9 @@ static void ipw2100_pci_remove_one(struct pci_dev *pci_dev)
 	IPW_DEBUG_INFO("exit\n");
 }
 
-#ifdef CONFIG_PM
-static int ipw2100_suspend(struct pci_dev *pci_dev, pm_message_t state)
+static int __maybe_unused ipw2100_suspend(struct device *dev_d)
 {
-	struct ipw2100_priv *priv = pci_get_drvdata(pci_dev);
+	struct ipw2100_priv *priv = dev_get_drvdata(dev_d);
 	struct net_device *dev = priv->net_dev;
 
 	IPW_DEBUG_INFO("%s: Going into suspend...\n", dev->name);
@@ -6414,10 +6413,6 @@ static int ipw2100_suspend(struct pci_dev *pci_dev, pm_message_t state)
 	/* Remove the PRESENT state of the device */
 	netif_device_detach(dev);
 
-	pci_save_state(pci_dev);
-	pci_disable_device(pci_dev);
-	pci_set_power_state(pci_dev, PCI_D3hot);
-
 	priv->suspend_at = ktime_get_boottime_seconds();
 
 	mutex_unlock(&priv->action_mutex);
@@ -6425,11 +6420,11 @@ static int ipw2100_suspend(struct pci_dev *pci_dev, pm_message_t state)
 	return 0;
 }
 
-static int ipw2100_resume(struct pci_dev *pci_dev)
+static int __maybe_unused ipw2100_resume(struct device *dev_d)
 {
+	struct pci_dev *pci_dev = to_pci_dev(dev_d);
 	struct ipw2100_priv *priv = pci_get_drvdata(pci_dev);
 	struct net_device *dev = priv->net_dev;
-	int err;
 	u32 val;
 
 	if (IPW2100_PM_DISABLED)
@@ -6439,16 +6434,6 @@ static int ipw2100_resume(struct pci_dev *pci_dev)
 
 	IPW_DEBUG_INFO("%s: Coming out of suspend...\n", dev->name);
 
-	pci_set_power_state(pci_dev, PCI_D0);
-	err = pci_enable_device(pci_dev);
-	if (err) {
-		printk(KERN_ERR "%s: pci_enable_device failed on resume\n",
-		       dev->name);
-		mutex_unlock(&priv->action_mutex);
-		return err;
-	}
-	pci_restore_state(pci_dev);
-
 	/*
 	 * Suspend/Resume resets the PCI configuration space, so we have to
 	 * re-disable the RETRY_TIMEOUT register (0x41) to keep PCI Tx retries
@@ -6473,7 +6458,6 @@ static int ipw2100_resume(struct pci_dev *pci_dev)
 
 	return 0;
 }
-#endif
 
 static void ipw2100_shutdown(struct pci_dev *pci_dev)
 {
@@ -6539,15 +6523,14 @@ static const struct pci_device_id ipw2100_pci_id_table[] = {
 
 MODULE_DEVICE_TABLE(pci, ipw2100_pci_id_table);
 
+static SIMPLE_DEV_PM_OPS(ipw2100_pm_ops, ipw2100_suspend, ipw2100_resume);
+
 static struct pci_driver ipw2100_pci_driver = {
 	.name = DRV_NAME,
 	.id_table = ipw2100_pci_id_table,
 	.probe = ipw2100_pci_init_one,
 	.remove = ipw2100_pci_remove_one,
-#ifdef CONFIG_PM
-	.suspend = ipw2100_suspend,
-	.resume = ipw2100_resume,
-#endif
+	.driver.pm = &ipw2100_pm_ops,
 	.shutdown = ipw2100_shutdown,
 };