firewire: ohci: use devres for memory object of ohci structure

The managed device resource (devres) framework is convenient to maintain
lifetime of allocated memory object for device.

This commit utilizes the framework for the object of ohci structure. The
extra operation for power management is required in Apple PowerMac based
machines, thus release callback is assigned to the object to call the
operation.

Link: https://lore.kernel.org/r/20230604054451.161076-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Author: takaswie

drivers/firewire/ohci.c

@@ -3557,6 +3557,15 @@ static inline void pmac_ohci_on(struct pci_dev *dev) {}
 static inline void pmac_ohci_off(struct pci_dev *dev) {}
 #endif /* CONFIG_PPC_PMAC */
 
+static void release_ohci(struct device *dev, void *data)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	pmac_ohci_off(pdev);
+
+	dev_notice(dev, "removed fw-ohci device\n");
+}
+
 static int pci_probe(struct pci_dev *dev,
 			       const struct pci_device_id *ent)
 {
@@ -3571,25 +3580,22 @@ static int pci_probe(struct pci_dev *dev,
 		return -ENOSYS;
 	}
 
-	ohci = kzalloc(sizeof(*ohci), GFP_KERNEL);
-	if (ohci == NULL) {
-		err = -ENOMEM;
-		goto fail;
-	}
-
+	ohci = devres_alloc(release_ohci, sizeof(*ohci), GFP_KERNEL);
+	if (ohci == NULL)
+		return -ENOMEM;
 	fw_card_initialize(&ohci->card, &ohci_driver, &dev->dev);
-
+	pci_set_drvdata(dev, ohci);
 	pmac_ohci_on(dev);
+	devres_add(&dev->dev, ohci);
 
 	err = pci_enable_device(dev);
 	if (err) {
 		dev_err(&dev->dev, "failed to enable OHCI hardware\n");
-		goto fail_free;
+		return err;
 	}
 
 	pci_set_master(dev);
 	pci_write_config_dword(dev, OHCI1394_PCI_HCI_Control, 0);
-	pci_set_drvdata(dev, ohci);
 
 	spin_lock_init(&ohci->lock);
 	mutex_init(&ohci->phy_reg_mutex);
@@ -3748,10 +3754,7 @@ static int pci_probe(struct pci_dev *dev,
 	pci_release_region(dev, 0);
  fail_disable:
 	pci_disable_device(dev);
- fail_free:
-	kfree(ohci);
-	pmac_ohci_off(dev);
- fail:
+
 	return err;
 }
 
@@ -3796,10 +3799,8 @@ static void pci_remove(struct pci_dev *dev)
 	pci_iounmap(dev, ohci->registers);
 	pci_release_region(dev, 0);
 	pci_disable_device(dev);
-	kfree(ohci);
-	pmac_ohci_off(dev);
 
-	dev_notice(&dev->dev, "removed fw-ohci device\n");
+	dev_notice(&dev->dev, "removing fw-ohci device\n");
 }
 
 #ifdef CONFIG_PM