eeepc-laptop: Implement rfkill hotplugging in eeepc-laptop

The Eee implements rfkill by logically unplugging the wireless card from the
PCI bus. Despite sending ACPI notifications, this does not appear to be
implemented using standard ACPI hotplug - nor does the firmware provide the
_OSC method required to support native PCIe hotplug. The only sensible choice
appears to be to handle the hotplugging directly in the eeepc-laptop driver.
Tested successfully on a 700, 900 and 901.

Signed-off-by: Matthew Garrett <[e-mail]>
Signed-off-by: Corentin Chary <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/platform/x86/eeepc-laptop.c

···
 #include <linux/uaccess.h>
 #include <linux/input.h>
 #include <linux/rfkill.h>
+#include <linux/pci.h>
 
 #define EEEPC_LAPTOP_VERSION	"0.1"
 
···
 	bd->props.brightness = read_brightness(bd);
 }
 
+static void eeepc_rfkill_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct pci_dev *dev;
+	struct pci_bus *bus = pci_find_bus(0, 1);
+
+	if (event != ACPI_NOTIFY_BUS_CHECK)
+		return;
+
+	if (!bus) {
+		printk(EEEPC_WARNING "Unable to find PCI bus 1?\n");
+		return;
+	}
+
+	if (get_acpi(CM_ASL_WLAN) == 1) {
+		dev = pci_get_slot(bus, 0);
+		if (dev) {
+			/* Device already present */
+			pci_dev_put(dev);
+			return;
+		}
+		dev = pci_scan_single_device(bus, 0);
+		if (dev) {
+			pci_bus_assign_resources(bus);
+			if (pci_bus_add_device(dev))
+				printk(EEEPC_ERR "Unable to hotplug wifi\n");
+		}
+	} else {
+		dev = pci_get_slot(bus, 0);
+		if (dev) {
+			pci_remove_bus_device(dev);
+			pci_dev_put(dev);
+		}
+	}
+}
+
 static void eeepc_hotk_notify(acpi_handle handle, u32 event, void *data)
 {
 	static struct key_entry *key;
···
 				break;
 			}
 		}
+	}
+}
+
+static int eeepc_register_rfkill_notifier(char *node)
+{
+	acpi_status status = AE_OK;
+	acpi_handle handle;
+
+	status = acpi_get_handle(NULL, node, &handle);
+
+	if (ACPI_SUCCESS(status)) {
+		status = acpi_install_notify_handler(handle,
+						     ACPI_SYSTEM_NOTIFY,
+						     eeepc_rfkill_notify,
+						     NULL);
+		if (ACPI_FAILURE(status))
+			printk(EEEPC_WARNING
+			       "Failed to register notify on %s\n", node);
+	} else
+		return -ENODEV;
+
+	return 0;
+}
+
+static void eeepc_unregister_rfkill_notifier(char *node)
+{
+	acpi_status status = AE_OK;
+	acpi_handle handle;
+
+	status = acpi_get_handle(NULL, node, &handle);
+
+	if (ACPI_SUCCESS(status)) {
+		status = acpi_remove_notify_handler(handle,
+						     ACPI_SYSTEM_NOTIFY,
+						     eeepc_rfkill_notify);
+		if (ACPI_FAILURE(status))
+			printk(EEEPC_ERR
+			       "Error removing rfkill notify handler %s\n",
+				node);
 	}
 }
 
···
 		if (result)
 			goto bluetooth_fail;
 	}
+
+	eeepc_register_rfkill_notifier("\\_SB.PCI0.P0P6");
+	eeepc_register_rfkill_notifier("\\_SB.PCI0.P0P7");
+
 	return 0;
 
  bluetooth_fail:
···
 					    eeepc_hotk_notify);
 	if (ACPI_FAILURE(status))
 		printk(EEEPC_ERR "Error removing notify handler\n");
+
+	eeepc_unregister_rfkill_notifier("\\_SB.PCI0.P0P6");
+	eeepc_unregister_rfkill_notifier("\\_SB.PCI0.P0P7");
+
 	kfree(ehotk);
 	return 0;
 }