dell-laptop: create a platform device as a parent for the rfkill devices etc.

dell-laptop may not need to export any sysfs files, but it should still
create a platform device as a parent for the rfkill and backlight
devices.  Otherwise sysfs will display these as "virtual" devices,
with no connection to either physical hardware or the dell-laptop
module.

Apparently this is useful for hardware detection.
Signed-off-by: NAlan Jenkins <alan-jenkins@tuffmail.co.uk>
Acked-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/platform/x86/dell-laptop.c

@@ -58,6 +58,14 @@ static int da_command_code;
 static int da_num_tokens;
 static struct calling_interface_token *da_tokens;
 
+static struct platform_driver platform_driver = {
+	.driver = {
+		.name = "dell-laptop",
+		.owner = THIS_MODULE,
+	}
+};
+
+static struct platform_device *platform_device;
 static struct backlight_device *dell_backlight_device;
 static struct rfkill *wifi_rfkill;
 static struct rfkill *bluetooth_rfkill;
@@ -217,7 +225,8 @@ static int dell_setup_rfkill(void)
 	status = buffer.output[1];
 
 	if ((status & (1<<2|1<<8)) == (1<<2|1<<8)) {
-		wifi_rfkill = rfkill_alloc("dell-wifi", NULL, RFKILL_TYPE_WLAN,
+		wifi_rfkill = rfkill_alloc("dell-wifi", &platform_device->dev,
+					   RFKILL_TYPE_WLAN,
 					   &dell_rfkill_ops, (void *) 1);
 		if (!wifi_rfkill) {
 			ret = -ENOMEM;
@@ -229,7 +238,8 @@ static int dell_setup_rfkill(void)
 	}
 
 	if ((status & (1<<3|1<<9)) == (1<<3|1<<9)) {
-		bluetooth_rfkill = rfkill_alloc("dell-bluetooth", NULL,
+		bluetooth_rfkill = rfkill_alloc("dell-bluetooth",
+						&platform_device->dev,
 						RFKILL_TYPE_BLUETOOTH,
 						&dell_rfkill_ops, (void *) 2);
 		if (!bluetooth_rfkill) {
@@ -242,7 +252,9 @@ static int dell_setup_rfkill(void)
 	}
 
 	if ((status & (1<<4|1<<10)) == (1<<4|1<<10)) {
-		wwan_rfkill = rfkill_alloc("dell-wwan", NULL, RFKILL_TYPE_WWAN,
+		wwan_rfkill = rfkill_alloc("dell-wwan",
+					   &platform_device->dev,
+					   RFKILL_TYPE_WWAN,
 					   &dell_rfkill_ops, (void *) 3);
 		if (!wwan_rfkill) {
 			ret = -ENOMEM;
@@ -342,6 +354,18 @@ static int __init dell_init(void)
 		return -ENODEV;
 	}
 
+	ret = platform_driver_register(&platform_driver);
+	if (ret)
+		goto fail_platform_driver;
+	platform_device = platform_device_alloc("dell-laptop", -1);
+	if (!platform_device) {
+		ret = -ENOMEM;
+		goto fail_platform_device1;
+	}
+	ret = platform_device_add(platform_device);
+	if (ret)
+		goto fail_platform_device2;
+
 	ret = dell_setup_rfkill();
 
 	if (ret) {
@@ -368,7 +392,7 @@ static int __init dell_init(void)
 	if (max_intensity) {
 		dell_backlight_device = backlight_device_register(
 			"dell_backlight",
-			NULL, NULL,
+			&platform_device->dev, NULL,
 			&dell_ops);
 
 		if (IS_ERR(dell_backlight_device)) {
@@ -388,6 +412,12 @@ static int __init dell_init(void)
 fail_backlight:
 	dell_cleanup_rfkill();
 fail_rfkill:
+	platform_device_del(platform_device);
+fail_platform_device2:
+	platform_device_put(platform_device);
+fail_platform_device1:
+	platform_driver_unregister(&platform_driver);
+fail_platform_driver:
 	kfree(da_tokens);
 	return ret;
 }