msi-laptop: Detect 3G device exists by standard ec command

Detect 3G device exists by standard ec command. Driver will not create the threeg sysfs
file and threeg rfkill interface if there have no internal 3G device in MSI notebook/netbook.
Signed-off-by: Lee, Chun-Yi <jlee@novell.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/platform/x86/msi-laptop.c

@@ -79,6 +79,8 @@
 
 static int msi_laptop_resume(struct platform_device *device);
 
+#define MSI_STANDARD_EC_DEVICES_EXISTS_ADDRESS	0x2f
+
 static int force;
 module_param(force, bool, 0);
 MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
@@ -89,6 +91,7 @@ MODULE_PARM_DESC(auto_brightness, "Enable automatic brightness control (0: disab
 
 static bool old_ec_model;
 static int wlan_s, bluetooth_s, threeg_s;
+static int threeg_exists;
 
 /* Some MSI 3G netbook only have one fn key to control Wlan/Bluetooth/3G,
  * those netbook will load the SCM (windows app) to disable the original
@@ -224,6 +227,20 @@ static int get_wireless_state_ec_standard(void)
 	return 0;
 }
 
+static int get_threeg_exists(void)
+{
+	u8 rdata;
+	int result;
+
+	result = ec_read(MSI_STANDARD_EC_DEVICES_EXISTS_ADDRESS, &rdata);
+	if (result < 0)
+		return -1;
+
+	threeg_exists = !!(rdata & MSI_STANDARD_EC_3G_MASK);
+
+	return 0;
+}
+
 /* Backlight device stuff */
 
 static int bl_get_brightness(struct backlight_device *b)
@@ -561,15 +578,17 @@ static int rfkill_init(struct platform_device *sdev)
 	if (retval)
 		goto err_wlan;
 
-	rfk_threeg = rfkill_alloc("msi-threeg", &sdev->dev, RFKILL_TYPE_WWAN,
-				&rfkill_threeg_ops, NULL);
-	if (!rfk_threeg) {
-		retval = -ENOMEM;
-		goto err_threeg;
+	if (threeg_exists) {
+		rfk_threeg = rfkill_alloc("msi-threeg", &sdev->dev,
+				RFKILL_TYPE_WWAN, &rfkill_threeg_ops, NULL);
+		if (!rfk_threeg) {
+			retval = -ENOMEM;
+			goto err_threeg;
+		}
+		retval = rfkill_register(rfk_threeg);
+		if (retval)
+			goto err_threeg;
 	}
-	retval = rfkill_register(rfk_threeg);
-	if (retval)
-		goto err_threeg;
 
 	return 0;
 
@@ -649,6 +668,9 @@ static int __init msi_init(void)
 	if (force || dmi_check_system(msi_dmi_table))
 		old_ec_model = 1;
 
+	if (!old_ec_model)
+		get_threeg_exists();
+
 	if (!old_ec_model && dmi_check_system(msi_load_scm_models_dmi_table))
 		load_scm_model = 1;
 
@@ -694,7 +716,9 @@ static int __init msi_init(void)
 		goto fail_platform_device2;
 
 	if (!old_ec_model) {
-		ret = device_create_file(&msipf_device->dev, &dev_attr_threeg);
+		if (threeg_exists)
+			ret = device_create_file(&msipf_device->dev,
+						&dev_attr_threeg);
 		if (ret)
 			goto fail_platform_device2;
 	}
@@ -733,7 +757,7 @@ static void __exit msi_cleanup(void)
 {
 
 	sysfs_remove_group(&msipf_device->dev.kobj, &msipf_attribute_group);
-	if (!old_ec_model)
+	if (!old_ec_model && threeg_exists)
 		device_remove_file(&msipf_device->dev, &dev_attr_threeg);
 	platform_device_unregister(msipf_device);
 	platform_driver_unregister(&msipf_driver);