--- zzzz-none-000/linux-3.10.107/Documentation/extcon/porting-android-switch-class	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/extcon/porting-android-switch-class	2021-02-04 17:41:59.000000000 +0000
@@ -25,8 +25,10 @@
     @print_state: no change but type change (switch_dev->extcon_dev)
 
 - switch_dev_register(sdev, dev)
-	=> extcon_dev_register(edev, dev)
-	: no change but type change (sdev->edev)
+	=> extcon_dev_register(edev)
+	: type change (sdev->edev)
+	: remove second param('dev'). if edev has parent device, should store
+	  'dev' to 'edev.dev.parent' before registering extcon device
 - switch_dev_unregister(sdev)
 	=> extcon_dev_unregister(edev)
 	: no change but type change (sdev->edev)
@@ -48,7 +50,7 @@
 	Extcon's extended features for switch device drivers with
 	complex features usually required magic numbers in state
 	value of switch_dev. With extcon, such magic numbers that
-	support multiple cables (
+	support multiple cables are no more required or supported.
 
   1. Define cable names at edev->supported_cable.
   2. (Recommended) remove print_state callback.
@@ -112,11 +114,8 @@
 
 ****** ABI Location
 
-  If "CONFIG_ANDROID" is enabled and "CONFIG_ANDROID_SWITCH" is
-disabled, /sys/class/switch/* are created as symbolic links to
-/sys/class/extcon/*. Because CONFIG_ANDROID_SWITCH creates
-/sys/class/switch directory, we disable symboling linking if
-CONFIG_ANDROID_SWITCH is enabled.
+  If "CONFIG_ANDROID" is enabled, /sys/class/switch/* are created
+as symbolic links to /sys/class/extcon/*.
 
   The two files of switch class, name and state, are provided with
 extcon, too. When the multistate support (STEP 2 of CHAPTER 1.) is