dell-rbtn: Dell Airplane Mode Switch driver

This is an ACPI driver for Dell laptops which receive HW slider radio
switch or hotkey toggle wifi button events. It exports rfkill device
dell-rbtn (which provide correct hard rfkill state) or hotkey input device.

Alex Hung is author of original hotkey input device code.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Cc: Alex Hung <alex.hung@canonical.com>
[fengguang.wu@intel.com: rbtn_ops can be static]
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
[dvhart@linux.intel.com: Correct multi-line comment formatting]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 399085d..bca0aee 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -138,6 +138,22 @@
 	  To compile this driver as a module, choose M here: the module will
 	  be called dell-smo8800.
 
+config DELL_RBTN
+	tristate "Dell Airplane Mode Switch driver"
+	depends on ACPI
+	depends on INPUT
+	depends on RFKILL
+	---help---
+	  Say Y here if you want to support Dell Airplane Mode Switch ACPI
+	  device on Dell laptops. Sometimes it has names: DELLABCE or DELRBTN.
+	  This driver register rfkill device or input hotkey device depending
+	  on hardware type (hw switch slider or keyboard toggle button). For
+	  rfkill devices it receive HW switch events and set correct hard
+	  rfkill state.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called dell-rbtn.
+
 
 config FUJITSU_LAPTOP
 	tristate "Fujitsu Laptop Extras"