tty: Add msm_smd_tty driver

msm_smd_tty driver provides tty device interface
to 'DS' and 'GPSNMEA' streaming SMD ports.

Cc: Brian Swetland <swetland@google.com>
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index aaedbad..90d939a 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1600,4 +1600,13 @@
 	  Output Hub) which is for IVI(In-Vehicle Infotainment) use.
 	  ML7213 is companion chip for Intel Atom E6xx series.
 	  ML7213 is completely compatible for Intel EG20T PCH.
+
+config SERIAL_MSM_SMD
+	bool "Enable tty device interface for some SMD ports"
+	default n
+	depends on MSM_SMD
+	help
+	  Enables userspace clients to read and write to some streaming SMD
+	  ports via tty device interface for MSM chipset.
+
 endmenu