drivers/lcd: Add suppose for a generic front-end that will convert any LCD...

drivers/lcd:  Add suppose for a generic front-end that will convert any LCD driver into a framebuffer driver.

drivers/lcd/Kconfig

@@ -21,6 +21,23 @@ if LCD
 
 comment "Common Graphic LCD Settings"
 
+config LCD_FRAMEBUFFER
+	bool "LCD framebuffer front end"
+	default n
+	select NX_UPDATE if NX
+	---help---
+		Enable a "front end" that converts an sequential LCD driver into a
+		standard, NuttX frame buffer driver.
+
+		NOTE: Some LCD drivers implement an internal framebuffer for
+		effeciency reasons but do not export a framebuffer interface.  So
+		those LCD cannot be used as framebuffer drivers.  If the option is
+		available, then such internal framebuffer support should be
+		disabled because this external commone framebuffer interface will
+		provide the necessary buffering.
+
+menu "LCD driver selection"
+
 config LCD_CONSOLE
 	bool "LCD console output"
 	default n
@@ -118,6 +135,11 @@ config P14201_FRAMEBUFFER
 		All pixel writes must be aligned to byte boundaries.
 		The latter limitation effectively reduces the 128x96 disply to 64x96.
 
+		NOTE: This option should not be used if CONFIG_LCD_FRAMBEBUFFER is
+		enabled.  That options provides for a more geneneralized, external
+		LCD framebuffer.  This internal framebuffer support should not be
+		enabled with CONFIG_LCD_FRAMBEBUFFER because this external commone
+		framebuffer interface will provide the necessary buffering.
 endif
 
 config LCD_NOKIA6100
@@ -1083,6 +1105,7 @@ config LCD_RA8875_EXTENDED
 		driver anyway.
 
 endif # LCD_RA8875
+endmenu # LCD Driver selection
 endif # LCD
 
 menuconfig SLCD

drivers/lcd/Make.defs

 ############################################################################
 # drivers/lcd/Make.defs
 #
-#   Copyright (C) 2010-2012 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2010-2012, 2017 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -33,7 +33,13 @@
 #
 ############################################################################
 
-ifeq ($(CONFIG_NX_LCDDRIVER),y)
+ifeq ($(CONFIG_LCD),y)
+
+# Support for the generic LCD framebufer front-end
+
+ifeq ($(CONFIG_LCD_FRAMEBUFFER),y)
+  CSRCS += lcd_framebuffer.c
+endif
 
 # Include support for Graphics LCD drivers
 
@@ -117,7 +123,7 @@ endif # CONFIG_SLCD
 
 # Include LCD driver build support (the nested if-then-else implements an OR)
 
-ifeq ($(CONFIG_NX_LCDDRIVER),y)
+ifeq ($(CONFIG_LCD),y)
   DEPPATH += --dep-path lcd
   VPATH += :lcd
   CFLAGS += ${shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)drivers$(DELIM)lcd}