common/lcd_console: introduce display/framebuffer rotation

Sometimes, for example if the display is mounted in portrait mode or even if it
is mounted landscape but rotated by 180 degrees, we need to rotate our content
of the display respectively the framebuffer, so that user can read the messages
which are printed out.

For this we introduce the feature called "CONFIG_LCD_ROTATION", this may be
defined in the board-configuration if needed. After this the lcd_console will
be initialized with a given rotation from "vl_rot" out of "vidinfo_t" which is
provided by the board specific code.

If CONFIG_LCD_ROTATION is not defined, the console will be initialized with
0 degrees rotation.

Signed-off-by: Hannes Petermaier <hannes.petermaier@br-automation.com>
Signed-off-by: Hannes Petermaier <oe5hpm@oevsv.at>
Acked-by: Nikita Kiryanov <nikita@compulab.co.il>
[agust: fixed 'struct vidinfo' has no member named 'vl_rot' errors]
Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/README b/README
index 9b748cc..b662eb9 100644
--- a/README
+++ b/README
@@ -1947,6 +1947,26 @@
 		the console jump but can help speed up operation when scrolling
 		is slow.
 
+		CONFIG_LCD_ROTATION
+
+		Sometimes, for example if the display is mounted in portrait
+		mode or even if it's mounted landscape but rotated by 180degree,
+		we need to rotate our content of the display relative to the
+		framebuffer, so that user can read the messages which are
+		printed out.
+		Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
+		initialized with a given rotation from "vl_rot" out of
+		"vidinfo_t" which is provided by the board specific code.
+		The value for vl_rot is coded as following (matching to
+		fbcon=rotate:<n> linux-kernel commandline):
+		0 = no rotation respectively 0 degree
+		1 = 90 degree rotation
+		2 = 180 degree rotation
+		3 = 270 degree rotation
+
+		If CONFIG_LCD_ROTATION is not defined, the console will be
+		initialized with 0degree rotation.
+
 		CONFIG_LCD_BMP_RLE8
 
 		Support drawing of RLE8-compressed bitmaps on the LCD.