common/lcd_console: introduce display/framebuffer rotation

[karo-tx-uboot.git] / README

diff --git a/README b/README
index 3c23d164bd84e07aba2d3b6cd5a8d4383772619d..0184bbf59a1ed33a7400408fd231a525ac55c919 100644 (file)
--- a/README
+++ b/README
@@ -2057,6 +2057,26 @@ CBFS (Coreboot Filesystem) support
                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.