Basic braille screen reader support

This adds a minimalistic braille screen reader support.  This is meant to
be used by blind people e.g.  on boot failures or when / cannot be mounted
etc and thus the userland screen readers can not work.

[akpm@linux-foundation.org: fix exports]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 3ce193f..0ba0861 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -496,6 +496,11 @@
 			switching to the matching ttyS device later.  The
 			options are the same as for ttyS, above.
 
+                If the device connected to the port is not a TTY but a braille
+                device, prepend "brl," before the device type, for instance
+			console=brl,ttyS0
+		For now, only VisioBraille is supported.
+
 	earlycon=	[KNL] Output early console device and options.
 		uart[8250],io,<addr>[,options]
 		uart[8250],mmio,<addr>[,options]