From: Maxime Ripard <maxime.ripard@free-electrons.com>
Date: Fri, 11 Jan 2013 22:31:43 +0000 (-0800)
Subject: drivers/video/ssd1307fb.c: fix bit order bug in the byte translation function
X-Git-Tag: firefly_0821_release~3680^2~1275^2~18
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=552f0cc72aadfc8657876ce310e7a8dc37529536;p=firefly-linux-kernel-4.4.55.git

drivers/video/ssd1307fb.c: fix bit order bug in the byte translation function

This was leading to a strange behaviour when using the fbcon driver on
top of this one: the letters were in the right order, but each letter
had a vertical symmetry.

This was because the addressing was right for the byte, but the
addressing of each individual bit was inverted.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Brian Lilly <brian@crystalfontz.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Thomas Petazzoni <thomas@free-electrons.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/video/ssd1307fb.c b/drivers/video/ssd1307fb.c
index 4d99dd7a6831..395cb6a8d8f3 100644
--- a/drivers/video/ssd1307fb.c
+++ b/drivers/video/ssd1307fb.c
@@ -145,8 +145,8 @@ static void ssd1307fb_update_display(struct ssd1307fb_par *par)
 				u32 page_length = SSD1307FB_WIDTH * i;
 				u32 index = page_length + (SSD1307FB_WIDTH * k + j) / 8;
 				u8 byte = *(vmem + index);
-				u8 bit = byte & (1 << (7 - (j % 8)));
-				bit = bit >> (7 - (j % 8));
+				u8 bit = byte & (1 << (j % 8));
+				bit = bit >> (j % 8);
 				buf |= bit << k;
 			}
 			ssd1307fb_write_data(par->client, buf);