From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: linux-fbdev@vger.kernel.org
Subject: [PATCH] video: ssd1307fb: Fix bit order bug in the byte translation function
Date: Tue, 18 Dec 2012 13:49:29 +0000 [thread overview]
Message-ID: <1355838569-30225-1-git-send-email-maxime.ripard@free-electrons.com> (raw)
This was leading to a strange behaviour when using the fbcon driver on
top of this one: the letter were in the right order, but each letter was
having 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>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
drivers/video/ssd1307fb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/ssd1307fb.c b/drivers/video/ssd1307fb.c
index 9e46633..7f5f824 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);
--
1.7.9.5
next reply other threads:[~2012-12-18 13:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-18 13:49 Maxime Ripard [this message]
-- strict thread matches above, loose matches on Subject: below --
2013-01-07 16:06 [PATCH] video: ssd1307fb: Fix bit order bug in the byte translation function Maxime Ripard
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