Am 29.01.2016 um 12:55 schrieb Tomi Valkeinen:
On 18/01/16 22:20, Julian Scheel wrote:
On 15.11.15 14:36, Julian Scheel wrote:
The charge pump setting must have bit D4 set all time according to the
SSD1306
App Note. Instead of doing an logical and off shifted setting bit with
0x14 it
must be an logical or with 0x10 to ensure D4 is set.
The code change looks ok, but I can't quite decipher the commit
description. "an logical and off shifted setting bit with 0x14"?
Appears I was not awake when writing the commit message. Besides that
the sentence is really cludgy it must be "of" instead of "off".
It might be simplified to: "Applying logical and to 0x14 and the
chargepump bit prevents bit 4 from being set. Fix it by or'ing bit 4 and
the chargepump enable bit"
Signed-off-by: Julian Scheel <julian@xxxxxxxx>
---
drivers/video/fbdev/ssd1307fb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c
b/drivers/video/fbdev/ssd1307fb.c
index 1611215..5965a9b 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -389,7 +389,7 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
return ret;
ret = ssd1307fb_write_cmd(par->client,
- (par->device_info->need_chargepump & 0x1 << 2) & 0x14);
+ 0x10 | ((par->device_info->need_chargepump & 0x01) << 2));
I presume 'need_chargepump' is really supposed to be a bool, instead of
int. And if it's really bool, something like this makes it more readable
to me:
BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0)
Yes, this is easier to read.
Let me update the patch and send a v2.
-Julian
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