| Message ID | 1447594603-3243-1-git-send-email-julian@jusst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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. > > Signed-off-by: Julian Scheel <julian@jusst.de> > --- > 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)); > if (ret < 0) > return ret; > > + Adding Jean-Christophe and Tomi in CC as maintainers and Thomas as the one who did last major changes to the driver. Any objections on this patch? Regards, Julian -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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"? >> Signed-off-by: Julian Scheel <julian@jusst.de> >> --- >> 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) Tomi
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@jusst.de> >>> --- >>> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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)); if (ret < 0) return ret;
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. Signed-off-by: Julian Scheel <julian@jusst.de> --- drivers/video/fbdev/ssd1307fb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)