Re: [PATCH] fbdev: ssd1307fb: Fix chargepump setting

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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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


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