Am Sat, 23 May 2015 20:32:45 +0300 schrieb Dan Carpenter <dan.carpenter@xxxxxxxxxx>: > Hello Thomas Niederprüm, > > The patch a3998fe03e87: "fbdev: ssd1307fb: Unify init code and obtain > hw specific bits from DT" from Mar 31, 2015, leads to the following > static checker warning: > > drivers/video/fbdev/ssd1307fb.c:371 ssd1307fb_init() > warn: add some parenthesis here? > > drivers/video/fbdev/ssd1307fb.c > 366 /* Set COM pins configuration */ > 367 ret = ssd1307fb_write_cmd(par->client, > SSD1307FB_SET_COM_PINS_CONFIG); 368 if (ret < 0) > 369 return ret; > 370 > 371 compins = 0x02 | (!par->com_seq & 0x1) << 4 > 372 | (par->com_lrremap & 0x1) > << 5; > > Smatch is complaining because it's normally "!par->com_seq & 0x1" is > a bug and "!(par->com_seq & 0x1)" is intended. I don't know what was > intended here though. If the current code is correct, you can silence > the static checker warning by writing it as "(!par->com_seq) & 0x1". Indeed "!(par->com_seq & 0x1)" is what I intended. Thanks for spotting this. What is the best way to handle this now? Will you send a fixup patch as for the backlight code or will this be my task? > > But I also have a hard time remembering if | or << is higher > precedence so that might be clearer with parenthesis as well even > though the code is clearly correct when I google for "order of > operations" in C. > > 373 ret = ssd1307fb_write_cmd(par->client, compins); > 374 if (ret < 0) > 375 return ret; > Thanks! Thomas -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
