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Date:	Thu, 10 Jul 2014 08:40:01 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Jingoo Han <jg1.han@...sung.com>
Cc:	'Rickard Strandqvist' <rickard_strandqvist@...ctrumdigital.se>,
	'Bryan Wu' <cooloney@...il.com>,
	'Jean-Christophe Plagniol-Villard' <plagnioj@...osoft.com>,
	'Tomi Valkeinen' <tomi.valkeinen@...com>,
	'Linux Fbdev development list' <linux-fbdev@...r.kernel.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] video: backlight: jornada720_lcd.c: Cleaning up variable
 that is never used

On Thu, 10 Jul 2014, Jingoo Han wrote:

> On Thursday, July 10, 2014 7:08 AM, Rickard Strandqvist wrote:
> > 2014-07-09 18:30 GMT+02:00 Lee Jones <lee.jones@...aro.org>:
> > > On Mon, 07 Jul 2014, Rickard Strandqvist wrote:
> > >
> > >> Variable ar assigned a value that is never used.
> > >> I have also removed all the code that thereby serves no purpose,
> > >> and made same change to clarify the similarities in function.
> > >>
> > >> This was found using a static code analysis program called cppcheck
> > >>
> > >> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
> > >> ---
> > >>  drivers/video/backlight/jornada720_lcd.c |   31 ++++++++++++++----------------
> > >>  1 file changed, 14 insertions(+), 17 deletions(-)
> > >>
> > >> diff --git a/drivers/video/backlight/jornada720_lcd.c b/drivers/video/backlight/jornada720_lcd.c
> > >> index da3876c..d16abcf 100644
> > >> --- a/drivers/video/backlight/jornada720_lcd.c
> > >> +++ b/drivers/video/backlight/jornada720_lcd.c
> > >> @@ -36,44 +36,41 @@ static int jornada_lcd_get_power(struct lcd_device *ld)
> > >>
> > >>  static int jornada_lcd_get_contrast(struct lcd_device *ld)
> > >>  {
> > >> -     int ret;
> > >> +     int ret = -ETIMEDOUT;
> > >>
> > >>       if (jornada_lcd_get_power(ld) != FB_BLANK_UNBLANK)
> > >>               return 0;
> > >>
> > >>       jornada_ssp_start();
> > >>
> > >> -     if (jornada_ssp_byte(GETCONTRAST) != TXDUMMY) {
> > >> +     if (jornada_ssp_byte(GETCONTRAST) != TXDUMMY)
> > >>               dev_err(&ld->dev, "get contrast failed\n");
> > >> -             jornada_ssp_end();
> > >> -             return -ETIMEDOUT;
> > >> -     } else {
> > >> +     else
> > >>               ret = jornada_ssp_byte(TXDUMMY);
> > >> -             jornada_ssp_end();
> > >> -             return ret;
> > >> -     }
> > >> +
> > >> +     jornada_ssp_end();
> > >> +
> > >> +     return ret;
> > >>  }
> > >>
> > >>  static int jornada_lcd_set_contrast(struct lcd_device *ld, int value)
> > >>  {
> > >> -     int ret;
> > >> +     int ret = -ETIMEDOUT;
> > >>
> > >>       jornada_ssp_start();
> > >>
> > >>       /* start by sending our set contrast cmd to mcu */
> > >> -     ret = jornada_ssp_byte(SETCONTRAST);
> > >> -
> > >> +     if (jornada_ssp_byte(SETCONTRAST) != TXDUMMY)
> > >> +             dev_err(&ld->dev, "set contrast failed\n");
> > >>       /* push the new value */
> > >> -     if (jornada_ssp_byte(value) != TXDUMMY) {
> > >> +     else if (jornada_ssp_byte(value) != TXDUMMY)
> > >>               dev_err(&ld->dev, "set contrast failed\n");
> > >> -             jornada_ssp_end();
> > >> -             return -ETIMEDOUT;
> > >> -     }
> > >> +     else /* if we get here we can assume everything went well */
> > >> +             ret = 0;
> > >>
> > >> -     /* if we get here we can assume everything went well */
> > >>       jornada_ssp_end();
> > >>
> > >> -     return 0;
> > >> +     return ret;
> > >>  }
> > >>
> > >>  static int jornada_lcd_set_power(struct lcd_device *ld, int power)
> > >
> > > Counter suggestion.
> > >
> > > What do you think, I think this looks cleaner:
> > >
> > > static int jornada_lcd_get_contrast(struct lcd_device *ld)
> > > {
> > >         int ret;
> > >
> > >         if (jornada_lcd_get_power(ld) != FB_BLANK_UNBLANK)
> > >                 return 0;
> > >
> > >         jornada_ssp_start();
> > >
> > >         if (jornada_ssp_byte(GETCONTRAST) == TXDUMMY) {
> > >                 ret = jornada_ssp_byte(TXDUMMY);
> > >                 goto success;
> > >         }
> > >
> > >         dev_err(&ld->dev, "failed to set contrast\n");
> > >         ret = -ETIMEDOUT;
> > >
> > > success:
> > >         jornada_ssp_end();
> > >         return ret;
> > > }
> > >
> > > static int jornada_lcd_set_contrast(struct lcd_device *ld, int value)
> > > {
> > >         int ret = 0;
> > >
> > >         jornada_ssp_start();
> > >
> > >         /* start by sending our set contrast cmd to mcu */
> > >         if (jornada_ssp_byte(SETCONTRAST) == TXDUMMY) {
> > >                 /* if successful, push the new value */
> > >                 if (jornada_ssp_byte(value) == TXDUMMY)
> > >                         goto success;
> > >         }
> > >
> > >         dev_err(&ld->dev, "failed to set contrast\n");
> > >         ret = -ETIMEDOUT;
> > >
> > > success:
> > >         jornada_ssp_end();
> > >         return ret;
> > > }
> > 
> > 
> > Hi Lee!
> > 
> > Yes, I agree!
> > Both are clean without so much repetition of code, which was what annoyd me.
> > But yours is clearer when things go good or bad, nice 1 ;)
> 
> Hi Rickard Strandqvist,
> 
> I would liked to prefer Lee Jones's code. It looks cleaner.
> 
> > 
> > I do not know what I can/may do, but I'll try. Remove what is not ok :-)
> > 
> > Reviewed-by: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
> > Suggested-by: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
> 
> I suggest the following.
> 
> Suggested-by: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
> Signed-off-by: Lee Jones <lee.jones@...aro.org>
> Acked-by: Jingoo Han <jg1.han@...sung.com>
> Cc: Bryan Wu <cooloney@...il.com>

Very well, I will submit as a patch with Jingoo's Ack and Rickard's
Suggested-by and Reviewed-by.  Is anyone able to test this patch?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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