Re: [PATCH] video: backlight: jornada720_lcd.c: Cleaning up variable that is never used

On Thursday, July 10, 2014 7:08 AM, Rickard Strandqvist wrote:

2014-07-09 18:30 GMT+02:00 Lee Jones [off-list ref]:

quoted

On Mon, 07 Jul 2014, Rickard Strandqvist wrote:

quoted

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 <redacted>
---
 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 <redacted>
Suggested-by: Rickard Strandqvist <redacted>

I suggest the following.

Suggested-by: Rickard Strandqvist <redacted>
Signed-off-by: Lee Jones <redacted>
Acked-by: Jingoo Han <redacted>
Cc: Bryan Wu <redacted>

Best regards,
Jingoo Han

Kind regards
Rickard Strandqvist