linux-kernel - [PATCH] ASoC: rt5665: Fix uninitialized warning in rt5665_i2s_pin

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Date:   Mon, 15 May 2017 10:33:59 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Bard Liao <bardliao@...ltek.com>,
        Oder Chiou <oder_chiou@...ltek.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>
Cc:     Arnd Bergmann <arnd@...db.de>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: [PATCH] ASoC: rt5665: Fix uninitialized warning in rt5665_i2s_pin_event()

With gcc 4.1.2:

    sound/soc/codecs/rt5665.c: In function ‘rt5665_i2s_pin_event’:
    sound/soc/codecs/rt5665.c:2610: warning: ‘mask1’ may be used uninitialized in this function
    sound/soc/codecs/rt5665.c:2610: warning: ‘val2’ may be used uninitialized in this function
    sound/soc/codecs/rt5665.c:2610: warning: ‘val1’ may be used uninitialized in this function

The first one is currently a false positive, as rt5665_i2s_pin_event()
is never called with snd_soc_dapm_widget.shift set to a value not
handled by the switch() statement.  But that may change, so
preinitialize mask1 to fix this, like is already done for mask2.

The last two are false-positives, the compiler is just not smart enough
to notice the mask and val variables are always used together.

Fixes: 9b5d3865b3b410d2 ("ASoC: rt5665: set i2s pin share configuration")
Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
---
 sound/soc/codecs/rt5665.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/sound/soc/codecs/rt5665.c b/sound/soc/codecs/rt5665.c
index 8cd22307f5b6e6ab..5e42f4ee51ba5b20 100644
--- a/sound/soc/codecs/rt5665.c
+++ b/sound/soc/codecs/rt5665.c
@@ -2607,7 +2607,7 @@ static int rt5665_i2s_pin_event(struct snd_soc_dapm_widget *w,
 	struct snd_kcontrol *kcontrol, int event)
 {
 	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);
-	unsigned int val1, val2, mask1, mask2 = 0;
+	unsigned int val1, val2, mask1 = 0, mask2 = 0;
 
 	switch (w->shift) {
 	case RT5665_PWR_I2S2_1_BIT:
@@ -2635,13 +2635,17 @@ static int rt5665_i2s_pin_event(struct snd_soc_dapm_widget *w,
 	}
 	switch (event) {
 	case SND_SOC_DAPM_PRE_PMU:
-		snd_soc_update_bits(codec, RT5665_GPIO_CTRL_1, mask1, val1);
+		if (mask1)
+			snd_soc_update_bits(codec, RT5665_GPIO_CTRL_1,
+					    mask1, val1);
 		if (mask2)
 			snd_soc_update_bits(codec, RT5665_GPIO_CTRL_2,
 					    mask2, val2);
 		break;
 	case SND_SOC_DAPM_POST_PMD:
-		snd_soc_update_bits(codec, RT5665_GPIO_CTRL_1, mask1, 0);
+		if (mask1)
+			snd_soc_update_bits(codec, RT5665_GPIO_CTRL_1,
+					    mask1, 0);
 		if (mask2)
 			snd_soc_update_bits(codec, RT5665_GPIO_CTRL_2,
 					    mask2, 0);
-- 
2.7.4