linux-kernel - [PATCH v2] ASoC: tlv320aic32x4: Kernel OOPS while entering DAPM standby mode

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Date:   Mon, 7 Jan 2019 22:30:22 +0530
From:   b-ak <anur.bhargav@...il.com>
To:     Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: [PATCH v2] ASoC: tlv320aic32x4: Kernel OOPS while entering DAPM
 standby mode

During the bootup of the kernel, the DAPM bias level is in the OFF
state. As soon as the DAPM framework kicks in it pushes the codec
into STANDBY state.

The probe function doesn't prepare the clock, and STANDBY state
does a clk_disable_unprepare() without checking the previous state.
This leads to an OOPS.

Not transitioning from an OFF state to the STANDBY state fixes the
problem.

Signed-off-by: b-ak <anur.bhargav@...il.com>
---
 sound/soc/codecs/tlv320aic32x4.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/soc/codecs/tlv320aic32x4.c b/sound/soc/codecs/tlv320aic32x4.c
index e2b5a11b16d1..f03195d2ab2e 100644
--- a/sound/soc/codecs/tlv320aic32x4.c
+++ b/sound/soc/codecs/tlv320aic32x4.c
@@ -822,6 +822,10 @@ static int aic32x4_set_bias_level(struct snd_soc_component *component,
 	case SND_SOC_BIAS_PREPARE:
 		break;
 	case SND_SOC_BIAS_STANDBY:
+		/* Initial cold start */
+		if (snd_soc_component_get_bias_level(component) == SND_SOC_BIAS_OFF)
+			break;
+
 		/* Switch off BCLK_N Divider */
 		snd_soc_component_update_bits(component, AIC32X4_BCLKN,
 				    AIC32X4_BCLKEN, 0);
-- 
2.19.1