linux-kernel - [PATCH] ASoC: stm32: sai: fix sysclk management on shutdown

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Date:   Fri, 18 Oct 2019 10:20:40 +0200
From:   Olivier Moysan <olivier.moysan@...com>
To:     <lgirdwood@...il.com>, <broonie@...nel.org>, <perex@...ex.cz>,
        <tiwai@...e.com>, <mcoquelin.stm32@...il.com>,
        <alexandre.torgue@...com>, <alsa-devel@...a-project.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-kernel@...r.kernel.org>, <olivier.moysan@...com>,
        <arnaud.pouliquen@...com>
CC:     <benjamin.gaignard@...com>
Subject: [PATCH] ASoC: stm32: sai: fix sysclk management on shutdown

The commit below, adds a call to sysclk callback on shutdown.
This introduces a regression in stm32 SAI driver, as some clock
services are called twice, leading to unbalanced calls.
Move processing related to mclk from shutdown to sysclk callback.
When requested frequency is 0, assume shutdown and release mclk.

Fixes: 2458adb8f92a ("SoC: simple-card-utils: set 0Hz to sysclk when shutdown")

Signed-off-by: Olivier Moysan <olivier.moysan@...com>
---
 sound/soc/stm/stm32_sai_sub.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
index d7501f88aaa6..a4060813bc74 100644
--- a/sound/soc/stm/stm32_sai_sub.c
+++ b/sound/soc/stm/stm32_sai_sub.c
@@ -505,10 +505,20 @@ static int stm32_sai_set_sysclk(struct snd_soc_dai *cpu_dai,
 	if (dir == SND_SOC_CLOCK_OUT && sai->sai_mclk) {
 		ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
 					 SAI_XCR1_NODIV,
-					 (unsigned int)~SAI_XCR1_NODIV);
+					 freq ? 0 : SAI_XCR1_NODIV);
 		if (ret < 0)
 			return ret;
 
+		/* Assume shutdown if requested frequency is 0Hz */
+		if (!freq) {
+			/* Release mclk rate only if rate was actually set */
+			if (sai->mclk_rate) {
+				clk_rate_exclusive_put(sai->sai_mclk);
+				sai->mclk_rate = 0;
+			}
+			return 0;
+		}
+
 		/* If master clock is used, set parent clock now */
 		ret = stm32_sai_set_parent_clock(sai, freq);
 		if (ret)
@@ -1093,15 +1103,6 @@ static void stm32_sai_shutdown(struct snd_pcm_substream *substream,
 
 	regmap_update_bits(sai->regmap, STM_SAI_IMR_REGX, SAI_XIMR_MASK, 0);
 
-	regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, SAI_XCR1_NODIV,
-			   SAI_XCR1_NODIV);
-
-	/* Release mclk rate only if rate was actually set */
-	if (sai->mclk_rate) {
-		clk_rate_exclusive_put(sai->sai_mclk);
-		sai->mclk_rate = 0;
-	}
-
 	clk_disable_unprepare(sai->sai_ck);
 
 	spin_lock_irqsave(&sai->irq_lock, flags);
-- 
2.17.1