linux-kernel - [PATCH] ASoC: codecs: va-macro: use fsgen as clock

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Date:   Wed, 27 Jul 2022 13:47:49 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     broonie@...nel.org
Cc:     alsa-devel@...a-project.org, lgirdwood@...il.com, perex@...ex.cz,
        tiwai@...e.com, linux-kernel@...r.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Srinivasa Rao Mandadapu <quic_srivasam@...cinc.com>
Subject: [PATCH] ASoC: codecs: va-macro: use fsgen as clock

VA Macro fsgen clock is supplied to other LPASS Macros using proper
clock apis, however the internal user uses the registers directly without
clk apis. This approch has race condition where in external users of
the clock might cut the clock while VA macro is actively using this.

Moving the internal usage to clk apis would provide a proper refcounting
and avoid such race conditions.

This issue was noticed while headset was pulled out while recording is
in progress and shifting record patch to DMIC.

Reported-by: Srinivasa Rao Mandadapu <quic_srivasam@...cinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 sound/soc/codecs/lpass-va-macro.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/lpass-va-macro.c b/sound/soc/codecs/lpass-va-macro.c
index d18b56e60433..1ea10dc70748 100644
--- a/sound/soc/codecs/lpass-va-macro.c
+++ b/sound/soc/codecs/lpass-va-macro.c
@@ -199,6 +199,7 @@ struct va_macro {
 	struct clk *mclk;
 	struct clk *macro;
 	struct clk *dcodec;
+	struct clk *fsgen;
 	struct clk_hw hw;
 	struct lpass_macro *pds;
 
@@ -467,9 +468,9 @@ static int va_macro_mclk_event(struct snd_soc_dapm_widget *w,
 
 	switch (event) {
 	case SND_SOC_DAPM_PRE_PMU:
-		return va_macro_mclk_enable(va, true);
+		return clk_prepare_enable(va->fsgen);
 	case SND_SOC_DAPM_POST_PMD:
-		return va_macro_mclk_enable(va, false);
+		clk_disable_unprepare(va->fsgen);
 	}
 
 	return 0;
@@ -1473,6 +1474,12 @@ static int va_macro_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_clkout;
 
+	va->fsgen = clk_hw_get_clk(&va->hw, "fsgen");
+	if (IS_ERR(va->fsgen)) {
+		ret = PTR_ERR(va->fsgen);
+		goto err_clkout;
+	}
+
 	ret = devm_snd_soc_register_component(dev, &va_macro_component_drv,
 					      va_macro_dais,
 					      ARRAY_SIZE(va_macro_dais));
-- 
2.25.1