linux-kernel - [PATCH] ASoC: uniphier: Fix double reset assersion when transitioning to suspend state

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Message-Id: <1566281764-14059-1-git-send-email-hayashi.kunihiko@socionext.com>
Date:   Tue, 20 Aug 2019 15:16:04 +0900
From:   Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
To:     alsa-devel@...a-project.org, Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>
Cc:     Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Subject: [PATCH] ASoC: uniphier: Fix double reset assersion when transitioning to suspend state

When transitioning to supend state, uniphier_aio_dai_suspend() is called
and asserts reset lines and disables clocks.

However, if there are two or more DAIs, uniphier_aio_dai_suspend() are
called multiple times, and double reset assersion will cause.

This patch defines the counter that has the number of DAIs at first, and
whenever uniphier_aio_dai_suspend() are called, it decrements the
counter. And only if the counter is zero, it asserts reset lines and
disables clocks.

In the same way, uniphier_aio_dai_resume() are called, it increments the
counter after deasserting reset lines and enabling clocks.

Fixes: 139a34200233 ("ASoC: uniphier: add support for UniPhier AIO CPU DAI driver")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
---
 sound/soc/uniphier/aio-cpu.c | 31 +++++++++++++++++++++----------
 sound/soc/uniphier/aio.h     |  1 +
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/sound/soc/uniphier/aio-cpu.c b/sound/soc/uniphier/aio-cpu.c
index ee90e6c..2ae582a 100644
--- a/sound/soc/uniphier/aio-cpu.c
+++ b/sound/soc/uniphier/aio-cpu.c
@@ -424,8 +424,11 @@ int uniphier_aio_dai_suspend(struct snd_soc_dai *dai)
 {
 	struct uniphier_aio *aio = uniphier_priv(dai);
 
-	reset_control_assert(aio->chip->rst);
-	clk_disable_unprepare(aio->chip->clk);
+	aio->chip->num_wup_aios--;
+	if (!aio->chip->num_wup_aios) {
+		reset_control_assert(aio->chip->rst);
+		clk_disable_unprepare(aio->chip->clk);
+	}
 
 	return 0;
 }
@@ -439,13 +442,15 @@ int uniphier_aio_dai_resume(struct snd_soc_dai *dai)
 	if (!aio->chip->active)
 		return 0;
 
-	ret = clk_prepare_enable(aio->chip->clk);
-	if (ret)
-		return ret;
+	if (!aio->chip->num_wup_aios) {
+		ret = clk_prepare_enable(aio->chip->clk);
+		if (ret)
+			return ret;
 
-	ret = reset_control_deassert(aio->chip->rst);
-	if (ret)
-		goto err_out_clock;
+		ret = reset_control_deassert(aio->chip->rst);
+		if (ret)
+			goto err_out_clock;
+	}
 
 	aio_iecout_set_enable(aio->chip, true);
 	aio_chip_init(aio->chip);
@@ -458,7 +463,7 @@ int uniphier_aio_dai_resume(struct snd_soc_dai *dai)
 
 		ret = aio_init(sub);
 		if (ret)
-			goto err_out_clock;
+			goto err_out_reset;
 
 		if (!sub->setting)
 			continue;
@@ -466,11 +471,16 @@ int uniphier_aio_dai_resume(struct snd_soc_dai *dai)
 		aio_port_reset(sub);
 		aio_src_reset(sub);
 	}
+	aio->chip->num_wup_aios++;
 
 	return 0;
 
+err_out_reset:
+	if (!aio->chip->num_wup_aios)
+		reset_control_assert(aio->chip->rst);
 err_out_clock:
-	clk_disable_unprepare(aio->chip->clk);
+	if (!aio->chip->num_wup_aios)
+		clk_disable_unprepare(aio->chip->clk);
 
 	return ret;
 }
@@ -619,6 +629,7 @@ int uniphier_aio_probe(struct platform_device *pdev)
 		return PTR_ERR(chip->rst);
 
 	chip->num_aios = chip->chip_spec->num_dais;
+	chip->num_wup_aios = chip->num_aios;
 	chip->aios = devm_kcalloc(dev,
 				  chip->num_aios, sizeof(struct uniphier_aio),
 				  GFP_KERNEL);
diff --git a/sound/soc/uniphier/aio.h b/sound/soc/uniphier/aio.h
index ca6ccba..a7ff7e5 100644
--- a/sound/soc/uniphier/aio.h
+++ b/sound/soc/uniphier/aio.h
@@ -285,6 +285,7 @@ struct uniphier_aio_chip {
 
 	struct uniphier_aio *aios;
 	int num_aios;
+	int num_wup_aios;
 	struct uniphier_aio_pll *plls;
 	int num_plls;
 
-- 
2.7.4