linux-kernel - [PATCH AUTOSEL 5.4 006/187] ASoC: max98090: exit workaround earlier if PLL is locked

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Date:   Fri, 27 Dec 2019 12:37:54 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Tzung-Bi Shih <tzungbi@...gle.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>, alsa-devel@...a-project.org
Subject: [PATCH AUTOSEL 5.4 006/187] ASoC: max98090: exit workaround earlier if PLL is locked

From: Tzung-Bi Shih <tzungbi@...gle.com>

[ Upstream commit 6f49919d11690a9b5614445ba30fde18083fdd63 ]

According to the datasheet, PLL lock time typically takes 2 msec and
at most takes 7 msec.

Check the lock status every 1 msec and exit the workaround if PLL is
locked.

Signed-off-by: Tzung-Bi Shih <tzungbi@...gle.com>
Link: https://lore.kernel.org/r/20191122073114.219945-3-tzungbi@google.com
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/soc/codecs/max98090.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/max98090.c b/sound/soc/codecs/max98090.c
index 12cb87c0d463..f531e5a11bdd 100644
--- a/sound/soc/codecs/max98090.c
+++ b/sound/soc/codecs/max98090.c
@@ -2108,6 +2108,8 @@ static void max98090_pll_work(struct work_struct *work)
 	struct max98090_priv *max98090 =
 		container_of(work, struct max98090_priv, pll_work);
 	struct snd_soc_component *component = max98090->component;
+	unsigned int pll;
+	int i;
 
 	if (!snd_soc_component_is_active(component))
 		return;
@@ -2127,8 +2129,16 @@ static void max98090_pll_work(struct work_struct *work)
 	snd_soc_component_update_bits(component, M98090_REG_DEVICE_SHUTDOWN,
 			    M98090_SHDNN_MASK, M98090_SHDNN_MASK);
 
-	/* Give PLL time to lock */
-	msleep(10);
+	for (i = 0; i < 10; ++i) {
+		/* Give PLL time to lock */
+		usleep_range(1000, 1200);
+
+		/* Check lock status */
+		pll = snd_soc_component_read32(
+				component, M98090_REG_DEVICE_STATUS);
+		if (!(pll & M98090_ULK_MASK))
+			break;
+	}
 }
 
 static void max98090_jack_work(struct work_struct *work)
-- 
2.20.1