linux-kernel - [PATCH 4.19 06/37] ASoC: wm8960: Fix clock configuration on slave mode

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Message-Id: <20211025190929.547841507@linuxfoundation.org>
Date:   Mon, 25 Oct 2021 21:14:31 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Shengjiu Wang <shengjiu.wang@....com>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 06/37] ASoC: wm8960: Fix clock configuration on slave mode

From: Shengjiu Wang <shengjiu.wang@....com>

[ Upstream commit 6b9b546dc00797c74bef491668ce5431ff54e1e2 ]

There is a noise issue for 8kHz sample rate on slave mode.
Compared with master mode, the difference is the DACDIV
setting, after correcting the DACDIV, the noise is gone.

There is no noise issue for 48kHz sample rate, because
the default value of DACDIV is correct for 48kHz.

So wm8960_configure_clocking() should be functional for
ADC and DAC function even if it is slave mode.

In order to be compatible for old use case, just add
condition for checking that sysclk is zero with
slave mode.

Fixes: 0e50b51aa22f ("ASoC: wm8960: Let wm8960 driver configure its bit clock and frame clock")
Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>
Acked-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
Link: https://lore.kernel.org/r/1634102224-3922-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/soc/codecs/wm8960.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index 88e869d16714..abd5c12764f0 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -755,9 +755,16 @@ static int wm8960_configure_clocking(struct snd_soc_component *component)
 	int i, j, k;
 	int ret;
 
-	if (!(iface1 & (1<<6))) {
-		dev_dbg(component->dev,
-			"Codec is slave mode, no need to configure clock\n");
+	/*
+	 * For Slave mode clocking should still be configured,
+	 * so this if statement should be removed, but some platform
+	 * may not work if the sysclk is not configured, to avoid such
+	 * compatible issue, just add '!wm8960->sysclk' condition in
+	 * this if statement.
+	 */
+	if (!(iface1 & (1 << 6)) && !wm8960->sysclk) {
+		dev_warn(component->dev,
+			 "slave mode, but proceeding with no clock configuration\n");
 		return 0;
 	}
 
-- 
2.33.0