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From:   Arnaud Ferraris <arnaud.ferraris@collabora.com>
To:     alsa-devel@alsa-project.org
Cc:     Timur Tabi <timur@kernel.org>,
        Nicolin Chen <nicoleotsuka@gmail.com>,
        Xiubo Li <Xiubo.Lee@gmail.com>,
        Fabio Estevam <festevam@gmail.com>,
        Shengjiu Wang <shengjiu.wang@gmail.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>, linux-kernel@vger.kernel.org,
        kernel@collabora.com,
        Arnaud Ferraris <arnaud.ferraris@collabora.com>
Subject: [PATCH v2 1/2] ASoC: fsl_asrc: make sure the input and output clocks are different
Date:   Thu, 16 Jul 2020 17:13:52 +0200
Message-Id: <20200716151352.193451-2-arnaud.ferraris@collabora.com>
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 <20200716151352.193451-1-arnaud.ferraris@collabora.com>
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The current clock selection algorithm might select the same clock for
both input and output. This can happen when, for instance, the output
sample rate is a multiple of the input rate.

This patch makes sure it always selects distinct input and output
clocks.

Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>
---
 sound/soc/fsl/fsl_asrc.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
index 02c81d2e34ad..6d43cab6c885 100644
--- a/sound/soc/fsl/fsl_asrc.c
+++ b/sound/soc/fsl/fsl_asrc.c
@@ -608,8 +608,8 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv,
 {
 	struct fsl_asrc_pair_priv *pair_priv = pair->private;
 	struct asrc_config *config = pair_priv->config;
-	int rate[2], select_clk[2]; /* Array size 2 means IN and OUT */
-	int clk_rate, clk_index;
+	int rate[2], select_clk[2], clk_index[2]; /* Array size 2 means IN and OUT */
+	int clk_rate;
 	int i = 0, j = 0;
 
 	rate[IN] = in_rate;
@@ -618,11 +618,12 @@ static void fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv,
 	/* Select proper clock source for internal ratio mode */
 	for (j = 0; j < 2; j++) {
 		for (i = 0; i < ASRC_CLK_MAP_LEN; i++) {
-			clk_index = asrc_priv->clk_map[j][i];
-			clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index]);
+			clk_index[j] = asrc_priv->clk_map[j][i];
+			clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index[j]]);
 			/* Only match a perfect clock source with no remainder */
 			if (clk_rate != 0 && (clk_rate / rate[j]) <= 1024 &&
-			    (clk_rate % rate[j]) == 0)
+			    (clk_rate % rate[j]) == 0 &&
+			    (j == 0 || clk_index[j] != clk_index[j-1]))
 				break;
 		}
 
-- 
2.27.0