1 files changed, 34 insertions, 11 deletions

diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
index 0bf91a6f54b9..a3cfceea7d2f 100644
--- a/sound/soc/fsl/fsl_asrc.c
+++ b/sound/soc/fsl/fsl_asrc.c
@@ -259,8 +259,15 @@ static int fsl_asrc_set_ideal_ratio(struct fsl_asrc_pair *pair,
  * It configures those ASRC registers according to a configuration instance
  * of struct asrc_config which includes in/output sample rate, width, channel
  * and clock settings.
+ *
+ * Note:
+ * The ideal ratio configuration can work with a flexible clock rate setting.
+ * Using IDEAL_RATIO_RATE gives a faster converting speed but overloads ASRC.
+ * For a regular audio playback, the clock rate should not be slower than an
+ * clock rate aligning with the output sample rate; For a use case requiring
+ * faster conversion, set use_ideal_rate to have the faster speed.
  */
-static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair)
+static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair, bool use_ideal_rate)
 {
 	struct asrc_config *config = pair->config;
 	struct fsl_asrc *asrc_priv = pair->asrc_priv;
@@ -268,7 +275,8 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair)
 	enum asrc_word_width input_word_width;
 	enum asrc_word_width output_word_width;
 	u32 inrate, outrate, indiv, outdiv;
-	u32 clk_index[2], div[2];
+	u32 clk_index[2], div[2], rem[2];
+	u64 clk_rate;
 	int in, out, channels;
 	int pre_proc, post_proc;
 	struct clk *clk;
@@ -351,27 +359,42 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair)
 	/* We only have output clock for ideal ratio mode */
 	clk = asrc_priv->asrck_clk[clk_index[ideal ? OUT : IN]];
 
-	div[IN] = clk_get_rate(clk) / inrate;
-	if (div[IN] == 0) {
+	clk_rate = clk_get_rate(clk);
+	rem[IN] = do_div(clk_rate, inrate);
+	div[IN] = (u32)clk_rate;
+
+	/*
+	 * The divider range is [1, 1024], defined by the hardware. For non-
+	 * ideal ratio configuration, clock rate has to be strictly aligned
+	 * with the sample rate. For ideal ratio configuration, clock rates
+	 * only result in different converting speeds. So remainder does not
+	 * matter, as long as we keep the divider within its valid range.
+	 */
+	if (div[IN] == 0 || (!ideal && (div[IN] > 1024 || rem[IN] != 0))) {
 		pair_err("failed to support input sample rate %dHz by asrck_%x\n",
 				inrate, clk_index[ideal ? OUT : IN]);
 		return -EINVAL;
 	}
 
-	clk = asrc_priv->asrck_clk[clk_index[OUT]];
+	div[IN] = min_t(u32, 1024, div[IN]);
 
-	/* Use fixed output rate for Ideal Ratio mode (INCLK_NONE) */
-	if (ideal)
-		div[OUT] = clk_get_rate(clk) / IDEAL_RATIO_RATE;
+	clk = asrc_priv->asrck_clk[clk_index[OUT]];
+	clk_rate = clk_get_rate(clk);
+	if (ideal && use_ideal_rate)
+		rem[OUT] = do_div(clk_rate, IDEAL_RATIO_RATE);
 	else
-		div[OUT] = clk_get_rate(clk) / outrate;
+		rem[OUT] = do_div(clk_rate, outrate);
+	div[OUT] = clk_rate;
 
-	if (div[OUT] == 0) {
+	/* Output divider has the same limitation as the input one */
+	if (div[OUT] == 0 || (!ideal && (div[OUT] > 1024 || rem[OUT] != 0))) {
 		pair_err("failed to support output sample rate %dHz by asrck_%x\n",
 				outrate, clk_index[OUT]);
 		return -EINVAL;
 	}
 
+	div[OUT] = min_t(u32, 1024, div[OUT]);
+
 	/* Set the channel number */
 	channels = config->channel_num;
 
@@ -560,7 +583,7 @@ static int fsl_asrc_dai_hw_params(struct snd_pcm_substream *substream,
 		config.output_sample_rate = rate;
 	}
 
-	ret = fsl_asrc_config_pair(pair);
+	ret = fsl_asrc_config_pair(pair, false);
 	if (ret) {
 		dev_err(dai->dev, "fail to config asrc pair\n");
 		return ret;