ASoC: atmel-i2s: Fix usage of capture and playback at the same time

[ Upstream commit 3b7961a ]

For both capture and playback streams to work at the same time, only the
needed values from a register need to be updated. Also, clocks should be
enabled only when the first stream is started and stopped when there is no
running stream.

Fixes: b543e46 ("ASoC: atmel-i2s: add driver for the new Atmel I2S controller")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20210618150741.401739-2-codrin.ciubotariu@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

sound/soc/atmel/atmel-i2s.c

@@ -200,6 +200,7 @@ struct atmel_i2s_dev {
 	unsigned int				fmt;
 	const struct atmel_i2s_gck_param	*gck_param;
 	const struct atmel_i2s_caps		*caps;
+	int					clk_use_no;
 };
 
 static irqreturn_t atmel_i2s_interrupt(int irq, void *dev_id)
@@ -321,9 +322,16 @@ static int atmel_i2s_hw_params(struct snd_pcm_substream *substream,
 {
 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
-	unsigned int mr = 0;
+	unsigned int mr = 0, mr_mask;
 	int ret;
 
+	mr_mask = ATMEL_I2SC_MR_FORMAT_MASK | ATMEL_I2SC_MR_MODE_MASK |
+		ATMEL_I2SC_MR_DATALENGTH_MASK;
+	if (is_playback)
+		mr_mask |= ATMEL_I2SC_MR_TXMONO;
+	else
+		mr_mask |= ATMEL_I2SC_MR_RXMONO;
+
 	switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
 	case SND_SOC_DAIFMT_I2S:
 		mr |= ATMEL_I2SC_MR_FORMAT_I2S;
@@ -402,7 +410,7 @@ static int atmel_i2s_hw_params(struct snd_pcm_substream *substream,
 		return -EINVAL;
 	}
 
-	return regmap_write(dev->regmap, ATMEL_I2SC_MR, mr);
+	return regmap_update_bits(dev->regmap, ATMEL_I2SC_MR, mr_mask, mr);
 }
 
 static int atmel_i2s_switch_mck_generator(struct atmel_i2s_dev *dev,
@@ -495,18 +503,28 @@ static int atmel_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
 	is_master = (mr & ATMEL_I2SC_MR_MODE_MASK) == ATMEL_I2SC_MR_MODE_MASTER;
 
 	/* If master starts, enable the audio clock. */
-	if (is_master && mck_enabled)
-		err = atmel_i2s_switch_mck_generator(dev, true);
-	if (err)
-		return err;
+	if (is_master && mck_enabled) {
+		if (!dev->clk_use_no) {
+			err = atmel_i2s_switch_mck_generator(dev, true);
+			if (err)
+				return err;
+		}
+		dev->clk_use_no++;
+	}
 
 	err = regmap_write(dev->regmap, ATMEL_I2SC_CR, cr);
 	if (err)
 		return err;
 
 	/* If master stops, disable the audio clock. */
-	if (is_master && !mck_enabled)
-		err = atmel_i2s_switch_mck_generator(dev, false);
+	if (is_master && !mck_enabled) {
+		if (dev->clk_use_no == 1) {
+			err = atmel_i2s_switch_mck_generator(dev, false);
+			if (err)
+				return err;
+		}
+		dev->clk_use_no--;
+	}
 
 	return err;
 }