[PATCH v2 02/10] ASoC: tegra: Fix kcontrol put callback in I2S

[Sameer Pujar <spujar@nvidia.com>]

The kcontrol put callback is expected to return 1 when there is change
in HW or when the update is acknowledged by driver. This would ensure
that change notifications are sent to subscribed applications. Update
the I2S driver accordingly.

Fixes: c0bfa98349d1 ("ASoC: tegra: Add Tegra210 based I2S driver")
Suggested-by: Jaroslav Kysela <perex@perex.cz>
Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
---
 sound/soc/tegra/tegra210_i2s.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/sound/soc/tegra/tegra210_i2s.c b/sound/soc/tegra/tegra210_i2s.c
index 45f31cc..70505b5 100644
--- a/sound/soc/tegra/tegra210_i2s.c
+++ b/sound/soc/tegra/tegra210_i2s.c
@@ -347,6 +347,9 @@ static int tegra210_i2s_put_control(struct snd_kcontrol *kcontrol,
 	int value = ucontrol->value.integer.value[0];
 
 	if (strstr(kcontrol->id.name, "Loopback")) {
+		if (i2s->loopback == value)
+			return 0;
+
 		i2s->loopback = value;
 
 		regmap_update_bits(i2s->regmap, TEGRA210_I2S_CTRL,
@@ -362,6 +365,9 @@ static int tegra210_i2s_put_control(struct snd_kcontrol *kcontrol,
 		 * cases mixer control is used to update custom values. A value
 		 * of "N" here means, width is "N + 1" bit clock wide.
 		 */
+		if (i2s->fsync_width == value)
+			return 0;
+
 		i2s->fsync_width = value;
 
 		regmap_update_bits(i2s->regmap, TEGRA210_I2S_CTRL,
@@ -369,20 +375,38 @@ static int tegra210_i2s_put_control(struct snd_kcontrol *kcontrol,
 				   i2s->fsync_width << I2S_FSYNC_WIDTH_SHIFT);
 
 	} else if (strstr(kcontrol->id.name, "Capture Stereo To Mono")) {
+		if (i2s->stereo_to_mono[I2S_TX_PATH] == value)
+			return 0;
+
 		i2s->stereo_to_mono[I2S_TX_PATH] = value;
 	} else if (strstr(kcontrol->id.name, "Capture Mono To Stereo")) {
+		if (i2s->mono_to_stereo[I2S_TX_PATH] == value)
+			return 0;
+
 		i2s->mono_to_stereo[I2S_TX_PATH] = value;
 	} else if (strstr(kcontrol->id.name, "Playback Stereo To Mono")) {
+		if (i2s->stereo_to_mono[I2S_RX_PATH] == value)
+			return 0;
+
 		i2s->stereo_to_mono[I2S_RX_PATH] = value;
 	} else if (strstr(kcontrol->id.name, "Playback Mono To Stereo")) {
+		if (i2s->mono_to_stereo[I2S_RX_PATH] == value)
+			return 0;
+
 		i2s->mono_to_stereo[I2S_RX_PATH] = value;
 	} else if (strstr(kcontrol->id.name, "Playback FIFO Threshold")) {
+		if (i2s->rx_fifo_th == value)
+			return 0;
+
 		i2s->rx_fifo_th = value;
 	} else if (strstr(kcontrol->id.name, "BCLK Ratio")) {
+		if (i2s->bclk_ratio == value)
+			return 0;
+
 		i2s->bclk_ratio = value;
 	}
 
-	return 0;
+	return 1;
 }
 
 static int tegra210_i2s_set_timing_params(struct device *dev,
-- 
2.7.4