ASoC: tegra: Fix kcontrol put callback in AMX

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. Filter
out duplicate updates in AMX driver.

Fixes: 77f7df3 ("ASoC: tegra: Add Tegra210 based AMX driver")
Signed-off-by: Sameer Pujar <[email protected]>
Suggested-by: Jaroslav Kysela <[email protected]>
Suggested-by: Mark Brown <[email protected]>
Reviewed-by: Takashi Iwai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: pujars

sound/soc/tegra/tegra210_amx.c

@@ -222,6 +222,9 @@ static int tegra210_amx_put_byte_map(struct snd_kcontrol *kcontrol,
 	int reg = mc->reg;
 	int value = ucontrol->value.integer.value[0];
 
+	if (value == bytes_map[reg])
+		return 0;
+
 	if (value >= 0 && value <= 255) {
 		/* Update byte map and enable slot */
 		bytes_map[reg] = value;