ASoC: da7219: Fix change notifications for tone generator frequency

The tone generator frequency control just returns 0 on successful write, not a boolean value indicating if there was a change or not. Compare what was written with the value that was there previously so that notifications are generated appropriately when the value changes. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220420133437.569229-1-broonie@kernel.org Signed-off-by: Mark Brown <broonie@kernel.org>

Author: broonie

sound/soc/codecs/da7219.c

@@ -446,21 +446,27 @@ static int da7219_tonegen_freq_put(struct snd_kcontrol *kcontrol,
 struct soc_mixer_control *mixer_ctrl =
 (struct soc_mixer_control *) kcontrol->private_value;
 unsigned int reg = mixer_ctrl->reg;
-__le16 val;
+__le16 val_new, val_old;
 int ret;
 
 /*
  * Frequency value spans two 8-bit registers, lower then upper byte.
  * Therefore we need to convert to little endian here to align with
  * HW registers.
  */
-val = cpu_to_le16(ucontrol->value.integer.value[0]);
+val_new = cpu_to_le16(ucontrol->value.integer.value[0]);
 
 mutex_lock(&da7219->ctrl_lock);
-ret = regmap_raw_write(da7219->regmap, reg, &val, sizeof(val));
+ret = regmap_raw_read(da7219->regmap, reg, &val_old, sizeof(val_old));
+if (ret == 0 && (val_old != val_new))
+ret = regmap_raw_write(da7219->regmap, reg,
+&val_new, sizeof(val_new));
 mutex_unlock(&da7219->ctrl_lock);
 
-return ret;
+if (ret < 0)
+return ret;
+
+return val_old != val_new;
 }