ASoC: fsl_spdif: add ALSA event on dpll locked

Add an ALSA event on the RX Sample Rate controller upon the dpll locked
interrupt, making it possible for audio applications to monitor changes
in the hardware.
Signed-off-by: Robert Rosengren <robert.rosengren@axis.com>
Acked-by: Shengjiu Wang <shengjiu.wang@gmail.com>
Link: https://lore.kernel.org/r/20220912105407.3157868-1-robert.rosengren@axis.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_spdif.c

@@ -44,6 +44,8 @@ static u8 srpc_dpll_locked[] = { 0x0, 0x1, 0x2, 0x3, 0x4, 0xa, 0xb };
 
 #define DEFAULT_RXCLK_SRC	1
 
+#define RX_SAMPLE_RATE_KCONTROL "RX Sample Rate"
+
 /**
  * struct fsl_spdif_soc_data: soc specific data
  *
@@ -98,6 +100,8 @@ struct spdif_mixer_control {
  * @soc: SPDIF soc data
  * @fsl_spdif_control: SPDIF control data
  * @cpu_dai_drv: cpu dai driver
+ * @snd_card: sound card pointer
+ * @rxrate_kcontrol: kcontrol for RX Sample Rate
  * @pdev: platform device pointer
  * @regmap: regmap handler
  * @dpll_locked: dpll lock flag
@@ -122,6 +126,8 @@ struct fsl_spdif_priv {
 	const struct fsl_spdif_soc_data *soc;
 	struct spdif_mixer_control fsl_spdif_control;
 	struct snd_soc_dai_driver cpu_dai_drv;
+	struct snd_card *snd_card;
+	struct snd_kcontrol *rxrate_kcontrol;
 	struct platform_device *pdev;
 	struct regmap *regmap;
 	bool dpll_locked;
@@ -226,6 +232,12 @@ static void spdif_irq_dpll_lock(struct fsl_spdif_priv *spdif_priv)
 			locked ? "locked" : "loss lock");
 
 	spdif_priv->dpll_locked = locked ? true : false;
+
+	if (spdif_priv->snd_card && spdif_priv->rxrate_kcontrol) {
+		snd_ctl_notify(spdif_priv->snd_card,
+			       SNDRV_CTL_EVENT_MASK_VALUE,
+			       &spdif_priv->rxrate_kcontrol->id);
+	}
 }
 
 /* Receiver found illegal symbol interrupt handler */
@@ -1197,7 +1209,7 @@ static struct snd_kcontrol_new fsl_spdif_ctrls[] = {
 	/* DPLL lock info get controller */
 	{
 		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
-		.name = "RX Sample Rate",
+		.name = RX_SAMPLE_RATE_KCONTROL,
 		.access = SNDRV_CTL_ELEM_ACCESS_READ |
 			SNDRV_CTL_ELEM_ACCESS_VOLATILE,
 		.info = fsl_spdif_rxrate_info,
@@ -1251,6 +1263,13 @@ static int fsl_spdif_dai_probe(struct snd_soc_dai *dai)
 		snd_soc_add_dai_controls(dai, fsl_spdif_ctrls_rcm,
 					 ARRAY_SIZE(fsl_spdif_ctrls_rcm));
 
+	spdif_private->snd_card = dai->component->card->snd_card;
+	spdif_private->rxrate_kcontrol = snd_soc_card_get_kcontrol(dai->component->card,
+								   RX_SAMPLE_RATE_KCONTROL);
+	if (!spdif_private->rxrate_kcontrol)
+		dev_err(&spdif_private->pdev->dev, "failed to get %s kcontrol\n",
+			RX_SAMPLE_RATE_KCONTROL);
+
 	/*Clear the val bit for Tx*/
 	regmap_update_bits(spdif_private->regmap, REG_SPDIF_SCR,
 			   SCR_VAL_MASK, SCR_VAL_CLEAR);