ASoC: meson: axg-toddr: add support for spdifin backend

add IEC958_SUBFRAME_LE to the list of format accepted by the fifo frontend.

As opposed to what was initially noted in the toddr dai driver, the spdifin
does not place the msb at bit 28, it just output a whole spdif subframe.

Placing the msb at bit 28 in the toddr driver just filters out the parity,
user, channel status and validity bits. It is better to just provide the
whole spdif subframe to the userspace and let the iec958 plugin deal with
it.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/meson/axg-fifo.h

@@ -25,7 +25,8 @@ struct snd_soc_pcm_runtime;
 					 SNDRV_PCM_FMTBIT_S16_LE |	\
 					 SNDRV_PCM_FMTBIT_S20_LE |	\
 					 SNDRV_PCM_FMTBIT_S24_LE |	\
-					 SNDRV_PCM_FMTBIT_S32_LE)
+					 SNDRV_PCM_FMTBIT_S32_LE |	\
+					 SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE)
 
 #define AXG_FIFO_BURST			8
 #define AXG_FIFO_MIN_CNT		64

sound/soc/meson/axg-toddr.c

@@ -25,6 +25,8 @@
 #define CTRL0_TODDR_LSB_POS_MASK	GENMASK(7, 3)
 #define CTRL0_TODDR_LSB_POS(x)		((x) << 3)
 
+#define TODDR_MSB_POS	31
+
 static int axg_toddr_pcm_new(struct snd_soc_pcm_runtime *rtd,
 			     struct snd_soc_dai *dai)
 {
@@ -36,14 +38,7 @@ static int axg_toddr_dai_hw_params(struct snd_pcm_substream *substream,
 				   struct snd_soc_dai *dai)
 {
 	struct axg_fifo *fifo = snd_soc_dai_get_drvdata(dai);
-	unsigned int type, width, msb = 31;
-
-	/*
-	 * NOTE:
-	 * Almost all backend will place the MSB at bit 31, except SPDIF Input
-	 * which will put it at index 28. When adding support for the SPDIF
-	 * Input, we'll need to find which type of backend we are connected to.
-	 */
+	unsigned int type, width;
 
 	switch (params_physical_width(params)) {
 	case 8:
@@ -66,8 +61,8 @@ static int axg_toddr_dai_hw_params(struct snd_pcm_substream *substream,
 			   CTRL0_TODDR_MSB_POS_MASK |
 			   CTRL0_TODDR_LSB_POS_MASK,
 			   CTRL0_TODDR_TYPE(type) |
-			   CTRL0_TODDR_MSB_POS(msb) |
-			   CTRL0_TODDR_LSB_POS(msb - (width - 1)));
+			   CTRL0_TODDR_MSB_POS(TODDR_MSB_POS) |
+			   CTRL0_TODDR_LSB_POS(TODDR_MSB_POS - (width - 1)));
 
 	return 0;
 }