ASoC: rsnd: more clear rsnd_get_dalign() for DALIGN

On Renesas sound device, DALIGN which exchanges channel position
is needed because SW and HW are using defferent data order if
16bit data. It is not needed when 24bit data.
rsnd_get_dalign() returns necessary value, but it was confusable
code. This patch makes it more simple.
Tested-by: NHiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/sh/rcar/core.c

@@ -294,11 +294,12 @@ u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
 	struct rsnd_mod *ssiu = rsnd_io_to_mod_ssiu(io);
 	struct rsnd_mod *target;
 	struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
-	u32 val = 0x76543210;
-	u32 mask = ~0;
 
 	/*
-	 * *Hardware* L/R and *Software* L/R are inverted.
+	 * *Hardware* L/R and *Software* L/R are inverted for 16bit data.
+	 *	    31..16 15...0
+	 *	HW: [L ch] [R ch]
+	 *	SW: [R ch] [L ch]
 	 * We need to care about inversion timing to control
 	 * Playback/Capture correctly.
 	 * The point is [DVC] needs *Hardware* L/R, [MEM] needs *Software* L/R
@@ -325,27 +326,13 @@ u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
 		target = cmd ? cmd : ssiu;
 	}
 
-	mask <<= runtime->channels * 4;
-	val = val & mask;
-
-	switch (runtime->sample_bits) {
-	case 16:
-		val |= 0x67452301 & ~mask;
-		break;
-	case 32:
-		val |= 0x76543210 & ~mask;
-		break;
-	}
-
-	/*
-	 * exchange channeles on SRC if possible,
-	 * otherwise, R/L volume settings on DVC
-	 * changes inverted channels
-	 */
-	if (mod == target)
-		return val;
-	else
+	/* Non target mod or 24bit data needs normal DALIGN */
+	if ((runtime->sample_bits != 16) ||
+	    (mod != target))
 		return 0x76543210;
+	/* Target mod needs inverted DALIGN when 16bit */
+	else
+		return 0x67452301;
 }
 
 u32 rsnd_get_busif_shift(struct rsnd_dai_stream *io, struct rsnd_mod *mod)