ASoC: Use network mode with 2 slots for 16-bit stereo in pxa-ssp/Zylonite

For consistency with 24-bit and 32-bit modes, don't send 16-bit stereo
in one 32-bit transfer. Use 2 slots instead on Zylonite. It should result
in exactly the same behaviour.
Now it is possible to use 16-bit single slot transfers in pxa-ssp, which
are needed for Magician to get two frame clock pulses per sample
(one for each channel).
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Tested-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/pxa/pxa-ssp.c

@@ -644,8 +644,7 @@ static int pxa_ssp_hw_params(struct snd_pcm_substream *substream,
 			sscr0 |= SSCR0_FPCKE;
 #endif
 		sscr0 |= SSCR0_DataSize(16);
-		if (params_channels(params) > 1)
-			sscr0 |= SSCR0_EDSS;
+		/* use network mode (2 slots) for 16 bit stereo */
 		break;
 	case SNDRV_PCM_FORMAT_S24_LE:
 		sscr0 |= (SSCR0_EDSS | SSCR0_DataSize(8));

sound/soc/pxa/zylonite.c

@@ -127,8 +127,11 @@ static int zylonite_voice_hw_params(struct snd_pcm_substream *substream,
 	if (ret < 0)
 		return ret;
 
-	/* We're not really in network mode but the emulation wants this. */
-	ret = snd_soc_dai_set_tdm_slot(cpu_dai, 1, 1);
+	/* Use network mode for stereo, one slot per channel. */
+	if (params_channels(params) > 1)
+		ret = snd_soc_dai_set_tdm_slot(cpu_dai, 0x3, 2);
+	else
+		ret = snd_soc_dai_set_tdm_slot(cpu_dai, 1, 1);
 	if (ret < 0)
 		return ret;