ASoC: omap-mcbsp: Save, and use wlen for threshold configuration

Save the word length configuration of McBSP, and use that information
to calculate, and configure the threshold in McBSP.
Previously the calculation was only correct when the stream had 16bit
audio.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

sound/soc/omap/omap-mcbsp.c

@@ -59,6 +59,7 @@ struct omap_mcbsp_data {
 	int				configured;
 	unsigned int			in_freq;
 	int				clk_div;
+	int				wlen;
 };
 
 #define to_mcbsp(priv)	container_of((priv), struct omap_mcbsp_data, bus_id)
@@ -155,19 +156,21 @@ static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
 	struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
 	struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
 	int dma_op_mode = omap_mcbsp_get_dma_op_mode(mcbsp_data->bus_id);
-	int samples;
+	int words;
 
 	/* TODO: Currently, MODE_ELEMENT == MODE_FRAME */
 	if (dma_op_mode == MCBSP_DMA_MODE_THRESHOLD)
-		samples = snd_pcm_lib_period_bytes(substream) >> 1;
+		/* The FIFO size depends on the McBSP word configuration */
+		words = snd_pcm_lib_period_bytes(substream) /
+							(mcbsp_data->wlen / 8);
 	else
-		samples = 1;
+		words = 1;
 
 	/* Configure McBSP internal buffer usage */
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-		omap_mcbsp_set_tx_threshold(mcbsp_data->bus_id, samples - 1);
+		omap_mcbsp_set_tx_threshold(mcbsp_data->bus_id, words);
 	else
-		omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, samples - 1);
+		omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, words);
 }
 
 static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
@@ -409,6 +412,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
 	}
 
 	omap_mcbsp_config(bus_id, &mcbsp_data->regs);
+	mcbsp_data->wlen = wlen;
 	mcbsp_data->configured = 1;
 
 	return 0;