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[3/6] ASoC: davinci-mcasp: Active slots depend on active serializers

Message ID 1415615540-28981-4-git-send-email-peter.ujfalusi@ti.com (mailing list archive)
State Accepted
Commit 18a4f55756ac945bd89d1fe63dafe36462ecba86
Headers show

Commit Message

Peter Ujfalusi Nov. 10, 2014, 10:32 a.m. UTC 
From: Misael Lopez Cruz <misael.lopez@ti.com>

Active slots count depends on the number of channels in the stream
and the number of active serializers. Each serializer will handle
at most the number of channels specified via 'tdm-slots' parameter
in DT.

There are two possible scenarios:

- Single serializer: channel count fits in the max slots supported by
  McASP serializers, active slots is same as channel count

- Multiple serializers: channel count is bigger than max slots supported
  by a serializer. Channel count determines how many serializers are
  needed at their max slot count configuration

Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 sound/soc/davinci/davinci-mcasp.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

Comments

Mark Brown Nov. 10, 2014, 3 p.m. UTC | #1 
On Mon, Nov 10, 2014 at 12:32:17PM +0200, Peter Ujfalusi wrote:
> From: Misael Lopez Cruz <misael.lopez@ti.com>
> 
> Active slots count depends on the number of channels in the stream
> and the number of active serializers. Each serializer will handle
> at most the number of channels specified via 'tdm-slots' parameter
> in DT.

Applied, thanks.
diff mbox

Patch

diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index 10ae75e19d99..a9822c7bbb0b 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -629,13 +629,29 @@  static int mcasp_common_hw_param(struct davinci_mcasp *mcasp, int stream,
 	return 0;
 }
 
-static int mcasp_i2s_hw_param(struct davinci_mcasp *mcasp, int stream)
+static int mcasp_i2s_hw_param(struct davinci_mcasp *mcasp, int stream,
+			      int channels)
 {
 	int i, active_slots;
+	int total_slots;
+	int active_serializers;
 	u32 mask = 0;
 	u32 busel = 0;
 
-	active_slots = mcasp->tdm_slots;
+	total_slots = mcasp->tdm_slots;
+
+	/*
+	 * If more than one serializer is needed, then use them with
+	 * their specified tdm_slots count. Otherwise, one serializer
+	 * can cope with the transaction using as many slots as channels
+	 * in the stream, requires channels symmetry
+	 */
+	active_serializers = (channels + total_slots - 1) / total_slots;
+	if (active_serializers == 1)
+		active_slots = channels;
+	else
+		active_slots = total_slots;
+
 	for (i = 0; i < active_slots; i++)
 		mask |= (1 << i);
 
@@ -647,12 +663,12 @@  static int mcasp_i2s_hw_param(struct davinci_mcasp *mcasp, int stream)
 	mcasp_set_reg(mcasp, DAVINCI_MCASP_TXTDM_REG, mask);
 	mcasp_set_bits(mcasp, DAVINCI_MCASP_TXFMT_REG, busel | TXORD);
 	mcasp_mod_bits(mcasp, DAVINCI_MCASP_TXFMCTL_REG,
-		       FSXMOD(active_slots), FSXMOD(0x1FF));
+		       FSXMOD(total_slots), FSXMOD(0x1FF));
 
 	mcasp_set_reg(mcasp, DAVINCI_MCASP_RXTDM_REG, mask);
 	mcasp_set_bits(mcasp, DAVINCI_MCASP_RXFMT_REG, busel | RXORD);
 	mcasp_mod_bits(mcasp, DAVINCI_MCASP_RXFMCTL_REG,
-		       FSRMOD(active_slots), FSRMOD(0x1FF));
+		       FSRMOD(total_slots), FSRMOD(0x1FF));
 
 	return 0;
 }
@@ -766,7 +782,8 @@  static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
 	if (mcasp->op_mode == DAVINCI_MCASP_DIT_MODE)
 		ret = mcasp_dit_hw_param(mcasp, params_rate(params));
 	else
-		ret = mcasp_i2s_hw_param(mcasp, substream->stream);
+		ret = mcasp_i2s_hw_param(mcasp, substream->stream,
+					 channels);
 
 	if (ret)
 		return ret;