ASoC/mpc5200: fix enable/disable of AC97 slots

The MPC5200 AC97 driver is disabling the slots when a stop
trigger is received, but not reenabling them if the stream
is started again without processing the hw_params again.

This patch fixes the problem by caching the slot enable bit
settings calculated at hw_params time so that they can be
reapplied every time the start trigger is received.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 25 insertions, 18 deletions

diff --git a/sound/soc/fsl/mpc5200_dma.h b/sound/soc/fsl/mpc5200_dma.h
index 956d6a5f5a8c..22208b373fb9 100644
--- a/sound/soc/fsl/mpc5200_dma.h
+++ b/sound/soc/fsl/mpc5200_dma.h
@@ -16,6 +16,7 @@
  * @period_end:         physical address of end of DMA region
  * @period_next_pt:     physical address of next DMA buffer to enqueue
  * @period_bytes:       size of DMA period in bytes
+ * @ac97_slot_bits:     Enable bits for turning on the correct AC97 slot
  */
 struct psc_dma_stream {
         struct snd_pcm_runtime *runtime;
@@ -28,6 +29,9 @@ struct psc_dma_stream {
         int period_current;
         int period_bytes;
         int period_count;
+
+        /* AC97 state */
+        u32 ac97_slot_bits;
 };
 
 /**
diff --git a/sound/soc/fsl/mpc5200_psc_ac97.c b/sound/soc/fsl/mpc5200_psc_ac97.c
index c4ae3e096bb9..3dbc7f7cd7b9 100644
--- a/sound/soc/fsl/mpc5200_psc_ac97.c
+++ b/sound/soc/fsl/mpc5200_psc_ac97.c
@@ -130,6 +130,7 @@ static int psc_ac97_hw_analog_params(struct snd_pcm_substream *substream,
                                  struct snd_soc_dai *cpu_dai)
 {
         struct psc_dma *psc_dma = cpu_dai->private_data;
+        struct psc_dma_stream *s = to_psc_dma_stream(substream, psc_dma);
 
         dev_dbg(psc_dma->dev, "%s(substream=%p) p_size=%i p_bytes=%i"
                 " periods=%i buffer_size=%i  buffer_bytes=%i channels=%i"
@@ -140,20 +141,10 @@ static int psc_ac97_hw_analog_params(struct snd_pcm_substream *substream,
                 params_channels(params), params_rate(params),
                 params_format(params));
 
-
-        if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
-                if (params_channels(params) == 1)
-                        psc_dma->slots |= 0x00000100;
-                else
-                        psc_dma->slots |= 0x00000300;
-        } else {
-                if (params_channels(params) == 1)
-                        psc_dma->slots |= 0x01000000;
-                else
-                        psc_dma->slots |= 0x03000000;
-        }
-        out_be32(&psc_dma->psc_regs->ac97_slots, psc_dma->slots);
-
+        /* Determine the set of enable bits to turn on */
+        s->ac97_slot_bits = (params_channels(params) == 1) ? 0x100 : 0x300;
+        if (substream->pstr->stream != SNDRV_PCM_STREAM_CAPTURE)
+                s->ac97_slot_bits <<= 16;
         return 0;
 }
 
@@ -163,6 +154,8 @@ static int psc_ac97_hw_digital_params(struct snd_pcm_substream *substream,
 {
         struct psc_dma *psc_dma = cpu_dai->private_data;
 
+        dev_dbg(psc_dma->dev, "%s(substream=%p)\n", __func__, substream);
+
         if (params_channels(params) == 1)
                 out_be32(&psc_dma->psc_regs->ac97_slots, 0x01000000);
         else
@@ -176,14 +169,24 @@ static int psc_ac97_trigger(struct snd_pcm_substream *substream, int cmd,
 {
         struct snd_soc_pcm_runtime *rtd = substream->private_data;
         struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
+        struct psc_dma_stream *s = to_psc_dma_stream(substream, psc_dma);
 
         switch (cmd) {
+        case SNDRV_PCM_TRIGGER_START:
+                dev_dbg(psc_dma->dev, "AC97 START: stream=%i\n",
+                        substream->pstr->stream);
+
+                /* Set the slot enable bits */
+                psc_dma->slots |= s->ac97_slot_bits;
+                out_be32(&psc_dma->psc_regs->ac97_slots, psc_dma->slots);
+                break;
+
         case SNDRV_PCM_TRIGGER_STOP:
-                if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
-                        psc_dma->slots &= 0xFFFF0000;
-                else
-                        psc_dma->slots &= 0x0000FFFF;
+                dev_dbg(psc_dma->dev, "AC97 STOP: stream=%i\n",
+                        substream->pstr->stream);
 
+                /* Clear the slot enable bits */
+                psc_dma->slots &= ~(s->ac97_slot_bits);
                 out_be32(&psc_dma->psc_regs->ac97_slots, psc_dma->slots);
                 break;
         }