ASoC: atmel_ssc_dai: if not provided, default to sensible dividers

When this driver masters BCLK and/or LRCLK, and noone has stated
differently, assume that all the bits of a frame are used.

This relieves the cpu dai users from the duty to fill in the dividers for
the common case.

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 77 insertions, 7 deletions

diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
index 16e459aedffe..a1e2c5682dcd 100644
--- a/sound/soc/atmel/atmel_ssc_dai.c
+++ b/sound/soc/atmel/atmel_ssc_dai.c
@@ -380,6 +380,7 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
                 ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));
                 /* Clear the SSC dividers */
                 ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
+                ssc_p->forced_divider = 0;
         }
         spin_unlock_irq(&ssc_p->lock);
 
@@ -426,14 +427,17 @@ static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
                 else
                         if (div != ssc_p->cmr_div)
                                 return -EBUSY;
+                ssc_p->forced_divider |= BIT(ATMEL_SSC_CMR_DIV);
                 break;
 
         case ATMEL_SSC_TCMR_PERIOD:
                 ssc_p->tcmr_period = div;
+                ssc_p->forced_divider |= BIT(ATMEL_SSC_TCMR_PERIOD);
                 break;
 
         case ATMEL_SSC_RCMR_PERIOD:
                 ssc_p->rcmr_period = div;
+                ssc_p->forced_divider |= BIT(ATMEL_SSC_RCMR_PERIOD);
                 break;
 
         default:
@@ -443,6 +447,28 @@ static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
         return 0;
 }
 
+/* Is the cpu-dai master of the frame clock? */
+static int atmel_ssc_cfs(struct atmel_ssc_info *ssc_p)
+{
+        switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
+        case SND_SOC_DAIFMT_CBM_CFS:
+        case SND_SOC_DAIFMT_CBS_CFS:
+                return 1;
+        }
+        return 0;
+}
+
+/* Is the cpu-dai master of the bit clock? */
+static int atmel_ssc_cbs(struct atmel_ssc_info *ssc_p)
+{
+        switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
+        case SND_SOC_DAIFMT_CBS_CFM:
+        case SND_SOC_DAIFMT_CBS_CFS:
+                return 1;
+        }
+        return 0;
+}
+
 /*
  * Configure the SSC.
  */
@@ -459,6 +485,9 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
         u32 tfmr, rfmr, tcmr, rcmr;
         int ret;
         int fslen, fslen_ext;
+        u32 cmr_div;
+        u32 tcmr_period;
+        u32 rcmr_period;
 
         /*
          * Currently, there is only one set of dma params for
@@ -470,6 +499,46 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
         else
                 dir = 1;
 
+        /*
+         * If the cpu dai should provide BCLK, but noone has provided the
+         * divider needed for that to work, fall back to something sensible.
+         */
+        cmr_div = ssc_p->cmr_div;
+        if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_CMR_DIV)) &&
+            atmel_ssc_cbs(ssc_p)) {
+                int bclk_rate = snd_soc_params_to_bclk(params);
+
+                if (bclk_rate < 0) {
+                        dev_err(dai->dev, "unable to calculate cmr_div: %d\n",
+                                bclk_rate);
+                        return bclk_rate;
+                }
+
+                cmr_div = DIV_ROUND_CLOSEST(ssc_p->mck_rate, 2 * bclk_rate);
+        }
+
+        /*
+         * If the cpu dai should provide LRCLK, but noone has provided the
+         * dividers needed for that to work, fall back to something sensible.
+         */
+        tcmr_period = ssc_p->tcmr_period;
+        rcmr_period = ssc_p->rcmr_period;
+        if (atmel_ssc_cfs(ssc_p)) {
+                int frame_size = snd_soc_params_to_frame_size(params);
+
+                if (frame_size < 0) {
+                        dev_err(dai->dev,
+                                "unable to calculate tx/rx cmr_period: %d\n",
+                                frame_size);
+                        return frame_size;
+                }
+
+                if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_TCMR_PERIOD)))
+                        tcmr_period = frame_size / 2 - 1;
+                if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_RCMR_PERIOD)))
+                        rcmr_period = frame_size / 2 - 1;
+        }
+
         dma_params = ssc_p->dma_params[dir];
 
         channels = params_channels(params);
@@ -524,7 +593,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
                 fslen_ext = (bits - 1) / 16;
                 fslen = (bits - 1) % 16;
 
-                rcmr =    SSC_BF(RCMR_PERIOD, ssc_p->rcmr_period)
+                rcmr =    SSC_BF(RCMR_PERIOD, rcmr_period)
                         | SSC_BF(RCMR_STTDLY, START_DELAY)
                         | SSC_BF(RCMR_START, SSC_START_FALLING_RF)
                         | SSC_BF(RCMR_CKI, SSC_CKI_RISING)
@@ -540,7 +609,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
                         | SSC_BF(RFMR_LOOP, 0)
                         | SSC_BF(RFMR_DATLEN, (bits - 1));
 
-                tcmr =    SSC_BF(TCMR_PERIOD, ssc_p->tcmr_period)
+                tcmr =    SSC_BF(TCMR_PERIOD, tcmr_period)
                         | SSC_BF(TCMR_STTDLY, START_DELAY)
                         | SSC_BF(TCMR_START, SSC_START_FALLING_RF)
                         | SSC_BF(TCMR_CKI, SSC_CKI_FALLING)
@@ -606,7 +675,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
                 fslen_ext = (bits - 1) / 16;
                 fslen = (bits - 1) % 16;
 
-                rcmr =    SSC_BF(RCMR_PERIOD, ssc_p->rcmr_period)
+                rcmr =    SSC_BF(RCMR_PERIOD, rcmr_period)
                         | SSC_BF(RCMR_STTDLY, START_DELAY)
                         | SSC_BF(RCMR_START, SSC_START_FALLING_RF)
                         | SSC_BF(RCMR_CKI, SSC_CKI_RISING)
@@ -623,7 +692,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
                         | SSC_BF(RFMR_LOOP, 0)
                         | SSC_BF(RFMR_DATLEN, (bits - 1));
 
-                tcmr =    SSC_BF(TCMR_PERIOD, ssc_p->tcmr_period)
+                tcmr =    SSC_BF(TCMR_PERIOD, tcmr_period)
                         | SSC_BF(TCMR_STTDLY, START_DELAY)
                         | SSC_BF(TCMR_START, SSC_START_FALLING_RF)
                         | SSC_BF(TCMR_CKI, SSC_CKI_FALLING)
@@ -650,7 +719,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
                  * MCK divider, and the BCLK signal is output
                  * on the SSC TK line.
                  */
-                rcmr =    SSC_BF(RCMR_PERIOD, ssc_p->rcmr_period)
+                rcmr =    SSC_BF(RCMR_PERIOD, rcmr_period)
                         | SSC_BF(RCMR_STTDLY, 1)
                         | SSC_BF(RCMR_START, SSC_START_RISING_RF)
                         | SSC_BF(RCMR_CKI, SSC_CKI_RISING)
@@ -665,7 +734,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
                         | SSC_BF(RFMR_LOOP, 0)
                         | SSC_BF(RFMR_DATLEN, (bits - 1));
 
-                tcmr =    SSC_BF(TCMR_PERIOD, ssc_p->tcmr_period)
+                tcmr =    SSC_BF(TCMR_PERIOD, tcmr_period)
                         | SSC_BF(TCMR_STTDLY, 1)
                         | SSC_BF(TCMR_START, SSC_START_RISING_RF)
                         | SSC_BF(TCMR_CKI, SSC_CKI_FALLING)
@@ -760,7 +829,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
         }
 
         /* set SSC clock mode register */
-        ssc_writel(ssc_p->ssc->regs, CMR, ssc_p->cmr_div);
+        ssc_writel(ssc_p->ssc->regs, CMR, cmr_div);
 
         /* set receive clock mode and format */
         ssc_writel(ssc_p->ssc->regs, RCMR, rcmr);
diff --git a/sound/soc/atmel/atmel_ssc_dai.h b/sound/soc/atmel/atmel_ssc_dai.h
index 80b153857a88..75194f582131 100644
--- a/sound/soc/atmel/atmel_ssc_dai.h
+++ b/sound/soc/atmel/atmel_ssc_dai.h
@@ -113,6 +113,7 @@ struct atmel_ssc_info {
         unsigned short cmr_div;
         unsigned short tcmr_period;
         unsigned short rcmr_period;
+        unsigned int forced_divider;
         struct atmel_pcm_dma_params *dma_params[2];
         struct atmel_ssc_state ssc_state;
         unsigned long mck_rate;