ASoC: tlv320dac33: Revisit the FIFO Mode1 handling

Replace the hardwired latency definition with platform data
parameter, and simplify the nSample parameter calculation.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

2 files changed, 35 insertions, 37 deletions

diff --git a/include/sound/tlv320dac33-plat.h b/include/sound/tlv320dac33-plat.h
index 3f428d53195b..1aa7bdbc208c 100644
--- a/include/sound/tlv320dac33-plat.h
+++ b/include/sound/tlv320dac33-plat.h
@@ -15,6 +15,7 @@
 
 struct tlv320dac33_platform_data {
         int power_gpio;
+        int mode1_latency; /* latency caused by the i2c writes in us */
         int keep_bclk;  /* Keep the BCLK running in FIFO modes */
         u8 burst_bclkdiv;
 };
diff --git a/sound/soc/codecs/tlv320dac33.c b/sound/soc/codecs/tlv320dac33.c
index 2fa946ce23a2..ced6fbbc9d91 100644
--- a/sound/soc/codecs/tlv320dac33.c
+++ b/sound/soc/codecs/tlv320dac33.c
@@ -49,8 +49,6 @@
 
 #define NSAMPLE_MAX             5700
 
-#define LATENCY_TIME_MS         20
-
 #define MODE7_LTHR              10
 #define MODE7_UTHR              (DAC33_BUFFER_SIZE_SAMPLES - 10)
 
@@ -107,6 +105,8 @@ struct tlv320dac33_priv {
                                          * this */
         enum dac33_fifo_modes fifo_mode;/* FIFO mode selection */
         unsigned int nsample;           /* burst read amount from host */
+        int mode1_latency;              /* latency caused by the i2c writes in
+                                         * us */
         u8 burst_bclkdiv;               /* BCLK divider value in burst mode */
         unsigned int burst_rate;        /* Interface speed in Burst modes */
 
@@ -649,7 +649,7 @@ static inline void dac33_prefill_handler(struct tlv320dac33_priv *dac33)
         switch (dac33->fifo_mode) {
         case DAC33_FIFO_MODE1:
                 dac33_write16(codec, DAC33_NSAMPLE_MSB,
-                        DAC33_THRREG(dac33->nsample + dac33->alarm_threshold));
+                        DAC33_THRREG(dac33->nsample));
 
                 /* Take the timestamps */
                 spin_lock_irq(&dac33->lock);
@@ -798,6 +798,10 @@ static void dac33_shutdown(struct snd_pcm_substream *substream,
         struct tlv320dac33_priv *dac33 = snd_soc_codec_get_drvdata(codec);
 
         dac33->substream = NULL;
+
+        /* Reset the nSample restrictions */
+        dac33->nsample_min = 0;
+        dac33->nsample_max = NSAMPLE_MAX;
 }
 
 static int dac33_hw_params(struct snd_pcm_substream *substream,
@@ -1040,48 +1044,38 @@ static void dac33_calculate_times(struct snd_pcm_substream *substream)
         struct snd_soc_device *socdev = rtd->socdev;
         struct snd_soc_codec *codec = socdev->card->codec;
         struct tlv320dac33_priv *dac33 = snd_soc_codec_get_drvdata(codec);
+        unsigned int period_size = substream->runtime->period_size;
+        unsigned int rate = substream->runtime->rate;
         unsigned int nsample_limit;
 
         /* In bypass mode we don't need to calculate */
         if (!dac33->fifo_mode)
                 return;
 
-        /* Number of samples (16bit, stereo) in one period */
-        dac33->nsample_min = snd_pcm_lib_period_bytes(substream) / 4;
-
-        /* Number of samples (16bit, stereo) in ALSA buffer */
-        dac33->nsample_max = snd_pcm_lib_buffer_bytes(substream) / 4;
-        /* Subtract one period from the total */
-        dac33->nsample_max -= dac33->nsample_min;
-
-        /* Number of samples for LATENCY_TIME_MS / 2 */
-        dac33->alarm_threshold = substream->runtime->rate /
-                                 (1000 / (LATENCY_TIME_MS / 2));
-
-        /* Find and fix up the lowest nsmaple limit */
-        nsample_limit = substream->runtime->rate / (1000 / LATENCY_TIME_MS);
-
-        if (dac33->nsample_min < nsample_limit)
-                dac33->nsample_min = nsample_limit;
-
-        if (dac33->nsample < dac33->nsample_min)
-                dac33->nsample = dac33->nsample_min;
-
-        /*
-         * Find and fix up the highest nsmaple limit
-         * In order to not overflow the DAC33 buffer substract the
-         * alarm_threshold value from the size of the DAC33 buffer
-         */
-        nsample_limit = DAC33_BUFFER_SIZE_SAMPLES - dac33->alarm_threshold;
-
-        if (dac33->nsample_max > nsample_limit)
-                dac33->nsample_max = nsample_limit;
-
-        if (dac33->nsample > dac33->nsample_max)
-                dac33->nsample = dac33->nsample_max;
-
         switch (dac33->fifo_mode) {
         case DAC33_FIFO_MODE1:
+                /* Number of samples under i2c latency */
+                dac33->alarm_threshold = US_TO_SAMPLES(rate,
+                                                dac33->mode1_latency);
+                /* nSample time shall not be shorter than i2c latency */
+                dac33->nsample_min = dac33->alarm_threshold;
+                /*
+                 * nSample should not be bigger than alsa buffer minus
+                 * size of one period to avoid overruns
+                 */
+                dac33->nsample_max = substream->runtime->buffer_size -
+                                        period_size;
+                nsample_limit = DAC33_BUFFER_SIZE_SAMPLES -
+                                dac33->alarm_threshold;
+                if (dac33->nsample_max > nsample_limit)
+                        dac33->nsample_max = nsample_limit;
+
+                /* Correct the nSample if it is outside of the ranges */
+                if (dac33->nsample < dac33->nsample_min)
+                        dac33->nsample = dac33->nsample_min;
+                if (dac33->nsample > dac33->nsample_max)
+                        dac33->nsample = dac33->nsample_max;
+
                 dac33->mode1_us_burst = SAMPLES_TO_US(dac33->burst_rate,
                                                       dac33->nsample);
                 dac33->t_stamp1 = 0;
@@ -1519,6 +1513,9 @@ static int __devinit dac33_i2c_probe(struct i2c_client *client,
         /* Pre calculate the burst rate */
         dac33->burst_rate = BURST_BASEFREQ_HZ / dac33->burst_bclkdiv / 32;
         dac33->keep_bclk = pdata->keep_bclk;
+        dac33->mode1_latency = pdata->mode1_latency;
+        if (!dac33->mode1_latency)
+                dac33->mode1_latency = 10000; /* 10ms */
         dac33->irq = client->irq;
         dac33->nsample = NSAMPLE_MAX;
         dac33->nsample_max = NSAMPLE_MAX;