[ALSA] at73c213: Add constraints for periods value

The interrupt handler always provide runtime->period_size data, so it
works correctly only if buffer_size was a multiple of period_size.

This patch fixes periodic click noise.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/sound/spi/at73c213.c b/sound/spi/at73c213.c
index aa571152f034..09802e8a6fb8 100644
--- a/sound/spi/at73c213.c
+++ b/sound/spi/at73c213.c
@@ -210,7 +210,13 @@ static int snd_at73c213_pcm_open(struct snd_pcm_substream *substream)
 {
         struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
         struct snd_pcm_runtime *runtime = substream->runtime;
+        int err;
 
+        /* ensure buffer_size is a multiple of period_size */
+        err = snd_pcm_hw_constraint_integer(runtime,
+                                        SNDRV_PCM_HW_PARAM_PERIODS);
+        if (err < 0)
+                return err;
         snd_at73c213_playback_hw.rate_min = chip->bitrate;
         snd_at73c213_playback_hw.rate_max = chip->bitrate;
         runtime->hw = snd_at73c213_playback_hw;