[ALSA] pcm: add snd_pcm_rate_to_rate_bit() helper

Add a snd_pcm_rate_to_rate_bit() function to factor out common code used
by several drivers.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 18 insertions, 0 deletions

diff --git a/sound/core/pcm_misc.c b/sound/core/pcm_misc.c
index afd1e4929755..e5f25ae73ee2 100644
--- a/sound/core/pcm_misc.c
+++ b/sound/core/pcm_misc.c
@@ -450,3 +450,21 @@ int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime)
 }
 
 EXPORT_SYMBOL(snd_pcm_limit_hw_rates);
+
+/**
+ * snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit
+ * @rate: the sample rate to convert
+ *
+ * Returns the SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or
+ * SNDRV_PCM_RATE_KNOT for an unknown rate.
+ */
+unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate)
+{
+        unsigned int i;
+
+        for (i = 0; i < snd_pcm_known_rates.count; i++)
+                if (snd_pcm_known_rates.list[i] == rate)
+                        return 1u << i;
+        return SNDRV_PCM_RATE_KNOT;
+}
+EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit);