ALSA: oxfw: Add hwdep interface

This interface is designed for mixer/control application. By using this
interface, an application can get information about firewire node, can
lock/unlock kernel streaming and can get notification at starting/stopping
kernel streaming.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 11 insertions, 1 deletions

diff --git a/sound/firewire/oxfw/oxfw-pcm.c b/sound/firewire/oxfw/oxfw-pcm.c
index e84fc9c4bfd1..9bc556b15a92 100644
--- a/sound/firewire/oxfw/oxfw-pcm.c
+++ b/sound/firewire/oxfw/oxfw-pcm.c
@@ -192,10 +192,14 @@ static int pcm_open(struct snd_pcm_substream *substream)
         struct snd_oxfw *oxfw = substream->private_data;
         int err;
 
-        err = init_hw_params(oxfw, substream);
+        err = snd_oxfw_stream_lock_try(oxfw);
         if (err < 0)
                 goto end;
 
+        err = init_hw_params(oxfw, substream);
+        if (err < 0)
+                goto err_locked;
+
         /*
          * When any PCM streams are already running, the available sampling
          * rate is limited at current value.
@@ -210,10 +214,16 @@ static int pcm_open(struct snd_pcm_substream *substream)
         snd_pcm_set_sync(substream);
 end:
         return err;
+err_locked:
+        snd_oxfw_stream_lock_release(oxfw);
+        return err;
 }
 
 static int pcm_close(struct snd_pcm_substream *substream)
 {
+        struct snd_oxfw *oxfw = substream->private_data;
+
+        snd_oxfw_stream_lock_release(oxfw);
         return 0;
 }