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authorPankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>2017-01-11 08:57:06 +0530
committerPankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>2017-01-11 10:38:28 +0530
commit010121a131a8092ca7cfc9e219b6fb1e3f4346bf (patch)
treeb3d0a62040df593cdc8513ca509f3fcbc0205733 /src
parent3e9a64211e76529aae4ff08e7a661bcffdee02a5 (diff)
Tinyalsa: Add support to poll on alsa control
ALSA controls support polling on the kcontrols, this is used in HD-A for jack notifcation. In tinyalsa we can use this for notfication from sound card for any events detected by DSP Change-Id: I4193809bfcdb60f4dc11e1c2ad6a07b29cfa80e9 Signed-off-by: Hardik T Shah <hardik.t.shah@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Diffstat (limited to 'src')
-rw-r--r--src/mixer.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/src/mixer.c b/src/mixer.c
index b7239fd..73fbc66 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -36,6 +36,7 @@
#include <ctype.h>
#include <limits.h>
#include <time.h>
+#include <poll.h>
#include <sys/ioctl.h>
@@ -302,6 +303,49 @@ unsigned int mixer_get_num_ctls_by_name(const struct mixer *mixer, const char *n
return count;
}
+/** Subscribes for the mixer events.
+ * @param mixer A mixer handle.
+ * @param subscribe value indicating subscribe or unsubscribe for events
+ * @returns On success, zero.
+ * On failure, non-zero.
+ * @ingroup libtinyalsa-mixer
+ */
+int mixer_subscribe_events(struct mixer *mixer, int subscribe)
+{
+ if (ioctl(mixer->fd, SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS, &subscribe) < 0) {
+ return -1;
+ }
+ return 0;
+}
+
+/** Wait for mixer events.
+ * @param mixer A mixer handle.
+ * @param timeout timout value
+ * @returns On success, zero.
+ * On failure, non-zero.
+ * @ingroup libtinyalsa-mixer
+ */
+int mixer_wait_event(struct mixer *mixer, int timeout)
+{
+ struct pollfd pfd;
+
+ pfd.fd = mixer->fd;
+ pfd.events = POLLIN | POLLOUT | POLLERR | POLLNVAL;
+
+ for (;;) {
+ int err;
+ err = poll(&pfd, 1, timeout);
+ if (err < 0)
+ return -errno;
+ if (!err)
+ return 0;
+ if (pfd.revents & (POLLERR | POLLNVAL))
+ return -EIO;
+ if (pfd.revents & (POLLIN | POLLOUT))
+ return 1;
+ }
+}
+
/** Gets a mixer control handle, by the mixer control's id.
* For non-const access, see @ref mixer_get_ctl
* @param mixer An initialized mixer handle.