[RFC 16/22] media: Add poll support

Sakari Ailus
2016-05-06T10:56:42Z

Implement poll for events. POLLPRI is used to notify users on incoming
events.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
drivers/media/media-device.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 0b1ab88..2a9bf80 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -956,6 +956,32 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
ioctl_info, ARRAY_SIZE(ioctl_info));
}

+unsigned int media_device_poll(struct file *filp, struct poll_table_struct *wait)
+{
+ struct media_device_fh *fh = media_device_fh(filp);
+ unsigned int poll_events = poll_requested_events(wait);
+ int ret = 0;
+
+ if (poll_events & (POLLIN | POLLOUT))
+ return POLLERR;
+
+ if (poll_events & POLLPRI) {
+ unsigned long flags;
+ bool empty;
+
+ spin_lock_irqsave(&fh->kevents.lock, flags);
+ empty = list_empty(&fh->kevents.head);
+ spin_unlock_irqrestore(&fh->kevents.lock, flags);
+
+ if (empty)
+ poll_wait(filp, &fh->kevents.wait, wait);
+ else
+ ret |= POLLPRI;
+ }
+
+ return ret;
+}
+
#ifdef CONFIG_COMPAT

struct media_links_enum32 {
@@ -1010,6 +1036,7 @@ static const struct media_file_operations media_device_fops = {
.owner = THIS_MODULE,
.open = media_device_open,
.ioctl = media_device_ioctl,
+ .poll = media_device_poll,
#ifdef CONFIG_COMPAT
.compat_ioctl = media_device_compat_ioctl,
#endif /* CONFIG_COMPAT */
--
1.9.1