[media] uvcvideo: Add support for control events

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 170 insertions, 14 deletions

diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c
index 0c27cc154eaf..f15a437e5861 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -21,6 +21,7 @@
 #include <linux/vmalloc.h>
 #include <linux/wait.h>
 #include <linux/atomic.h>
+#include <media/v4l2-ctrls.h>
 
 #include "uvcvideo.h"
 
@@ -1102,6 +1103,117 @@ done:
         return ret;
 }
 
+/* --------------------------------------------------------------------------
+ * Ctrl event handling
+ */
+
+static void uvc_ctrl_fill_event(struct uvc_video_chain *chain,
+        struct v4l2_event *ev,
+        struct uvc_control *ctrl,
+        struct uvc_control_mapping *mapping,
+        s32 value, u32 changes)
+{
+        struct v4l2_queryctrl v4l2_ctrl;
+
+        __uvc_query_v4l2_ctrl(chain, ctrl, mapping, &v4l2_ctrl);
+
+        memset(ev->reserved, 0, sizeof(ev->reserved));
+        ev->type = V4L2_EVENT_CTRL;
+        ev->id = v4l2_ctrl.id;
+        ev->u.ctrl.value = value;
+        ev->u.ctrl.changes = changes;
+        ev->u.ctrl.type = v4l2_ctrl.type;
+        ev->u.ctrl.flags = v4l2_ctrl.flags;
+        ev->u.ctrl.minimum = v4l2_ctrl.minimum;
+        ev->u.ctrl.maximum = v4l2_ctrl.maximum;
+        ev->u.ctrl.step = v4l2_ctrl.step;
+        ev->u.ctrl.default_value = v4l2_ctrl.default_value;
+}
+
+static void uvc_ctrl_send_event(struct uvc_fh *handle,
+        struct uvc_control *ctrl, struct uvc_control_mapping *mapping,
+        s32 value, u32 changes)
+{
+        struct v4l2_subscribed_event *sev;
+        struct v4l2_event ev;
+
+        if (list_empty(&mapping->ev_subs))
+                return;
+
+        uvc_ctrl_fill_event(handle->chain, &ev, ctrl, mapping, value, changes);
+
+        list_for_each_entry(sev, &mapping->ev_subs, node) {
+                if (sev->fh && (sev->fh != &handle->vfh ||
+                    (sev->flags & V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK)))
+                        v4l2_event_queue_fh(sev->fh, &ev);
+        }
+}
+
+static void uvc_ctrl_send_events(struct uvc_fh *handle,
+        const struct v4l2_ext_control *xctrls, unsigned int xctrls_count)
+{
+        struct uvc_control_mapping *mapping;
+        struct uvc_control *ctrl;
+        unsigned int i;
+
+        for (i = 0; i < xctrls_count; ++i) {
+                ctrl = uvc_find_control(handle->chain, xctrls[i].id, &mapping);
+                uvc_ctrl_send_event(handle, ctrl, mapping, xctrls[i].value,
+                                    V4L2_EVENT_CTRL_CH_VALUE);
+        }
+}
+
+static int uvc_ctrl_add_event(struct v4l2_subscribed_event *sev)
+{
+        struct uvc_fh *handle = container_of(sev->fh, struct uvc_fh, vfh);
+        struct uvc_control_mapping *mapping;
+        struct uvc_control *ctrl;
+        int ret;
+
+        ret = mutex_lock_interruptible(&handle->chain->ctrl_mutex);
+        if (ret < 0)
+                return -ERESTARTSYS;
+
+        ctrl = uvc_find_control(handle->chain, sev->id, &mapping);
+        if (ctrl == NULL) {
+                ret = -EINVAL;
+                goto done;
+        }
+
+        list_add_tail(&sev->node, &mapping->ev_subs);
+        if (sev->flags & V4L2_EVENT_SUB_FL_SEND_INITIAL) {
+                struct v4l2_event ev;
+                u32 changes = V4L2_EVENT_CTRL_CH_FLAGS;
+                s32 val = 0;
+
+                if (__uvc_ctrl_get(handle->chain, ctrl, mapping, &val) == 0)
+                        changes |= V4L2_EVENT_CTRL_CH_VALUE;
+
+                uvc_ctrl_fill_event(handle->chain, &ev, ctrl, mapping, val,
+                                    changes);
+                v4l2_event_queue_fh(sev->fh, &ev);
+        }
+
+done:
+        mutex_unlock(&handle->chain->ctrl_mutex);
+        return ret;
+}
+
+static void uvc_ctrl_del_event(struct v4l2_subscribed_event *sev)
+{
+        struct uvc_fh *handle = container_of(sev->fh, struct uvc_fh, vfh);
+
+        mutex_lock(&handle->chain->ctrl_mutex);
+        list_del(&sev->node);
+        mutex_unlock(&handle->chain->ctrl_mutex);
+}
+
+const struct v4l2_subscribed_event_ops uvc_ctrl_sub_ev_ops = {
+        .add = uvc_ctrl_add_event,
+        .del = uvc_ctrl_del_event,
+        .replace = v4l2_ctrl_replace,
+        .merge = v4l2_ctrl_merge,
+};
 
 /* --------------------------------------------------------------------------
  * Control transactions
@@ -1179,8 +1291,11 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
         return 0;
 }
 
-int __uvc_ctrl_commit(struct uvc_video_chain *chain, int rollback)
+int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
+                      const struct v4l2_ext_control *xctrls,
+                      unsigned int xctrls_count)
 {
+        struct uvc_video_chain *chain = handle->chain;
         struct uvc_entity *entity;
         int ret = 0;
 
@@ -1191,6 +1306,8 @@ int __uvc_ctrl_commit(struct uvc_video_chain *chain, int rollback)
                         goto done;
         }
 
+        if (!rollback)
+                uvc_ctrl_send_events(handle, xctrls, xctrls_count);
 done:
         mutex_unlock(&chain->ctrl_mutex);
         return ret;
@@ -1662,6 +1779,8 @@ static int __uvc_ctrl_add_mapping(struct uvc_device *dev,
         if (map == NULL)
                 return -ENOMEM;
 
+        INIT_LIST_HEAD(&map->ev_subs);
+
         size = sizeof(*mapping->menu_info) * mapping->menu_count;
         map->menu_info = kmemdup(mapping->menu_info, size, GFP_KERNEL);
         if (map->menu_info == NULL) {
diff --git a/drivers/media/video/uvc/uvc_v4l2.c b/drivers/media/video/uvc/uvc_v4l2.c
index 4ef21e9cb28c..a3322ed81e39 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -25,6 +25,8 @@
 #include <linux/atomic.h>
 
 #include <media/v4l2-common.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
 #include <media/v4l2-ioctl.h>
 
 #include "uvcvideo.h"
@@ -505,6 +507,8 @@ static int uvc_v4l2_open(struct file *file)
                 }
         }
 
+        v4l2_fh_init(&handle->vfh, stream->vdev);
+        v4l2_fh_add(&handle->vfh);
         handle->chain = stream->chain;
         handle->stream = stream;
         handle->state = UVC_HANDLE_PASSIVE;
@@ -528,6 +532,8 @@ static int uvc_v4l2_release(struct file *file)
 
         /* Release the file handle. */
         uvc_dismiss_privileges(handle);
+        v4l2_fh_del(&handle->vfh);
+        v4l2_fh_exit(&handle->vfh);
         kfree(handle);
         file->private_data = NULL;
 
@@ -584,7 +590,7 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                         return ret;
 
                 ret = uvc_ctrl_get(chain, &xctrl);
-                uvc_ctrl_rollback(chain);
+                uvc_ctrl_rollback(handle);
                 if (ret >= 0)
                         ctrl->value = xctrl.value;
                 break;
@@ -605,10 +611,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
                 ret = uvc_ctrl_set(chain, &xctrl);
                 if (ret < 0) {
-                        uvc_ctrl_rollback(chain);
+                        uvc_ctrl_rollback(handle);
                         return ret;
                 }
-                ret = uvc_ctrl_commit(chain);
+                ret = uvc_ctrl_commit(handle, &xctrl, 1);
                 if (ret == 0)
                         ctrl->value = xctrl.value;
                 break;
@@ -630,13 +636,13 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                 for (i = 0; i < ctrls->count; ++ctrl, ++i) {
                         ret = uvc_ctrl_get(chain, ctrl);
                         if (ret < 0) {
-                                uvc_ctrl_rollback(chain);
+                                uvc_ctrl_rollback(handle);
                                 ctrls->error_idx = i;
                                 return ret;
                         }
                 }
                 ctrls->error_idx = 0;
-                ret = uvc_ctrl_rollback(chain);
+                ret = uvc_ctrl_rollback(handle);
                 break;
         }
 
@@ -654,7 +660,7 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                 for (i = 0; i < ctrls->count; ++ctrl, ++i) {
                         ret = uvc_ctrl_set(chain, ctrl);
                         if (ret < 0) {
-                                uvc_ctrl_rollback(chain);
+                                uvc_ctrl_rollback(handle);
                                 ctrls->error_idx = i;
                                 return ret;
                         }
@@ -663,9 +669,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                 ctrls->error_idx = 0;
 
                 if (cmd == VIDIOC_S_EXT_CTRLS)
-                        ret = uvc_ctrl_commit(chain);
+                        ret = uvc_ctrl_commit(handle,
+                                              ctrls->controls, ctrls->count);
                 else
-                        ret = uvc_ctrl_rollback(chain);
+                        ret = uvc_ctrl_rollback(handle);
                 break;
         }
 
@@ -990,6 +997,26 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                 return uvc_video_enable(stream, 0);
         }
 
+        case VIDIOC_SUBSCRIBE_EVENT:
+        {
+                struct v4l2_event_subscription *sub = arg;
+
+                switch (sub->type) {
+                case V4L2_EVENT_CTRL:
+                        return v4l2_event_subscribe(&handle->vfh, sub, 0,
+                                                    &uvc_ctrl_sub_ev_ops);
+                default:
+                        return -EINVAL;
+                }
+        }
+
+        case VIDIOC_UNSUBSCRIBE_EVENT:
+                return v4l2_event_unsubscribe(&handle->vfh, arg);
+
+        case VIDIOC_DQEVENT:
+                return v4l2_event_dequeue(&handle->vfh, arg,
+                                          file->f_flags & O_NONBLOCK);
+
         /* Analog video standards make no sense for digital cameras. */
         case VIDIOC_ENUMSTD:
         case VIDIOC_QUERYSTD:
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index 67f88d85bb16..e43deb715d98 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -13,6 +13,8 @@
 #include <linux/videodev2.h>
 #include <media/media-device.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-fh.h>
 #include <media/videobuf2-core.h>
 
 /* --------------------------------------------------------------------------
@@ -153,6 +155,7 @@ struct uvc_control_info {
 
 struct uvc_control_mapping {
         struct list_head list;
+        struct list_head ev_subs;
 
         struct uvc_control_info *ctrl;
 
@@ -524,6 +527,7 @@ enum uvc_handle_state {
 };
 
 struct uvc_fh {
+        struct v4l2_fh vfh;
         struct uvc_video_chain *chain;
         struct uvc_streaming *stream;
         enum uvc_handle_state state;
@@ -643,6 +647,8 @@ extern int uvc_status_suspend(struct uvc_device *dev);
 extern int uvc_status_resume(struct uvc_device *dev);
 
 /* Controls */
+extern const struct v4l2_subscribed_event_ops uvc_ctrl_sub_ev_ops;
+
 extern int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
                 struct v4l2_queryctrl *v4l2_ctrl);
 extern int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
@@ -655,14 +661,18 @@ extern void uvc_ctrl_cleanup_device(struct uvc_device *dev);
 extern int uvc_ctrl_resume_device(struct uvc_device *dev);
 
 extern int uvc_ctrl_begin(struct uvc_video_chain *chain);
-extern int __uvc_ctrl_commit(struct uvc_video_chain *chain, int rollback);
-static inline int uvc_ctrl_commit(struct uvc_video_chain *chain)
+extern int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
+                        const struct v4l2_ext_control *xctrls,
+                        unsigned int xctrls_count);
+static inline int uvc_ctrl_commit(struct uvc_fh *handle,
+                        const struct v4l2_ext_control *xctrls,
+                        unsigned int xctrls_count)
 {
-        return __uvc_ctrl_commit(chain, 0);
+        return __uvc_ctrl_commit(handle, 0, xctrls, xctrls_count);
 }
-static inline int uvc_ctrl_rollback(struct uvc_video_chain *chain)
+static inline int uvc_ctrl_rollback(struct uvc_fh *handle)
 {
-        return __uvc_ctrl_commit(chain, 1);
+        return __uvc_ctrl_commit(handle, 1, NULL, 0);
 }
 
 extern int uvc_ctrl_get(struct uvc_video_chain *chain,