diff options
Diffstat (limited to 'drivers/media/video/uvc/uvc_ctrl.c')
| -rw-r--r-- | drivers/media/video/uvc/uvc_ctrl.c | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c index f169f773667..59f8a9ad379 100644 --- a/drivers/media/video/uvc/uvc_ctrl.c +++ b/drivers/media/video/uvc/uvc_ctrl.c @@ -785,7 +785,7 @@ static void __uvc_find_control(struct uvc_entity *entity, __u32 v4l2_id, } } -struct uvc_control *uvc_find_control(struct uvc_video_chain *chain, +static struct uvc_control *uvc_find_control(struct uvc_video_chain *chain, __u32 v4l2_id, struct uvc_control_mapping **mapping) { struct uvc_control *ctrl = NULL; @@ -944,6 +944,52 @@ done: return ret; } +/* + * Mapping V4L2 controls to UVC controls can be straighforward if done well. + * Most of the UVC controls exist in V4L2, and can be mapped directly. Some + * must be grouped (for instance the Red Balance, Blue Balance and Do White + * Balance V4L2 controls use the White Balance Component UVC control) or + * otherwise translated. The approach we take here is to use a translation + * table for the controls that can be mapped directly, and handle the others + * manually. + */ +int uvc_query_v4l2_menu(struct uvc_video_chain *chain, + struct v4l2_querymenu *query_menu) +{ + struct uvc_menu_info *menu_info; + struct uvc_control_mapping *mapping; + struct uvc_control *ctrl; + u32 index = query_menu->index; + u32 id = query_menu->id; + int ret; + + memset(query_menu, 0, sizeof(*query_menu)); + query_menu->id = id; + query_menu->index = index; + + ret = mutex_lock_interruptible(&chain->ctrl_mutex); + if (ret < 0) + return -ERESTARTSYS; + + ctrl = uvc_find_control(chain, query_menu->id, &mapping); + if (ctrl == NULL || mapping->v4l2_type != V4L2_CTRL_TYPE_MENU) { + ret = -EINVAL; + goto done; + } + + if (query_menu->index >= mapping->menu_count) { + ret = -EINVAL; + goto done; + } + + menu_info = &mapping->menu_info[query_menu->index]; + strlcpy(query_menu->name, menu_info->name, sizeof query_menu->name); + +done: + mutex_unlock(&chain->ctrl_mutex); + return ret; +} + /* -------------------------------------------------------------------------- * Control transactions |