We want to support fetching the min and max values with g_ext_ctrls,
this patch is a preparation for that.

Instead of abusing uvc_query_v4l2_ctrl(), add an extra parameter to
uvc_ctrl_get, so it can support fetching the default value.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 21 ++++++++++++++++++---
 drivers/media/usb/uvc/uvc_v4l2.c | 28 +++++++++++-----------------
 drivers/media/usb/uvc/uvcvideo.h |  3 ++-
 3 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index c975e0ab479b..d6afa131a5e1 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1902,8 +1902,8 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
 	return ret;
 }
 
-int uvc_ctrl_get(struct uvc_video_chain *chain,
-	struct v4l2_ext_control *xctrl)
+int uvc_ctrl_get(struct uvc_video_chain *chain, u32 which,
+		 struct v4l2_ext_control *xctrl)
 {
 	struct uvc_control *ctrl;
 	struct uvc_control_mapping *mapping;
@@ -1915,7 +1915,22 @@ int uvc_ctrl_get(struct uvc_video_chain *chain,
 	if (ctrl == NULL)
 		return -EINVAL;
 
-	return __uvc_ctrl_get(chain, ctrl, mapping, &xctrl->value);
+	switch (which) {
+	case V4L2_CTRL_WHICH_CUR_VAL:
+		return __uvc_ctrl_get(chain, ctrl, mapping, &xctrl->value);
+	case V4L2_CTRL_WHICH_DEF_VAL:
+		if (!ctrl->cached) {
+			int ret = uvc_ctrl_populate_cache(chain, ctrl);
+
+			if (ret < 0)
+				return ret;
+		}
+		xctrl->value = mapping->get(mapping, UVC_GET_DEF,
+					    uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF));
+		return 0;
+	}
+
+	return -EINVAL;
 }
 
 int uvc_ctrl_set(struct uvc_fh *handle,
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 97c5407f6603..02fd5cbc3474 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -1078,34 +1078,28 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,
 	struct uvc_video_chain *chain = handle->chain;
 	struct v4l2_ext_control *ctrl = ctrls->controls;
 	unsigned int i;
+	u32 which;
 	int ret;
 
+	switch (ctrls->which) {
+	case V4L2_CTRL_WHICH_DEF_VAL:
+	case V4L2_CTRL_WHICH_CUR_VAL:
+		which = ctrls->which;
+		break;
+	default:
+		which = V4L2_CTRL_WHICH_CUR_VAL;
+	}
+
 	ret = uvc_ctrl_check_access(chain, ctrls, VIDIOC_G_EXT_CTRLS);
 	if (ret < 0)
 		return ret;
 
-	if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
-		for (i = 0; i < ctrls->count; ++ctrl, ++i) {
-			struct v4l2_queryctrl qc = { .id = ctrl->id };
-
-			ret = uvc_query_v4l2_ctrl(chain, &qc);
-			if (ret < 0) {
-				ctrls->error_idx = i;
-				return ret;
-			}
-
-			ctrl->value = qc.default_value;
-		}
-
-		return 0;
-	}
-
 	ret = uvc_ctrl_begin(chain);
 	if (ret < 0)
 		return ret;
 
 	for (i = 0; i < ctrls->count; ++ctrl, ++i) {
-		ret = uvc_ctrl_get(chain, ctrl);
+		ret = uvc_ctrl_get(chain, which, ctrl);
 		if (ret < 0) {
 			uvc_ctrl_rollback(handle);
 			ctrls->error_idx = i;
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 07f9921d83f2..6ebaabd11443 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -788,7 +788,8 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle)
 	return __uvc_ctrl_commit(handle, 1, NULL);
 }
 
-int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl);
+int uvc_ctrl_get(struct uvc_video_chain *chain, u32 which,
+		 struct v4l2_ext_control *xctrl);
 int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl);
 int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
 			   const struct v4l2_ext_controls *ctrls,

-- 
2.47.0.338.g60cca15819-goog