media: imx274: fix frame interval handling

[ Upstream commit 49b20d981d723fae5a93843c617af2b2c23611ec ]

1) the numerator and/or denominator might be 0, in that case
   fall back to the default frame interval. This is per the spec
   and this caused a v4l2-compliance failure.

2) the updated frame interval wasn't returned in the s_frame_interval
   subdev op.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
index 8cc3bdb..0fe8b86 100644
--- a/drivers/media/i2c/imx274.c
+++ b/drivers/media/i2c/imx274.c
@@ -1239,6 +1239,8 @@
 	ret = imx274_set_frame_interval(imx274, fi->interval);
 
 	if (!ret) {
+		fi->interval = imx274->frame_interval;
+
 		/*
 		 * exposure time range is decided by frame interval
 		 * need to update it after frame interval changes
@@ -1760,9 +1762,9 @@
 		__func__, frame_interval.numerator,
 		frame_interval.denominator);
 
-	if (frame_interval.numerator == 0) {
-		err = -EINVAL;
-		goto fail;
+	if (frame_interval.numerator == 0 || frame_interval.denominator == 0) {
+		frame_interval.denominator = IMX274_DEF_FRAME_RATE;
+		frame_interval.numerator = 1;
 	}
 
 	req_frame_rate = (u32)(frame_interval.denominator