[PATCH 4/4] media: qcom: camss: do not fail CSID power up without a matching VFE

[Allan Siriani]

csid_set_power() powers up the VFE with the same index as the CSID
before the CSID itself, through parent_dev_ops->get(). The VFE
implementation, vfe_parent_dev_ops_get(), returns -EINVAL when there is
no VFE with that index.

On the ISPIF based SoCs there are more CSIDs than VFEs: MSM8916 (and
MSM8226) have two CSIDs and a single VFE, and the ISPIF routes either
CSID to it. Streaming from CSID1 then fails right away with

  qcom-camss ...: Failed to power up pipeline: -22

although the pipeline CSID1 -> ISPIF -> VFE0 is valid.

Return 0 when there is no VFE of the same index: there is nothing to
power up for that CSID, the VFE in the pipeline is powered by its own
subdev. vfe_parent_dev_ops_put() already ignores such indexes.

Signed-off-by: Allan Siriani <allan@xxxxxxxxxxxxxxxxxxx>
---
 drivers/media/platform/qcom/camss/camss.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index c54185c93..532f6d36d 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
@@ -4631,15 +4631,16 @@ static int camss_read_version(struct camss *camss)
 
 static int vfe_parent_dev_ops_get(struct camss *camss, int id)
 {
-	int ret = -EINVAL;
-
-	if (id < camss->res->vfe_num) {
-		struct vfe_device *vfe = &camss->vfe[id];
-
-		ret = vfe_get(vfe);
-	}
+	/*
+	 * On the ISPIF based SoCs any CSID can feed any VFE, and there may be
+	 * more CSIDs than VFEs (MSM8916: two CSIDs, one VFE). A CSID without a
+	 * VFE of the same index has no parent to power up: the VFE that ends
+	 * up in the pipeline is powered by its own subdev.
+	 */
+	if (id >= camss->res->vfe_num)
+		return 0;
 
-	return ret;
+	return vfe_get(&camss->vfe[id]);
 }
 
 static int vfe_parent_dev_ops_put(struct camss *camss, int id)
-- 
2.43.0