Hello, This small patch series adds support to the i.MX6 IPU CSI driver for external (on-board) devices that exhibit complex topologies. My use case is a CSI-2 camera sensor that has a single DT node (as an I2C device) and creates two V4L2 subdevs. "Complex" may thus be a bit of an exageration, but the series nonetheless makes such a sensor usable with the driver. There are two issues, fixed by two patches. Patch 1/2 removes the assumption that OF port ids and pad indices are equivalent. This holds true in many cases, but is incorrect in my case, with the topology being +------------+ +--------------+ +---------------------+ | Sensor _| |_ Sensor _| |_ | | Subdev A |0| ----> |0| Subdev B |1| ----> |0| imx6-mipi-csi2 ...| | ¯| |¯ ¯| |¯ | +------------+ +--------------+ +---------------------+ while the sensor has a single DT node with a single port. The IPU CSI driver then tries to connect 'Sensor Subdev B':0 to 'imx6-mipi-csi2':0, which isn't right. The fix isn't perfect, as we ideally need media entity operations to handle the translation between port ids and pad indices. Nonetheless, the heuristic in patch 1/2 should cover most, if not all, use cases and is in my opinion a good way forward. Patch 2/2 then stops creating links between external entities. The IPU CSI driver iterates over the list of subdevs registered with the V4L2 device, and creates links based on the OF graph for all of them. That's fine for devices internal to the i.MX6, but is oversteps the driver's responsibility as links between external entities are supposed to be handled by their respective driver. In my use case, the driver attempts to link 'Sensor Subdev A' by checking OF graph connections in DT, which results in 'Sensor Subdev A':0 being linked to 'imx6-mipi-csi2':0. The patch skips external entities for link creation, which fixes the issue. The link between the closest external entities and the internal entities are still created by the IPU CSI driver as part of link creation for all internal entities. Laurent Pinchart (2): media: staging/imx: Don't assume OF port id equals pad index media: staging/imx: Don't create links between external entities drivers/staging/media/imx/imx-media-csi.c | 29 ++++++++++- .../staging/media/imx/imx-media-dev-common.c | 7 +-- drivers/staging/media/imx/imx-media-of.c | 52 ++++++++++++++++--- drivers/staging/media/imx/imx-media.h | 1 + 4 files changed, 75 insertions(+), 14 deletions(-) -- Regards, Laurent Pinchart
