Hello, This series aims to extend the video interface bindings with a new property to describe the CSI-2 C-PHY line orders. In comparison with CSI-2 D-PHY where each data-lane is constructed from two lines making up a differential pair the C-PHY uses three phase encoding constructed from three lines to create a single data lane. The three lines making up the C-PHY data lane are labeled A, B and C in the specification and can be ordered in any combination (ABC, ACB, BAC, BCA, CAB and CBA). This can be compared to the D-PHY model where the two lines in the differential pair can be "normal" or "inverted" to do the same thing. For the D-PHY uses-case the exists a property 'lane-polarities' can be used to describe this line wiring. However there are no property to describe this ordering of the C-PHY lines in the video interfaces definition nor in the V4L2 fwnode structures or parser. Patch 1/4 extends the video bindings with a new property 'line-orders' which can describe this property of the C-PHY. The property name and the const values used for different line configurations are taken from the MIPI Discovery and Configuration (DisCo) Specification for Imaging document. Patch 2/4 extends the V4L2 fwnode data structure and parser to consume and exposes this property to drivers. While patch 3/4 and 4/4 adds an example use of the property both in the bindings and in the driver using the R-Car CSI-2 receiver driver on V4H. A note on the changes to the R-Car driver not relevant to the core V4L2 or bindings work. The V4H WhiteHawk development platform is the only model where the CSI-2 bus is used in a C-PHY configuration. Early datasheets where used to add support for it and at that time the line order registers where not documented so magic values where used as-is. This have been addressed in later versions of the datasheet and this can now be done properly. The magic values used however configured one of the data lanes used in a BCA configuration, which is required for proper operation on that development platform. Thus the change in patch 4/4 breaks proper operation with older DTS files lacking the new line-orders property. I think this is fine as the only known use-case for this platform is together with the MAX96712 CSI-2 transmitter and for this we only have a staging driver capable of generating test patterns. To extend this to a capture pipeline capable of capturing frames from a real source DTS changes are needed to describe the video source, so an updated DTS are need anyhow. See individual patches for changelog. Niklas Söderlund (4): media: dt-bindings: Add property to describe CSI-2 C-PHY line orders media: v4l: fwnode: Parse MiPI DisCo for C-PHY line-orders arm64: dts: renesas: white-hawk-csi-dsi: Define CSI-2 data line orders media: rcar-csi2: Allow specifying C-PHY line order .../bindings/media/video-interfaces.yaml | 21 ++++++ .../boot/dts/renesas/white-hawk-csi-dsi.dtsi | 6 ++ drivers/media/platform/renesas/rcar-csi2.c | 74 +++++++++++++++++-- drivers/media/v4l2-core/v4l2-fwnode.c | 43 ++++++++++- include/dt-bindings/media/video-interfaces.h | 7 ++ include/media/v4l2-mediabus.h | 21 ++++++ 6 files changed, 164 insertions(+), 8 deletions(-) -- 2.47.0
