It is possible that the number of desired active MIPI CSI2 data lanes
does not match the maximum listed in device tree. Add a helper function
to v4l2_common that calls the get_mbus_config op to get the number of
actively used data lanes in drivers that support it.

Compare it to the number of lanes configured in device tree, and if its
invalid, use the number present in device tree.

This series also uses the helper in imx-mipi-csis driver to set the
currently configured num_data_lanes, while keeping track of the number
of data lanes set in device tree to ensure we can still use all possible
lanes if we need to, and the upstream subdev driver requests them.

Tested on v6.15, compile tested on v6.17-rc4.

---------

Changes v1 -> v2:

- Added helper function to get active data lanes in v4l2-common
- Store the maximum data lanes possible, as configured in device tree
- Added media: prefix to commit titles

Isaac Scott (3):
  media: v4l: Add helper to get number of active lanes via a pad
  media: imx-mipi-csis: Store the number of data_lanes configured in dt
  media: imx-mipi-csis: Get number of active lanes via mbus_config

 drivers/media/platform/nxp/imx-mipi-csis.c |  8 ++++++-
 drivers/media/v4l2-core/v4l2-common.c      | 25 ++++++++++++++++++++++
 include/media/v4l2-common.h                |  1 +
 3 files changed, 33 insertions(+), 1 deletion(-)

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2.43.0