The bcm2835-unicam driver is currently in staging mainly for two reasons: - Handling of CSI-2 embedded data - Usage of both media controller API and subdev kAPI Provide a more detailed description of the currently on-going design discussions in the associated TODO file. Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx> --- drivers/staging/media/bcm2835-unicam/TODO | 37 +++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 drivers/staging/media/bcm2835-unicam/TODO diff --git a/drivers/staging/media/bcm2835-unicam/TODO b/drivers/staging/media/bcm2835-unicam/TODO new file mode 100644 index 0000000000000..c7840872eea4c --- /dev/null +++ b/drivers/staging/media/bcm2835-unicam/TODO @@ -0,0 +1,37 @@ +BCM2835 Unicam driver TODO list +=============================== + +The unicam driver could be considered ready to be moved out of the staging +directory in terms of code quality and expected functionalities. + +However there currently are two design issues that suggest the driver is +better kept in staging for the time being. + +CSI-2 Embedded data support: +---------------------------- + +The RaspberryPi camera stack and camera applications rely on the availability of +the sensor produced CSI-2 embedded data, whose support is currently not +finalized in mainline Linux. + +The driver conditionally registers an additional video device node +'unicam-embedded' with a single sink pad which connects to the sensor +sub-device source pad #1 to expose ancillary data. + +Currently none of the mainline sensor drivers register more than a single pad, +and consequentially no embedded data from the sensor are exposed to userspace. + +The current implementation is then subject to changes depending on how support +for CSI-2 embedded data gets finalized in Linux. + +Media controller support: +------------------------- + +Due to compatibility reasons with the existing RaspberryPi software ecosystem +the unicam driver implements the media controller interface to allow the +enumeration of the connected entities but handles the configuration of the +sensor sub-device using the v4l2-subdev kAPI instead of delegating that to +user-space. + +Discussions are on-going on how this should be better handled (driver option, +KConfig option etc etc). -- 2.29.1
