Hi Dave, On 06/09/2022 18:14, Dave Stevenson wrote: > Hi All. > > I realise that I'm in a slightly different position from many mainline > Linux-media developers in that I see multiple use cases for the same > sensor, rather than a driver predominantly being for one > product/platform. I'm therefore wanting to look at generic solutions > and fully featured drivers. Users get to decide the use cases, not the > hardware designers. > > The issues I've raised are things that I've encountered and would > benefit from a discussion to get views as to the direction that is > perceived to be workable. I appreciate that some can not be solved > immediately, but want to avoid too much bikeshedding in the first > round of patches. > What's realistic, and what pitfalls/limitations immediately jump out at people. > > Slides are at https://drive.google.com/file/d/1vjYJjTNRL1P3j6G4Nx2ZpjFtTBTNdeFG/view?usp=sharing > > See you on Monday. > > Dave Some comments for the meeting on Monday: - On-sensor temperature sensing: If a control is used to read this, but the value is not available yet, then -EACCES can be returned. That's already defined as a valid return code in the API, it would just need to be extended for this use-case. - Sync sensors: Should it be part of the DT? That depends, I think, on whether this is a pure sw mechanism, or whether the wiring dictates which sensor can be master and which can be slaves. I assume that at the very least there has to be a way to group sensors that are/can be connected to the same master sync signal. - Lens assemblies: For what it is worth, Cisco uses motor controlled lenses and irises. We extended the camera controls with these new controls: #define V4L2_CID_FOCUS_CURRENT (V4L2_CID_CAMERA_CLASS_BASE+36) #define V4L2_CID_IRIS_CURRENT (V4L2_CID_CAMERA_CLASS_BASE+38) #define V4L2_CID_FOCUS_MOTOR_STATUS (V4L2_CID_CAMERA_CLASS_BASE+41) #define V4L2_CID_IRIS_MOTOR_STATUS (V4L2_CID_CAMERA_CLASS_BASE+43) enum v4l2_motor_status { V4L2_MOTOR_STATUS_IDLE = (0), V4L2_MOTOR_STATUS_MOVING = (1 << 0), V4L2_MOTOR_STATUS_FAILED = (1 << 1), V4L2_MOTOR_STATUS_NOTCALIBRATED = (1 << 2), }; #define V4L2_CID_FOCUS_MOTOR_SPEED (V4L2_CID_CAMERA_CLASS_BASE+46) #define V4L2_CID_IRIS_MOTOR_SPEED (V4L2_CID_CAMERA_CLASS_BASE+48) This worked well for our use-case, but for us userspace has complete knowledge about the camera assembly properties. Regards, Hans
