media: i2c: alvium: store frame interval in subdev state

Use the newly added storage for frame interval in the subdev state to
simplify the driver.

Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: i2c: alvium: remove the fr field of the alvium_dev structure

The fr (frame rate) field of the alvium_dev structure is
only used to pass result from alvium_set_frame_interval() to
alvium_set_frame_rate() that writes this info into the hw reg.
Replace it with a function parameter.

Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: i2c: alvium: removal of dft_fr, min_fr and max_fr

The dft_fr, min_fr and max_fr fields of the alvium_dev structure are
only used to pass results from alvium_get_frame_interval() to its
caller. Replace them with function parameters.

Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: i2c: Add support for alvium camera

The Alvium camera is shipped with sensor + isp in the same housing.
The camera can be equipped with one out of various sensor and abstract
the user from this. Camera is connected via MIPI CSI-2.

Most of the camera module features are supported, with the main exception
being fw update.

The driver provides all mandatory, optional and recommended V4L2 controls
for maximum compatibility with libcamera

References:
- https://www.alliedvision.com/en/products/embedded-vision-solutions

Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
[Sakari Ailus: Assign ret before using it in probe and squash Tommaso's
other fixes.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: alvium-csi2.h: SPDX must use /* */ instead of //]