Consolidating the interface for camera components

Consolidating the interface for camera components

[Philip Molloy]

Hello,

I'm trying to consolidate the interface for several camera components into one place to represent a single camera.

Each of the camera modules includes a LED driver (0x63) and camera (0x3c) that sit behind a couple muxes. For example:

/sys/devices/platform/amba/ff030000.i2c/i2c-1/i2c-3/i2c-5/5-003c/
/sys/devices/platform/amba/ff030000.i2c/i2c-1/i2c-3/i2c-7/7-0063/

The LEDs are also available under /sys/class/leds/ based on their labels as defined in the devicetree.

The image data captured by the camera passes through two soft IP blocks. The driver for the second block maps the image into memory and exposes it as a block device in /dev.

In #kernel-newbies on OFC it was suggested that I could use udev to symlink the above into one place in /dev, but I'm having trouble creating a symlink between /sys and /dev (e.g. /sys/.../5-003c -> /dev/camera-name/camera). Perhaps that isn't possible or intended? I've only seen symlinks between /dev and /dev in /usr/lib/udev/rules.d/*.rules on my development system.

If it is I can explain what I've tried in more detail, but basically I'd like to do something like the following:

DRIVER=="aptina-ar0330", SYMLINK+="camera/$attr{../../of_node/name}/$env{OF_NAME}"

If it is not possible any other recommendations would be greatly appreciated.

Best,
Philip

Re: Consolidating the interface for camera components

[Greg KH]

On Fri, Dec 06, 2019 at 04:50:09PM +0000, Philip Molloy wrote:
> Hello,
> 
> I'm trying to consolidate the interface for several camera components into one place to represent a single camera.
> 
> Each of the camera modules includes a LED driver (0x63) and camera (0x3c) that sit behind a couple muxes. For example:
> 
> /sys/devices/platform/amba/ff030000.i2c/i2c-1/i2c-3/i2c-5/5-003c/
> /sys/devices/platform/amba/ff030000.i2c/i2c-1/i2c-3/i2c-7/7-0063/
> 
> The LEDs are also available under /sys/class/leds/ based on their labels as defined in the devicetree.
> 
> The image data captured by the camera passes through two soft IP blocks. The driver for the second block maps the image into memory and exposes it as a block device in /dev.
> 
> In #kernel-newbies on OFC it was suggested that I could use udev to symlink the above into one place in /dev, but I'm having trouble creating a symlink between /sys and /dev (e.g. /sys/.../5-003c -> /dev/camera-name/camera). Perhaps that isn't possible or intended? I've only seen symlinks between /dev and /dev in /usr/lib/udev/rules.d/*.rules on my development system.
> 
> If it is I can explain what I've tried in more detail, but basically I'd like to do something like the following:
> 
> DRIVER="aptina-ar0330", SYMLINK+="camera/$attr{../../of_node/name}/$env{OF_NAME}"
> 
> If it is not possible any other recommendations would be greatly appreciated.

Try asking on the linux-media mailing list as this is the API those
drivers expose.

thanks,

greg k-h

Consolidating the interface for camera components

[Philip Molloy]

Hello,

I'm trying to consolidate the interface for several camera components into one place to represent a single camera. Note the camera module is a specialized custom device, not a general purpose camera, in case that matters.

Each of the camera modules includes a LED driver (0x63) and camera (0x3c) that sit behind a couple muxes. For example:

/sys/devices/platform/amba/ff030000.i2c/i2c-1/i2c-3/i2c-5/5-003c/
/sys/devices/platform/amba/ff030000.i2c/i2c-1/i2c-3/i2c-7/7-0063/

The LEDs are also available under /sys/class/leds/ based on their labels as defined in the devicetree.

The image data captured by the camera passes through two soft IP blocks. The driver for the second block maps the image into memory and exposes it as a block device in /dev.

Is there a way to consolidate that into one place rather than having it spread across /sys/devices/platform, /sys/class/leds, and /dev?

Best,
Philip