Re: [PATCH 3/5] media: dt-bindings: Add Apple ISP

On Wed, 19 Feb 2025 at 11:53, Laurent Pinchart
[off-list ref] wrote:

quoted

Those are board-specific and not discoverable via the ISP protocol.

But they are settable through the ISP protocol, aren't they ? For
instance, looking at isp-imx248.dtsi, the first four entries are

        /* 1280x720 */
        preset0 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <1280 720>;
                apple,crop = <8 8 1280 720>;
        };

        /* 960x720 (4:3) */
        preset1 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <960 720>;
                apple,crop = <168 8 960 720>;
        };

        /* 960x540 (16:9) */
        preset2 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <960 540>;
                apple,crop = <8 8 1280 720>;
        };

        /* 640x480 (4:3) */
        preset3 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <640 480>;
                apple,crop = <168 8 960 720>;
        };

But I may be interested in capturing a 640x480 frame with cropping only
and without scaling, with

input-size = 1296x736
output-size = 640x480
crop = (328,128)/640x480

Or I may want my cropped frame to be located in the upper-left corner:

input-size = 1296x736
output-size = 640x480
crop = (8,8)/640x480

If I set those parameters through the ISP protocol, won't it work ?

--
Regards,

Laurent Pinchart

For cropping - you do not want to change those parameters, the sensor
is partially occluded, and the crop area is specified in such a way
to not expose those pixels. As for scaling - we can expose only the 1:1
scale and let userspace deal with it, but it appears that it expects
the other common output sizes to exist.