beagleplay/test-reports/dvt/test-procedure/test_camera.md

Testing Camera

Prereqs

• Cable cable or cable - Longer ones are known to create signal integrity issues - shorter the better.
• Camera

Sensor module:

⚠️ Notice the crystal - at times with other ov5640 modules, you'd have to dig up the datasheet and update the crystal frequency in the devicetree overlay for the sensor or worst case probe the crystal to find the crystal frequency

Enabling the camera:

Edit the file /boot/firmware/extlinux/extlinux.conf and add the following line just after fdtdir

 fdtoverlays /overlays/k3-am625-lc-csi2-ov5640.dtbo

Example for emmc boot:

label Linux eMMC
    kernel /Image
    append quiet quiet quiet console=ttyS2,115200n8 earlycon=ns16550a,mmio32,0x02800000 root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait net.ifnames=0 quiet
    fdtdir /
    fdtoverlays /overlays/k3-am625-lc-csi2-ov5640.dtbo
    initrd /initrd.img

Testing Camera

Open a terminal on the GUI

sudo apt-get install -y mplayer
mplayer tv:// -tv driver=v4l2:device=/dev/video0:width=640:height=480:fps=30:outfmt=yuy2

At a basic level, test can be performed to capture the YUV data itself for analysis later on for a frame by frame basis

mkdir camera_capture;cd camera_capture

yavta -c10 -Fframe-#.bin -f UYVY -s 640x480 /dev/video0

This generates frame-...bin files which can then be analysed with 7yuv for frame by frame analysis.

Switching sensor module frequency

Typically (subject to manufacturer), it's 12mhz for alinx and pcam, 24mhz for technexion

In case you do have a camera ov5640 module with a different crystal frequency (Say 24MHz), then, modify:

arch/arm64/boot/dts/ti/k3-am625-lc-csi2-ov5640.dts

diff --git a/arch/arm64/boot/dts/ti/k3-am625-lc-csi2-ov5640.dts b/arch/arm64/boot/dts/ti/k3-am625-lc-csi2-ov5640.dts
index 468986f4095e..f89c93963dd3 100644
--- a/arch/arm64/boot/dts/ti/k3-am625-lc-csi2-ov5640.dts
+++ b/arch/arm64/boot/dts/ti/k3-am625-lc-csi2-ov5640.dts
@@ -16,7 +16,7 @@ __overlay__ {
                        clk_ov5640_fixed: ov5640-xclk {
                                compatible = "fixed-clock";
                                #clock-cells = <0>;
-                               clock-frequency = <12000000>;
+                               clock-frequency = <24000000>;
                        };
                };
        };