Re: [PATCH v3 2/2] arm64: dts: qcom: qcs6490-rubikpi3: Add IMX219 camera overlays

On 8/25/26 1:13 PM, Hongyang Zhao wrote:

Hi Konrad,

Thanks for the review.

[...]

quoted

No reset GPIOs?

Yes. The RubikPi camera connector does not route a dedicated sensor reset
signal. It exposes PWR_EN and CAMERA_GPIO, but neither is connected
directly to the IMX219 reset input when using the official Raspberry Pi
Camera Module 2.

PWR_EN is connected to the module's ENABLE signal and controls the
module-local power supplies. CAMERA_GPIO corresponds to a pin that is
not connected on Camera Module 2. The IMX219 /PWDN signal remains local
to the camera module and is tied to its 1.8 V rail.

Therefore, there is no board-controllable reset GPIO to describe for
this camera configuration.

quoted

You should also have a reference to the mclk pin state to make sure
the correct pin function kicks in

The Camera Module 2 provides its own 24 MHz oscillator, which is
connected to the IMX219 MCLK input on the module. RubikPi does not route
a SoC CAM_MCLK signal to this connector. The fixed-clock node represents
that module-local oscillator, so there is no corresponding TLMM MCLK
pin state.

The Camera Module 2 schematic shows both connections:
https://datasheets.raspberrypi.com/camera/camera-module-2-schematics.pdf

RUBIK Pi 3 schematic (CSI connector, page 13):
https://thundercomm.s3-accelerate.amazonaws.com/uploads/web/rubik-pi-3/RUBIKPI3-IOB-V02-RELEASE.pdf

Got it, thanks for the explanation

Reviewed-by: Konrad Dybcio <redacted>

Konrad