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

[Hongyang Zhao]

Hi Konrad,

Thanks for the review.

On 8/12/26 4:22 AM, Hongyang Zhao wrote:
> > RUBIK Pi 3 ships without camera sensors, and its two connectors support
> > multiple modules. Keep module-specific nodes out of the base board DTS
> > and add per-connector overlays for Raspberry Pi Camera Module V2 IMX219
> > sensors.
> > 
> > CAM1 uses CCI1 and CSIPHY1, while CAM2 uses CCI0 and CSIPHY4. Each
> > overlay describes the 24 MHz sensor input clock and models the module
> > power domain controlled through the connector PWR_EN signal. The
> > baseboard supplies VCC3V3_OUTPUT separately and has no per-camera
> > regulator.
> > 
> > Describe each connector CAMERA_GPIO signal as a privacy indicator LED
> > and associate it with the corresponding sensor. This lets the V4L2 core
> > control the LED while the sensor is streaming.
> > 
> > Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> > Signed-off-by: Hongyang Zhao <hongyang.zhao@xxxxxxxxxxxxxxx>
> > ---
> 
> [...]
> 
> > +	camera@10 {
> > +		compatible = "sony,imx219";
> > +		reg = <0x10>;
> > +
> > +		clocks = <&cam1_imx219_clk>;
> > +
> > +		VANA-supply = <&vreg_cam1_pwr>;
> > +		VDIG-supply = <&vreg_cam1_pwr>;
> > +		VDDL-supply = <&vreg_cam1_pwr>;
> > +
> > +		leds = <&cam1_privacy_led>;
> > +		led-names = "privacy";
> 
> 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.

> 
> 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

Best regards,
Hongyang