boards: nxp: frdm_mcxn947: migrate ov7670 to a shield

The OV7670 was defined as part of the FRDM-MCXN947 board attached to the
SmartDMA and I2C peripheral. Migrate the devicetree to a reusable shield
that can be swapped with other image sensors.

Signed-off-by: Josuah Demangeon <[email protected]>

Author: josuah

boards/nxp/frdm_mcxn947/frdm_mcxn947.dtsi

@@ -7,6 +7,7 @@
 #include "frdm_mcxn947-pinctrl.dtsi"
 #include <zephyr/dt-bindings/i2c/i2c.h>
 #include <zephyr/dt-bindings/input/input-event-codes.h>
+#include <zephyr/dt-bindings/gpio/dvp-20pin-connector.h>
 
 / {
 	aliases{
@@ -95,38 +96,22 @@ nxp_8080_touch_panel_i2c: &flexcomm2_lpi2c2 {
 	pinctrl-0 = <&pinmux_flexcomm7_lpi2c>;
 	pinctrl-names = "default";
 	clock-frequency = <I2C_BITRATE_STANDARD>;
-	ov7670: ov7670@21 {
-		compatible = "ovti,ov7670";
-		reset-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
-		pwdn-gpios = <&gpio1 18 GPIO_ACTIVE_HIGH>;
-		reg = <0x21>;
-
-		port {
-			ov7670_ep_out: endpoint {
-				remote-endpoint-label = "sdma_ep_in";
-			};
-		};
-	};
 };
 
 /* SmartDMA is used for video driver on this board */
 &smartdma {
+	/* Shields do not enable video-sdma parent node so enable it by default */
 	status = "okay";
 	program-mem = <0x4000000>;
+
 	video_sdma: video-sdma {
-		status = "okay";
+		status = "disabled";
 		compatible = "nxp,video-smartdma";
 		pinctrl-0 = <&pinmux_smartdma_camera>;
 		pinctrl-names = "default";
 		vsync-pin = <4>;
 		hsync-pin = <11>;
 		pclk-pin = <5>;
-
-		port {
-			sdma_ep_in: endpoint {
-				remote-endpoint-label = "ov7670_ep_out";
-			};
-		};
 	};
 };
 
@@ -300,3 +285,22 @@ zephyr_mipi_dbi_parallel: &flexio0_lcd {
 	pinctrl-0 = <&pinmux_sctimer>;
 	pinctrl-names = "default";
 };
+
+/*
+ * Connection with camera modules such as the dvp_20pin_ov7670 shield
+ */
+
+/ {
+	dvp_20pin_gpio: dvp-20pin-connector {
+		compatible = "arducam,dvp-20pin-connector";
+		#gpio-cells = <2>;
+		gpio-map-mask = <DVP_20PIN_MASK 0x0>;
+		gpio-map-pass-thru = <0x0 GPIO_DT_FLAGS_MASK>;
+		gpio-map =	<DVP_20PIN_PEN 0 &gpio1 19 0>,
+				<DVP_20PIN_PDN 0 &gpio1 18 0>;
+	};
+};
+
+dvp_20pin_i2c: &flexcomm7_lpi2c7 {};
+
+dvp_20pin_interface: &video_sdma {};

boards/shields/dvp_20pin_ov7670/Kconfig.shield

@@ -0,0 +1,5 @@
+# Copyright 2025 tinyVision.ai Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+config SHIELD_DVP_20PIN_OV7670
+	def_bool $(shields_list_contains,SHIELD_DVP_20PIN_OV7670)

boards/shields/dvp_20pin_ov7670/doc/index.rst

@@ -0,0 +1,81 @@
+.. _dvp_20pin_ov7670:
+
+DVP 20-pin OV7670 Camera Module
+###############################
+
+Overview
+********
+
+This series of shields supports the camera modules which use a 18-pin connector compatible with
+the ``arducam,dvp-20pin-connector`` to connect a devkit to an OV7670 image sensor via  DVP
+(Digital Video Port), aka parallel interface.
+
+Only 18 pins out of the 20-pin connector are present
+
+It was originally produced by `Arducam`_ but is discontinuited, and now `Olimex`_ provides it.
+
+Pins assignment
+===============
+
++-----+--------------+-----+--------------+
+| Pin | Function     | Pin | Function     |
++=====+==============+=====+==============+
+| 1   | 3V3          | 2   | GND          |
++-----+--------------+-----+--------------+
+| 3   | SCL          | 4   | SDA          |
++-----+--------------+-----+--------------+
+| 5   | VS           | 6   | HS           |
++-----+--------------+-----+--------------+
+| 7   | PCLK         | 8   | XCLK         |
++-----+--------------+-----+--------------+
+| 9   | D7           | 10  | D6           |
++-----+--------------+-----+--------------+
+| 11  | D5           | 12  | D4           |
++-----+--------------+-----+--------------+
+| 13  | D3           | 14  | D2           |
++-----+--------------+-----+--------------+
+| 15  | D1           | 16  | D0           |
++-----+--------------+-----+--------------+
+| 17  | POWER_EN     | 18  | POWER_DOWN   |
++-----+--------------+-----+--------------+
+
+Requirements
+************
+
+This shield can be used with any board which provides a 18 or 20-pin header spread over two rows
+of 9 or 10 pins each with the above pinout, such as the `arduino Giga R1`_, `NXP FRDM-MCXN947`_,
+ST boards with the `ST-CAMS-OMV`_ adapter, or any other board with a compatible connector.
+
+Alternatively, it is possible to use jumper wires to connect the module to any devkit that
+exposes their camera parallel port to pin headers.
+
+Programming
+***********
+
+Set ``--shield dvp_20pin_ov7670`` when you invoke ``west build``. For example:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/drivers/video/capture
+   :board: frdm_mcxn947
+   :shield: dvp_20pin_ov7670
+   :goals: build
+
+References
+**********
+
+.. target-notes::
+
+.. _ST-CAMS-OMV:
+   https://www.st.com/en/evaluation-tools/b-cams-omv.html
+
+.. _Arducam:
+   https://docs.arducam.com/DVP-Camera-Module/Arduino-GIGA/Arduino-GIGA/Quick-Start-Guide/
+
+.. _Arduino Giga R1:
+   https://docs.arduino.cc/tutorials/giga-r1-wifi/giga-camera/
+
+.. _NXP FRDM-MCXN947:
+   https://www.nxp.com/docs/en/application-note/AN14191.pdf
+
+.. _Olimex:
+   https://www.olimex.com/Products/Components/Camera/CAMERA-OV7670/

boards/shields/dvp_20pin_ov7670/dvp_20pin_ov7670.overlay

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2024 NXP
+ * Copyright 2025 tinyVision.ai Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	chosen {
+		zephyr,camera = &dvp_20pin_interface;
+	};
+};
+
+&dvp_20pin_i2c {
+	ov7670: ov7670@21 {
+		compatible = "ovti,ov7670";
+		reg = <0x21>;
+		reset-gpios = <&dvp_20pin_gpio DVP_20PIN_PEN GPIO_ACTIVE_HIGH>;
+		pwdn-gpios  = <&dvp_20pin_gpio DVP_20PIN_PDN GPIO_ACTIVE_HIGH>;
+
+		port {
+			ov7670_ep_out: endpoint {
+				remote-endpoint-label = "dvp_20pin_ep_in";
+			};
+		};
+	};
+};
+
+&dvp_20pin_interface {
+	status = "okay";
+
+	port {
+		dvp_20pin_ep_in: endpoint {
+			remote-endpoint-label = "ov7670_ep_out";
+		};
+	};
+};