zephyr-cp: dynamic buses on the Feather nRF52840 boards

.github/workflows/build-board-custom.yml

@@ -72,7 +72,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Board to port
       id: board-to-port
       run: |

.github/workflows/build-boards.yml

@@ -39,7 +39,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: ${{ inputs.port == 'zephyr-cp' && '3.13' || '3.x' }}
+        python-version: ${{ inputs.port == 'zephyr-cp' && '3.13' || '3.14' }}  # minify_html has no Python 3.15 wheel yet
 
     - name: Set up port
       id: set-up-port

.github/workflows/build-mpy-cross.yml

@@ -37,7 +37,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Set up submodules
       uses: ./.github/actions/deps/submodules
       with:

.github/workflows/build.yml

@@ -42,7 +42,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Duplicate USB VID/PID check
       run: python3 -u -m tools.ci_check_duplicate_usb_vid_pid
     - name: Set up submodules
@@ -135,7 +135,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Set up submodules
       uses: ./.github/actions/deps/submodules
     - name: Versions
@@ -177,7 +177,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Set up submodules
       uses: ./.github/actions/deps/submodules
       with:

.github/workflows/create-website-pr.yml

@@ -26,7 +26,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Set up submodules
       uses: ./.github/actions/deps/submodules
       with:

.github/workflows/pre-commit.yml

@@ -30,7 +30,7 @@ jobs:
     - name: Set up python
       uses: actions/setup-python@v6
       with:
-        python-version: 3.x
+        python-version: "3.14"  # minify_html has no Python 3.15 wheel yet
     - name: Set up submodules
       uses: ./.github/actions/deps/submodules
     - name: Set up external

ports/zephyr-cp/Makefile

@@ -61,16 +61,25 @@ endif
 # When DEBUG=1, apply additional Kconfig fragments for debug-friendly settings.
 DEBUG_CONF_FILE ?= $(CURDIR)/debug.conf
 ifeq ($(DEBUG),1)
-ifneq ($(CP_BOARD_CONF),)
-CP_BOARD_CONF := $(CP_BOARD_CONF);$(DEBUG_CONF_FILE)
-else
-CP_BOARD_CONF := $(DEBUG_CONF_FILE)
+CP_BOARD_CONF := $(strip $(CP_BOARD_CONF) $(DEBUG_CONF_FILE))
+endif
+# When CONSOLE=1 (implied by DEBUG=1), apply the board's console.overlay, if it has one, and the
+# port's console.conf. Boards whose console pins are also user pins enable the Zephyr UART console
+# only then.
+CONSOLE ?= $(DEBUG)
+CP_BOARD_CONSOLE_OVERLAY :=
+ifeq ($(CONSOLE),1)
+CP_BOARD_CONSOLE_OVERLAY := $(wildcard $(CP_BOARD_DIR)/console.overlay)
+ifneq ($(CP_BOARD_CONSOLE_OVERLAY),)
+CP_BOARD_CONF := $(strip $(CP_BOARD_CONF) $(CURDIR)/console.conf)
 endif
 endif
-# Always pass the conf file, even if empty. This undoes DEBUG=1 when it's omitted on a later run.
-# Quoted because with DEBUG=1 the value is a semicolon-separated list, and an unquoted semicolon
-# would end the shell command.
+CP_BOARD_CONF := $(subst $(eval) ,;,$(CP_BOARD_CONF))
+# Always pass the conf and console overlay files, even if empty. This undoes DEBUG=1 or CONSOLE=1
+# when it's omitted on a later run. Quoted because the conf value can be a semicolon-separated
+# list, and an unquoted semicolon would end the shell command.
 WEST_CMAKE_ARGS += -Dzephyr-cp_EXTRA_CONF_FILE="$(CP_BOARD_CONF)"
+WEST_CMAKE_ARGS += -Dzephyr-cp_EXTRA_DTC_OVERLAY_FILE="$(CP_BOARD_CONSOLE_OVERLAY)"
 
 # Boards can opt into building the MCUboot bootloader (and thus BLE OTA
 # updates) by shipping a sysbuild.conf fragment. It sets sysbuild-level

ports/zephyr-cp/README.md

@@ -28,6 +28,12 @@ make BOARD=nordic_nrf5340dk
 This uses Zephyr's cmake to generate Makefiles that then delegate to
 `tools/cpbuild/build_circuitpython.py` to build the CircuitPython bits in parallel.
 
+`DEBUG=1` adds the debug Kconfig settings in `debug.conf`. `CONSOLE=1` (implied
+by `DEBUG=1`) applies a board's `console.overlay`, if it has one, together with
+the port's `console.conf`, which turns the Zephyr UART console back on. Boards
+whose console UART pins are also user pins, such as the Feather nRF52840, have
+the Zephyr UART console only in those builds.
+
 ## Native simulator build container
 
 Building the native sim requires `libsdl2-dev:i386` and other 32bit dependencies that

ports/zephyr-cp/boards/adafruit/clue_nrf52840_zephyr/board.overlay

@@ -1,6 +1,8 @@
 /* Partition layout is owned by the mcuboot fork
  * (dts/adafruit/adafruit_clue_nrf52840.dtsi) and applied to this image by
  * sysbuild. This overlay only adds board/app config. */
+/* No Zephyr console by default, so TX/RX are free for busio.UART. A CONSOLE=1
+ * build puts the console back on UART0 (console.overlay). */
 / {
 	chosen {
 		/delete-property/ zephyr,console;
@@ -15,11 +17,15 @@
 	/delete-node/ board_cdc_acm_uart;
 };
 
-// UART0, I2C1 and SPI3 are enabled with all pins disconnected and marked
-// zephyr,deferred-init so nothing is claimed at boot: the iobroker
+// UART0, I2C0, I2C1 and SPI3 are enabled with all pins disconnected and
+// marked zephyr,deferred-init so nothing is claimed at boot: the iobroker
 // initializes and routes a device to arbitrary pins when a busio object is
-// constructed, and de-initializes it on release. (I2C0 is the fixed sensor
-// bus, SPI2 the fixed display bus, and QSPI the fixed external flash.)
+// constructed, and de-initializes it on release. (SPI2 is the fixed display
+// bus and QSPI the fixed external flash. The onboard sensors are on SCL/SDA
+// but have no devicetree nodes, so I2C0 does not need to be fixed.)
+//
+// See "nRF serial instances" in internal-modules/iobroker/README.md for how
+// the instances are shared and allocated.
 //
 // I2C1 and SPI1 are the same peripheral instance (0x40004000), so only one
 // mode can be enabled: I2C is the more useful dynamic bus on the CLUE.
@@ -41,6 +47,20 @@
 		};
 	};
 
+	i2c0_dyn_default: i2c0_dyn_default {
+		group1 {
+			psels = <NRF_PSEL_DISCONNECTED(TWIM_SDA)>,
+				<NRF_PSEL_DISCONNECTED(TWIM_SCL)>;
+		};
+	};
+
+	i2c0_dyn_sleep: i2c0_dyn_sleep {
+		group1 {
+			psels = <NRF_PSEL_DISCONNECTED(TWIM_SDA)>,
+				<NRF_PSEL_DISCONNECTED(TWIM_SCL)>;
+		};
+	};
+
 	i2c1_dyn_default: i2c1_dyn_default {
 		group1 {
 			psels = <NRF_PSEL_DISCONNECTED(TWIM_SDA)>,
@@ -144,7 +164,11 @@
 	};
 };
 
+// The upstream board uses the legacy UART driver for UART0, which can't be
+// de-initialized, so iobroker could not route it again once it was released.
+// Instead, use the UARTE driver, which can be deinited.
 &uart0 {
+	compatible = "nordic,nrf-uarte";
 	status = "okay";
 	zephyr,deferred-init;
 	current-speed = <115200>;
@@ -153,6 +177,17 @@
 	pinctrl-names = "default", "sleep";
 };
 
+// The upstream board fixes I2C0 to SCL/SDA with the legacy TWI driver. Use
+// TWIM like I2C1 so iobroker can route it.
+&i2c0 {
+	compatible = "nordic,nrf-twim";
+	status = "okay";
+	zephyr,deferred-init;
+	pinctrl-0 = <&i2c0_dyn_default>;
+	pinctrl-1 = <&i2c0_dyn_sleep>;
+	pinctrl-names = "default", "sleep";
+};
+
 &i2c1 {
 	status = "okay";
 	zephyr,deferred-init;

ports/zephyr-cp/boards/adafruit/clue_nrf52840_zephyr/console.overlay

@@ -0,0 +1,18 @@
+/* Applied after board.overlay in CONSOLE=1 and DEBUG=1 builds: the Zephyr
+ * console on UART0, fixed to the TX/RX pins. TX/RX are then not available to
+ * busio.UART. */
+/ {
+	chosen {
+		zephyr,console = &uart0;
+		zephyr,shell-uart = &uart0;
+		zephyr,uart-mcumgr = &uart0;
+		zephyr,bt-mon-uart = &uart0;
+		zephyr,bt-c2h-uart = &uart0;
+	};
+};
+
+&uart0 {
+	/delete-property/ zephyr,deferred-init;
+	pinctrl-0 = <&uart0_default>;
+	pinctrl-1 = <&uart0_sleep>;
+};

ports/zephyr-cp/boards/adafruit/feather_nrf52840_sense_zephyr/board.conf

@@ -1,5 +1,10 @@
 CONFIG_BOARD_SERIAL_BACKEND_CDC_ACM=n
 
+# No Zephyr UART console by default (see board.overlay); a CONSOLE=1 build turns
+# it back on in console.conf.
+CONFIG_UART_CONSOLE=n
+CONFIG_LOG_BACKEND_UART=n
+
 # Pin numbers are module pins (MDBT50Q-1MV2 carries the aQFN73 inside).
 # The feathers use the MDBT50Q-1MV2 module, so pin numbers are module pins.
 CONFIG_IOBROKER_PACKAGE_MDBT50Q_1MV2=y