drivers: serial: nrfx: Ensure that instances have some pins assigned

Add build assertions that will ensure that every peripheral for
which a driver instance is created has some pins assigned to it.
Neither pinctrl-0 nor *-pin properties can be currently marked as
required in devicetree, so these assertions will help users avoid
invalid configurations where it could be hard to figure out why
the UART is not working.

Signed-off-by: Andrzej Głąbek <[email protected]>

Author: anangl

drivers/serial/uart_nrfx_uart.c

@@ -10,6 +10,7 @@
 
 #include <drivers/uart.h>
 #include <pm/device.h>
+#include <soc.h>
 #include <hal/nrf_uart.h>
 
 #ifdef CONFIG_PINCTRL
@@ -1192,6 +1193,8 @@ static int uart_nrfx_pm_action(const struct device *dev,
 PINCTRL_DT_INST_DEFINE(0);
 #endif /* CONFIG_PINCTRL */
 
+NRF_DT_ENSURE_PINS_ASSIGNED(DT_DRV_INST(0), tx_pin, rx_pin);
+
 static const struct uart_nrfx_config uart_nrfx_uart0_config = {
 #ifdef CONFIG_PINCTRL
 	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(0),

drivers/serial/uart_nrfx_uarte.c

@@ -14,6 +14,7 @@
 #include <nrfx_timer.h>
 #include <sys/util.h>
 #include <kernel.h>
+#include <soc.h>
 #include <logging/log.h>
 #include <helpers/nrfx_gppi.h>
 LOG_MODULE_REGISTER(uart_nrfx_uarte, LOG_LEVEL_ERR);
@@ -2047,6 +2048,7 @@ static int uarte_nrfx_pm_action(const struct device *dev,
 #endif /* CONFIG_PINCTRL */
 
 #define UART_NRF_UARTE_DEVICE(idx)					       \
+	NRF_DT_ENSURE_PINS_ASSIGNED(UARTE(idx), tx_pin, rx_pin);	       \
 	UARTE_INT_DRIVEN(idx);						       \
 	UARTE_ASYNC(idx);						       \
 	IF_ENABLED(CONFIG_PINCTRL, (PINCTRL_DT_DEFINE(UARTE(idx));))	       \

samples/boards/nrf/dynamic_pinctrl/boards/nrf52840dk_nrf52840.overlay

@@ -17,6 +17,12 @@
 	pinctrl-names = "default", "sleep";
 };
 
+/* Disable uart1 so that it is not left without any pins assigned. */
+/* TODO: remove once all boards enable pinctrl by default */
+&uart1 {
+	status = "disabled";
+};
+
 &pinctrl {
 	/* pin configuration for UART0 */
 	/* TODO: move to board dts once all boards enable pinctrl by default */

soc/arm/nordic_nrf/common/soc_nrf_common.h

@@ -179,6 +179,42 @@
 				  "NRF_DT_CHECK_GPIO_CTLR_IS_SOC: OK")))
 /* Note: allow a trailing ";" either way */
 
+/**
+ * @brief Helper macro for NRF_DT_ENSURE_PINS_ASSIGNED
+ *
+ * This macro is neeeded only because the order of parameters taken by
+ * DT_NODE_HAS_PROP is different than that required for a macro to be
+ * invoked by FOR_EACH_FIXED_ARG.
+ *
+ * @param prop lowercase-and-underscores property name
+ * @param node_id node identifier
+ * @return 1 if the node has the property, 0 otherwise.
+ */
+#define NRF_DT_ENSURE_NODE_HAS_PROP(prop, node_id) \
+	DT_NODE_HAS_PROP(node_id, prop)
+
+/**
+ * Error out the build if PINCTRL is enabled and the specified node does not
+ * have the required pinctrl-N properties defined (pinctrl-0 always, pinctrl-1
+ * when PM_DEVICE is enabled) or if PINCTRL is not enabled and the node does
+ * not have at least one of the specified legacy pin properties defined.
+ *
+ * @param node_id node identifier
+ * @param ... list of lowercase-and-underscores legacy pin properties from
+ *            which at least one needs to be defined if PINCTRL is not enabled
+ */
+#define NRF_DT_ENSURE_PINS_ASSIGNED(node_id, ...)			\
+	BUILD_ASSERT((IS_ENABLED(CONFIG_PINCTRL) &&			\
+		      DT_PINCTRL_HAS_IDX(node_id, 0) &&			\
+		      (DT_PINCTRL_HAS_IDX(node_id, 1) ||		\
+		       !IS_ENABLED(CONFIG_PM_DEVICE)))			\
+		     ||							\
+		     (!IS_ENABLED(CONFIG_PINCTRL) &&			\
+		      (FOR_EACH_FIXED_ARG(NRF_DT_ENSURE_NODE_HAS_PROP,	\
+					  (||), node_id, __VA_ARGS__))),\
+		DT_NODE_PATH(node_id)					\
+			" defined without required pin configuration")
+
 #endif /* !_ASMLANGUAGE */
 
 #endif