protocol_serialization: Fix random k_oops in nrf54l.

Commit fixes random k_oops on nrf54l15pdk caused by overlapping init
of DK buttons and comunication UART.

Signed-off-by: Przemyslaw Bida <[email protected]>

samples/nrf_rpc/protocols_serialization/server/Kconfig

@@ -24,7 +24,6 @@ config LOG_BACKEND_UART
 
 config NRF_PS_SERVER_FATAL_ERROR_TRIGGER
 	bool "Fatal error trigger"
-	select DK_LIBRARY
 	help
 	  Enables triggering a fatal error by pressing Button 1 on the development
 	  kit. This trigger allows for testing the feature of logging over RPC that

samples/nrf_rpc/protocols_serialization/server/README.rst

@@ -48,10 +48,19 @@ The following snippets are available:
 User interface
 **************
 
-Button 1:
-   * When the ``log_rpc`` snippet is enabled: triggers a fatal error.
-     This is used for testing the crash log feature.
-   * Otherwise: not available.
+.. tabs::
+   .. group-tab:: nRF52840 DK
+
+      Button 4:
+         * When the ``log_rpc`` snippet is enabled: triggers a fatal error.
+            This is used for testing the crash log feature.
+         * Otherwise: not available.
+
+   .. group-tab:: nRF54L15 DK
+      Button 3:
+         * When the ``log_rpc`` snippet is enabled: triggers a fatal error.
+           This is used for testing the crash log feature.
+         * Otherwise: not available.
 
 Building and running
 ********************
@@ -113,7 +122,7 @@ In the protocols serialization samples, one peripheral is used for shell and log
         .. figure:: /images/ps_nrf52_connections.png
             :alt: nRF52840 DK server and client pin connections
 
-    .. group-tab:: nRF54l15 DK
+    .. group-tab:: nRF54L15 DK
 
         By default, the nRF54L15 DK uses the ``uart20`` peripheral for shell and logging purposes, and the ``uart21`` peripheral for sending OpenThread and Bluetooth remote procedure calls (RPCs).
 

samples/nrf_rpc/protocols_serialization/server/src/fatal_error_trigger.c

@@ -4,21 +4,58 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
-#include <dk_buttons_and_leds.h>
-
 #include <zephyr/init.h>
 #include <zephyr/kernel.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_DECLARE(nrf_ps_server, CONFIG_NRF_PS_SERVER_LOG_LEVEL);
+
+/*
+ * This module intentionally do not use DK library.
+ * On nRF54l15 default buttons overlap with UART pins configuration.
+ */
+
+#define SW0_NODE DT_ALIAS(sw3)
 
-static void button_handler(uint32_t button_state, uint32_t has_changed)
+static const struct gpio_dt_spec button = GPIO_DT_SPEC_GET_OR(SW0_NODE, gpios, {0});
+static struct gpio_callback button_cb_data;
+
+void button_pressed(const struct device *dev, struct gpio_callback *cb, uint32_t pins)
 {
-	if (button_state & DK_BTN1_MSK) {
-		k_oops();
-	}
+	LOG_ERR("Button causing k_oops pressed.\n");
+	k_oops();
 }
 
 static int button_handler_init(void)
 {
-	return dk_buttons_init(button_handler);
+	int ret;
+
+	if (!gpio_is_ready_dt(&button)) {
+		LOG_DBG("Error: button device %s is not ready\n", button.port->name);
+		return 0;
+	}
+
+	ret = gpio_pin_configure_dt(&button, GPIO_INPUT);
+	if (ret != 0) {
+		LOG_DBG("Error %d: failed to configure %s pin %d\n", ret, button.port->name,
+			button.pin);
+		return 0;
+	}
+
+	ret = gpio_pin_interrupt_configure_dt(&button, GPIO_INT_EDGE_TO_ACTIVE);
+	if (ret != 0) {
+		LOG_DBG("Error %d: failed to configure interrupt on %s pin %d\n", ret,
+			button.port->name, button.pin);
+		return 0;
+	}
+
+	gpio_init_callback(&button_cb_data, button_pressed, BIT(button.pin));
+	gpio_add_callback(button.port, &button_cb_data);
+	LOG_DBG("Set up button at %s pin %d\n", button.port->name, button.pin);
+
+	return 0;
 }
 
-SYS_INIT(button_handler_init, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
+SYS_INIT(button_handler_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);