serial: bt: Set configurable options for the NUS Work-queue

Default priority set to Main Thread's and Stack-size set to 1KiB. This
should still allow for the System work-queue, considering this
Work-queue could be temporarily blocked on BT TX commands.

Signed-off-by: Luis Ubieda <luisf@croxel.com>

Author: ubieda

drivers/serial/Kconfig.bt

@@ -11,3 +11,19 @@ config UART_BT
 	help
 	  Enable the UART over NUS Bluetooth driver, which can be used to pipe
 	  serial data over Bluetooth LE GATT using NUS (Nordic UART Service).
+
+if UART_BT
+
+config UART_BT_WORKQUEUE_PRIORITY
+	int "UART NUS Work-queue Priority"
+	default MAIN_THREAD_PRIORITY
+	help
+	  Select UART NUS Work-queue priority based on the application context.
+
+config UART_BT_WORKQUEUE_STACK_SIZE
+	int "UART NUS Work-queue Stack Size"
+	default 1024
+	help
+	  Set UART NUS Work-queue Stack-size based on the application context.
+
+endif

drivers/serial/uart_bt.c

@@ -15,7 +15,7 @@
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(uart_nus, CONFIG_UART_LOG_LEVEL);
 
-K_THREAD_STACK_DEFINE(nus_work_queue_stack, 2048);
+K_THREAD_STACK_DEFINE(nus_work_queue_stack, CONFIG_UART_BT_WORKQUEUE_STACK_SIZE);
 static struct k_work_q nus_work_queue;
 
 struct uart_bt_data {
@@ -276,7 +276,7 @@ static int uart_bt_workqueue_init(void)
 	k_work_queue_init(&nus_work_queue);
 	k_work_queue_start(&nus_work_queue, nus_work_queue_stack,
 			   K_THREAD_STACK_SIZEOF(nus_work_queue_stack),
-			   K_LOWEST_APPLICATION_THREAD_PRIO, NULL);
+			   CONFIG_UART_BT_WORKQUEUE_PRIORITY, NULL);
 
 	return 0;
 }