drivers: can: set default initial bitrates via Kconfig

Set the default initial bitrates globally via Kconfig. The initial bitrates
can still be overridden using the "bus-speed" and "bus-speed-data"
devicetree properties.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

drivers/can/Kconfig

@@ -23,6 +23,21 @@ config CAN_INIT_PRIORITY
 	help
 	  CAN driver device initialization priority.
 
+config CAN_DEFAULT_BITRATE
+	int "Default CAN bitrate"
+	default 125000
+	help
+	  Default initial CAN bitrate in bits/s. This can be overridden per CAN controller using the
+	  "bus-speed" devicetree property.
+
+config CAN_DEFAULT_BITRATE_DATA
+	int "Default CAN data phase bitrate"
+	default 1000000
+	depends on CAN_FD_MODE
+	help
+	  Default initial CAN data phase bitrate in bits/s. This can be overridden per CAN controller
+	  using the "bus-speed-data" devicetree property.
+
 config CAN_SHELL
 	bool "CAN shell"
 	depends on SHELL

dts/bindings/can/can-controller.yaml

@@ -5,9 +5,9 @@ include: base.yaml
 properties:
   bus-speed:
     type: int
-    required: true
     description: |
-      Initial bitrate in bit/s.
+      Initial bitrate in bit/s. If this is unset, the initial bitrate is set to
+      CONFIG_CAN_DEFAULT_BITRATE.
   sample-point:
     type: int
     description: |

dts/bindings/can/can-fd-controller.yaml

@@ -5,9 +5,9 @@ include: can-controller.yaml
 properties:
   bus-speed-data:
     type: int
-    required: true
     description: |
-      Initial data phase bitrate in bit/s.
+      Initial data phase bitrate in bit/s.  If this is unset, the initial data phase bitrate is set
+      to CONFIG_CAN_DEFAULT_BITRATE_DATA.
   sample-point-data:
     type: int
     description: |

include/zephyr/drivers/can.h

@@ -374,10 +374,11 @@ struct can_driver_config {
 		.phy = DEVICE_DT_GET_OR_NULL(DT_PHANDLE(node_id, phys)),			\
 		.min_bitrate = DT_CAN_TRANSCEIVER_MIN_BITRATE(node_id, _min_bitrate),		\
 		.max_bitrate = DT_CAN_TRANSCEIVER_MAX_BITRATE(node_id, _max_bitrate),		\
-		.bus_speed = DT_PROP(node_id, bus_speed),					\
+		.bus_speed = DT_PROP_OR(node_id, bus_speed, CONFIG_CAN_DEFAULT_BITRATE),	\
 		.sample_point = DT_PROP_OR(node_id, sample_point, 0),				\
 		IF_ENABLED(CONFIG_CAN_FD_MODE,							\
-			(.bus_speed_data = DT_PROP_OR(node_id, bus_speed_data, 0),		\
+			(.bus_speed_data = DT_PROP_OR(node_id, bus_speed_data,			\
+						      CONFIG_CAN_DEFAULT_BITRATE_DATA),		\
 			 .sample_point_data = DT_PROP_OR(node_id, sample_point_data, 0),))	\
 	}
 

samples/modules/canopennode/src/main.c

@@ -15,7 +15,8 @@
 LOG_MODULE_REGISTER(app);
 
 #define CAN_INTERFACE DEVICE_DT_GET(DT_CHOSEN(zephyr_canbus))
-#define CAN_BITRATE (DT_PROP(DT_CHOSEN(zephyr_canbus), bus_speed) / 1000)
+#define CAN_BITRATE (DT_PROP_OR(DT_CHOSEN(zephyr_canbus), bus_speed, \
+				CONFIG_CAN_DEFAULT_BITRATE) / 1000)
 
 static struct gpio_dt_spec led_green_gpio = GPIO_DT_SPEC_GET_OR(
 		DT_ALIAS(green_led), gpios, {0});