drivers: can: Add Kconfig option for CANFD datalenght

Add Kconfig option to select appropriate can data field length

Signed-off-by: Alexander Wachter <[email protected]>

drivers/can/Kconfig

@@ -29,6 +29,18 @@ config CAN_FD_MODE
 	help
 	  Enable CAN-FD compatible API
 
+if CAN_FD_MODE
+
+config CANFD_MAX_DLC
+	int "Max data length code in CAN frames"
+	range 8 15
+	default 15
+	help
+	  Maximum allowed DLC in a CAN frame. This parameter sets the
+	  data buffer size in a CAN frame and is therefore only used to
+	  optimize memory consumption.
+endif # CAN_FD_MODE
+
 config CAN_INIT_PRIORITY
 	int "CAN driver init priority"
 	default 80

include/drivers/can.h

@@ -33,7 +33,22 @@ extern "C" {
 #define CAN_STD_ID_MASK CAN_MAX_STD_ID
 #define CAN_EXT_ID_MASK (0x1FFFFFFF)
 #define CAN_MAX_DLC    (8)
+#define CANFD_MAX_DLC  CONFIG_CANFD_MAX_DLC
+#ifndef CONFIG_CANFD_MAX_DLC
 #define CAN_MAX_DLEN    8
+#else
+#if CONFIG_CANFD_MAX_DLC <= 8
+#define CAN_MAX_DLEN    CONFIG_CANFD_MAX_DLC
+#elif CONFIG_CANFD_MAX_DLC <= 12
+#define CAN_MAX_DLEN    CONFIG_CANFD_MAX_DLC + (CONFIG_CANFD_MAX_DLC - 8) * 4
+#elif CONFIG_CANFD_MAX_DLC == 13
+#define CAN_MAX_DLEN 32
+#elif CONFIG_CANFD_MAX_DLC == 14
+#define CAN_MAX_DLEN 48
+#elif CONFIG_CANFD_MAX_DLC == 15
+#define CAN_MAX_DLEN 64
+#endif
+#endif /* CONFIG_CANFD_MAX_DLC */
 
 /* CAN_TX_* are the error flags from tx_callback and send.*/
 /** send successfully */