drivers: can: add API for getting supported capabilities

Add API function for getting the supported capabilities of a CAN
controller. This allows for writing portable CAN applications.

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

drivers/can/can_handlers.c

@@ -138,6 +138,15 @@ static inline int z_vrfy_can_get_max_filters(const struct device *dev, enum can_
 }
 #include <syscalls/can_get_max_filters_mrsh.c>
 
+static inline int z_vrfy_can_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	Z_OOPS(Z_SYSCALL_DRIVER_CAN(dev, get_capabilities));
+	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(cap, sizeof(*cap)));
+
+	return z_impl_can_get_capabilities(dev, cap);
+}
+#include <syscalls/can_get_capabilities_mrsh.c>
+
 static inline int z_vrfy_can_set_mode(const struct device *dev, can_mode_t mode)
 {
 	Z_OOPS(Z_SYSCALL_DRIVER_CAN(dev, set_mode));

drivers/can/can_loopback.c

@@ -197,6 +197,15 @@ static void can_loopback_remove_rx_filter(const struct device *dev, int filter_i
 	k_mutex_unlock(&data->mtx);
 }
 
+static int can_loopback_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	ARG_UNUSED(dev);
+
+	*cap = CAN_MODE_NORMAL | CAN_MODE_LOOPBACK;
+
+	return 0;
+}
+
 static int can_loopback_set_mode(const struct device *dev, can_mode_t mode)
 {
 	struct can_loopback_data *data = dev->data;
@@ -265,6 +274,7 @@ static int can_loopback_get_max_filters(const struct device *dev, enum can_ide i
 }
 
 static const struct can_driver_api can_loopback_driver_api = {
+	.get_capabilities = can_loopback_get_capabilities,
 	.set_mode = can_loopback_set_mode,
 	.set_timing = can_loopback_set_timing,
 	.send = can_loopback_send,

drivers/can/can_mcan.c

@@ -240,6 +240,19 @@ int can_mcan_set_timing_data(const struct device *dev,
 }
 #endif /* CONFIG_CAN_FD_MODE */
 
+int can_mcan_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	ARG_UNUSED(dev);
+
+	*cap = CAN_MODE_NORMAL | CAN_MODE_LOOPBACK | CAN_MODE_LISTENONLY;
+
+#if CONFIG_CAN_FD_MODE
+	*cap |= CAN_MODE_FD;
+#endif /* CONFIG_CAN_FD_MODE */
+
+	return 0;
+}
+
 int can_mcan_set_mode(const struct device *dev, can_mode_t mode)
 {
 	const struct can_mcan_config *cfg = dev->config;

drivers/can/can_mcan.h

@@ -257,6 +257,8 @@ struct can_mcan_reg;
 		.custom = _custom_data,					\
 	}
 
+int can_mcan_get_capabilities(const struct device *dev, can_mode_t *cap);
+
 int can_mcan_set_mode(const struct device *dev, can_mode_t mode);
 
 int can_mcan_set_timing(const struct device *dev,

drivers/can/can_mcp2515.c

@@ -440,6 +440,15 @@ done:
 	return ret;
 }
 
+static int mcp2515_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	ARG_UNUSED(dev);
+
+	*cap = CAN_MODE_NORMAL | CAN_MODE_LISTENONLY | CAN_MODE_LOOPBACK;
+
+	return 0;
+}
+
 static int mcp2515_set_mode(const struct device *dev, can_mode_t mode)
 {
 	const struct mcp2515_config *dev_cfg = dev->config;
@@ -827,6 +836,7 @@ static void mcp2515_int_gpio_callback(const struct device *dev,
 }
 
 static const struct can_driver_api can_api_funcs = {
+	.get_capabilities = mcp2515_get_capabilities,
 	.set_timing = mcp2515_set_timing,
 	.set_mode = mcp2515_set_mode,
 	.send = mcp2515_send,

drivers/can/can_mcux_flexcan.c

@@ -179,6 +179,15 @@ static int mcux_flexcan_set_timing(const struct device *dev,
 	return 0;
 }
 
+static int mcux_flexcan_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	ARG_UNUSED(dev);
+
+	*cap = CAN_MODE_NORMAL | CAN_MODE_LOOPBACK | CAN_MODE_LISTENONLY;
+
+	return 0;
+}
+
 static int mcux_flexcan_set_mode(const struct device *dev, can_mode_t mode)
 {
 	const struct mcux_flexcan_config *config = dev->config;
@@ -783,6 +792,7 @@ static int mcux_flexcan_init(const struct device *dev)
 }
 
 static const struct can_driver_api mcux_flexcan_driver_api = {
+	.get_capabilities = mcux_flexcan_get_capabilities,
 	.set_mode = mcux_flexcan_set_mode,
 	.set_timing = mcux_flexcan_set_timing,
 	.send = mcux_flexcan_send,

drivers/can/can_mcux_mcan.c

@@ -58,6 +58,7 @@ static int mcux_mcan_init(const struct device *dev)
 }
 
 static const struct can_driver_api mcux_mcan_driver_api = {
+	.get_capabilities = can_mcan_get_capabilities,
 	.set_mode = can_mcan_set_mode,
 	.set_timing = can_mcan_set_timing,
 	.send = can_mcan_send,

drivers/can/can_rcar.c

@@ -571,6 +571,15 @@ static int can_rcar_enter_operation_mode(const struct can_rcar_cfg *config)
 	return 0;
 }
 
+static int can_rcar_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	ARG_UNUSED(dev);
+
+	*cap = CAN_MODE_NORMAL | CAN_MODE_LOOPBACK | CAN_MODE_LISTENONLY;
+
+	return 0;
+}
+
 static int can_rcar_set_mode(const struct device *dev, can_mode_t mode)
 {
 	const struct can_rcar_cfg *config = dev->config;
@@ -1072,6 +1081,7 @@ static int can_rcar_get_max_bitrate(const struct device *dev, uint32_t *max_bitr
 }
 
 static const struct can_driver_api can_rcar_driver_api = {
+	.get_capabilities = can_rcar_get_capabilities,
 	.set_mode = can_rcar_set_mode,
 	.set_timing = can_rcar_set_timing,
 	.send = can_rcar_send,

drivers/can/can_sam.c

@@ -70,6 +70,7 @@ static int can_sam_init(const struct device *dev)
 }
 
 static const struct can_driver_api can_sam_driver_api = {
+	.get_capabilities = can_mcan_get_capabilities,
 	.set_mode = can_mcan_set_mode,
 	.set_timing = can_mcan_set_timing,
 	.send = can_mcan_send,

drivers/can/can_stm32.c

@@ -342,6 +342,15 @@ static int can_leave_sleep_mode(CAN_TypeDef *can)
 	return 0;
 }
 
+static int can_stm32_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	ARG_UNUSED(dev);
+
+	*cap = CAN_MODE_NORMAL | CAN_MODE_LOOPBACK | CAN_MODE_LISTENONLY;
+
+	return 0;
+}
+
 static int can_stm32_set_mode(const struct device *dev, can_mode_t mode)
 {
 	const struct can_stm32_config *cfg = dev->config;
@@ -1126,6 +1135,7 @@ static void can_stm32_remove_rx_filter(const struct device *dev, int filter_id)
 }
 
 static const struct can_driver_api can_api_funcs = {
+	.get_capabilities = can_stm32_get_capabilities,
 	.set_mode = can_stm32_set_mode,
 	.set_timing = can_stm32_set_timing,
 	.send = can_stm32_send,

drivers/can/can_stm32fd.c

@@ -123,6 +123,7 @@ static int can_stm32fd_init(const struct device *dev)
 }
 
 static const struct can_driver_api can_stm32fd_driver_api = {
+	.get_capabilities = can_mcan_get_capabilities,
 	.set_mode = can_mcan_set_mode,
 	.set_timing = can_mcan_set_timing,
 	.send = can_mcan_send,

drivers/can/can_stm32h7.c

@@ -95,6 +95,7 @@ static int can_stm32h7_init(const struct device *dev)
 }
 
 static const struct can_driver_api can_stm32h7_driver_api = {
+	.get_capabilities = can_mcan_get_capabilities,
 	.set_mode = can_mcan_set_mode,
 	.set_timing = can_mcan_set_timing,
 	.send = can_mcan_send,

include/zephyr/drivers/can.h

@@ -326,6 +326,12 @@ typedef int (*can_set_timing_t)(const struct device *dev,
 typedef int (*can_set_timing_data_t)(const struct device *dev,
 				     const struct can_timing *timing_data);
 
+/**
+ * @brief Callback API upon getting CAN controller capabilities
+ * See @a can_get_capabilities() for argument description
+ */
+typedef int (*can_get_capabilities_t)(const struct device *dev, can_mode_t *cap);
+
 /**
  * @brief Callback API upon setting CAN controller mode
  * See @a can_set_mode() for argument description
@@ -396,6 +402,7 @@ typedef int (*can_get_max_filters_t)(const struct device *dev, enum can_ide id_t
 typedef int (*can_get_max_bitrate_t)(const struct device *dev, uint32_t *max_bitrate);
 
 __subsystem struct can_driver_api {
+	can_get_capabilities_t get_capabilities;
 	can_set_mode_t set_mode;
 	can_set_timing_t set_timing;
 	can_send_t send;
@@ -902,6 +909,28 @@ static inline int z_impl_can_set_timing(const struct device *dev,
 	return api->set_timing(dev, timing);
 }
 
+/**
+ * @brief Get the supported modes of the CAN controller
+ *
+ * The returned capabilities may not necessarily be supported at the same time (e.g. some CAN
+ * controllers support both ``CAN_MODE_LOOPBACK`` and ``CAN_MODE_LISTENONLY``, but not at the same
+ * time).
+ *
+ * @param dev      Pointer to the device structure for the driver instance.
+ * @param[out] cap Supported capabilities.
+ *
+ * @retval 0 If successful.
+ * @retval -EIO General input/output error, failed to get capabilities.
+ */
+__syscall int can_get_capabilities(const struct device *dev, can_mode_t *cap);
+
+static inline int z_impl_can_get_capabilities(const struct device *dev, can_mode_t *cap)
+{
+	const struct can_driver_api *api = (const struct can_driver_api *)dev->api;
+
+	return api->get_capabilities(dev, cap);
+}
+
 /**
  * @brief Set the CAN controller to the given operation mode
  *