drivers: can: add generic GPIO controlled CAN transceiver driver

Add generic driver for GPIO controlled CAN transceivers.

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

drivers/can/CMakeLists.txt

@@ -16,3 +16,5 @@ zephyr_library_sources_ifdef(CONFIG_CAN_RCAR         can_rcar.c)
 
 zephyr_library_sources_ifdef(CONFIG_USERSPACE        can_handlers.c)
 zephyr_library_sources_ifdef(CONFIG_CAN_SHELL        can_shell.c)
+
+add_subdirectory(transceiver)

drivers/can/Kconfig

@@ -102,4 +102,6 @@ source "drivers/can/Kconfig.mcan"
 source "drivers/can/Kconfig.rcar"
 source "drivers/can/Kconfig.loopback"
 
+source "drivers/can/transceiver/Kconfig"
+
 endif # CAN

drivers/can/transceiver/CMakeLists.txt

@@ -0,0 +1,6 @@
+# Copyright (c) 2022 Vestas Wind Systems A/S
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+zephyr_library_property(ALLOW_EMPTY TRUE)
+zephyr_library_sources_ifdef(CONFIG_CAN_TRANSCEIVER_GPIO can_transceiver_gpio.c)

drivers/can/transceiver/Kconfig

@@ -0,0 +1,21 @@
+# CAN transceiver configuration options
+
+# Copyright (c) 2022 Vestas Wind Systems A/S
+# SPDX-License-Identifier: Apache-2.0
+
+menu "CAN transceiver drivers"
+
+config CAN_TRANSCEIVER_INIT_PRIORITY
+	int "CAN transceiver driver init priority"
+	default 70
+	help
+	  CAN transceiver device driver initialization priority.
+
+config CAN_TRANSCEIVER_GPIO
+	bool "GPIO controlled CAN transceiver"
+	depends on GPIO
+	default $(dt_compat_enabled,can-transceiver-gpio)
+	help
+	  Enable support for GPIO controlled CAN transceivers.
+
+endmenu

drivers/can/transceiver/can_transceiver_gpio.c

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2022 Vestas Wind Systems A/S
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT can_transceiver_gpio
+
+#include <device.h>
+#include <drivers/can/transceiver.h>
+#include <drivers/gpio.h>
+#include <logging/log.h>
+
+LOG_MODULE_REGISTER(can_transceiver_gpio, CONFIG_CAN_LOG_LEVEL);
+
+/* Does any devicetree instance have an enable-gpios property? */
+#define INST_HAS_ENABLE_GPIOS_OR(inst) DT_INST_NODE_HAS_PROP(inst, enable_gpios) ||
+#define ANY_INST_HAS_ENABLE_GPIOS DT_INST_FOREACH_STATUS_OKAY(INST_HAS_ENABLE_GPIOS_OR) 0
+
+/* Does any devicetree instance have a standby-gpios property? */
+#define INST_HAS_STANDBY_GPIOS_OR(inst) DT_INST_NODE_HAS_PROP(inst, standby_gpios) ||
+#define ANY_INST_HAS_STANDBY_GPIOS DT_INST_FOREACH_STATUS_OKAY(INST_HAS_STANDBY_GPIOS_OR) 0
+
+struct can_transceiver_gpio_config {
+#if ANY_INST_HAS_ENABLE_GPIOS
+	struct gpio_dt_spec enable_gpio;
+#endif /* ANY_INST_HAS_ENABLE_GPIOS */
+#if ANY_INST_HAS_STANDBY_GPIOS
+	struct gpio_dt_spec standby_gpio;
+#endif /* ANY_INST_HAS_STANDBY_GPIOS */
+};
+
+static int can_transceiver_gpio_set_state(const struct device *dev, bool enabled)
+{
+	const struct can_transceiver_gpio_config *config = dev->config;
+	int err;
+
+#if ANY_INST_HAS_ENABLE_GPIOS
+	if (config->enable_gpio.port != NULL) {
+		err = gpio_pin_set_dt(&config->enable_gpio, enabled ? 1 : 0);
+		if (err != 0) {
+			LOG_ERR("failed to set enable GPIO pin (err %d)", err);
+			return -EIO;
+		}
+	}
+#endif /* ANY_INST_HAS_ENABLE_GPIOS */
+
+#if ANY_INST_HAS_STANDBY_GPIOS
+	if (config->standby_gpio.port != NULL) {
+		err = gpio_pin_set_dt(&config->standby_gpio, enabled ? 0 : 1);
+		if (err != 0) {
+			LOG_ERR("failed to set standby GPIO pin (err %d)", err);
+			return -EIO;
+		}
+	}
+#endif /* ANY_INST_HAS_STANDBY_GPIOS */
+
+	return 0;
+}
+
+static int can_transceiver_gpio_enable(const struct device *dev)
+{
+	return can_transceiver_gpio_set_state(dev, true);
+}
+
+static int can_transceiver_gpio_disable(const struct device *dev)
+{
+	return can_transceiver_gpio_set_state(dev, false);
+}
+
+static int can_transceiver_gpio_init(const struct device *dev)
+{
+	const struct can_transceiver_gpio_config *config = dev->config;
+	int err;
+
+#if ANY_INST_HAS_ENABLE_GPIOS
+	if (config->enable_gpio.port != NULL) {
+		if (!device_is_ready(config->enable_gpio.port)) {
+			LOG_ERR("enable pin GPIO device not ready");
+			return -EINVAL;
+		}
+
+		/* CAN transceiver is disabled during initialization */
+		err = gpio_pin_configure_dt(&config->enable_gpio, GPIO_OUTPUT_INACTIVE);
+		if (err != 0) {
+			LOG_ERR("failed to configure enable GPIO pin (err %d)", err);
+			return err;
+		}
+	}
+#endif /* ANY_INST_HAS_ENABLE_GPIOS */
+
+#if ANY_INST_HAS_STANDBY_GPIOS
+	if (config->standby_gpio.port != NULL) {
+		if (!device_is_ready(config->standby_gpio.port)) {
+			LOG_ERR("standby pin GPIO device not ready");
+			return -EINVAL;
+		}
+
+		/* CAN transceiver is put in standby during initialization */
+		err = gpio_pin_configure_dt(&config->standby_gpio, GPIO_OUTPUT_ACTIVE);
+		if (err != 0) {
+			LOG_ERR("failed to configure standby GPIO pin (err %d)", err);
+			return err;
+		}
+	}
+#endif /* ANY_INST_HAS_STANDBY_GPIOS */
+
+	return 0;
+}
+
+static const struct can_transceiver_driver_api can_transceiver_gpio_driver_api = {
+	.enable = can_transceiver_gpio_enable,
+	.disable = can_transceiver_gpio_disable,
+};
+
+#define CAN_TRANSCEIVER_GPIO_COND(inst, name)				\
+	IF_ENABLED(DT_INST_NODE_HAS_PROP(inst, name##_gpios),		\
+		   (.name##_gpio = GPIO_DT_SPEC_INST_GET(inst, name##_gpios),))
+
+#define CAN_TRANSCEIVER_GPIO_INIT(inst)					\
+	static const struct can_transceiver_gpio_config	can_transceiver_gpio_config_##inst = { \
+		CAN_TRANSCEIVER_GPIO_COND(inst, enable)			\
+		CAN_TRANSCEIVER_GPIO_COND(inst, standby)		\
+	};								\
+									\
+	DEVICE_DT_INST_DEFINE(inst, &can_transceiver_gpio_init,		\
+			NULL, NULL, &can_transceiver_gpio_config_##inst,\
+			POST_KERNEL, CONFIG_CAN_TRANSCEIVER_INIT_PRIORITY, \
+			&can_transceiver_gpio_driver_api);		\
+
+DT_INST_FOREACH_STATUS_OKAY(CAN_TRANSCEIVER_GPIO_INIT)