[PATCH v5 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>

Add of_find_serdev_controller_by_node() API to find the serdev controller
device associated with the devicetree node.

Tested-by: Hans de Goede <johannes.goede@xxxxxxxxxxxxxxxx> # ThinkPad T14s gen6 (arm64)
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
---
 drivers/tty/serdev/core.c | 19 +++++++++++++++++++
 include/linux/serdev.h    |  9 +++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 8f25510f89b6..bf88b95f7458 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -514,6 +514,25 @@ struct serdev_controller *serdev_controller_alloc(struct device *host,
 }
 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 
+#ifdef CONFIG_OF
+/**
+ * of_find_serdev_controller_by_node() - Find the serdev controller associated
+ *					 with the devicetree node
+ * @node:	Devicetree node
+ *
+ * Return: Pointer to the serdev controller associated with the node. NULL if
+ * the controller is not found. Caller is responsible for calling
+ * serdev_controller_put() to drop the reference.
+ */
+struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
+{
+	struct device *dev = bus_find_device_by_of_node(&serdev_bus_type, node);
+
+	return (dev && dev->type == &serdev_ctrl_type) ? to_serdev_controller(dev) : NULL;
+}
+EXPORT_SYMBOL_GPL(of_find_serdev_controller_by_node);
+#endif
+
 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 {
 	struct device_node *node;
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 0c7d3c27d1f8..188c0ba62d50 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -334,4 +334,13 @@ static inline bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
 }
 #endif /* CONFIG_ACPI */
 
+#ifdef CONFIG_OF
+struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node);
+#else
+static inline struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
+{
+	return NULL;
+}
+#endif /* CONFIG_OF */
+
 #endif /*_LINUX_SERDEV_H */

-- 
2.51.0