From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

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

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/tty/serdev/core.c | 16 ++++++++++++++++
 include/linux/serdev.h    |  9 +++++++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index b33e708cb245..25382c2d63e6 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -504,6 +504,22 @@ struct serdev_controller *serdev_controller_alloc(struct device *host,
 }
 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 
+/**
+ * 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.
+ */
+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);
+
 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 ecde0ad3e248..db9bfaba0662 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -333,4 +333,13 @@ 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
+struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
+{
+	return NULL;
+}
+#endif /* CONFIG_OF */
+
 #endif /*_LINUX_SERDEV_H */

-- 
2.48.1

On Sat, Jan 10, 2026 at 12:26:20PM +0530, Manivannan Sadhasivam via B4 Relay wrote:

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

Why OF-centric code? No, please do it fwnode-based.

-- 
With Best Regards,
Andy Shevchenko

On Mon, Jan 12, 2026 at 09:50:33AM +0200, Andy Shevchenko wrote:
> On Sat, Jan 10, 2026 at 12:26:20PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> 
> > Add of_find_serdev_controller_by_node() API to find the serdev controller
> > device associated with the devicetree node.
> 
> Why OF-centric code? No, please do it fwnode-based.
> 

No issues for me. But the existing APIs in serdev are OF based. If uniformity is
not needed, I can change it to a fwnode based API.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

On Mon, 12 Jan 2026 08:55:21 +0100, Manivannan Sadhasivam
<mani@kernel.org> said:
> On Mon, Jan 12, 2026 at 09:50:33AM +0200, Andy Shevchenko wrote:
>> On Sat, Jan 10, 2026 at 12:26:20PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
>>
>> > Add of_find_serdev_controller_by_node() API to find the serdev controller
>> > device associated with the devicetree node.
>>
>> Why OF-centric code? No, please do it fwnode-based.
>>
>
> No issues for me. But the existing APIs in serdev are OF based. If uniformity is
> not needed, I can change it to a fwnode based API.
>

Using fwnodes here shouldn't be an issue, even though serdev core assigns
dev->of_node, it will be converted to dev->fwnode when the device is registered.

Bart

On Mon, Jan 12, 2026 at 01:25:21PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Jan 12, 2026 at 09:50:33AM +0200, Andy Shevchenko wrote:
> > On Sat, Jan 10, 2026 at 12:26:20PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> > 
> > > Add of_find_serdev_controller_by_node() API to find the serdev controller
> > > device associated with the devicetree node.
> > 
> > Why OF-centric code? No, please do it fwnode-based.
> 
> No issues for me. But the existing APIs in serdev are OF based. If uniformity is
> not needed, I can change it to a fwnode based API.

Really? serdev.h has no OF APIs.

-- 
With Best Regards,
Andy Shevchenko