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[PATCH v4 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node

Manivannan Sadhasivam via B4 Relay posted 9 patches 3 weeks, 6 days ago
[PATCH v4 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node
Posted by Manivannan Sadhasivam via B4 Relay 3 weeks, 6 days ago 
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
Re: [PATCH v4 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node
Posted by Hans de Goede 3 weeks, 4 days ago 
Hi Mani,

Thank you for your work in this.

On 12-Jan-26 17:26, Manivannan Sadhasivam via B4 Relay wrote:
> 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);
> +

This new of_find_serdev_controller_by_node() function needs:

#ifdef CONFIG_OF ... #endif

around it, to match the stubbing you are doing in serdev.h

>  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;
> +}

stubs like this one should be static inline to avoid warnings like this one:

In file included from drivers/tty/serdev/core.c:21:
./include/linux/serdev.h:339:27: warning: no previous prototype for ‘of_find_serdev_controller_by_node’ [-Wmissing-prototypes]
  339 | struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
      |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Regards,

Hans
Re: [PATCH v4 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node
Posted by Manivannan Sadhasivam 3 weeks, 4 days ago 
On Wed, Jan 14, 2026 at 03:01:51PM +0100, Hans de Goede wrote:
> Hi Mani,
> 
> Thank you for your work in this.
> 
> On 12-Jan-26 17:26, Manivannan Sadhasivam via B4 Relay wrote:
> > 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);
> > +
> 
> This new of_find_serdev_controller_by_node() function needs:
> 
> #ifdef CONFIG_OF ... #endif
> 
> around it, to match the stubbing you are doing in serdev.h
> 

Ack.

> >  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;
> > +}
> 
> stubs like this one should be static inline to avoid warnings like this one:
> 
> In file included from drivers/tty/serdev/core.c:21:
> ./include/linux/serdev.h:339:27: warning: no previous prototype for ‘of_find_serdev_controller_by_node’ [-Wmissing-prototypes]
>   339 | struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
>       |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 

Darn... Will fix it. Thanks for spotting!

- Mani

-- 
மணிவண்ணன் சதாசிவம்
Re: [PATCH v4 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node
Posted by Bartosz Golaszewski 3 weeks, 5 days ago 
On Mon, 12 Jan 2026 17:26:01 +0100, Manivannan Sadhasivam via B4 Relay
<devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org> said:
> 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.
> + */

Please also say that the caller is responsible for calling
serdev_controller_put() on the returned object.

Bart

> +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
>
>
>
Re: [PATCH v4 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node
Posted by Manivannan Sadhasivam 3 weeks, 4 days ago 
On Tue, Jan 13, 2026 at 08:54:55AM -0500, Bartosz Golaszewski wrote:
> On Mon, 12 Jan 2026 17:26:01 +0100, Manivannan Sadhasivam via B4 Relay
> <devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org> said:
> > 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.
> > + */
> 
> Please also say that the caller is responsible for calling
> serdev_controller_put() on the returned object.
> 

Ack.

- Mani

> Bart
> 
> > +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
> >
> >
> >

-- 
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