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

Add support to match serdev devices with serdev drivers based on the serdev
ID table defined in serdev_device_driver::id_table.

The matching function, serdev_driver_match_device() uses the serdev device
name to match against the entries in serdev_device_driver::id_table.

If there is no serdev id_table for the driver, then serdev_device_match()
will fallback to ACPI and DT based matching.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/tty/serdev/core.c         | 23 ++++++++++++++++++++++-
 include/linux/mod_devicetable.h   |  7 +++++++
 include/linux/serdev.h            |  4 ++++
 scripts/mod/devicetable-offsets.c |  3 +++
 4 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index b33e708cb245..2b5582cd5063 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -85,12 +85,33 @@ static const struct device_type serdev_ctrl_type = {
 	.release	= serdev_ctrl_release,
 };
 
+static int serdev_driver_match_device(struct device *dev, const struct device_driver *drv)
+{
+	const struct serdev_device_driver *serdev_drv = to_serdev_device_driver(drv);
+	struct serdev_device *serdev = to_serdev_device(dev);
+	const struct serdev_device_id *id;
+
+	if (!serdev_drv->id_table)
+		return 0;
+
+	for (id = serdev_drv->id_table; id->name[0]; id++) {
+		if (!strcmp(dev_name(dev), id->name)) {
+			serdev->id = id;
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
 static int serdev_device_match(struct device *dev, const struct device_driver *drv)
 {
 	if (!is_serdev_device(dev))
 		return 0;
 
-	/* TODO: platform matching */
+	if (serdev_driver_match_device(dev, drv))
+		return 1;
+
 	if (acpi_driver_match_device(dev, drv))
 		return 1;
 
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 6077972e8b45..70c54c4bedba 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -976,4 +976,11 @@ struct coreboot_device_id {
 	kernel_ulong_t driver_data;
 };
 
+#define SERDEV_NAME_SIZE 32
+
+struct serdev_device_id {
+	const char name[SERDEV_NAME_SIZE];
+	kernel_ulong_t driver_data;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index ecde0ad3e248..aca92e0ee6e7 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -39,6 +39,7 @@ struct serdev_device_ops {
  * @ops:	Device operations.
  * @write_comp	Completion used by serdev_device_write() internally
  * @write_lock	Lock to serialize access when writing data
+ * @id:		serdev device ID entry
  */
 struct serdev_device {
 	struct device dev;
@@ -47,6 +48,7 @@ struct serdev_device {
 	const struct serdev_device_ops *ops;
 	struct completion write_comp;
 	struct mutex write_lock;
+	const struct serdev_device_id *id;
 };
 
 #define to_serdev_device(d) container_of_const(d, struct serdev_device, dev)
@@ -55,11 +57,13 @@ struct serdev_device {
  * struct serdev_device_driver - serdev slave device driver
  * @driver:	serdev device drivers should initialize name field of this
  *		structure.
+ * @id_table:	serdev device ID table
  * @probe:	binds this driver to a serdev device.
  * @remove:	unbinds this driver from the serdev device.
  */
 struct serdev_device_driver {
 	struct device_driver driver;
+	const struct serdev_device_id *id_table;
 	int	(*probe)(struct serdev_device *);
 	void	(*remove)(struct serdev_device *);
 };
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index d3d00e85edf7..c1bfa8eddc4d 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -280,5 +280,8 @@ int main(void)
 	DEVID(coreboot_device_id);
 	DEVID_FIELD(coreboot_device_id, tag);
 
+	DEVID(serdev_device_id);
+	DEVID_FIELD(serdev_device_id, name);
+
 	return 0;
 }

-- 
2.48.1

On Tue, 25 Nov 2025 15:45:06 +0100, Manivannan Sadhasivam via B4 Relay
<devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org> said:
> From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
>
> Add support to match serdev devices with serdev drivers based on the serdev
> ID table defined in serdev_device_driver::id_table.
>
> The matching function, serdev_driver_match_device() uses the serdev device
> name to match against the entries in serdev_device_driver::id_table.
>
> If there is no serdev id_table for the driver, then serdev_device_match()
> will fallback to ACPI and DT based matching.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
>  drivers/tty/serdev/core.c         | 23 ++++++++++++++++++++++-
>  include/linux/mod_devicetable.h   |  7 +++++++
>  include/linux/serdev.h            |  4 ++++
>  scripts/mod/devicetable-offsets.c |  3 +++
>  4 files changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
> index b33e708cb245..2b5582cd5063 100644
> --- a/drivers/tty/serdev/core.c
> +++ b/drivers/tty/serdev/core.c
> @@ -85,12 +85,33 @@ static const struct device_type serdev_ctrl_type = {
>  	.release	= serdev_ctrl_release,
>  };
>
> +static int serdev_driver_match_device(struct device *dev, const struct device_driver *drv)
> +{
> +	const struct serdev_device_driver *serdev_drv = to_serdev_device_driver(drv);
> +	struct serdev_device *serdev = to_serdev_device(dev);
> +	const struct serdev_device_id *id;
> +
> +	if (!serdev_drv->id_table)
> +		return 0;
> +
> +	for (id = serdev_drv->id_table; id->name[0]; id++) {
> +		if (!strcmp(dev_name(dev), id->name)) {
> +			serdev->id = id;
> +			return 1;
> +		}
> +	}
> +
> +	return 0;
> +}
> +

I don't know if Rob agrees with me but I would very much prefer to see
software-node-based approach instead of an ID table matching.

Could you in the pwrseq driver, create a software node for the serdev device
you allocate, set its "compatible" to "qcom,wcn7850-bt" and match against it
here?

This has several benefits: if you ever need to pass more properties to the
serdev devices, you already have a medium for that and you can also leave
serdev_device_add() alone. You're comparing the entire name here - what if
someone sets device's ID to some value and the name will be "WCN7850.2"?

You could also drop the serdev_id field from struct serdev_device. For matching
you could even reuse the of_device_id from the device driver.

Which also makes me think that maybe we should finally think about a generic,
fwnode-based device driver matching in the driver model...

Bartosz

>  static int serdev_device_match(struct device *dev, const struct device_driver *drv)
>  {
>  	if (!is_serdev_device(dev))
>  		return 0;
>
> -	/* TODO: platform matching */
> +	if (serdev_driver_match_device(dev, drv))
> +		return 1;
> +
>  	if (acpi_driver_match_device(dev, drv))
>  		return 1;
>
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 6077972e8b45..70c54c4bedba 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -976,4 +976,11 @@ struct coreboot_device_id {
>  	kernel_ulong_t driver_data;
>  };
>
> +#define SERDEV_NAME_SIZE 32
> +
> +struct serdev_device_id {
> +	const char name[SERDEV_NAME_SIZE];
> +	kernel_ulong_t driver_data;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/include/linux/serdev.h b/include/linux/serdev.h
> index ecde0ad3e248..aca92e0ee6e7 100644
> --- a/include/linux/serdev.h
> +++ b/include/linux/serdev.h
> @@ -39,6 +39,7 @@ struct serdev_device_ops {
>   * @ops:	Device operations.
>   * @write_comp	Completion used by serdev_device_write() internally
>   * @write_lock	Lock to serialize access when writing data
> + * @id:		serdev device ID entry
>   */
>  struct serdev_device {
>  	struct device dev;
> @@ -47,6 +48,7 @@ struct serdev_device {
>  	const struct serdev_device_ops *ops;
>  	struct completion write_comp;
>  	struct mutex write_lock;
> +	const struct serdev_device_id *id;
>  };
>
>  #define to_serdev_device(d) container_of_const(d, struct serdev_device, dev)
> @@ -55,11 +57,13 @@ struct serdev_device {
>   * struct serdev_device_driver - serdev slave device driver
>   * @driver:	serdev device drivers should initialize name field of this
>   *		structure.
> + * @id_table:	serdev device ID table
>   * @probe:	binds this driver to a serdev device.
>   * @remove:	unbinds this driver from the serdev device.
>   */
>  struct serdev_device_driver {
>  	struct device_driver driver;
> +	const struct serdev_device_id *id_table;
>  	int	(*probe)(struct serdev_device *);
>  	void	(*remove)(struct serdev_device *);
>  };
> diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
> index d3d00e85edf7..c1bfa8eddc4d 100644
> --- a/scripts/mod/devicetable-offsets.c
> +++ b/scripts/mod/devicetable-offsets.c
> @@ -280,5 +280,8 @@ int main(void)
>  	DEVID(coreboot_device_id);
>  	DEVID_FIELD(coreboot_device_id, tag);
>
> +	DEVID(serdev_device_id);
> +	DEVID_FIELD(serdev_device_id, name);
> +
>  	return 0;
>  }
>
> --
> 2.48.1
>
>
>