[PATCH v1 0/4] serdev: Stop using device_driver callbacks

[PATCH v1 0/4] serdev: Stop using device_driver callbacks

[Uwe Kleine-König]

Hello,

the serdev subsystem currently doesn't provide a shutdown callback, thus
drivers that want being notified on shutdown have to implement the
respective callback in struct device_driver. This (and more)
functionality can be provided by a bus method as it already done for
.probe() and .remove().

The eventual goal is to remove .shutdown() (and .probe() and .remove())
from struct device_driver.

Note that the first patch introduces a warning when the three affected
drivers are registered (in driver_register() because `drv->bus->shutdown
&& drv->shutdown`). Patches #2 - #4 fix these warnings. So from a user
perspective it would be good to get the whole series in during a single
merge window---either by creating an immutable branch containing patch
#1 that is merged into the respective subsystems before applying the
following patches, or merging the complete series via a single tree.

At a later point in time the added check in
__serdev_device_driver_register() and the function
serdev_legacy_shutdown() can be dropped. I intend to cope for that in
the merge window that removes the callbacks from struct device_driver
because drivers that I might have missed to convert or that are rebased
over that change break silently as long as struct
device_driver::shutdown exists.

Best regards
Uwe

Uwe Kleine-König (4):
  serdev: Provide a bustype shutdown function
  Bluetooth: hci_aml: Migrate to serdev specific shutdown function
  Bluetooth: hci_qca: Migrate to serdev specific shutdown function
  platform/surface: Migrate to serdev specific shutdown function

 drivers/bluetooth/hci_aml.c                | 16 ++++++++--------
 drivers/bluetooth/hci_qca.c                |  5 ++---
 drivers/platform/surface/aggregator/core.c |  6 +++---
 drivers/tty/serdev/core.c                  | 21 +++++++++++++++++++++
 include/linux/serdev.h                     |  1 +
 5 files changed, 35 insertions(+), 14 deletions(-)


base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
-- 
2.47.3

[PATCH v1 1/4] serdev: Provide a bustype shutdown function

[Uwe Kleine-König]

To prepare serdev driver to migrate away from struct device_driver::shutdown
(and then eventually remove that callback) create a serdev driver shutdown
callback and migration code to keep the existing behaviour. Note this
introduces a warning for each driver at register time that isn't converted
yet to that callback.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 drivers/tty/serdev/core.c | 21 +++++++++++++++++++++
 include/linux/serdev.h    |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index b33e708cb245..40eedc15277c 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -414,11 +414,21 @@ static void serdev_drv_remove(struct device *dev)
 		sdrv->remove(to_serdev_device(dev));
 }
 
+static void serdev_drv_shutdown(struct device *dev)
+{
+	const struct serdev_device_driver *sdrv =
+		to_serdev_device_driver(dev->driver);
+
+	if (dev->driver && sdrv->shutdown)
+		sdrv->shutdown(to_serdev_device(dev));
+}
+
 static const struct bus_type serdev_bus_type = {
 	.name		= "serial",
 	.match		= serdev_device_match,
 	.probe		= serdev_drv_probe,
 	.remove		= serdev_drv_remove,
+	.shutdown	= serdev_drv_shutdown,
 };
 
 /**
@@ -814,6 +824,14 @@ void serdev_controller_remove(struct serdev_controller *ctrl)
 }
 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 
+static void serdev_legacy_shutdown(struct serdev_device *serdev)
+{
+	struct device *dev = &serdev->dev;
+	struct device_driver *driver = dev->driver;
+
+	driver->shutdown(dev);
+}
+
 /**
  * __serdev_device_driver_register() - Register client driver with serdev core
  * @sdrv:	client driver to be associated with client-device.
@@ -830,6 +848,9 @@ int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct mo
 	/* force drivers to async probe so I/O is possible in probe */
         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 
+	if (!sdrv->shutdown && sdrv->driver.shutdown)
+		sdrv->shutdown = serdev_legacy_shutdown;
+
 	return driver_register(&sdrv->driver);
 }
 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 34562eb99931..5654c58eb73c 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -65,6 +65,7 @@ struct serdev_device_driver {
 	struct device_driver driver;
 	int	(*probe)(struct serdev_device *);
 	void	(*remove)(struct serdev_device *);
+	void	(*shutdown)(struct serdev_device *);
 };
 
 static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
-- 
2.47.3

[PATCH v1 4/4] platform/surface: Migrate to serdev specific shutdown function

[Uwe Kleine-König]

The motivation is stop using the callback .shutdown in
qca_serdev_driver.driver to make it possible to drop that.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 drivers/platform/surface/aggregator/core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
index c58e1fdd1a5f..860702c4266f 100644
--- a/drivers/platform/surface/aggregator/core.c
+++ b/drivers/platform/surface/aggregator/core.c
@@ -380,9 +380,9 @@ static int ssam_serdev_setup(struct acpi_device *ssh, struct serdev_device *serd
 
 /* -- Power management. ----------------------------------------------------- */
 
-static void ssam_serial_hub_shutdown(struct device *dev)
+static void ssam_serial_hub_shutdown(struct serdev_device *serdev)
 {
-	struct ssam_controller *c = dev_get_drvdata(dev);
+	struct ssam_controller *c = dev_get_drvdata(&serdev->dev);
 	int status;
 
 	/*
@@ -834,12 +834,12 @@ MODULE_DEVICE_TABLE(of, ssam_serial_hub_of_match);
 static struct serdev_device_driver ssam_serial_hub = {
 	.probe = ssam_serial_hub_probe,
 	.remove = ssam_serial_hub_remove,
+	.shutdown = ssam_serial_hub_shutdown,
 	.driver = {
 		.name = "surface_serial_hub",
 		.acpi_match_table = ACPI_PTR(ssam_serial_hub_acpi_match),
 		.of_match_table = of_match_ptr(ssam_serial_hub_of_match),
 		.pm = &ssam_serial_hub_pm_ops,
-		.shutdown = ssam_serial_hub_shutdown,
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 };
-- 
2.47.3

Re: [PATCH v1 4/4] platform/surface: Migrate to serdev specific shutdown function

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 1809 bytes --]

On Fri, 12 Dec 2025, Uwe Kleine-König wrote:

> The motivation is stop using the callback .shutdown in
> qca_serdev_driver.driver to make it possible to drop that.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>

In case somebody wants to take the entire series,

Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

-- 
 i.


> ---
>  drivers/platform/surface/aggregator/core.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
> index c58e1fdd1a5f..860702c4266f 100644
> --- a/drivers/platform/surface/aggregator/core.c
> +++ b/drivers/platform/surface/aggregator/core.c
> @@ -380,9 +380,9 @@ static int ssam_serdev_setup(struct acpi_device *ssh, struct serdev_device *serd
>  
>  /* -- Power management. ----------------------------------------------------- */
>  
> -static void ssam_serial_hub_shutdown(struct device *dev)
> +static void ssam_serial_hub_shutdown(struct serdev_device *serdev)
>  {
> -	struct ssam_controller *c = dev_get_drvdata(dev);
> +	struct ssam_controller *c = dev_get_drvdata(&serdev->dev);
>  	int status;
>  
>  	/*
> @@ -834,12 +834,12 @@ MODULE_DEVICE_TABLE(of, ssam_serial_hub_of_match);
>  static struct serdev_device_driver ssam_serial_hub = {
>  	.probe = ssam_serial_hub_probe,
>  	.remove = ssam_serial_hub_remove,
> +	.shutdown = ssam_serial_hub_shutdown,
>  	.driver = {
>  		.name = "surface_serial_hub",
>  		.acpi_match_table = ACPI_PTR(ssam_serial_hub_acpi_match),
>  		.of_match_table = of_match_ptr(ssam_serial_hub_of_match),
>  		.pm = &ssam_serial_hub_pm_ops,
> -		.shutdown = ssam_serial_hub_shutdown,
>  		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
>  	},
>  };
>