[PATCH v3 8/9] firmware: arm_scmi: Add scmi_driver optional setup/teardown callbacks

[Cristian Marussi]

Add optional .setup and .teardown methods to the scmi_driver descriptor:
such callbacks, if provided, will be called by the SCIM core at driver
registration time, so that, an SCMI driver, registered as usual with the
module_scmi_driver() helper macro, can provide custom callbacks to be
run once for all at module load/unload time to perform specific setup
or teardown operations before/after .probe and .remove steps.

Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
---
 drivers/firmware/arm_scmi/bus.c | 15 +++++++++++++--
 include/linux/scmi_protocol.h   |  2 ++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index f6fe723ab869..e95085a66bc4 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -132,12 +132,21 @@ int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
 {
 	int retval;
 
-	if (!driver->probe)
+	if (!driver->probe || !driver->id_table)
 		return -EINVAL;
 
+	if (driver->setup) {
+		retval = driver->setup();
+		if (retval)
+			return retval;
+	}
+
 	retval = scmi_protocol_device_request(driver->id_table);
-	if (retval)
+	if (retval) {
+		if (driver->teardown)
+			driver->teardown();
 		return retval;
+	}
 
 	driver->driver.bus = &scmi_bus_type;
 	driver->driver.name = driver->name;
@@ -156,6 +165,8 @@ void scmi_driver_unregister(struct scmi_driver *driver)
 {
 	driver_unregister(&driver->driver);
 	scmi_protocol_device_unrequest(driver->id_table);
+	if (driver->teardown)
+		driver->teardown();
 }
 EXPORT_SYMBOL_GPL(scmi_driver_unregister);
 
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index ad9641dbdd25..a922707bdfe8 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -805,6 +805,8 @@ struct scmi_device_id {
 
 struct scmi_driver {
 	const char *name;
+	int (*setup)(void);
+	void (*teardown)(void);
 	int (*probe)(struct scmi_device *sdev);
 	void (*remove)(struct scmi_device *sdev);
 	const struct scmi_device_id *id_table;
-- 
2.32.0