tee: Add probe, remove and shutdown bus callbacks to tee_client_driver

Introduce a bus specific probe, remove and shutdown function. For now
this only allows to get rid of a cast of the generic device to a
tee_client device in the drivers and changes the remove prototype to
return void---a non-zero return value is ignored anyhow.

The objective is to get rid of users of struct device_driver callbacks
.probe(), .remove() and .shutdown() to eventually remove these. Until
all tee_client drivers are converted this results in a runtime warning
about the drivers needing an update because there is a bus probe
function and a driver probe function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Author: ukleinek

drivers/tee/tee_core.c

@@ -1398,19 +1398,87 @@ static int tee_client_device_uevent(const struct device *dev,
 	return add_uevent_var(env, "MODALIAS=tee:%pUb", dev_id);
 }
 
+static int tee_client_device_probe(struct device *dev)
+{
+	struct tee_client_device *tcdev = to_tee_client_device(dev);
+	struct tee_client_driver *drv = to_tee_client_driver(dev->driver);
+
+	if (drv->probe)
+		return drv->probe(tcdev);
+	else
+		return 0;
+}
+
+static void tee_client_device_remove(struct device *dev)
+{
+	struct tee_client_device *tcdev = to_tee_client_device(dev);
+	struct tee_client_driver *drv = to_tee_client_driver(dev->driver);
+
+	if (drv->remove)
+		drv->remove(tcdev);
+}
+
+static void tee_client_device_shutdown(struct device *dev)
+{
+	struct tee_client_device *tcdev = to_tee_client_device(dev);
+	struct tee_client_driver *drv = to_tee_client_driver(dev->driver);
+
+	if (dev->driver && drv->shutdown)
+		drv->shutdown(tcdev);
+}
+
 const struct bus_type tee_bus_type = {
 	.name		= "tee",
 	.match		= tee_client_device_match,
 	.uevent		= tee_client_device_uevent,
+	.probe		= tee_client_device_probe,
+	.remove		= tee_client_device_remove,
+	.shutdown	= tee_client_device_shutdown,
 };
 EXPORT_SYMBOL_GPL(tee_bus_type);
 
+static int tee_client_device_probe_legacy(struct tee_client_device *tcdev)
+{
+	struct device *dev = &tcdev->dev;
+	struct device_driver *driver = dev->driver;
+
+	return driver->probe(dev);
+}
+
+static void tee_client_device_remove_legacy(struct tee_client_device *tcdev)
+{
+	struct device *dev = &tcdev->dev;
+	struct device_driver *driver = dev->driver;
+
+	driver->remove(dev);
+}
+
+static void tee_client_device_shutdown_legacy(struct tee_client_device *tcdev)
+{
+	struct device *dev = &tcdev->dev;
+	struct device_driver *driver = dev->driver;
+
+	driver->shutdown(dev);
+}
+
 int __tee_client_driver_register(struct tee_client_driver *tee_driver,
 				 struct module *owner)
 {
 	tee_driver->driver.owner = owner;
 	tee_driver->driver.bus = &tee_bus_type;
 
+	/*
+	 * Drivers that have callbacks set for tee_driver->driver need updating
+	 * to use the callbacks in tee_driver instead. driver_register() warns
+	 * about that, so no need to warn here, too.
+	 */
+	if (!tee_driver->probe && tee_driver->driver.probe)
+		tee_driver->probe = tee_client_device_probe_legacy;
+	if (!tee_driver->remove && tee_driver->driver.remove)
+		tee_driver->remove = tee_client_device_remove_legacy;
+	if (!tee_driver->shutdown && tee_driver->driver.probe)
+		tee_driver->shutdown = tee_client_device_shutdown_legacy;
+
 	return driver_register(&tee_driver->driver);
 }
 EXPORT_SYMBOL_GPL(__tee_client_driver_register);

include/linux/tee_drv.h

@@ -315,6 +315,9 @@ struct tee_client_device {
  * @driver:		driver structure
  */
 struct tee_client_driver {
+	int (*probe)(struct tee_client_device *);
+	void (*remove)(struct tee_client_device *);
+	void (*shutdown)(struct tee_client_device *);
 	const struct tee_client_device_id *id_table;
 	struct device_driver driver;
 };