spi: Use bus_type functions for probe, remove and shutdown

The eventual goal is to get rid of the callbacks in struct
device_driver. Other than not using driver callbacks there should be no
side effect of this patch.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-2-u.kleine-koenig@pengutronix.deSigned-off-by: NMark Brown <broonie@kernel.org>

drivers/spi/spi.c

@@ -374,16 +374,7 @@ static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 }
 
-struct bus_type spi_bus_type = {
-	.name		= "spi",
-	.dev_groups	= spi_dev_groups,
-	.match		= spi_match_device,
-	.uevent		= spi_uevent,
-};
-EXPORT_SYMBOL_GPL(spi_bus_type);
-
-
-static int spi_drv_probe(struct device *dev)
+static int spi_probe(struct device *dev)
 {
 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
 	struct spi_device		*spi = to_spi_device(dev);
@@ -414,7 +405,7 @@ static int spi_drv_probe(struct device *dev)
 	return ret;
 }
 
-static int spi_drv_remove(struct device *dev)
+static int spi_remove(struct device *dev)
 {
 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
 	int ret = 0;
@@ -426,13 +417,25 @@ static int spi_drv_remove(struct device *dev)
 	return ret;
 }
 
-static void spi_drv_shutdown(struct device *dev)
+static void spi_shutdown(struct device *dev)
 {
 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
 
-	sdrv->shutdown(to_spi_device(dev));
+	if (sdrv->shutdown)
+		sdrv->shutdown(to_spi_device(dev));
 }
 
+struct bus_type spi_bus_type = {
+	.name		= "spi",
+	.dev_groups	= spi_dev_groups,
+	.match		= spi_match_device,
+	.uevent		= spi_uevent,
+	.probe		= spi_probe,
+	.remove		= spi_remove,
+	.shutdown	= spi_shutdown,
+};
+EXPORT_SYMBOL_GPL(spi_bus_type);
+
 /**
  * __spi_register_driver - register a SPI driver
  * @owner: owner module of the driver to register
@@ -445,10 +448,6 @@ int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 {
 	sdrv->driver.owner = owner;
 	sdrv->driver.bus = &spi_bus_type;
-	sdrv->driver.probe = spi_drv_probe;
-	sdrv->driver.remove = spi_drv_remove;
-	if (sdrv->shutdown)
-		sdrv->driver.shutdown = spi_drv_shutdown;
 	return driver_register(&sdrv->driver);
 }
 EXPORT_SYMBOL_GPL(__spi_register_driver);