[PATCH v2 1/2] drivers: fwnode: Extend device_get_match_data() to struct bus_type

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

Extend device_get_match_data() to buses (for eg: I2C) by adding a
callback device_get_match_data() to struct bus_type() and call this method
as a fallback for generic fwnode based device_get_match_data().

Suggested-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
RFC v1-> v2:
 * Replaced "Signed-off-by"->"Suggested-by" tag for Dmitry.
 * Documented device_get_match_data().
 * Added multiple returns to make code path for generic fwnode-based
   lookup faster.
---
 drivers/base/property.c    | 21 ++++++++++++++++++++-
 include/linux/device/bus.h |  3 +++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 8c40abed7852..e12af9ff0f51 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1275,9 +1275,28 @@ int fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL(fwnode_graph_parse_endpoint);
 
+/**
+ * device_get_match_data - get match data from OF/ACPI/Bus match tables
+ * @dev: device to find the match data
+ *
+ * Find match data using generic fwnode-based lookup and if there is no
+ * match, call the bus->get_match_data() for finding match data.
+ *
+ * Return: a match data pointer or NULL if there is no match in the matching
+ * table.
+ */
 const void *device_get_match_data(const struct device *dev)
 {
-	return fwnode_call_ptr_op(dev_fwnode(dev), device_get_match_data, dev);
+	const void *data;
+
+	data = fwnode_call_ptr_op(dev_fwnode(dev), device_get_match_data, dev);
+	if (data)
+		return data;
+
+	if (dev->bus && dev->bus->get_match_data)
+		return dev->bus->get_match_data(dev);
+
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(device_get_match_data);
 
diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h
index ae10c4322754..2e15b0ae5384 100644
--- a/include/linux/device/bus.h
+++ b/include/linux/device/bus.h
@@ -60,6 +60,7 @@ struct fwnode_handle;
  *			this bus.
  * @dma_cleanup:	Called to cleanup DMA configuration on a device on
  *			this bus.
+ * @get_match_data:	Called to get match data on a device on this bus.
  * @pm:		Power management operations of this bus, callback the specific
  *		device driver's pm-ops.
  * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
@@ -102,6 +103,8 @@ struct bus_type {
 	int (*dma_configure)(struct device *dev);
 	void (*dma_cleanup)(struct device *dev);
 
+	const void *(*get_match_data)(const struct device *dev);
+
 	const struct dev_pm_ops *pm;
 
 	const struct iommu_ops *iommu_ops;
-- 
2.25.1