[PATCH v7 1/4] drivers: fwnode: Extend device_get_match_data() to struct bus_type

Biju Das
2023-08-04T16:17:49Z

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@gmail.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
v6->v7:
* Added ack from Greg Kroah-Hartman.
v5->v6:
* Added Rb tag from Sakari.
v4->v5:
* No change
v3->v4:
* Documented corner case.
v2->v3:
* Added Rb tag from Andy.
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 | 27 ++++++++++++++++++++++++++-
include/linux/device/bus.h | 3 +++
2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 8c40abed7852..a3c188cf68bb 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1275,9 +1275,34 @@ 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.
+ *
+ * Besides the fact that some drivers abuse the device ID driver_data type
+ * and claim it to be integer, for the bus specific ID tables the driver_data
+ * may be defined as kernel_ulong_t. For these tables 0 is a valid response,
+ * but not for this function. It's recommended to convert those either to avoid
+ * 0 or use a real pointer to the predefined driver data.
+ */
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