[PATCH v2] software node: Implement device_get_match_data fwnode callback

[Sui Jingfeng]

Because the software node backend of the fwnode API framework lacks an
implementation for the .device_get_match_data function callback. This
makes it difficult to use(and/or test) a few drivers that originates
from DT world on the non-DT platform.

Implement the .device_get_match_data fwnode callback, device drivers or
platform setup codes are expected to provide a string property, named as
"compatible", the value of this software node string property is used to
match against the compatible entries in the of_device_id table.

This also helps to keep the three backends of the fwnode API aligned as
much as possible, which is a fundamential step to make device driver
OF-independent truely possible.

Fixes: ffb42e64561e ("drm/tiny/repaper: Make driver OF-independent")
Fixes: 5703d6ae9573 ("drm/tiny/st7735r: Make driver OF-independent")
Closes: https://lore.kernel.org/lkml/20230223203713.hcse3mkbq3m6sogb@skbuf/
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Daniel Scally <djrscally@xxxxxxxxx>
Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Signed-off-by: Sui Jingfeng <sui.jingfeng@xxxxxxxxx>
---
 V2: Update commit message
 drivers/base/swnode.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index eb6eb25b343b..48d18a90b97b 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/kobject.h>
 #include <linux/kstrtox.h>
+#include <linux/mod_devicetable.h>
 #include <linux/list.h>
 #include <linux/property.h>
 #include <linux/slab.h>
@@ -390,6 +391,30 @@ static void software_node_put(struct fwnode_handle *fwnode)
 	kobject_put(&swnode->kobj);
 }
 
+static const void *
+software_node_get_match_data(const struct fwnode_handle *fwnode,
+			     const struct device *dev)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+	const struct of_device_id *matches = dev->driver->of_match_table;
+	const char *val = NULL;
+	int ret;
+
+	ret = property_entry_read_string_array(swnode->node->properties,
+					       "compatible", &val, 1);
+	if (ret < 0 || !val)
+		return NULL;
+
+	while (matches && matches->compatible[0]) {
+		if (!strcmp(matches->compatible, val))
+			return matches->data;
+
+		matches++;
+	}
+
+	return NULL;
+}
+
 static bool software_node_property_present(const struct fwnode_handle *fwnode,
 					   const char *propname)
 {
@@ -676,6 +701,7 @@ software_node_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 static const struct fwnode_operations software_node_ops = {
 	.get = software_node_get,
 	.put = software_node_put,
+	.device_get_match_data = software_node_get_match_data,
 	.property_present = software_node_property_present,
 	.property_read_int_array = software_node_read_int_array,
 	.property_read_string_array = software_node_read_string_array,
-- 
2.34.1