[PATCH v2 2/2] i2c: Add i2c_device_get_match_data() callback

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

Add i2c_device_get_match_data() callback to struct bus_type().

While at it, introduced i2c_get_match_data_helper() to avoid code
duplication with i2c_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.
 * Fixed build warnings reported by kernel test robot <lkp@xxxxxxxxx>
 * Added const qualifier to return type and parameter struct i2c_driver
   in i2c_get_match_data_helper().
 * Added const qualifier to struct i2c_driver in i2c_get_match_data()
 * Dropped driver variable from i2c_device_get_match_data()
 * Replaced to_i2c_client with logic for assigning verify_client as it
   returns non const pointer.
---
 drivers/i2c/i2c-core-base.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 60746652fd52..6183e9e36889 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -114,20 +114,37 @@ const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
 }
 EXPORT_SYMBOL_GPL(i2c_match_id);
 
-const void *i2c_get_match_data(const struct i2c_client *client)
+static const void *i2c_get_match_data_helper(const struct i2c_driver *driver,
+					     const struct i2c_client *client)
 {
-	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
 	const struct i2c_device_id *match;
+
+	match = i2c_match_id(driver->id_table, client);
+	if (!match)
+		return NULL;
+
+	return (const void *)match->driver_data;
+}
+
+static const void *i2c_device_get_match_data(const struct device *dev)
+{
+	const struct i2c_client *client = (dev->type == &i2c_client_type) ?
+					  to_i2c_client(dev) : NULL;
+
+	if (!dev->driver)
+		return NULL;
+
+	return i2c_get_match_data_helper(to_i2c_driver(dev->driver), client);
+}
+
+const void *i2c_get_match_data(const struct i2c_client *client)
+{
+	const struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
 	const void *data;
 
 	data = device_get_match_data(&client->dev);
-	if (!data) {
-		match = i2c_match_id(driver->id_table, client);
-		if (!match)
-			return NULL;
-
-		data = (const void *)match->driver_data;
-	}
+	if (!data)
+		data = i2c_get_match_data_helper(driver, client);
 
 	return data;
 }
@@ -695,6 +712,7 @@ struct bus_type i2c_bus_type = {
 	.probe		= i2c_device_probe,
 	.remove		= i2c_device_remove,
 	.shutdown	= i2c_device_shutdown,
+	.get_match_data	= i2c_device_get_match_data,
 };
 EXPORT_SYMBOL_GPL(i2c_bus_type);
 
-- 
2.25.1