[PATCH v7 2/4] i2c: Enhance i2c_get_match_data()

[Biju Das <biju.das.jz@bp.renesas.com>]

Enhance i2c_get_match_data() for a faster path for device_get_match_data().

While at it, add const to struct i2c_driver to prevent overriding the
driver pointer.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v6->v7:
 * Updated commit description by removing unnecessary wrapping.
 * Moved the patch from #3 to #2.
 * Added Rb tag from Andy
v6:
 * Separate patch to prepare for better difference for
   i2c_match_id() changes.
---
 drivers/i2c/i2c-core-base.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 60746652fd52..7005dfe64066 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -116,20 +116,19 @@ EXPORT_SYMBOL_GPL(i2c_match_id);
 
 const void *i2c_get_match_data(const struct i2c_client *client)
 {
-	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
+	const struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
 	const struct i2c_device_id *match;
 	const void *data;
 
 	data = device_get_match_data(&client->dev);
-	if (!data) {
-		match = i2c_match_id(driver->id_table, client);
-		if (!match)
-			return NULL;
+	if (data)
+		return data;
 
-		data = (const void *)match->driver_data;
-	}
+	match = i2c_match_id(driver->id_table, client);
+	if (!match)
+		return NULL;
 
-	return data;
+	return (const void *)match->driver_data;
 }
 EXPORT_SYMBOL(i2c_get_match_data);
 
-- 
2.25.1