[PATCH] i2c: make i2c_bus_type const

[Greg Kroah-Hartman]

Now that the driver core can properly handle constant struct bus_type,
move the i2c_bus_type variable to be a constant structure as well, placing
it into read-only memory which can not be modified at runtime.

Note, the sound/soc/rockchip/rk3399_gru_sound.c also needed tweaking as
it decided to save off a pointer to a bus type for internal stuff, and
it was using the i2c_bus_type as well.

Cc: Wolfram Sang <wsa@xxxxxxxxxx>
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Jaroslav Kysela <perex@xxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxxx>
Cc: Heiko Stuebner <heiko@xxxxxxxxx>
Cc: linux-i2c@xxxxxxxxxxxxxxx
Cc: linux-sound@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-rockchip@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/i2c/i2c-core-base.c           | 2 +-
 include/linux/i2c.h                   | 2 +-
 sound/soc/rockchip/rk3399_gru_sound.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index eac90a3cf61a..24c6e1b52668 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -689,7 +689,7 @@ static struct attribute *i2c_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(i2c_dev);
 
-struct bus_type i2c_bus_type = {
+const struct bus_type i2c_bus_type = {
 	.name		= "i2c",
 	.match		= i2c_device_match,
 	.probe		= i2c_device_probe,
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 0dae9db27538..180462d1a373 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -23,7 +23,7 @@
 #include <linux/swab.h>		/* for swab16 */
 #include <uapi/linux/i2c.h>
 
-extern struct bus_type i2c_bus_type;
+extern const struct bus_type i2c_bus_type;
 extern struct device_type i2c_adapter_type;
 extern struct device_type i2c_client_type;
 
diff --git a/sound/soc/rockchip/rk3399_gru_sound.c b/sound/soc/rockchip/rk3399_gru_sound.c
index 1a504ebd3a0e..6c89c7331229 100644
--- a/sound/soc/rockchip/rk3399_gru_sound.c
+++ b/sound/soc/rockchip/rk3399_gru_sound.c
@@ -446,7 +446,7 @@ static const struct rockchip_sound_route rockchip_routes[] = {
 
 struct dailink_match_data {
 	const char *compatible;
-	struct bus_type *bus_type;
+	const struct bus_type *bus_type;
 };
 
 static const struct dailink_match_data dailink_match[] = {
-- 
2.43.0