[PATCH] i2c: make i2c_bus_type const

Greg Kroah-Hartman
2023-12-19T15:23:23Z

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@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-i2c@vger.kernel.org
Cc: linux-sound@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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