return i2c_smbus_write_byte_data(i2c, reg, val);
 }
 
-static struct regmap_bus regmap_smbus_byte = {
+static const struct regmap_bus regmap_smbus_byte = {
        .reg_write = regmap_smbus_byte_reg_write,
        .reg_read = regmap_smbus_byte_reg_read,
 };
        return i2c_smbus_write_word_data(i2c, reg, val);
 }
 
-static struct regmap_bus regmap_smbus_word = {
+static const struct regmap_bus regmap_smbus_word = {
        .reg_write = regmap_smbus_word_reg_write,
        .reg_read = regmap_smbus_word_reg_read,
 };
        return i2c_smbus_write_word_swapped(i2c, reg, val);
 }
 
-static struct regmap_bus regmap_smbus_word_swapped = {
+static const struct regmap_bus regmap_smbus_word_swapped = {
        .reg_write = regmap_smbus_word_write_swapped,
        .reg_read = regmap_smbus_word_read_swapped,
 };
                return -EIO;
 }
 
-static struct regmap_bus regmap_i2c = {
+static const struct regmap_bus regmap_i2c = {
        .write = regmap_i2c_write,
        .gather_write = regmap_i2c_gather_write,
        .read = regmap_i2c_read,
                return -EIO;
 }
 
-static struct regmap_bus regmap_i2c_smbus_i2c_block = {
+static const struct regmap_bus regmap_i2c_smbus_i2c_block = {
        .write = regmap_i2c_smbus_i2c_write,
        .read = regmap_i2c_smbus_i2c_read,
        .max_raw_read = I2C_SMBUS_BLOCK_MAX,