Drivers would like to call i2c_detect_slave_mode() even if !I2C_SLAVE. Give them what they want to, Otherwise kernel will not compile: drivers/i2c/busses/i2c-designware-platdrv.c: In function ‘dw_i2c_plat_probe’: drivers/i2c/busses/i2c-designware-platdrv.c:331:6: error: implicit declaration of function ‘i2c_detect_slave_mode’ [-Werror=implicit-function-declaration] if (i2c_detect_slave_mode(&pdev->dev)) ^~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors Fixes: 6e38cf3b4421 ("i2c: designware: Let slave adapter support be optional") Reported-by: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> --- include/linux/i2c.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 72d0ece70ed3..00ca5b86a753 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -295,6 +295,8 @@ static inline int i2c_slave_event(struct i2c_client *client, { return client->slave_cb(client, event, val); } +#else +static inline bool i2c_detect_slave_mode(struct device *dev) { return false; } #endif /** -- 2.11.0