[PATCH] i2c: gxp: fix build failure without CONFIG_I2C_SLAVE

[Arnd Bergmann <arnd@kernel.org>]

From: Arnd Bergmann <arnd@arndb.de>

The gxp_i2c_slave_irq_handler() is hidden in an #ifdef, but the
caller uses an IS_ENABLED() check:

drivers/i2c/busses/i2c-gxp.c: In function 'gxp_i2c_irq_handler':
drivers/i2c/busses/i2c-gxp.c:467:29: error: implicit declaration of function 'gxp_i2c_slave_irq_handler'; did you mean 'gxp_i2c_irq_handler'? [-Werror=implicit-function-declaration]

It has to consistently use one method or the other to avoid warnings,
so move to IS_ENABLED() here for readability and build coverage, and
move the #ifdef in linux/i2c.h to allow building it as dead code.

Fixes: 4a55ed6f89f5 ("i2c: Add GXP SoC I2C Controller")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/i2c/busses/i2c-gxp.c | 2 --
 include/linux/i2c.h          | 4 ++--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-gxp.c b/drivers/i2c/busses/i2c-gxp.c
index d4b55d989a26..8ea3fb5e4c7f 100644
--- a/drivers/i2c/busses/i2c-gxp.c
+++ b/drivers/i2c/busses/i2c-gxp.c
@@ -353,7 +353,6 @@ static void gxp_i2c_chk_data_ack(struct gxp_i2c_drvdata *drvdata)
 	writew(value, drvdata->base + GXP_I2CMCMD);
 }
 
-#if IS_ENABLED(CONFIG_I2C_SLAVE)
 static bool gxp_i2c_slave_irq_handler(struct gxp_i2c_drvdata *drvdata)
 {
 	u8 value;
@@ -437,7 +436,6 @@ static bool gxp_i2c_slave_irq_handler(struct gxp_i2c_drvdata *drvdata)
 
 	return true;
 }
-#endif
 
 static irqreturn_t gxp_i2c_irq_handler(int irq, void *_drvdata)
 {
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 5ba89663ea86..13a1ce38cb0c 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -385,7 +385,6 @@ static inline void i2c_set_clientdata(struct i2c_client *client, void *data)
 
 /* I2C slave support */
 
-#if IS_ENABLED(CONFIG_I2C_SLAVE)
 enum i2c_slave_event {
 	I2C_SLAVE_READ_REQUESTED,
 	I2C_SLAVE_WRITE_REQUESTED,
@@ -396,9 +395,10 @@ enum i2c_slave_event {
 
 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
 int i2c_slave_unregister(struct i2c_client *client);
-bool i2c_detect_slave_mode(struct device *dev);
 int i2c_slave_event(struct i2c_client *client,
 		    enum i2c_slave_event event, u8 *val);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+bool i2c_detect_slave_mode(struct device *dev);
 #else
 static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
 #endif
-- 
2.39.2