i2c: reduce parent checking to a NOOP in non-I2C_MUX case

In 0826374 - i2c: Multiplexed I2C bus core support
core i2c code increased in size and complexity even when I2C_MUX
wasn't selected.

Turning this check into a constant NULL in the n case lets the
client functions in be simplified too, not needing to include
never-called calls to the mux-specific helpers.

Signed-off-by: Phil Carmody <phil.carmody@partner.samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index e988fa935b3c..b3c4b8dac1ce 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -447,11 +447,13 @@ static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
 static inline struct i2c_adapter *
 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 {
+#if IS_ENABLED(I2C_MUX)
         struct device *parent = adapter->dev.parent;
 
         if (parent != NULL && parent->type == &i2c_adapter_type)
                 return to_i2c_adapter(parent);
         else
+#endif
                 return NULL;
 }