+ - i2c-scl-falling-time : should contain the SCL falling time in nanoseconds.
+ This value which is by default 300ns is used to compute the tLOW period.
+
+ - i2c-sda-falling-time : should contain the SDA falling time in nanoseconds.
+ This value which is by default 300ns is used to compute the tHIGH period.
+