OMAP has 3 distinct i2c controllers, which line have you got your pressure sensor hooked up to? I believe the MADC is on i2c-1.
I am using an I2C pressure sensor that works fine alone. I also have an analog ambient light sensor, that I was using at ADCIN4.
The problem is that when I put them together I can't read the I2C sensor anymore, that is, the reading is not updated.
I think that this has something to do to the fact that the TWL4030 is accessed via I2C but I don't know where is the problem.