Arduino Due Analog input Pull-Up not working


Does anyone know why on Due analog input pull-up not working.
According to datasheet there is pull-up on analog input also.
I tried to put it on but there is nothing happens.

I tried pinMode(A0, INPUT_PULLUP);
then digitalWrite(A0, HIGH);
then REG_PIOA_SODR = 0x0000000F this is register for pull UP on A0 input.

Any help please?