Sitara AM3359 CIR problem

ok on reset if it is high , how can  i make it low from the software side.  When i use it as a gpio i' m able to control the low or high state  by using gpio_set_value(), I mean i can make the pin low , but when i configure it as UART it fails to make it low  , even if i try to make it low. i don't know why .

1. How can i make the default UART pin high low in UART mode

2. Whether setting the direction ( input or output ) of the pin affects the state of the pin .( high or low )

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So for writing onto the UART4_txd/ sending IR data ,  i need to first configure the MDR1 register for setting the UART in CIR mode , now once I'm done with that i will make it low by writng  '1' onto the BRK_EN bit onto LCR register . After this I need to send the data in 36 Khz so i have written the data onto CFPS register (  this was not defined  , i have defined it in serial_reg.h , hope it is okay ) , and setting the T period by writing onto DLL / DLH registers , after this I have to write onto fifo REGISTERS , TX   now,

1>there's a generic driver for omap-serial.c ( generic serial port )

http://pastebin.com/AcXB9RxY 

2> the header file where evrything is defined

http://pastebin.com/gBcdzEh1

so for writing onto UART I'm using a function like  

serial_out(up, UART_TX, up->port.x_char)

 where UART_TX needs to be the transmit buffer , since i didn't see any fifo.thr buffer 

1> How can i write something onto the UART buffer, cause in the omap-serial.c i didn't find any single function using FIFO.THR registers for writing data onto UART as specified in the document.

2>can any register  be added in the serial_reg.h file, since CFPS register was not defined , i had to define it i guess i don't have to use any address  referneces for writin this register in serial_reg file

3> Am I going wrong anywhere ? is my flow for implementing this driver  ok

the header file

http://pastebin.com/gBcdzEh1