doubt in arch/ppc/8260_io/uart.c

[Omanakuttan]

Hi,
in kernel 2.4.17, arch/ppc/8260/uart.c contains the following lines in
rs_8xx_stop()
{
....
sccp->scc_sccm &= ~UART_SCCM_TX;
....
}
UART_SCCM_TX is defined to 0x00000020
i.e, only the TX bit is 1

Now the manual (MPC8260UM.pdf) states that clearing a bit is 1 for both
SCCE and SCCM. Following it, what I understand is the above C statement
clears all the bits of ccp->scc_sccm except TX bit.

Then how does it stop the SCC/SCM?
Clearly something is wrong in _my_ logic, what can that be?


Thanks for your time,
Om.


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