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List:       linux-serial
Subject:    Re: question about drivers/serial/jsm/jsm_neo.c
From:       Julia Lawall <julia () diku ! dk>
Date:       2009-10-17 13:07:23
Message-ID: Pine.LNX.4.64.0910171506330.8556 () pc-004 ! diku ! dk
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On Sat, 17 Oct 2009, Julia Lawall wrote:

> The file drivers/serial/jsm/jsm_neo.c contains the following code in the 
> function neo_parse_modem:
> 
> 	jsm_printk(MSIGS, INFO, &ch->ch_bd->pci_dev,
> 			"Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
> 		ch->ch_portnum,
> 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
> 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
> 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
> 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
> 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
> 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
> 
> The whole function uses constants with the name "UART_MSR_..." except for 
> the first two lines of this print statement, which uses constants with the 
> name "UART_MCR_...".  Furthermore, UART_MCR_DTR is equivalent to 
> UART_MSR_DCTS and UART_MCR_RTS is equivalent to UART_MSR_DDSR.  Is this 
> intentional?

Hmm, maybe it is intentional because the | seems to be mixing both input 
(Status) and output (Control).

julia
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