RE: [PATCH 1/4] serial: xuartps: Fix termios issue for enabling odd parity

From: Anirudha Sarangi
Date: Mon Aug 17 2015 - 14:06:19 EST


Hi,

> -----Original Message-----
> From: Peter Hurley [mailto:peter@xxxxxxxxxxxxxxxxxx]
> Sent: Monday, August 17, 2015 9:54 PM
> To: Anirudha Sarangi; Michal Simek
> Cc: linux-kernel@xxxxxxxxxxxxxxx; monstr@xxxxxxxxx; Soren Brinkmann; Jiri
> Slaby; linux-serial@xxxxxxxxxxxxxxx; Greg Kroah-Hartman; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/4] serial: xuartps: Fix termios issue for enabling odd parity
>
> On 08/17/2015 11:55 AM, Anirudha Sarangi wrote:
> > Hi,
> >
> >> -----Original Message-----
> >> From: Peter Hurley [mailto:peter@xxxxxxxxxxxxxxxxxx]
> >> Sent: Monday, August 17, 2015 9:09 PM
> >> To: Michal Simek
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx; monstr@xxxxxxxxx; Anirudha Sarangi;
> >> Soren Brinkmann; Jiri Slaby; linux-serial@xxxxxxxxxxxxxxx; Greg
> >> Kroah-Hartman; linux- arm-kernel@xxxxxxxxxxxxxxxxxxx
> >> Subject: Re: [PATCH 1/4] serial: xuartps: Fix termios issue for
> >> enabling odd parity
> >>
> >> On 08/17/2015 03:22 AM, Michal Simek wrote:
> >>> From: Anirudha Sarangi <anirudha.sarangi@xxxxxxxxxx>
> >>>
> >>> Existing set_termios does not handle the option for enabling odd
> >>> parity. This patch fixes it.
> >>
> >> NAK. PARODD does not enable parity generation or detection.
> >>
> > What if someone is trying to change from even to odd parity?
>
> If userspace wants odd parity, then c_cflag must have both PARENB and PARODD
> set.
>
> Just PARODD does nothing.
>
> From SUS v4, General Terminal Interface, 11.2.4 Control Modes;
>
> "If PARENB is set, parity generation and detection shall be enabled and a parity
> bit is added to each byte. If parity is enabled, PARODD shall specify odd parity if
> set; otherwise, even parity shall be used."
>
>
Thanks a lot. I will incorporate the changes.
>
> > In this conditional case, we setup some register bit for the same.
> > Is the above use case not a valid one?
> >
> > Regards
> > Anirudha
> >
> >> Regards,
> >> Peter Hurley
> >>
> >>> Signed-off-by: Anirudha Sarangi <anirudh@xxxxxxxxxx>
> >>> Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
> >>> ---
> >>>
> >>> drivers/tty/serial/xilinx_uartps.c | 2 +-
> >>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/tty/serial/xilinx_uartps.c
> >>> b/drivers/tty/serial/xilinx_uartps.c
> >>> index 009e0dbc12d2..a3020344ac9d 100644
> >>> --- a/drivers/tty/serial/xilinx_uartps.c
> >>> +++ b/drivers/tty/serial/xilinx_uartps.c
> >>> @@ -723,7 +723,7 @@ static void cdns_uart_set_termios(struct
> >>> uart_port
> >> *port,
> >>> else
> >>> cval |= CDNS_UART_MR_STOPMODE_1_BIT; /* 1 STOP bit */
> >>>
> >>> - if (termios->c_cflag & PARENB) {
> >>> + if ((termios->c_cflag & PARENB) || (termios->c_cflag & PARODD))
> >>> + {
> >>> /* Mark or Space parity */
> >>> if (termios->c_cflag & CMSPAR) {
> >>> if (termios->c_cflag & PARODD)
> >>>
> >
> >
> >
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