tty: moxa: Add support for CMSPAR

The mode constants are taken from the GPL-2.0+ driver available
in the driver section of the Moxa homepage.

It is tested on a C320Turbo PCI card per logic analyzer and
per a device which requires 9 bit character communication.

The vendors driver supports CMSPAR unconditionally, so that all
other available firmware versions seems to support mark/space
parity modes as well.

Signed-off-by: Lars Kanis <kanis@comcard.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/moxa.c

@@ -1487,8 +1487,6 @@ static void moxa_set_tty_param(struct tty_struct *tty, struct ktermios *old_term
 	if (ts->c_iflag & IXANY)
 		xany = 1;
 
-	/* Clear the features we don't support */
-	ts->c_cflag &= ~CMSPAR;
 	MoxaPortFlowCtrl(ch, rts, cts, txflow, rxflow, xany);
 	baud = MoxaPortSetTermio(ch, ts, tty_get_baud_rate(tty));
 	if (baud == -1)
@@ -1781,10 +1779,17 @@ static int MoxaPortSetTermio(struct moxa_port *port, struct ktermios *termio,
 		mode |= MX_STOP1;
 
 	if (termio->c_cflag & PARENB) {
-		if (termio->c_cflag & PARODD)
-			mode |= MX_PARODD;
-		else
-			mode |= MX_PAREVEN;
+		if (termio->c_cflag & PARODD) {
+			if (termio->c_cflag & CMSPAR)
+				mode |= MX_PARMARK;
+			else
+				mode |= MX_PARODD;
+		} else {
+			if (termio->c_cflag & CMSPAR)
+				mode |= MX_PARSPACE;
+			else
+				mode |= MX_PAREVEN;
+		}
 	} else
 		mode |= MX_PARNONE;
 

drivers/tty/moxa.h

@@ -301,5 +301,7 @@
 #define	MX_PARNONE	0x00
 #define	MX_PAREVEN	0x40
 #define	MX_PARODD	0xC0
+#define	MX_PARMARK	0xA0
+#define	MX_PARSPACE	0x20
 
 #endif