[PATCH] Fix CTS handling in pmac-zilog.c

[PATCH] Fix CTS handling in pmac-zilog.c

[Benjamin Herrenschmidt]

(From: Paul Mackerras <paulus@samba.org>)

This patch fixes a bug in the pmac-zilog driver where if you enable
CRTSCTS mode, it won't output data when CTS is asserted.  On
powermacs, the CTS input is inverted.  It also fixes a logic bug in
testing for CTS and DCD changes.

diff -urN linux-2.5/drivers/serial/pmac_zilog.c pmac-2.5/drivers/serial/pmac_zilog.c
--- linux-2.5/drivers/serial/pmac_zilog.c	2004-04-01 06:59:37.000000000 +1000
+++ pmac-2.5/drivers/serial/pmac_zilog.c	2004-05-07 21:06:49.000000000 +1000
@@ -352,13 +352,14 @@
 		/* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
 		 * But it does not tell us which bit has changed, we have to keep
 		 * track of this ourselves.
+		 * The CTS input is inverted for some reason.  -- paulus
 		 */
-		if ((status & DCD) ^ uap->prev_status)
+		if ((status ^ uap->prev_status) & DCD)
 			uart_handle_dcd_change(&uap->port,
 					       (status & DCD));
-		if ((status & CTS) ^ uap->prev_status)
+		if ((status ^ uap->prev_status) & CTS)
 			uart_handle_cts_change(&uap->port,
-					       (status & CTS));
+					       !(status & CTS));
 
 		wake_up_interruptible(&uap->port.info->delta_msr_wait);
 	}
@@ -595,7 +596,7 @@
 		ret |= TIOCM_CAR;
 	if (status & SYNC_HUNT)
 		ret |= TIOCM_DSR;
-	if (status & CTS)
+	if (!(status & CTS))
 		ret |= TIOCM_CTS;
 
 	return ret;
-- 
Benjamin Herrenschmidt <benh@kernel.crashing.org>