diff --git a/sys/arch/sparc/dev/zs.c b/sys/arch/sparc/dev/zs.c
index 0a6998358ff0..3a211c64c305 100644
--- a/sys/arch/sparc/dev/zs.c
+++ b/sys/arch/sparc/dev/zs.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: zs.c,v 1.74 2000/03/06 21:36:11 thorpej Exp $	*/
+/*	$NetBSD: zs.c,v 1.75 2000/03/14 21:20:51 jdc Exp $	*/
 
 /*-
  * Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -71,6 +71,7 @@
 
 #include <sparc/sparc/vaddrs.h>
 #include <sparc/sparc/auxreg.h>
+#include <sparc/sparc/auxiotwo.h>
 #include <sparc/dev/cons.h>
 
 #include "kbd.h"	/* NKBD */
@@ -186,6 +187,10 @@ static struct intrhand levelsoft = { zssoft };
 
 static int zs_get_speed __P((struct zs_chanstate *));
 
+/* Power management hooks */
+int  zs_enable __P((struct zs_chanstate *));
+void zs_disable __P((struct zs_chanstate *));
+
 
 /*
  * Is the zs chip present?
@@ -258,6 +263,8 @@ zs_attach_obio(parent, self, aux)
 	if (uoba->uoba_isobio4 == 0) {
 		struct sbus_attach_args *sa = &uoba->uoba_sbus;
 		void *va;
+		struct zs_chanstate *cs;
+		int channel;
 
 		if (sa->sa_nintr == 0) {
 			printf(" no interrupt lines\n");
@@ -284,6 +291,19 @@ zs_attach_obio(parent, self, aux)
 			va = (void *)bh;
 		}
 
+		/*
+		 * Check if power state can be set, e.g. Tadpole 3GX
+		 */
+		if (getpropint(sa->sa_node, "pwr-on-auxio2", 0))
+		{
+			printf (" powered via auxio2");
+			for (channel = 0; channel < 2; channel++) {
+				cs = &zsc->zsc_cs_store[channel];
+				cs->enable = zs_enable;
+				cs->disable = zs_disable;
+			}
+		}
+
 		zsc->zsc_bustag = sa->sa_bustag;
 		zsc->zsc_dmatag = sa->sa_dmatag;
 		zs_attach(zsc, va, sa->sa_pri);
@@ -1074,3 +1094,24 @@ setup_console:
 	zs_kgdb_init();
 #endif
 }
+
+/*
+ * Power management hooks for zsopen() and zsclose().
+ * We use them to power on/off the ports, if necessary.
+ */
+int
+zs_enable(cs)
+	struct zs_chanstate *cs;
+{
+	auxiotwoserialendis (ZS_ENABLE);
+	cs->enabled = 1;
+	return(0);
+}
+
+void
+zs_disable(cs)
+	struct zs_chanstate *cs;
+{
+	auxiotwoserialendis (ZS_DISABLE);
+	cs->enabled = 0;
+}
diff --git a/sys/dev/ic/z8530sc.h b/sys/dev/ic/z8530sc.h
index 73a6fce4f267..2d547298669c 100644
--- a/sys/dev/ic/z8530sc.h
+++ b/sys/dev/ic/z8530sc.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: z8530sc.h,v 1.12 1999/03/27 01:22:36 wrstuden Exp $	*/
+/*	$NetBSD: z8530sc.h,v 1.13 2000/03/14 21:20:52 jdc Exp $	*/
 
 /*
  * Copyright (c) 1994 Gordon W. Ross
@@ -113,6 +113,12 @@ struct zs_chanstate {
 
 	char	cs_softreq;		/* need soft interrupt call */
 	char	cs_spare1;  	/* (for skippy :) */
+
+	/* power management hooks */
+	int	(*enable) __P((struct zs_chanstate *));
+	void	(*disable) __P((struct zs_chanstate *));
+	int	enabled;
+
 	/* MD code might define a larger variant of this. */
 };
 
diff --git a/sys/dev/ic/z8530tty.c b/sys/dev/ic/z8530tty.c
index 2dd01f303e9e..8a2bdfa2c9ab 100644
--- a/sys/dev/ic/z8530tty.c
+++ b/sys/dev/ic/z8530tty.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: z8530tty.c,v 1.62 1999/11/04 05:33:59 jonathan Exp $	*/
+/*	$NetBSD: z8530tty.c,v 1.63 2000/03/14 21:20:52 jdc Exp $	*/
 
 /*-
  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998, 1999
@@ -325,7 +325,10 @@ zstty_attach(parent, self, aux)
 	zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
 	zst->zst_rbavail = zstty_rbuf_size;
 
-	/* XXX - Do we need an MD hook here? */
+	/* if there are no enable/disable functions, assume the device
+	   is always enabled */
+	if (!cs->enable)
+		cs->enabled = 1;
 
 	/*
 	 * Hardware init
@@ -435,6 +438,15 @@ zs_shutdown(zst)
 		zs_write_reg(cs, 1, cs->cs_creg[1]);
 	}
 
+	/* Call the power management hook. */
+	if (cs->disable) {
+#ifdef DIAGNOSTIC
+		if (!cs->enabled)
+			panic("zs_shutdown: not enabled?");
+#endif
+		(*cs->disable)(zst->zst_cs);
+	}
+
 	splx(s);
 }
 
@@ -482,6 +494,17 @@ zsopen(dev, flags, mode, p)
 
 		tp->t_dev = dev;
 
+		/* Call the power management hook. */
+		if (cs->enable) {
+			if ((*cs->enable)(cs)) {
+				splx(s2);
+				splx(s);
+				printf("%s: device enable failed\n",
+			       	zst->zst_dev.dv_xname);
+				return (EIO);
+			}
+		}
+
 		/*
 		 * Initialize the termios status to the defaults.  Add in the
 		 * sticky bits from TIOCSFLAGS.