diff --git a/drivers/macintosh/macio-adb.c b/drivers/macintosh/macio-adb.c
new file mode 100644
index 0000000..cf6a6f2
--- /dev/null
+++ b/drivers/macintosh/macio-adb.c
@@ -0,0 +1,284 @@
+/*
+ * Driver for the ADB controller in the Mac I/O (Hydra) chip.
+ */
+#include <stdarg.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <asm/prom.h>
+#include <linux/adb.h>
+#include <asm/io.h>
+#include <asm/pgtable.h>
+#include <asm/hydra.h>
+#include <asm/irq.h>
+#include <asm/system.h>
+#include <linux/init.h>
+
+struct preg {
+	unsigned char r;
+	char pad[15];
+};
+
+struct adb_regs {
+	struct preg intr;
+	struct preg data[9];
+	struct preg intr_enb;
+	struct preg dcount;
+	struct preg error;
+	struct preg ctrl;
+	struct preg autopoll;
+	struct preg active_hi;
+	struct preg active_lo;
+	struct preg test;
+};
+
+/* Bits in intr and intr_enb registers */
+#define DFB	1		/* data from bus */
+#define TAG	2		/* transfer access grant */
+
+/* Bits in dcount register */
+#define HMB	0x0f		/* how many bytes */
+#define APD	0x10		/* auto-poll data */
+
+/* Bits in error register */
+#define NRE	1		/* no response error */
+#define DLE	2		/* data lost error */
+
+/* Bits in ctrl register */
+#define TAR	1		/* transfer access request */
+#define DTB	2		/* data to bus */
+#define CRE	4		/* command response expected */
+#define ADB_RST	8		/* ADB reset */
+
+/* Bits in autopoll register */
+#define APE	1		/* autopoll enable */
+
+static volatile struct adb_regs __iomem *adb;
+static struct adb_request *current_req, *last_req;
+static DEFINE_SPINLOCK(macio_lock);
+
+static int macio_probe(void);
+static int macio_init(void);
+static irqreturn_t macio_adb_interrupt(int irq, void *arg, struct pt_regs *regs);
+static int macio_send_request(struct adb_request *req, int sync);
+static int macio_adb_autopoll(int devs);
+static void macio_adb_poll(void);
+static int macio_adb_reset_bus(void);
+
+struct adb_driver macio_adb_driver = {
+	"MACIO",
+	macio_probe,
+	macio_init,
+	macio_send_request,
+	/*macio_write,*/
+	macio_adb_autopoll,
+	macio_adb_poll,
+	macio_adb_reset_bus
+};
+
+int macio_probe(void)
+{
+	return find_compatible_devices("adb", "chrp,adb0")? 0: -ENODEV;
+}
+
+int macio_init(void)
+{
+	struct device_node *adbs;
+
+	adbs = find_compatible_devices("adb", "chrp,adb0");
+	if (adbs == 0)
+		return -ENXIO;
+
+#if 0
+	{ int i;
+
+	printk("macio_adb_init: node = %p, addrs =", adbs->node);
+	for (i = 0; i < adbs->n_addrs; ++i)
+		printk(" %x(%x)", adbs->addrs[i].address, adbs->addrs[i].size);
+	printk(", intrs =");
+	for (i = 0; i < adbs->n_intrs; ++i)
+		printk(" %x", adbs->intrs[i].line);
+	printk("\n"); }
+#endif
+	
+	adb = ioremap(adbs->addrs->address, sizeof(struct adb_regs));
+
+	out_8(&adb->ctrl.r, 0);
+	out_8(&adb->intr.r, 0);
+	out_8(&adb->error.r, 0);
+	out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
+	out_8(&adb->active_lo.r, 0xff);
+	out_8(&adb->autopoll.r, APE);
+
+	if (request_irq(adbs->intrs[0].line, macio_adb_interrupt,
+			0, "ADB", (void *)0)) {
+		printk(KERN_ERR "ADB: can't get irq %d\n",
+		       adbs->intrs[0].line);
+		return -EAGAIN;
+	}
+	out_8(&adb->intr_enb.r, DFB | TAG);
+
+	printk("adb: mac-io driver 1.0 for unified ADB\n");
+
+	return 0;
+}
+
+static int macio_adb_autopoll(int devs)
+{
+	unsigned long flags;
+	
+	spin_lock_irqsave(&macio_lock, flags);
+	out_8(&adb->active_hi.r, devs >> 8);
+	out_8(&adb->active_lo.r, devs);
+	out_8(&adb->autopoll.r, devs? APE: 0);
+	spin_unlock_irqrestore(&macio_lock, flags);
+	return 0;
+}
+
+static int macio_adb_reset_bus(void)
+{
+	unsigned long flags;
+	int timeout = 1000000;
+
+	/* Hrm... we may want to not lock interrupts for so
+	 * long ... oh well, who uses that chip anyway ? :)
+	 * That function will be seldomly used during boot
+	 * on rare machines, so...
+	 */
+	spin_lock_irqsave(&macio_lock, flags);
+	out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
+	while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
+		if (--timeout == 0) {
+			out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
+			return -1;
+		}
+	}
+	spin_unlock_irqrestore(&macio_lock, flags);
+	return 0;
+}
+
+/* Send an ADB command */
+static int macio_send_request(struct adb_request *req, int sync)
+{
+	unsigned long flags;
+	int i;
+	
+	if (req->data[0] != ADB_PACKET)
+		return -EINVAL;
+	
+	for (i = 0; i < req->nbytes - 1; ++i)
+		req->data[i] = req->data[i+1];
+	--req->nbytes;
+	
+	req->next = NULL;
+	req->sent = 0;
+	req->complete = 0;
+	req->reply_len = 0;
+
+	spin_lock_irqsave(&macio_lock, flags);
+	if (current_req != 0) {
+		last_req->next = req;
+		last_req = req;
+	} else {
+		current_req = last_req = req;
+		out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
+	}
+	spin_unlock_irqrestore(&macio_lock, flags);
+	
+	if (sync) {
+		while (!req->complete)
+			macio_adb_poll();
+	}
+
+	return 0;
+}
+
+static irqreturn_t macio_adb_interrupt(int irq, void *arg,
+				       struct pt_regs *regs)
+{
+	int i, n, err;
+	struct adb_request *req = NULL;
+	unsigned char ibuf[16];
+	int ibuf_len = 0;
+	int complete = 0;
+	int autopoll = 0;
+	int handled = 0;
+
+	spin_lock(&macio_lock);
+	if (in_8(&adb->intr.r) & TAG) {
+		handled = 1;
+		if ((req = current_req) != 0) {
+			/* put the current request in */
+			for (i = 0; i < req->nbytes; ++i)
+				out_8(&adb->data[i].r, req->data[i]);
+			out_8(&adb->dcount.r, req->nbytes & HMB);
+			req->sent = 1;
+			if (req->reply_expected) {
+				out_8(&adb->ctrl.r, DTB + CRE);
+			} else {
+				out_8(&adb->ctrl.r, DTB);
+				current_req = req->next;
+				complete = 1;
+				if (current_req)
+					out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
+			}
+		}
+		out_8(&adb->intr.r, 0);
+	}
+
+	if (in_8(&adb->intr.r) & DFB) {
+		handled = 1;
+		err = in_8(&adb->error.r);
+		if (current_req && current_req->sent) {
+			/* this is the response to a command */
+			req = current_req;
+			if (err == 0) {
+				req->reply_len = in_8(&adb->dcount.r) & HMB;
+				for (i = 0; i < req->reply_len; ++i)
+					req->reply[i] = in_8(&adb->data[i].r);
+			}
+			current_req = req->next;
+			complete = 1;
+			if (current_req)
+				out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
+		} else if (err == 0) {
+			/* autopoll data */
+			n = in_8(&adb->dcount.r) & HMB;
+			for (i = 0; i < n; ++i)
+				ibuf[i] = in_8(&adb->data[i].r);
+			ibuf_len = n;
+			autopoll = (in_8(&adb->dcount.r) & APD) != 0;
+		}
+		out_8(&adb->error.r, 0);
+		out_8(&adb->intr.r, 0);
+	}
+	spin_unlock(&macio_lock);
+	if (complete && req) {
+	    void (*done)(struct adb_request *) = req->done;
+	    mb();
+	    req->complete = 1;
+	    /* Here, we assume that if the request has a done member, the
+    	     * struct request will survive to setting req->complete to 1
+	     */
+	    if (done)
+		(*done)(req);
+	}
+	if (ibuf_len)
+		adb_input(ibuf, ibuf_len, regs, autopoll);
+
+	return IRQ_RETVAL(handled);
+}
+
+static void macio_adb_poll(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	if (in_8(&adb->intr.r) != 0)
+		macio_adb_interrupt(0, NULL, NULL);
+	local_irq_restore(flags);
+}