rk30xx_gpio.c revision 278786 
1/*-
2 * Copyright (c) 2013 Ganbold Tsagaankhuu <ganbold@freebsd.org>
3 * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
4 * Copyright (c) 2012 Luiz Otavio O Souza.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 */
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/10/sys/arm/rockchip/rk30xx_gpio.c 278786 2015-02-14 21:16:19Z loos $");
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/bus.h>
35
36#include <sys/kernel.h>
37#include <sys/module.h>
38#include <sys/rman.h>
39#include <sys/lock.h>
40#include <sys/mutex.h>
41#include <sys/gpio.h>
42
43#include <machine/bus.h>
44#include <machine/cpu.h>
45#include <machine/cpufunc.h>
46#include <machine/resource.h>
47#include <machine/fdt.h>
48#include <machine/intr.h>
49
50#include <dev/fdt/fdt_common.h>
51#include <dev/ofw/ofw_bus.h>
52#include <dev/ofw/ofw_bus_subr.h>
53
54#include "gpio_if.h"
55
56#include "rk30xx_grf.h"
57#include "rk30xx_pmu.h"
58
59/*
60 * RK3188 has 4 banks of gpio.
61 * 32 pins per bank
62 * PA0 - PA7 | PB0 - PB7
63 * PC0 - PC7 | PD0 - PD7
64 */
65
66#define	RK30_GPIO_PINS		128
67#define	RK30_GPIO_DEFAULT_CAPS	(GPIO_PIN_INPUT | GPIO_PIN_OUTPUT | \
68    GPIO_PIN_PULLUP | GPIO_PIN_PULLDOWN)
69
70#define	RK30_GPIO_NONE			0
71#define	RK30_GPIO_PULLUP		1
72#define	RK30_GPIO_PULLDOWN		2
73
74#define	RK30_GPIO_INPUT			0
75#define	RK30_GPIO_OUTPUT		1
76
77struct rk30_gpio_softc {
78	device_t		sc_dev;
79	struct mtx		sc_mtx;
80	struct resource *	sc_mem_res;
81	struct resource *	sc_irq_res;
82	bus_space_tag_t		sc_bst;
83	bus_space_handle_t	sc_bsh;
84	void *			sc_intrhand;
85	int			sc_gpio_npins;
86	struct gpio_pin		sc_gpio_pins[RK30_GPIO_PINS];
87};
88
89static struct rk30_gpio_softc *rk30_gpio_sc = NULL;
90
91typedef int (*gpios_phandler_t)(phandle_t, pcell_t *, int);
92
93struct gpio_ctrl_entry {
94	const char		*compat;
95	gpios_phandler_t	handler;
96};
97
98int rk30_gpios_prop_handle(phandle_t ctrl, pcell_t *gpios, int len);
99static int rk30_gpio_init(void);
100
101struct gpio_ctrl_entry gpio_controllers[] = {
102	{ "rockchip,rk30xx-gpio", &rk30_gpios_prop_handle },
103	{ "rockchip,rk30xx-gpio", &rk30_gpios_prop_handle },
104	{ "rockchip,rk30xx-gpio", &rk30_gpios_prop_handle },
105	{ "rockchip,rk30xx-gpio", &rk30_gpios_prop_handle },
106	{ NULL, NULL }
107};
108
109#define	RK30_GPIO_LOCK(_sc)		mtx_lock(&_sc->sc_mtx)
110#define	RK30_GPIO_UNLOCK(_sc)		mtx_unlock(&_sc->sc_mtx)
111#define	RK30_GPIO_LOCK_ASSERT(_sc)	mtx_assert(&_sc->sc_mtx, MA_OWNED)
112
113#define	RK30_GPIO_SWPORT_DR		0x00
114#define	RK30_GPIO_SWPORT_DDR		0x04
115#define	RK30_GPIO_INTEN			0x30
116#define	RK30_GPIO_INTMASK		0x34
117#define	RK30_GPIO_INTTYPE_LEVEL		0x38
118#define	RK30_GPIO_INT_POLARITY		0x3c
119#define	RK30_GPIO_INT_STATUS		0x40
120#define	RK30_GPIO_INT_RAWSTATUS		0x44
121#define	RK30_GPIO_DEBOUNCE		0x48
122#define	RK30_GPIO_PORTS_EOI		0x4c
123#define	RK30_GPIO_EXT_PORT		0x50
124#define	RK30_GPIO_LS_SYNC		0x60
125
126#define	RK30_GPIO_WRITE(_sc, _off, _val)		\
127    bus_space_write_4(_sc->sc_bst, _sc->sc_bsh, _off, _val)
128#define	RK30_GPIO_READ(_sc, _off)			\
129    bus_space_read_4(_sc->sc_bst, _sc->sc_bsh, _off)
130
131static uint32_t
132rk30_gpio_get_function(struct rk30_gpio_softc *sc, uint32_t pin)
133{
134	uint32_t bank, func, offset;
135
136	bank = pin / 32;
137	pin = pin % 32;
138	offset = 1 << pin;
139
140	func = RK30_GPIO_READ(sc, RK30_GPIO_SWPORT_DDR);
141	func &= offset;
142
143	return (func);
144}
145
146static uint32_t
147rk30_gpio_func_flag(uint32_t nfunc)
148{
149
150	switch (nfunc) {
151	case RK30_GPIO_INPUT:
152		return (GPIO_PIN_INPUT);
153	case RK30_GPIO_OUTPUT:
154		return (GPIO_PIN_OUTPUT);
155	}
156	return (0);
157}
158
159static void
160rk30_gpio_set_function(struct rk30_gpio_softc *sc, uint32_t pin, uint32_t f)
161{
162	uint32_t bank, data, offset;
163
164	/* Must be called with lock held. */
165	RK30_GPIO_LOCK_ASSERT(sc);
166
167	bank = pin / 32;
168	pin = pin % 32;
169	offset = 1 << pin;
170
171	data = RK30_GPIO_READ(sc, RK30_GPIO_SWPORT_DDR);
172	if (f)
173		data |= offset;
174	else
175		data &= ~offset;
176	RK30_GPIO_WRITE(sc, RK30_GPIO_SWPORT_DDR, data);
177}
178
179static void
180rk30_gpio_set_pud(struct rk30_gpio_softc *sc, uint32_t pin, uint32_t state)
181{
182	uint32_t bank;
183
184	bank = pin / 32;
185
186	/* Must be called with lock held. */
187	RK30_GPIO_LOCK_ASSERT(sc);
188
189	if (bank == 0 && pin < 12)
190		rk30_pmu_gpio_pud(pin, state);
191	else
192		rk30_grf_gpio_pud(bank, pin, state);
193}
194
195static void
196rk30_gpio_pin_configure(struct rk30_gpio_softc *sc, struct gpio_pin *pin,
197    unsigned int flags)
198{
199
200	RK30_GPIO_LOCK(sc);
201
202	/*
203	 * Manage input/output.
204	 */
205	if (flags & (GPIO_PIN_INPUT|GPIO_PIN_OUTPUT)) {
206		pin->gp_flags &= ~(GPIO_PIN_INPUT|GPIO_PIN_OUTPUT);
207		if (flags & GPIO_PIN_OUTPUT) {
208			pin->gp_flags |= GPIO_PIN_OUTPUT;
209			rk30_gpio_set_function(sc, pin->gp_pin,
210			    RK30_GPIO_OUTPUT);
211		} else {
212			pin->gp_flags |= GPIO_PIN_INPUT;
213			rk30_gpio_set_function(sc, pin->gp_pin,
214			    RK30_GPIO_INPUT);
215		}
216	}
217
218	/* Manage Pull-up/pull-down. */
219	pin->gp_flags &= ~(GPIO_PIN_PULLUP|GPIO_PIN_PULLDOWN);
220	if (flags & (GPIO_PIN_PULLUP|GPIO_PIN_PULLDOWN)) {
221		if (flags & GPIO_PIN_PULLUP) {
222			pin->gp_flags |= GPIO_PIN_PULLUP;
223			rk30_gpio_set_pud(sc, pin->gp_pin,
224			    RK30_GPIO_PULLUP);
225		} else {
226			pin->gp_flags |= GPIO_PIN_PULLDOWN;
227			rk30_gpio_set_pud(sc, pin->gp_pin,
228			    RK30_GPIO_PULLDOWN);
229		}
230	} else
231		rk30_gpio_set_pud(sc, pin->gp_pin, RK30_GPIO_NONE);
232
233	RK30_GPIO_UNLOCK(sc);
234}
235
236static int
237rk30_gpio_pin_max(device_t dev, int *maxpin)
238{
239
240	*maxpin = RK30_GPIO_PINS - 1;
241	return (0);
242}
243
244static int
245rk30_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
246{
247	struct rk30_gpio_softc *sc = device_get_softc(dev);
248	int i;
249
250	for (i = 0; i < sc->sc_gpio_npins; i++) {
251		if (sc->sc_gpio_pins[i].gp_pin == pin)
252			break;
253	}
254
255	if (i >= sc->sc_gpio_npins)
256		return (EINVAL);
257
258	RK30_GPIO_LOCK(sc);
259	*caps = sc->sc_gpio_pins[i].gp_caps;
260	RK30_GPIO_UNLOCK(sc);
261
262	return (0);
263}
264
265static int
266rk30_gpio_pin_getflags(device_t dev, uint32_t pin, uint32_t *flags)
267{
268	struct rk30_gpio_softc *sc = device_get_softc(dev);
269	int i;
270
271	for (i = 0; i < sc->sc_gpio_npins; i++) {
272		if (sc->sc_gpio_pins[i].gp_pin == pin)
273			break;
274	}
275
276	if (i >= sc->sc_gpio_npins)
277		return (EINVAL);
278
279	RK30_GPIO_LOCK(sc);
280	*flags = sc->sc_gpio_pins[i].gp_flags;
281	RK30_GPIO_UNLOCK(sc);
282
283	return (0);
284}
285
286static int
287rk30_gpio_pin_getname(device_t dev, uint32_t pin, char *name)
288{
289	struct rk30_gpio_softc *sc = device_get_softc(dev);
290	int i;
291
292	for (i = 0; i < sc->sc_gpio_npins; i++) {
293		if (sc->sc_gpio_pins[i].gp_pin == pin)
294			break;
295	}
296
297	if (i >= sc->sc_gpio_npins)
298		return (EINVAL);
299
300	RK30_GPIO_LOCK(sc);
301	memcpy(name, sc->sc_gpio_pins[i].gp_name, GPIOMAXNAME);
302	RK30_GPIO_UNLOCK(sc);
303
304	return (0);
305}
306
307static int
308rk30_gpio_pin_setflags(device_t dev, uint32_t pin, uint32_t flags)
309{
310	struct rk30_gpio_softc *sc = device_get_softc(dev);
311	int i;
312
313	for (i = 0; i < sc->sc_gpio_npins; i++) {
314		if (sc->sc_gpio_pins[i].gp_pin == pin)
315			break;
316	}
317
318	if (i >= sc->sc_gpio_npins)
319		return (EINVAL);
320
321	rk30_gpio_pin_configure(sc, &sc->sc_gpio_pins[i], flags);
322
323	return (0);
324}
325
326static int
327rk30_gpio_pin_set(device_t dev, uint32_t pin, unsigned int value)
328{
329	struct rk30_gpio_softc *sc = device_get_softc(dev);
330	uint32_t bank, offset, data;
331	int i;
332
333	for (i = 0; i < sc->sc_gpio_npins; i++) {
334		if (sc->sc_gpio_pins[i].gp_pin == pin)
335			break;
336	}
337
338	if (i >= sc->sc_gpio_npins)
339		return (EINVAL);
340
341	bank = pin / 32;
342	pin = pin % 32;
343	offset = 1 << pin;
344
345	RK30_GPIO_LOCK(sc);
346	data = RK30_GPIO_READ(sc, RK30_GPIO_SWPORT_DDR);
347	data |= offset;
348	RK30_GPIO_WRITE(sc, RK30_GPIO_SWPORT_DDR, data);
349
350	data = RK30_GPIO_READ(sc, RK30_GPIO_SWPORT_DR);
351	if (value)
352		data |= offset;
353	else
354		data &= ~offset;
355	RK30_GPIO_WRITE(sc, RK30_GPIO_SWPORT_DR, data);
356	RK30_GPIO_UNLOCK(sc);
357
358	return (0);
359}
360
361static int
362rk30_gpio_pin_get(device_t dev, uint32_t pin, unsigned int *val)
363{
364	struct rk30_gpio_softc *sc = device_get_softc(dev);
365	uint32_t bank, offset, reg_data;
366	int i;
367
368	for (i = 0; i < sc->sc_gpio_npins; i++) {
369		if (sc->sc_gpio_pins[i].gp_pin == pin)
370			break;
371	}
372
373	if (i >= sc->sc_gpio_npins)
374		return (EINVAL);
375
376	bank = pin / 32;
377	pin = pin % 32;
378	offset = 1 << pin;
379
380	RK30_GPIO_LOCK(sc);
381	reg_data = RK30_GPIO_READ(sc, RK30_GPIO_EXT_PORT);
382	RK30_GPIO_UNLOCK(sc);
383	*val = (reg_data & offset) ? 1 : 0;
384
385	return (0);
386}
387
388static int
389rk30_gpio_pin_toggle(device_t dev, uint32_t pin)
390{
391	struct rk30_gpio_softc *sc = device_get_softc(dev);
392	uint32_t bank, data, offset;
393	int i;
394
395	for (i = 0; i < sc->sc_gpio_npins; i++) {
396		if (sc->sc_gpio_pins[i].gp_pin == pin)
397			break;
398	}
399
400	if (i >= sc->sc_gpio_npins)
401		return (EINVAL);
402
403	bank = pin / 32;
404	pin = pin % 32;
405	offset = 1 << pin;
406
407	RK30_GPIO_LOCK(sc);
408	data = RK30_GPIO_READ(sc, RK30_GPIO_SWPORT_DDR);
409	if (data & offset)
410		data &= ~offset;
411	else
412		data |= offset;
413	RK30_GPIO_WRITE(sc, RK30_GPIO_SWPORT_DDR, data);
414
415	data = RK30_GPIO_READ(sc, RK30_GPIO_SWPORT_DR);
416	if (data & offset)
417		data &= ~offset;
418	else
419		data |= offset;
420	RK30_GPIO_WRITE(sc, RK30_GPIO_SWPORT_DR, data);
421	RK30_GPIO_UNLOCK(sc);
422
423	return (0);
424}
425
426static int
427rk30_gpio_probe(device_t dev)
428{
429
430	if (!ofw_bus_status_okay(dev))
431		return (ENXIO);
432
433	if (!ofw_bus_is_compatible(dev, "rockchip,rk30xx-gpio"))
434		return (ENXIO);
435
436	device_set_desc(dev, "Rockchip RK30XX GPIO controller");
437	return (BUS_PROBE_DEFAULT);
438}
439
440static int
441rk30_gpio_attach(device_t dev)
442{
443	struct rk30_gpio_softc *sc = device_get_softc(dev);
444	uint32_t func;
445	int i, rid;
446	phandle_t gpio;
447
448	if (rk30_gpio_sc)
449		return (ENXIO);
450
451	sc->sc_dev = dev;
452
453	mtx_init(&sc->sc_mtx, "rk30 gpio", "gpio", MTX_DEF);
454
455	rid = 0;
456	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
457	    RF_ACTIVE);
458	if (!sc->sc_mem_res) {
459		device_printf(dev, "cannot allocate memory window\n");
460		return (ENXIO);
461	}
462
463	sc->sc_bst = rman_get_bustag(sc->sc_mem_res);
464	sc->sc_bsh = rman_get_bushandle(sc->sc_mem_res);
465
466	rid = 0;
467	sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
468	    RF_ACTIVE);
469	if (!sc->sc_irq_res) {
470		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
471		device_printf(dev, "cannot allocate interrupt\n");
472		return (ENXIO);
473	}
474
475	/* Find our node. */
476	gpio = ofw_bus_get_node(sc->sc_dev);
477
478	if (!OF_hasprop(gpio, "gpio-controller"))
479		/* Node is not a GPIO controller. */
480		goto fail;
481
482	/* Initialize the software controlled pins. */
483	for (i = 0; i < RK30_GPIO_PINS; i++) {
484		snprintf(sc->sc_gpio_pins[i].gp_name, GPIOMAXNAME,
485		    "pin %d", i);
486		func = rk30_gpio_get_function(sc, i);
487		sc->sc_gpio_pins[i].gp_pin = i;
488		sc->sc_gpio_pins[i].gp_caps = RK30_GPIO_DEFAULT_CAPS;
489		sc->sc_gpio_pins[i].gp_flags = rk30_gpio_func_flag(func);
490	}
491	sc->sc_gpio_npins = i;
492
493	device_add_child(dev, "gpioc", -1);
494	device_add_child(dev, "gpiobus", -1);
495
496	rk30_gpio_sc = sc;
497
498	rk30_gpio_init();
499
500	return (bus_generic_attach(dev));
501
502fail:
503	if (sc->sc_irq_res)
504		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
505	if (sc->sc_mem_res)
506		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
507	return (ENXIO);
508}
509
510static int
511rk30_gpio_detach(device_t dev)
512{
513
514	return (EBUSY);
515}
516
517static device_method_t rk30_gpio_methods[] = {
518	/* Device interface */
519	DEVMETHOD(device_probe,		rk30_gpio_probe),
520	DEVMETHOD(device_attach,	rk30_gpio_attach),
521	DEVMETHOD(device_detach,	rk30_gpio_detach),
522
523	/* GPIO protocol */
524	DEVMETHOD(gpio_pin_max,		rk30_gpio_pin_max),
525	DEVMETHOD(gpio_pin_getname,	rk30_gpio_pin_getname),
526	DEVMETHOD(gpio_pin_getflags,	rk30_gpio_pin_getflags),
527	DEVMETHOD(gpio_pin_getcaps,	rk30_gpio_pin_getcaps),
528	DEVMETHOD(gpio_pin_setflags,	rk30_gpio_pin_setflags),
529	DEVMETHOD(gpio_pin_get,		rk30_gpio_pin_get),
530	DEVMETHOD(gpio_pin_set,		rk30_gpio_pin_set),
531	DEVMETHOD(gpio_pin_toggle,	rk30_gpio_pin_toggle),
532
533	DEVMETHOD_END
534};
535
536static devclass_t rk30_gpio_devclass;
537
538static driver_t rk30_gpio_driver = {
539	"gpio",
540	rk30_gpio_methods,
541	sizeof(struct rk30_gpio_softc),
542};
543
544DRIVER_MODULE(rk30_gpio, simplebus, rk30_gpio_driver, rk30_gpio_devclass, 0, 0);
545
546int
547rk30_gpios_prop_handle(phandle_t ctrl, pcell_t *gpios, int len)
548{
549	struct rk30_gpio_softc *sc;
550	pcell_t gpio_cells;
551	int inc, t, tuples, tuple_size;
552	int dir, flags, pin, i;
553	u_long gpio_ctrl, size;
554
555	sc = rk30_gpio_sc;
556	if (sc == NULL)
557		return ENXIO;
558
559	if (OF_getprop(ctrl, "#gpio-cells", &gpio_cells, sizeof(pcell_t)) < 0)
560		return (ENXIO);
561
562	gpio_cells = fdt32_to_cpu(gpio_cells);
563	if (gpio_cells != 2)
564		return (ENXIO);
565
566	tuple_size = gpio_cells * sizeof(pcell_t) + sizeof(phandle_t);
567	tuples = len / tuple_size;
568
569	if (fdt_regsize(ctrl, &gpio_ctrl, &size))
570		return (ENXIO);
571
572	/*
573	 * Skip controller reference, since controller's phandle is given
574	 * explicitly (in a function argument).
575	 */
576	inc = sizeof(ihandle_t) / sizeof(pcell_t);
577	gpios += inc;
578	for (t = 0; t < tuples; t++) {
579		pin = fdt32_to_cpu(gpios[0]);
580		dir = fdt32_to_cpu(gpios[1]);
581		flags = fdt32_to_cpu(gpios[2]);
582
583		for (i = 0; i < sc->sc_gpio_npins; i++) {
584			if (sc->sc_gpio_pins[i].gp_pin == pin)
585				break;
586		}
587		if (i >= sc->sc_gpio_npins)
588			return (EINVAL);
589
590		rk30_gpio_pin_configure(sc, &sc->sc_gpio_pins[i], flags);
591
592		if (dir == 1) {
593			/* Input. */
594			rk30_gpio_pin_set(sc->sc_dev, pin, RK30_GPIO_INPUT);
595		} else {
596			/* Output. */
597			rk30_gpio_pin_set(sc->sc_dev, pin, RK30_GPIO_OUTPUT);
598		}
599		gpios += gpio_cells + inc;
600	}
601
602	return (0);
603}
604
605#define	MAX_PINS_PER_NODE	5
606#define	GPIOS_PROP_CELLS	4
607
608static int
609rk30_gpio_init(void)
610{
611	phandle_t child, parent, root, ctrl;
612	pcell_t gpios[MAX_PINS_PER_NODE * GPIOS_PROP_CELLS];
613	struct gpio_ctrl_entry *e;
614	int len, rv;
615
616	root = OF_finddevice("/");
617	len = 0;
618	parent = root;
619
620	/* Traverse through entire tree to find nodes with 'gpios' prop */
621	for (child = OF_child(parent); child != 0; child = OF_peer(child)) {
622
623		/* Find a 'leaf'. Start the search from this node. */
624		while (OF_child(child)) {
625			parent = child;
626			child = OF_child(child);
627		}
628		if ((len = OF_getproplen(child, "gpios")) > 0) {
629
630			if (len > sizeof(gpios))
631				return (ENXIO);
632
633			/* Get 'gpios' property. */
634			OF_getprop(child, "gpios", &gpios, len);
635
636			e = (struct gpio_ctrl_entry *)&gpio_controllers;
637
638			/* Find and call a handler. */
639			for (; e->compat; e++) {
640				/*
641				 * First cell of 'gpios' property should
642				 * contain a ref. to a node defining GPIO
643				 * controller.
644				 */
645				ctrl = OF_node_from_xref(fdt32_to_cpu(gpios[0]));
646
647				if (fdt_is_compatible(ctrl, e->compat))
648					/* Call a handler. */
649					if ((rv = e->handler(ctrl,
650					    (pcell_t *)&gpios, len)))
651						return (rv);
652			}
653		}
654
655		if (OF_peer(child) == 0) {
656			/* No more siblings. */
657			child = parent;
658			parent = OF_parent(child);
659		}
660	}
661	return (0);
662}
663