1/* $NetBSD: fdt_pwm.c,v 1.2 2018/06/30 20:34:43 jmcneill Exp $ */
2
3/*-
4 * Copyright (c) 2018 Jared McNeill <jmcneill@invisible.ca>
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 ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * 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__KERNEL_RCSID(0, "$NetBSD: fdt_pwm.c,v 1.2 2018/06/30 20:34:43 jmcneill Exp $");
31
32#include <sys/param.h>
33#include <sys/bus.h>
34#include <sys/kmem.h>
35#include <sys/queue.h>
36
37#include <libfdt.h>
38#include <dev/fdt/fdtvar.h>
39
40struct fdtbus_pwm_controller {
41	device_t pc_dev;
42	int pc_phandle;
43	const struct fdtbus_pwm_controller_func *pc_funcs;
44
45	LIST_ENTRY(fdtbus_pwm_controller) pc_next;
46};
47
48static LIST_HEAD(, fdtbus_pwm_controller) fdtbus_pwm_controllers =
49    LIST_HEAD_INITIALIZER(fdtbus_pwm_controllers);
50
51int
52fdtbus_register_pwm_controller(device_t dev, int phandle,
53    const struct fdtbus_pwm_controller_func *funcs)
54{
55	struct fdtbus_pwm_controller *pc;
56
57	pc = kmem_alloc(sizeof(*pc), KM_SLEEP);
58	pc->pc_dev = dev;
59	pc->pc_phandle = phandle;
60	pc->pc_funcs = funcs;
61
62	LIST_INSERT_HEAD(&fdtbus_pwm_controllers, pc, pc_next);
63
64	return 0;
65}
66
67static struct fdtbus_pwm_controller *
68fdtbus_get_pwm_controller(int phandle)
69{
70	struct fdtbus_pwm_controller *pc;
71
72	LIST_FOREACH(pc, &fdtbus_pwm_controllers, pc_next) {
73		if (pc->pc_phandle == phandle)
74			return pc;
75	}
76
77	return NULL;
78}
79
80pwm_tag_t
81fdtbus_pwm_acquire(int phandle, const char *prop)
82{
83	return fdtbus_pwm_acquire_index(phandle, prop, 0);
84}
85
86pwm_tag_t
87fdtbus_pwm_acquire_index(int phandle, const char *prop, int index)
88{
89	struct fdtbus_pwm_controller *pc;
90	const uint32_t *pwms, *p;
91	u_int n, pwm_cells;
92	int len, resid;
93
94	pwms = fdtbus_get_prop(phandle, prop, &len);
95	if (pwms == NULL)
96		return NULL;
97
98	p = pwms;
99	for (n = 0, resid = len; resid > 0; n++) {
100		const int pc_phandle =
101		    fdtbus_get_phandle_from_native(be32toh(p[0]));
102		if (of_getprop_uint32(pc_phandle, "#pwm-cells", &pwm_cells))
103			break;
104		if (n == index) {
105			pc = fdtbus_get_pwm_controller(pc_phandle);
106			if (pc == NULL)
107				return NULL;
108			return pc->pc_funcs->get_tag(pc->pc_dev,
109			    &p[0], (pwm_cells + 1) * 4);
110		}
111		resid -= (pwm_cells + 1) * 4;
112		p += pwm_cells + 1;
113	}
114
115	return NULL;
116}
117