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
40 struct 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
48 static LIST_HEAD(, fdtbus_pwm_controller) fdtbus_pwm_controllers =
49 LIST_HEAD_INITIALIZER(fdtbus_pwm_controllers);
50
51 int
fdtbus_register_pwm_controller(device_t dev,int phandle,const struct fdtbus_pwm_controller_func * funcs)52 fdtbus_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
67 static struct fdtbus_pwm_controller *
fdtbus_get_pwm_controller(int phandle)68 fdtbus_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
80 pwm_tag_t
fdtbus_pwm_acquire(int phandle,const char * prop)81 fdtbus_pwm_acquire(int phandle, const char *prop)
82 {
83 return fdtbus_pwm_acquire_index(phandle, prop, 0);
84 }
85
86 pwm_tag_t
fdtbus_pwm_acquire_index(int phandle,const char * prop,int index)87 fdtbus_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