1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/types.h>
29 #include <sys/ioctl.h>
30 #include <stdbool.h>
31 #include <sys/capsicum.h>
32 #include <dev/pwm/pwmc.h>
33
34 #include <err.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <limits.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 #include <capsicum_helpers.h>
43
44 #define PWM_ENABLE 0x0001
45 #define PWM_DISABLE 0x0002
46 #define PWM_SHOW_CONFIG 0x0004
47 #define PWM_PERIOD 0x0008
48 #define PWM_DUTY 0x0010
49 #define PWM_INVERTED 0x0020
50
51 static char device_name[PATH_MAX] = "/dev/pwm/pwmc0.0";
52
53 static void
set_device_name(const char * name)54 set_device_name(const char *name)
55 {
56
57 if (name[0] == '/')
58 strlcpy(device_name, name, sizeof(device_name));
59 else
60 snprintf(device_name, sizeof(device_name), "/dev/pwm/%s", name);
61 }
62
63 static void
usage(void)64 usage(void)
65 {
66 fprintf(stderr, "Usage:\n");
67 fprintf(stderr, "\tpwm [-f dev] -C\n");
68 fprintf(stderr, "\tpwm [-f dev] [-D | -E] [-I] [-p period] [-d duty[%%]]\n");
69 exit(1);
70 }
71
72 int
main(int argc,char * argv[])73 main(int argc, char *argv[])
74 {
75 struct pwm_state state;
76 int fd;
77 u_int period, duty;
78 int action, ch;
79 cap_rights_t right_ioctl;
80 const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
81 char *percent;
82 bool setname;
83
84 action = 0;
85 setname = false;
86 fd = -1;
87 period = duty = -1;
88
89 while ((ch = getopt(argc, argv, "f:EDCIp:d:")) != -1) {
90 switch (ch) {
91 case 'E':
92 if (action & (PWM_DISABLE | PWM_SHOW_CONFIG))
93 usage();
94 action |= PWM_ENABLE;
95 break;
96 case 'D':
97 if (action & (PWM_ENABLE | PWM_SHOW_CONFIG))
98 usage();
99 action |= PWM_DISABLE;
100 break;
101 case 'C':
102 if (action)
103 usage();
104 action = PWM_SHOW_CONFIG;
105 break;
106 case 'I':
107 if (action & PWM_SHOW_CONFIG)
108 usage();
109 action |= PWM_INVERTED;
110 break;
111 case 'p':
112 if (action & PWM_SHOW_CONFIG)
113 usage();
114 action |= PWM_PERIOD;
115 period = strtoul(optarg, NULL, 10);
116 break;
117 case 'd':
118 if (action & PWM_SHOW_CONFIG)
119 usage();
120 action |= PWM_DUTY;
121 duty = strtoul(optarg, &percent, 10);
122 if (*percent == '%') {
123 if (duty > 100) {
124 fprintf(stderr,
125 "Invalid duty percentage\n");
126 usage();
127 }
128 } else if (*percent != '\0')
129 usage();
130 break;
131 case 'f':
132 setname = true;
133 set_device_name(optarg);
134 break;
135 case '?':
136 usage();
137 break;
138 }
139 }
140
141 if (action == 0)
142 usage();
143
144 if ((fd = open(device_name, O_RDWR)) == -1) {
145 fprintf(stderr, "pwm: cannot open %s: %s\n",
146 device_name, strerror(errno));
147 if (setname)
148 exit(1);
149 else
150 usage();
151 }
152
153 if (caph_limit_stdio() < 0) {
154 fprintf(stderr, "can't limit stdio rights");
155 goto fail;
156 }
157 caph_cache_catpages();
158 cap_rights_init(&right_ioctl, CAP_IOCTL);
159 if (caph_rights_limit(fd, &right_ioctl) < 0) {
160 fprintf(stderr, "cap_right_limit() failed\n");
161 goto fail;
162 }
163 if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
164 fprintf(stderr, "caph_ioctls_limit() failed\n");
165 goto fail;
166 }
167 if (caph_enter() < 0) {
168 fprintf(stderr, "failed to enter capability mode\n");
169 goto fail;
170 }
171
172 /* Fill the common args */
173 if (ioctl(fd, PWMGETSTATE, &state) == -1) {
174 fprintf(stderr, "Cannot get current state of the pwm controller\n");
175 goto fail;
176 }
177
178 if (action == PWM_SHOW_CONFIG) {
179 printf("period: %u\nduty: %u\nenabled:%d\ninverted:%d\n",
180 state.period,
181 state.duty,
182 state.enable,
183 state.flags & PWM_POLARITY_INVERTED);
184 } else {
185 if (action & PWM_ENABLE)
186 state.enable = true;
187 if (action & PWM_DISABLE)
188 state.enable = false;
189 if (action & PWM_PERIOD)
190 state.period = period;
191 if (action & PWM_INVERTED)
192 state.flags |= PWM_POLARITY_INVERTED;
193 else
194 state.flags &= ~PWM_POLARITY_INVERTED;
195 if (action & PWM_DUTY) {
196 if (*percent != '\0')
197 state.duty = (uint64_t)state.period * duty / 100;
198 else
199 state.duty = duty;
200 }
201
202 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
203 fprintf(stderr,
204 "Cannot configure the pwm controller\n");
205 goto fail;
206 }
207 }
208
209 close(fd);
210 return (0);
211
212 fail:
213 close(fd);
214 return (1);
215 }
216