usr.sbin/pwm/pwm.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
   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  * $FreeBSD$
  29  */
  30
  31 #include <sys/types.h>
  32 #include <sys/ioctl.h>
  33 #include <stdbool.h>
  34 #include <sys/pwm.h>
  35 #include <sys/capsicum.h>
  36
  37 #include <err.h>
  38 #include <errno.h>
  39 #include <fcntl.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <capsicum_helpers.h>
  45
  46 #define PWM_ENABLE      0x0001
  47 #define PWM_DISABLE     0x0002
  48 #define PWM_SHOW_CONFIG 0x0004
  49 #define PWM_PERIOD      0x0008
  50 #define PWM_DUTY        0x0010
  51
  52 static void
  53 usage(void)
  54 {
  55         fprintf(stderr, "Usage:\n");
  56         fprintf(stderr, "\tpwm [-f dev] -c channel -E\n");
  57         fprintf(stderr, "\tpwm [-f dev] -c channel -D\n");
  58         fprintf(stderr, "\tpwm [-f dev] -c channel -C\n");
  59         fprintf(stderr, "\tpwm [-f dev] -c channel -p period\n");
  60         fprintf(stderr, "\tpwm [-f dev] -c channel -d duty\n");
  61         exit(1);
  62 }
  63
  64 int
  65 main(int argc, char *argv[])
  66 {
  67         struct pwm_state state;
  68         int fd;
  69         int channel, nchannels;
  70         int period, duty;
  71         int action, ch;
  72         cap_rights_t right_ioctl;
  73         const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE, PWMMAXCHANNEL};
  74         char *percent;
  75
  76         action = 0;
  77         fd = -1;
  78         channel = -1;
  79         period = duty = -1;
  80
  81         while ((ch = getopt(argc, argv, "f:c:EDCp:d:")) != -1) {
  82                 switch (ch) {
  83                 case 'E':
  84                         if (action)
  85                                 usage();
  86                         action = PWM_ENABLE;
  87                         break;
  88                 case 'D':
  89                         if (action)
  90                                 usage();
  91                         action = PWM_DISABLE;
  92                         break;
  93                 case 'C':
  94                         if (action)
  95                                 usage();
  96                         action = PWM_SHOW_CONFIG;
  97                         break;
  98                 case 'p':
  99                         if (action & ~(PWM_PERIOD | PWM_DUTY))
 100                                 usage();
 101                         action = PWM_PERIOD;
 102                         period = strtol(optarg, NULL, 10);
 103                         break;
 104                 case 'd':
 105                         if (action & ~(PWM_PERIOD | PWM_DUTY))
 106                                 usage();
 107                         action = PWM_DUTY;
 108                         duty = strtol(optarg, &percent, 10);
 109                         if (*percent != '\0' && *percent != '%')
 110                                 usage();
 111                         break;
 112                 case 'c':
 113                         if (channel != -1)
 114                                 usage();
 115                         channel = strtol(optarg, NULL, 10);
 116                         break;
 117                 case 'f':
 118                         if ((fd = open(optarg, O_RDWR)) < 0) {
 119                                 fprintf(stderr, "pwm: cannot open %s %s\n",
 120                                   optarg, strerror(errno));
 121                                 exit(1);
 122                         }
 123                 }
 124         }
 125
 126         if (fd == -1) {
 127                 if ((fd = open("/dev/pwmc0", O_RDWR)) < 0) {
 128                         fprintf(stderr, "pwm: cannot open %s %s\n",
 129                             optarg, strerror(errno));
 130                         exit(1);
 131                 }
 132         }
 133
 134         if (action == 0 || fd == -1)
 135                 usage();
 136
 137         if (caph_limit_stdio() < 0) {
 138                 fprintf(stderr, "can't limit stdio rights");
 139                 goto fail;
 140         }
 141         caph_cache_catpages();
 142         cap_rights_init(&right_ioctl, CAP_IOCTL);
 143         if (caph_rights_limit(fd, &right_ioctl) < 0) {
 144                 fprintf(stderr, "cap_right_limit() failed\n");
 145                 goto fail;
 146         }
 147         if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
 148                 fprintf(stderr, "caph_ioctls_limit() failed\n");
 149                 goto fail;
 150         }
 151         if (caph_enter() < 0) {
 152                 fprintf(stderr, "failed to enter capability mode\n");
 153                 goto fail;
 154         }
 155
 156         /* Check if the channel is correct */
 157         if (ioctl(fd, PWMMAXCHANNEL, &nchannels) == -1) {
 158                 fprintf(stderr, "ioctl: %s\n", strerror(errno));
 159                 goto fail;
 160         }
 161         if (channel > nchannels) {
 162                 fprintf(stderr, "pwm controller only support %d channels\n",
 163                     nchannels);
 164                 goto fail;
 165         }
 166
 167         /* Fill the common args */
 168         state.channel = channel;
 169         if (ioctl(fd, PWMGETSTATE, &state) == -1) {
 170                 fprintf(stderr, "Cannot get current state of the pwm controller\n");
 171                 goto fail;
 172         }
 173
 174         switch (action) {
 175         case PWM_ENABLE:
 176                 if (state.enable == false) {
 177                         state.enable = true;
 178                         if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 179                                 fprintf(stderr,
 180                                     "Cannot enable the pwm controller\n");
 181                                 goto fail;
 182                         }
 183                 }
 184                 break;
 185         case PWM_DISABLE:
 186                 if (state.enable == true) {
 187                         state.enable = false;
 188                         if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 189                                 fprintf(stderr,
 190                                     "Cannot disable the pwm controller\n");
 191                                 goto fail;
 192                         }
 193                 }
 194                 break;
 195         case PWM_SHOW_CONFIG:
 196                 printf("period: %u\nduty: %u\nenabled:%d\n",
 197                     state.period,
 198                     state.duty,
 199                     state.enable);
 200                 break;
 201         case PWM_PERIOD:
 202         case PWM_DUTY:
 203                 if (period != -1)
 204                         state.period = period;
 205                 if (duty != -1) {
 206                         if (*percent != '\0')
 207                                 state.duty = state.period * duty / 100;
 208                         else
 209                                 state.duty = duty;
 210                 }
 211                 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 212                         fprintf(stderr,
 213                           "Cannot configure the pwm controller\n");
 214                         goto fail;
 215                 }
 216                 break;
 217         }
 218
 219         close(fd);
 220         return (0);
 221
 222 fail:
 223         close(fd);
 224         return (1);
 225 }