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
  75         action = 0;
  76         fd = -1;
  77         channel = -1;
  78         period = duty = -1;
  79
  80         while ((ch = getopt(argc, argv, "f:c:EDCp:d:")) != -1) {
  81                 switch (ch) {
  82                 case 'E':
  83                         if (action)
  84                                 usage();
  85                         action = PWM_ENABLE;
  86                         break;
  87                 case 'D':
  88                         if (action)
  89                                 usage();
  90                         action = PWM_DISABLE;
  91                         break;
  92                 case 'C':
  93                         if (action)
  94                                 usage();
  95                         action = PWM_SHOW_CONFIG;
  96                         break;
  97                 case 'p':
  98                         if (action & ~(PWM_PERIOD | PWM_DUTY))
  99                                 usage();
 100                         action = PWM_PERIOD;
 101                         period = strtol(optarg, NULL, 10);
 102                         break;
 103                 case 'd':
 104                         if (action & ~(PWM_PERIOD | PWM_DUTY))
 105                                 usage();
 106                         action = PWM_DUTY;
 107                         duty = strtol(optarg, NULL, 10);
 108                         break;
 109                 case 'c':
 110                         if (channel != -1)
 111                                 usage();
 112                         channel = strtol(optarg, NULL, 10);
 113                         break;
 114                 case 'f':
 115                         if ((fd = open(optarg, O_RDWR)) < 0) {
 116                                 fprintf(stderr, "pwm: cannot open %s %s\n",
 117                                   optarg, strerror(errno));
 118                                 exit(1);
 119                         }
 120                 }
 121         }
 122
 123         if (fd == -1) {
 124                 if ((fd = open("/dev/pwmc0", O_RDWR)) < 0) {
 125                         fprintf(stderr, "pwm: cannot open %s %s\n",
 126                             optarg, strerror(errno));
 127                         exit(1);
 128                 }
 129         }
 130
 131         if (action == 0 || fd == -1)
 132                 usage();
 133
 134         if (caph_limit_stdio() < 0) {
 135                 fprintf(stderr, "can't limit stdio rights");
 136                 goto fail;
 137         }
 138         caph_cache_catpages();
 139         cap_rights_init(&right_ioctl, CAP_IOCTL);
 140         if (caph_rights_limit(fd, &right_ioctl) < 0) {
 141                 fprintf(stderr, "cap_right_limit() failed\n");
 142                 goto fail;
 143         }
 144         if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
 145                 fprintf(stderr, "caph_ioctls_limit() failed\n");
 146                 goto fail;
 147         }
 148         if (caph_enter() < 0) {
 149                 fprintf(stderr, "failed to enter capability mode\n");
 150                 goto fail;
 151         }
 152
 153         /* Check if the channel is correct */
 154         if (ioctl(fd, PWMMAXCHANNEL, &nchannels) == -1) {
 155                 fprintf(stderr, "ioctl: %s\n", strerror(errno));
 156                 goto fail;
 157         }
 158         if (channel > nchannels) {
 159                 fprintf(stderr, "pwm controller only support %d channels\n",
 160                     nchannels);
 161                 goto fail;
 162         }
 163
 164         /* Fill the common args */
 165         state.channel = channel;
 166         if (ioctl(fd, PWMGETSTATE, &state) == -1) {
 167                 fprintf(stderr, "Cannot get current state of the pwm controller\n");
 168                 goto fail;
 169         }
 170
 171         switch (action) {
 172         case PWM_ENABLE:
 173                 if (state.enable == false) {
 174                         state.enable = true;
 175                         if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 176                                 fprintf(stderr,
 177                                     "Cannot enable the pwm controller\n");
 178                                 goto fail;
 179                         }
 180                 }
 181                 break;
 182         case PWM_DISABLE:
 183                 if (state.enable == true) {
 184                         state.enable = false;
 185                         if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 186                                 fprintf(stderr,
 187                                     "Cannot disable the pwm controller\n");
 188                                 goto fail;
 189                         }
 190                 }
 191                 break;
 192         case PWM_SHOW_CONFIG:
 193                 printf("period: %u\nduty: %u\nenabled:%d\n",
 194                     state.period,
 195                     state.duty,
 196                     state.enable);
 197                 break;
 198         case PWM_PERIOD:
 199         case PWM_DUTY:
 200                 if (period != -1)
 201                         state.period = period;
 202                 if (duty != -1)
 203                         state.duty = duty;
 204                 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 205                         fprintf(stderr,
 206                           "Cannot configure the pwm controller\n");
 207                         goto fail;
 208                 }
 209                 break;
 210         }
 211
 212         close(fd);
 213         return (0);
 214
 215 fail:
 216         close(fd);
 217         return (1);
 218 }