/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdbool.h>
#include <sys/capsicum.h>
#include <dev/pwm/pwmc.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <capsicum_helpers.h>

#define PWM_ENABLE      0x0001
#define PWM_DISABLE     0x0002
#define PWM_SHOW_CONFIG 0x0004
#define PWM_PERIOD      0x0008
#define PWM_DUTY        0x0010
#define PWM_INVERTED    0x0020

static char device_name[PATH_MAX] = "/dev/pwm/pwmc0.0";

static void
set_device_name(const char *name)
{

        if (name[0] == '/')
                strlcpy(device_name, name, sizeof(device_name));
        else
                snprintf(device_name, sizeof(device_name), "/dev/pwm/%s", name);
}

static void
usage(void)
{
        fprintf(stderr, "Usage:\n");
        fprintf(stderr, "\tpwm [-f dev] -C\n");
        fprintf(stderr, "\tpwm [-f dev] [-D | -E] [-I] [-p period] [-d duty[%%]]\n");
        exit(1);
}

int
main(int argc, char *argv[])
{
        struct pwm_state state;
        int fd;
        u_int period, duty;
        int action, ch;
        cap_rights_t right_ioctl;
        const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
        char *percent;
        bool setname;

        action = 0;
        setname = false;
        fd = -1;
        period = duty = -1;

        while ((ch = getopt(argc, argv, "f:EDCIp:d:")) != -1) {
                switch (ch) {
                case 'E':
                        if (action & (PWM_DISABLE | PWM_SHOW_CONFIG))
                                usage();
                        action |= PWM_ENABLE;
                        break;
                case 'D':
                        if (action & (PWM_ENABLE | PWM_SHOW_CONFIG))
                                usage();
                        action |= PWM_DISABLE;
                        break;
                case 'C':
                        if (action)
                                usage();
                        action = PWM_SHOW_CONFIG;
                        break;
                case 'I':
                        if (action & PWM_SHOW_CONFIG)
                                usage();
                        action |= PWM_INVERTED;
                        break;
                case 'p':
                        if (action & PWM_SHOW_CONFIG)
                                usage();
                        action |= PWM_PERIOD;
                        period = strtoul(optarg, NULL, 10);
                        break;
                case 'd':
                        if (action & PWM_SHOW_CONFIG)
                                usage();
                        action |= PWM_DUTY;
                        duty = strtoul(optarg, &percent, 10);
                        if (*percent == '%') {
                                if (duty > 100) {
                                        fprintf(stderr,
                                            "Invalid duty percentage\n");
                                        usage();
                                }
                        } else if (*percent != '\0')
                                usage();
                        break;
                case 'f':
                        setname = true;
                        set_device_name(optarg);
                        break;
                case '?':
                        usage();
                        break;
                }
        }

        if (action == 0)
                usage();

        if ((fd = open(device_name, O_RDWR)) == -1) {
                fprintf(stderr, "pwm: cannot open %s: %s\n",
                    device_name, strerror(errno));
                if (setname)
                        exit(1);
                else
                        usage();
        }

        if (caph_limit_stdio() < 0) {
                fprintf(stderr, "can't limit stdio rights");
                goto fail;
        }
        caph_cache_catpages();
        cap_rights_init(&right_ioctl, CAP_IOCTL);
        if (caph_rights_limit(fd, &right_ioctl) < 0) {
                fprintf(stderr, "cap_right_limit() failed\n");
                goto fail;
        }
        if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
                fprintf(stderr, "caph_ioctls_limit() failed\n");
                goto fail;
        }
        if (caph_enter() < 0) {
                fprintf(stderr, "failed to enter capability mode\n");
                goto fail;
        }

        /* Fill the common args */
        if (ioctl(fd, PWMGETSTATE, &state) == -1) {
                fprintf(stderr, "Cannot get current state of the pwm controller\n");
                goto fail;
        }

        if (action == PWM_SHOW_CONFIG) {
                printf("period: %u\nduty: %u\nenabled:%d\ninverted:%d\n",
                    state.period,
                    state.duty,
                    state.enable,
                    state.flags & PWM_POLARITY_INVERTED);
        } else {
                if (action & PWM_ENABLE)
                        state.enable = true;
                if (action & PWM_DISABLE)
                        state.enable = false;
                if (action & PWM_PERIOD)
                        state.period = period;
                if (action & PWM_INVERTED)
                        state.flags |= PWM_POLARITY_INVERTED;
                else
                        state.flags &= ~PWM_POLARITY_INVERTED;
                if (action & PWM_DUTY) {
                        if (*percent != '\0')
                                state.duty = (uint64_t)state.period * duty / 100;
                        else
                                state.duty = duty;
                }

                if (ioctl(fd, PWMSETSTATE, &state) == -1) {
                        fprintf(stderr,
                          "Cannot configure the pwm controller\n");
                        goto fail;
                }
        }

        close(fd);
        return (0);

fail:
        close(fd);
        return (1);
}