/* $NetBSD: led.c,v 1.3 2018/01/10 15:58:40 jakllsch Exp $ */

/*-
 * Copyright (c) 2017 Jared McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * 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 ``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 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: led.c,v 1.3 2018/01/10 15:58:40 jakllsch Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <sys/once.h>

#include <dev/led.h>

struct led_device {
        char                    *name;
        led_getstate_fn         getstate;
        led_setstate_fn         setstate;
        void                    *priv;

        struct sysctllog        *slog;

        TAILQ_ENTRY(led_device) devices;
};

static TAILQ_HEAD(, led_device) led_devices =
    TAILQ_HEAD_INITIALIZER(led_devices);
static kmutex_t led_lock;

static int
led_init(void)
{
        mutex_init(&led_lock, MUTEX_DEFAULT, IPL_NONE);

        return 0;
}

static struct led_device *
led_lookup(const char *name)
{
        struct led_device *led;

        KASSERT(mutex_owned(&led_lock));

        TAILQ_FOREACH(led, &led_devices, devices)
                if (strcmp(led->name, name) == 0)
                        return led;

        return NULL;
}

static void
led_normalize_name(char *name)
{
        unsigned char *p;

        for (p = (unsigned char *)name; *p; p++)
                if (!isalpha(*p) && !isdigit(*p) && *p != '-' && *p != '_')
                        *p = '_';
}

static void
led_free(struct led_device *led)
{
        KASSERT(mutex_owned(&led_lock));

        kmem_free(led->name, strlen(led->name) + 1);
        kmem_free(led, sizeof(*led));
}

static int
led_sysctl_handler(SYSCTLFN_ARGS)
{
        struct sysctlnode node;
        struct led_device *led;
        int error;
        bool state;

        mutex_enter(&led_lock);

        node = *rnode;
        led = node.sysctl_data;
        state = led->getstate(led->priv);
        node.sysctl_data = &state;
        error = sysctl_lookup(SYSCTLFN_CALL(&node));
        if (error || newp == NULL) {
                mutex_exit(&led_lock);
                return error;
        }

        led->setstate(led->priv, state);

        mutex_exit(&led_lock);

        return 0;
}

void *
led_attach(const char *name, void *priv, led_getstate_fn getstate,
    led_setstate_fn setstate)
{
        static ONCE_DECL(control);
        struct led_device *led;
        const struct sysctlnode *node;
        int error;

        if (RUN_ONCE(&control, led_init) != 0)
                return NULL;

        led = kmem_zalloc(sizeof(*led), KM_SLEEP);
        led->name = kmem_asprintf("%s", name);
        led->getstate = getstate;
        led->setstate = setstate;
        led->priv = priv;

        /* Convert invalid sysctl node name characters to underscores */
        led_normalize_name(led->name);

        mutex_enter(&led_lock);
        if (led_lookup(name) != NULL) {
                led_free(led);
                led = NULL;
        } else {
                error = sysctl_createv(&led->slog, 0, NULL, &node,
                    CTLFLAG_PERMANENT, CTLTYPE_NODE, "led", NULL,
                    NULL, 0, NULL, 0,
                    CTL_HW, CTL_CREATE, CTL_EOL);
                if (error == 0) {
                        error = sysctl_createv(&led->slog, 0, &node, NULL,
                            CTLFLAG_READWRITE, CTLTYPE_BOOL, led->name, NULL,
                            led_sysctl_handler, 0,
                            (void *)led, 0,
                            CTL_CREATE, CTL_EOL);
                }
                if (error != 0) {
                        printf("led: failed to create sysctl hw.led.%s: %d\n",
                            led->name, error);
                        led_free(led);
                        led = NULL;
                }
        }
        if (led != NULL)
                TAILQ_INSERT_TAIL(&led_devices, led, devices);
        mutex_exit(&led_lock);

        return led;
}

void
led_detach(void *handle)
{
        struct led_device *led = handle;

        mutex_enter(&led_lock);

        TAILQ_REMOVE(&led_devices, led, devices);
        sysctl_teardown(&led->slog);
        led_free(led);

        mutex_exit(&led_lock);
}