/* $NetBSD: fdt_gpio.c,v 1.7 2020/12/23 04:07:34 thorpej Exp $ */

/*-
 * Copyright (c) 2015 Jared D. 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: fdt_gpio.c,v 1.7 2020/12/23 04:07:34 thorpej Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kmem.h>
#include <sys/queue.h>

#include <libfdt.h>
#include <dev/fdt/fdtvar.h>

struct fdtbus_gpio_controller {
        device_t gc_dev;
        int gc_phandle;
        const struct fdtbus_gpio_controller_func *gc_funcs;

        LIST_ENTRY(fdtbus_gpio_controller) gc_next;
};

static LIST_HEAD(, fdtbus_gpio_controller) fdtbus_gpio_controllers =
    LIST_HEAD_INITIALIZER(fdtbus_gpio_controllers);

int
fdtbus_register_gpio_controller(device_t dev, int phandle,
    const struct fdtbus_gpio_controller_func *funcs)
{
        struct fdtbus_gpio_controller *gc;

        gc = kmem_alloc(sizeof(*gc), KM_SLEEP);
        gc->gc_dev = dev;
        gc->gc_phandle = phandle;
        gc->gc_funcs = funcs;

        LIST_INSERT_HEAD(&fdtbus_gpio_controllers, gc, gc_next);

        return 0;
}

static struct fdtbus_gpio_controller *
fdtbus_get_gpio_controller(int phandle)
{
        struct fdtbus_gpio_controller *gc;

        LIST_FOREACH(gc, &fdtbus_gpio_controllers, gc_next) {
                if (gc->gc_phandle == phandle)
                        return gc;
        }

        return NULL;
}

int
fdtbus_gpio_count(int phandle, const char *prop)
{
        const uint32_t *gpios, *p;
        u_int n, gpio_cells;
        int len, resid;

        gpios = fdtbus_get_prop(phandle, prop, &len);
        if (gpios == NULL)
                return 0;

        p = gpios;
        for (n = 0, resid = len; resid > 0; n++) {
                const int gc_phandle =
                    fdtbus_get_phandle_from_native(be32toh(p[0]));
                if (of_getprop_uint32(gc_phandle, "#gpio-cells", &gpio_cells))
                        break;
                resid -= (gpio_cells + 1) * 4;
                p += gpio_cells + 1;
        }

        return n;
}

struct fdtbus_gpio_pin *
fdtbus_gpio_acquire(int phandle, const char *prop, int flags)
{
        return fdtbus_gpio_acquire_index(phandle, prop, 0, flags);
}

struct fdtbus_gpio_pin *
fdtbus_gpio_acquire_index(int phandle, const char *prop,
    int index, int flags)
{
        struct fdtbus_gpio_controller *gc;
        struct fdtbus_gpio_pin *gp = NULL;
        const uint32_t *gpios, *p;
        u_int n, gpio_cells;
        int len, resid;

        gpios = fdtbus_get_prop(phandle, prop, &len);
        if (gpios == NULL)
                return NULL;

        p = gpios;
        for (n = 0, resid = len; resid > 0; n++) {
                const int gc_phandle =
                    fdtbus_get_phandle_from_native(be32toh(p[0]));
                if (of_getprop_uint32(gc_phandle, "#gpio-cells", &gpio_cells))
                        break;
                if (n == index) {
                        gc = fdtbus_get_gpio_controller(gc_phandle);
                        if (gc == NULL)
                                return NULL;
                        gp = kmem_alloc(sizeof(*gp), KM_SLEEP);
                        gp->gp_gc = gc;
                        gp->gp_priv = gc->gc_funcs->acquire(gc->gc_dev,
                            &p[0], (gpio_cells + 1) * 4, flags);
                        if (gp->gp_priv == NULL) {
                                kmem_free(gp, sizeof(*gp));
                                return NULL;
                        }
                        break;
                }
                resid -= (gpio_cells + 1) * 4;
                p += gpio_cells + 1;
        }

        return gp;
}

void
fdtbus_gpio_release(struct fdtbus_gpio_pin *gp)
{
        struct fdtbus_gpio_controller *gc = gp->gp_gc;

        gc->gc_funcs->release(gc->gc_dev, gp->gp_priv);
        kmem_free(gp, sizeof(*gp));
}

int
fdtbus_gpio_read(struct fdtbus_gpio_pin *gp)
{
        struct fdtbus_gpio_controller *gc = gp->gp_gc;

        return gc->gc_funcs->read(gc->gc_dev, gp->gp_priv, false);
}

void
fdtbus_gpio_write(struct fdtbus_gpio_pin *gp, int val)
{
        struct fdtbus_gpio_controller *gc = gp->gp_gc;

        gc->gc_funcs->write(gc->gc_dev, gp->gp_priv, val, false);
}

int
fdtbus_gpio_read_raw(struct fdtbus_gpio_pin *gp)
{
        struct fdtbus_gpio_controller *gc = gp->gp_gc;

        return gc->gc_funcs->read(gc->gc_dev, gp->gp_priv, true);
}

void
fdtbus_gpio_write_raw(struct fdtbus_gpio_pin *gp, int val)
{
        struct fdtbus_gpio_controller *gc = gp->gp_gc;

        gc->gc_funcs->write(gc->gc_dev, gp->gp_priv, val, true);
}