/* $NetBSD: fdt_pwm.c,v 1.2 2018/06/30 20:34:43 jmcneill Exp $ */

/*-
* Copyright (c) 2018 Jared McNeill <[email protected]>
* 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_pwm.c,v 1.2 2018/06/30 20:34:43 jmcneill 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_pwm_controller {
       device_t pc_dev;
       int pc_phandle;
       const struct fdtbus_pwm_controller_func *pc_funcs;

       LIST_ENTRY(fdtbus_pwm_controller) pc_next;
};

static LIST_HEAD(, fdtbus_pwm_controller) fdtbus_pwm_controllers =
   LIST_HEAD_INITIALIZER(fdtbus_pwm_controllers);

int
fdtbus_register_pwm_controller(device_t dev, int phandle,
   const struct fdtbus_pwm_controller_func *funcs)
{
       struct fdtbus_pwm_controller *pc;

       pc = kmem_alloc(sizeof(*pc), KM_SLEEP);
       pc->pc_dev = dev;
       pc->pc_phandle = phandle;
       pc->pc_funcs = funcs;

       LIST_INSERT_HEAD(&fdtbus_pwm_controllers, pc, pc_next);

       return 0;
}

static struct fdtbus_pwm_controller *
fdtbus_get_pwm_controller(int phandle)
{
       struct fdtbus_pwm_controller *pc;

       LIST_FOREACH(pc, &fdtbus_pwm_controllers, pc_next) {
               if (pc->pc_phandle == phandle)
                       return pc;
       }

       return NULL;
}

pwm_tag_t
fdtbus_pwm_acquire(int phandle, const char *prop)
{
       return fdtbus_pwm_acquire_index(phandle, prop, 0);
}

pwm_tag_t
fdtbus_pwm_acquire_index(int phandle, const char *prop, int index)
{
       struct fdtbus_pwm_controller *pc;
       const uint32_t *pwms, *p;
       u_int n, pwm_cells;
       int len, resid;

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

       p = pwms;
       for (n = 0, resid = len; resid > 0; n++) {
               const int pc_phandle =
                   fdtbus_get_phandle_from_native(be32toh(p[0]));
               if (of_getprop_uint32(pc_phandle, "#pwm-cells", &pwm_cells))
                       break;
               if (n == index) {
                       pc = fdtbus_get_pwm_controller(pc_phandle);
                       if (pc == NULL)
                               return NULL;
                       return pc->pc_funcs->get_tag(pc->pc_dev,
                           &p[0], (pwm_cells + 1) * 4);
               }
               resid -= (pwm_cells + 1) * 4;
               p += pwm_cells + 1;
       }

       return NULL;
}