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      1 /* $NetBSD: fdt_i2c.c,v 1.15 2025/09/16 11:55:17 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015 Jared D. McNeill <jmcneill (at) invisible.ca>
      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 ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * 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 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: fdt_i2c.c,v 1.15 2025/09/16 11:55:17 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/kmem.h>
     35 #include <sys/queue.h>
     36 
     37 #include <libfdt.h>
     38 #include <dev/fdt/fdtvar.h>
     39 
     40 struct fdtbus_i2c_controller {
     41 	i2c_tag_t i2c_tag;
     42 	int i2c_phandle;
     43 
     44 	LIST_ENTRY(fdtbus_i2c_controller) i2c_next;
     45 };
     46 
     47 static LIST_HEAD(, fdtbus_i2c_controller) fdtbus_i2c_controllers =
     48     LIST_HEAD_INITIALIZER(fdtbus_i2c_controllers);
     49 
     50 void
     51 fdtbus_register_i2c_controller(device_t dev, i2c_tag_t tag)
     52 {
     53 	int phandle = devhandle_to_of(device_handle(dev));
     54 	struct fdtbus_i2c_controller *i2c;
     55 
     56 	i2c = kmem_alloc(sizeof(*i2c), KM_SLEEP);
     57 	i2c->i2c_tag = tag;
     58 	i2c->i2c_phandle = phandle;
     59 
     60 	LIST_INSERT_HEAD(&fdtbus_i2c_controllers, i2c, i2c_next);
     61 }
     62 
     63 static struct fdtbus_i2c_controller *
     64 fdtbus_get_i2c_controller(int phandle)
     65 {
     66 	struct fdtbus_i2c_controller *i2c;
     67 
     68 	LIST_FOREACH(i2c, &fdtbus_i2c_controllers, i2c_next) {
     69 		if (i2c->i2c_phandle == phandle)
     70 			return i2c;
     71 	}
     72 
     73 	return NULL;
     74 }
     75 
     76 i2c_tag_t
     77 fdtbus_i2c_get_tag(int phandle)
     78 {
     79 	struct fdtbus_i2c_controller *i2c;
     80 
     81 	i2c = fdtbus_get_i2c_controller(phandle);
     82 	if (i2c == NULL)
     83 		return NULL;
     84 
     85 	return i2c->i2c_tag;
     86 }
     87 
     88 i2c_tag_t
     89 fdtbus_i2c_acquire(int phandle, const char *prop)
     90 {
     91 	int i2c_phandle;
     92 
     93 	i2c_phandle = fdtbus_get_phandle(phandle, prop);
     94 	if (i2c_phandle == -1)
     95 		return NULL;
     96 
     97 	return fdtbus_i2c_get_tag(i2c_phandle);
     98 }
     99 
    100 prop_array_t
    101 fdtbus_copy_i2c_devs(device_t dev)
    102 {
    103 	int phandle = devhandle_to_of(device_handle(dev));
    104 	u_int address_cells;
    105 
    106 	if (of_getprop_uint32(phandle, "#address-cells", &address_cells)) {
    107 		address_cells = 1;
    108 	}
    109 
    110 	return of_copy_i2c_devs(phandle, address_cells * 4, 0);
    111 }
    112