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      1 /* $NetBSD: fdt_rtc.c,v 1.3 2025/09/08 13:06:16 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2017 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_rtc.c,v 1.3 2025/09/08 13:06:16 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/device_calls.h>
     35 
     36 #include <libfdt.h>
     37 #include <dev/fdt/fdtvar.h>
     38 #include <dev/ofw/openfirm.h>
     39 
     40 static int
     41 fdtbus_device_is_system_todr(device_t dev, devhandle_t call_handle, void *v)
     42 {
     43 	struct device_is_system_todr_args *args = v;
     44 	int phandle = devhandle_to_of(call_handle);
     45 	const char *prop;
     46 
     47 	/*
     48 	 * The kernel will only use the first device to register with
     49 	 * todr_attach. If we have an "rtc0" alias, ensure that it matches
     50 	 * this phandle and ignore all other RTC devices.
     51 	 */
     52 	prop = fdt_get_alias(fdtbus_get_data(), "rtc0");
     53 	if (prop == NULL) {
     54 		/* No "rtc0" alias.  System gets default policy. */
     55 		return ESRCH;
     56 	}
     57 	args->result = OF_finddevice(prop) == phandle;
     58 	return 0;
     59 }
     60 
     61 OF_DEVICE_CALL_REGISTER(DEVICE_IS_SYSTEM_TODR_STR,
     62 			fdtbus_device_is_system_todr)
     63