1.\" 2.\" Copyright (c) 2018 Oleksandr Tymoshenko <gonzo@FreeBSD.org> 3.\" 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.Dd April 9, 2018 27.Dt OF_FINDDEVICE 9 28.Os 29.Sh NAME 30.Nm OF_finddevice 31.Nd find node in device tree 32.Sh SYNOPSIS 33.In dev/ofw/ofw_bus.h 34.In dev/ofw/ofw_bus_subr.h 35.Ft phandle_t 36.Fn OF_finddevice "const char *path" 37.Sh DESCRIPTION 38.Fn OF_finddevice 39returns the phandle for the node specified by the 40.Fa path . 41Returns -1 if the path cannot be found in the tree. 42.Sh EXAMPLES 43.Bd -literal 44 phandle_t root, i2c; 45 46 root = OF_finddevice("/"); 47 i2c = OF_finddevice("/soc/axi/i2c@a0e0000"); 48 if (i2c != -1) { 49 ... 50 } 51.Ed 52.Sh SEE ALSO 53.Xr OF_child 9 , 54.Xr OF_parent 9 , 55.Xr OF_peer 9 56.Sh AUTHORS 57.An -nosplit 58This manual page was written by 59.An Oleksandr Tymoshenko Aq Mt gonzo@FreeBSD.org . 60.Sh CAVEATS 61The return value should only be checked with equality 62operators (equal to, not equal to) and not relational comparison 63(less than, greater than ). 64There is a discrepancy between IEEE 1275 standard and 65.Fx Ns 's 66internal representation of a phandle: IEEE 1275 67requires the return value of this function to be -1 if the path 68is not found. 69But phandle_t is an unsigned type, so it cannot 70be relationally compared with -1 or 0, this comparison 71is always true or always false. 72