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head/share/man/man9/OF_finddevice.9
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| .\" | |||||
| .\" Copyright (c) 2018 Oleksandr Tymoshenko <gonzo@FreeBSD.org> | |||||
| .\" | |||||
| .\" 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 DEVELOPERS ``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 DEVELOPERS 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 | |||||
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| .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |||||
| .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |||||
| .\" | |||||
| .\" $FreeBSD$ | |||||
| .\" | |||||
| .Dd April 9, 2018 | |||||
| .Dt OF_FINDDEVICE 9 | |||||
| .Os | |||||
| .Sh NAME | |||||
| .Nm OF_finddevice | |||||
| .Nd find node in device tree | |||||
| .Sh SYNOPSIS | |||||
| .In dev/ofw/ofw_bus.h | |||||
| .In dev/ofw/ofw_bus_subr.h | |||||
| .Ft phandle_t | |||||
| .Fn OF_finddevice "const char *path" | |||||
| .Sh DESCRIPTION | |||||
| .Pp | |||||
| .Fn OF_finddevice | |||||
| returns the phandle for the node specified by the | |||||
| .Fa path . | |||||
| Returns -1 if the path cannot be found in the tree. | |||||
| .Sh CAVEATS | |||||
| The return value should only be checked with equality | |||||
| operators (equal to, not equal to) and not relational comparison | |||||
| (less than, greater than ). | |||||
| There is a discrepancy between IEEE 1275 standard and | |||||
| .Fx Ns 's | |||||
| internal representation of a phandle: IEEE 1275 | |||||
| requires the return value of this function to be -1 if the path | |||||
| is not found. | |||||
| But phandle_t is an unsigned type, so it cannot | |||||
| be relationally compared with -1 or 0, this comparison | |||||
| is always true or always false. | |||||
| .Sh EXAMPLES | |||||
| .Bd -literal | |||||
| phandle_t root, i2c; | |||||
| root = OF_finddevice("/"); | |||||
| i2c = OF_finddevice("/soc/axi/i2c@a0e0000"); | |||||
| if (i2c != -1) { | |||||
| ... | |||||
| } | |||||
| .Ed | |||||
| .Sh SEE ALSO | |||||
| .Xr OF_child 9 | |||||
| .Xr OF_parent 9 | |||||
| .Xr OF_peer 9 | |||||
| .Sh AUTHORS | |||||
| .An -nosplit | |||||
| This manual page was written by | |||||
| .An Oleksandr Tymoshenko Aq Mt gonzo@FreeBSD.org . | |||||