BUS_GET_PROPERTY.9

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.Dd February 18, 2022
.Dt BUS_GET_PROPERTY 9
.Os
.Sh NAME
.Nm BUS_GET_PROPERTY
.Nd get child's specific property
.Sh SYNOPSIS
.In sys/param.h
.In sys/bus.h
.Ft ssize_t
.Fn BUS_GET_PROPERTY "device_t dev" "device_t child" "const char *propname" \
    "void *propvalue" "size_t size" "device_property_type_t type"
.Sh DESCRIPTION
The
.Fn BUS_GET_PROPERTY
method
is called from driver code which wants to access a child's specific data stored
on the bus.
A property has a name and an associated value.
Implementation shall copy to
.Fa propvalue
at most
.Fa size
bytes.
.Pp
.Fn BUS_GET_PROPERTY
supports different property types specified via the
.Fa type
argument.
The
.Fa size
is guaranteed to be a multiple of the underlying property type.
If a type is not supported,
.Fn BUS_GET_PROPERTY
shall return -1.
.Sh NOTES
If
.Fa propvalue
is NULL or
.Fa size
is zero, the implementation shall return only the size of the property.
.Sh RETURN VALUES
The property size if successful, otherwise -1.
.Sh SEE ALSO
.Xr device 9 ,
.Xr device_get_property 9
.Sh AUTHORS
This manual page was written by
.An Bartlomiej Grzesik .