xref: /freebsd/share/man/man9/device_get_property.9 (revision ebacd8013fe5f7fdf9f6a5b286f6680dd2891036)
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26.\" $FreeBSD$
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28.Dd September 29, 2022
29.Dt DEVICE_GET_PROPERTY 9
30.Os
31.Sh NAME
32.Nm device_get_property ,
33.Nm device_has_property
34.Nd access device specific data
35.Sh SYNOPSIS
36.In sys/param.h
37.In sys/bus.h
38.Ft ssize_t
39.Fn device_get_property "device_t dev" "const char *prop" "void *val" "size_t sz" \
40    "device_property_type_t type"
41.Ft bool
42.Fn device_has_property "device_t dev" "const char *prop"
43.Sh DESCRIPTION
44Access device specific data provided by the parent bus.
45Drivers can use these properties to obtain device capabilities and set
46necessary quirks.
47.Pp
48The underlying property type is specified with the
49.Fa type
50argument.
51Currently the following types are supported:
52.Bl -tag -width ".Dv DEVICE_PROP_BUFFER"
53.It Dv DEVICE_PROP_BUFFER
54The underlying property is a string of bytes.
55.It Dv DEVICE_PROP_ANY
56Wildcard property type.
57.It Dv DEVICE_PROP_HANDLE
58Following a reference the underlying property is a handle of the
59respective bus.
60.It Dv DEVICE_PROP_UINT32
61The underlying property is an array of unsigned 32 bit integers.
62The
63.Fa sz
64argument shall be a multiple of 4.
65.It Dv DEVICE_PROP_UINT64
66The underlying property is an array of unsigned 64 bit integers.
67The
68.Fa sz
69argument shall be a multiple of 8.
70.El
71.Sh NOTES
72You can pass NULL as pointer to property's value when calling
73.Fn device_get_property
74to obtain its size.
75.Pp
76Currently this interface is implemented by
77.Xr simplebus 4
78and
79.Xr acpi 4 .
80.Sh RETURN VALUES
81.Fn device_get_property
82if successful returns property's size, otherwise returns -1.
83.Pp
84.Fn device_has_property
85returns true if given property was found.
86.Sh SEE ALSO
87.Xr acpi 4 ,
88.Xr simplebus 4 ,
89.Xr device 9
90.Sh AUTHORS
91This manual page was written by
92.An Bartlomiej Grzesik .
93