1 .. SPDX-License-Identifier: GPL-2.0-only
2
3 =============
4 AD7944 driver
5 =============
6
7 ADC driver for Analog Devices Inc. AD7944 and
8 is ``ad7944``.
9
10
11 Supported devices
12 =================
13
14 The following chips are supported by this driv
15
16 * `AD7944 <https://www.analog.com/AD7944>`_
17 * `AD7985 <https://www.analog.com/AD7985>`_
18 * `AD7986 <https://www.analog.com/AD7986>`_
19
20
21 Supported features
22 ==================
23
24 SPI wiring modes
25 ----------------
26
27 The driver currently supports three of the man
28
29 CS mode, 3-wire, without busy indicator
30 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
31
32 .. code-block::
33
34 +----
35 +--------------------| CS
36 v |
37 VIO +--------------------+ |
38 | | CNV | |
39 +--->| SDI AD7944 SDO |-------->| SDI
40 | SCK | |
41 +--------------------+ |
42 ^ |
43 +--------------------| SCL
44 +----
45
46 To select this mode in the device tree, set th
47 ``"single"`` and omit the ``cnv-gpios`` proper
48
49 CS mode, 4-wire, without busy indicator
50 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
51
52 .. code-block::
53
54 +----
55 +-----------------------------------| CS
56 | |
57 | +--------------------| GPI
58 | v |
59 | +--------------------+ |
60 | | CNV | |
61 +--->| SDI AD7944 SDO |-------->| SDI
62 | SCK | |
63 +--------------------+ |
64 ^ |
65 +--------------------| SCL
66 +----
67
68 To select this mode in the device tree, omit t
69 provide the ``cnv-gpios`` property.
70
71 Chain mode, without busy indicator
72 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
73
74 .. code-block::
75
76
77 +-------------------------+-
78 v v
79 +--------------------+ +-----------
80 | CNV | | CNV
81 +--->| SDI AD7944 SDO |--->| SDI AD79
82 | | SCK | | SCK
83 GND +--------------------+ +-----------
84 ^ ^
85 +-------------------------+-
86
87
88 To select this mode in the device tree, set th
89 ``"chain"``, add the ``spi-cs-high`` flag, add
90 property, and omit the ``cnv-gpios`` property.
91
92 Reference voltage
93 -----------------
94
95 All 3 possible reference voltage sources are s
96
97 - Internal reference
98 - External 1.2V reference and internal buffer
99 - External reference
100
101 The source is determined by the device tree. I
102 the external reference is used. If ``refin-sup
103 buffer is used. If neither is present, then th
104
105 Unimplemented features
106 ----------------------
107
108 - ``BUSY`` indication
109 - ``TURBO`` mode
110
111
112 Device attributes
113 =================
114
115 There are two types of ADCs in this family, ps
116 differential. The channel name is different de
117
118 Pseudo-differential ADCs
119 ------------------------
120
121 AD7944 and AD7985 are pseudo-differential ADCs
122
123 +---------------------------------------+-----
124 | Attribute | Desc
125 +=======================================+=====
126 | ``in_voltage0_raw`` | Raw
127 +---------------------------------------+-----
128 | ``in_voltage0_scale`` | Scal
129 +---------------------------------------+-----
130
131 In "chain" mode, additional chips will appear
132 channels, e.g. ``in_voltage1_raw``.
133
134 Fully-differential ADCs
135 -----------------------
136
137 AD7986 is a fully-differential ADC and has the
138
139 +---------------------------------------+-----
140 | Attribute | Desc
141 +=======================================+=====
142 | ``in_voltage0-voltage1_raw`` | Raw
143 +---------------------------------------+-----
144 | ``in_voltage0-voltage1_scale`` | Scal
145 +---------------------------------------+-----
146
147 In "chain" mode, additional chips will appear
148 channels, e.g. ``in_voltage2-voltage3_raw``.
149
150
151 Device buffers
152 ==============
153
154 This driver supports IIO triggered buffers.
155
156 See :doc:`iio_devbuf` for more information.
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