1 .. SPDX-License-Identifier: GPL-2.0-only
2
3 =============
4 AD4695 driver
5 =============
6
7 ADC driver for Analog Devices Inc. AD4695 and
8 is ``ad4695``.
9
10
11 Supported devices
12 =================
13
14 The following chips are supported by this driv
15
16 * `AD4695 <https://www.analog.com/AD4695>`_
17 * `AD4696 <https://www.analog.com/AD4696>`_
18 * `AD4697 <https://www.analog.com/AD4697>`_
19 * `AD4698 <https://www.analog.com/AD4698>`_
20
21
22 Supported features
23 ==================
24
25 SPI wiring modes
26 ----------------
27
28 The driver currently supports the following SP
29
30 4-wire mode
31 ^^^^^^^^^^^
32
33 In this mode, CNV and CS are tied together and
34
35 .. code-block::
36
37 +-------------+ +-------------+
38 | CS |<-+------| CS |
39 | CNV |<-+ | |
40 | ADC | | HOST |
41 | | | |
42 | SDI |<--------| SDO |
43 | SDO |-------->| SDI |
44 | SCLK |<--------| SCLK |
45 +-------------+ +-------------+
46
47 To use this mode, in the device tree, omit the
48 ``spi-rx-bus-width`` properties.
49
50 Channel configuration
51 ---------------------
52
53 Since the chip supports multiple ways to confi
54 described in the device tree based on what is
55
56 There are three typical configurations:
57
58 An ``INx`` pin is used as the positive input w
59 the next ``INx`` pin as the negative input.
60
61 Pairing with REFGND
62 ^^^^^^^^^^^^^^^^^^^
63
64 Each ``INx`` pin can be used as a pseudo-diffe
65 the ``REFGND`` pin. The device tree will look
66
67 .. code-block::
68
69 channel@0 {
70 reg = <0>; /* IN0 */
71 };
72
73 If no other channel properties are needed (e.g
74 node can be omitted entirely.
75
76 This will appear on the IIO bus as the ``volta
77 (*raw × scale*) will be the voltage present o
78 ``REFGND``. (Offset is always 0 when pairing w
79
80 Pairing with COM
81 ^^^^^^^^^^^^^^^^
82
83 Each ``INx`` pin can be used as a pseudo-diffe
84 the ``COM`` pin. The device tree will look lik
85
86 .. code-block::
87
88 com-supply = <&vref_div_2>;
89
90 channel@1 {
91 reg = <1>; /* IN1 */
92 common-mode-channel = <AD4695_COMMON_M
93 bipolar;
94 };
95
96 This will appear on the IIO bus as the ``volta
97 (*(raw + offset) × scale*) will be the voltag
98 relative to ``REFGND``. (The offset is determi
99
100 The macro comes from:
101
102 .. code-block::
103
104 #include <dt-bindings/iio/adi,ad4695.h>
105
106 Pairing two INx pins
107 ^^^^^^^^^^^^^^^^^^^^
108
109 An even-numbered ``INx`` pin and the following
110 used as a pseudo-differential input. The devic
111 positive input and ``IN3`` as the negative inp
112
113 .. code-block::
114
115 in3-supply = <&vref_div_2>;
116
117 channel@2 {
118 reg = <2>; /* IN2 */
119 common-mode-channel = <3>; /* IN3 */
120 bipolar;
121 };
122
123 This will appear on the IIO bus as the ``volta
124 (*(raw + offset) × scale*) will be the voltag
125 relative to ``REFGND``. (Offset is determined
126
127 VCC supply
128 ----------
129
130 The chip supports being powered by an external
131 internal LDO via the ``LDO_IN`` input. The dri
132 determine which is being used. If ``ldo-supply
133 LDO is used. If ``vcc-supply`` is present, the
134 the internal LDO is disabled.
135
136 Reference voltage
137 -----------------
138
139 The chip supports an external reference voltag
140 internal buffered reference voltage via the ``
141 at the device tree to determine which is being
142 present, then the external reference voltage i
143 disabled. If ``refin-supply`` is present, then
144 voltage is used.
145
146 Gain/offset calibration
147 -----------------------
148
149 System calibration is supported using the chan
150 the ``calibscale`` and ``calibbias`` attribute
151
152 Unimplemented features
153 ----------------------
154
155 - Additional wiring modes
156 - Threshold events
157 - Oversampling
158 - GPIO support
159 - CRC support
160
161 Device buffers
162 ==============
163
164 This driver supports hardware triggered buffer
165 sequencer" feature of the chip to trigger a bu
166
167 Also see :doc:`iio_devbuf` for more general in
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.