Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
dt-bindings: iio: adc: Add AD4170-4
Add device tree documentation for AD4170-4 and similar sigma-delta ADCs.
The AD4170-4 is a 24-bit, multichannel, sigma-delta ADC.
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
Link: https://patch.msgid.link/aa4b3be541c7b759560f8e0c5340a456cb2f3801.1751895245.git.marcelo.schmitt@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
authored by
Marcelo Schmitt
and committed by
Jonathan Cameron
1b3cee41
7586eb9b
+561
+554
Documentation/devicetree/bindings/iio/adc/adi,ad4170-4.yaml
+554
Documentation/devicetree/bindings/iio/adc/adi,ad4170-4.yaml
···
1
+
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2
+
%YAML 1.2
3
+
---
4
+
$id: http://devicetree.org/schemas/iio/adc/adi,ad4170-4.yaml#
5
+
$schema: http://devicetree.org/meta-schemas/core.yaml#
6
+
7
+
title: Analog Devices AD4170-4 and similar Analog to Digital Converters
8
+
9
+
maintainers:
10
+
- Marcelo Schmitt <marcelo.schmitt@analog.com>
11
+
12
+
description: |
13
+
Analog Devices AD4170-4 series of Sigma-delta Analog to Digital Converters.
14
+
Specifications can be found at:
15
+
https://www.analog.com/media/en/technical-documentation/data-sheets/ad4170-4.pdf
16
+
https://www.analog.com/media/en/technical-documentation/data-sheets/ad4190-4.pdf
17
+
https://www.analog.com/media/en/technical-documentation/data-sheets/ad4195-4.pdf
18
+
19
+
$ref: /schemas/spi/spi-peripheral-props.yaml#
20
+
21
+
$defs:
22
+
reference-buffer:
23
+
description: |
24
+
Enable precharge buffer, full buffer, or skip reference buffering of
25
+
the positive/negative voltage reference. Because the output impedance
26
+
of the source driving the voltage reference inputs may be dynamic,
27
+
resistive/capacitive combinations of those inputs can cause DC gain
28
+
errors if the reference inputs go unbuffered into the ADC. Enable
29
+
reference buffering if the provided reference source has dynamic high
30
+
impedance output. Note the absolute voltage allowed on REFINn+ and REFINn-
31
+
inputs is from AVSS - 50 mV to AVDD + 50 mV when the reference buffers are
32
+
disabled but narrows to AVSS to AVDD when reference buffering is enabled
33
+
or in precharge mode.
34
+
$ref: /schemas/types.yaml#/definitions/string
35
+
enum: [ precharge, full, disabled ]
36
+
default: full
37
+
38
+
properties:
39
+
compatible:
40
+
enum:
41
+
- adi,ad4170-4
42
+
- adi,ad4190-4
43
+
- adi,ad4195-4
44
+
45
+
avss-supply:
46
+
description:
47
+
Reference voltage supply for AVSS. A −2.625V minimum and 0V maximum supply
48
+
that powers the chip. If not provided, AVSS is assumed to be at system
49
+
ground (0V).
50
+
51
+
avdd-supply:
52
+
description:
53
+
A supply of 4.75V to 5.25V relative to AVSS that powers the chip (AVDD).
54
+
55
+
iovdd-supply:
56
+
description: 1.7V to 5.25V reference supply to the serial interface (IOVDD).
57
+
58
+
refin1p-supply:
59
+
description: REFIN+ supply that can be used as reference for conversion.
60
+
61
+
refin1n-supply:
62
+
description: REFIN- supply that can be used as reference for conversion.
63
+
64
+
refin2p-supply:
65
+
description: REFIN2+ supply that can be used as reference for conversion.
66
+
67
+
refin2n-supply:
68
+
description: REFIN2- supply that can be used as reference for conversion.
69
+
70
+
spi-cpol: true
71
+
72
+
spi-cpha: true
73
+
74
+
interrupts:
75
+
description:
76
+
Interrupt for signaling the completion of conversion results. The data
77
+
ready signal (RDY) used as interrupt is by default provided on the SDO
78
+
pin. Alternatively, it can be provided on the DIG_AUX1 pin in which case
79
+
the chip disables the RDY function on SDO. Thus, there can be only one
80
+
data ready interrupt enabled at a time.
81
+
82
+
interrupt-names:
83
+
description:
84
+
Specify which pin should be configured as Data Ready interrupt.
85
+
enum:
86
+
- sdo
87
+
- dig_aux1
88
+
89
+
clocks:
90
+
maxItems: 1
91
+
description:
92
+
Optional external clock source. Can specify either an external clock or
93
+
external crystal.
94
+
95
+
clock-names:
96
+
enum:
97
+
- ext-clk
98
+
- xtal
99
+
default: ext-clk
100
+
101
+
'#clock-cells':
102
+
const: 0
103
+
104
+
clock-output-names:
105
+
maxItems: 1
106
+
107
+
gpio-controller: true
108
+
109
+
"#gpio-cells":
110
+
const: 2
111
+
description: |
112
+
The first cell is for the GPIO number: 0 to 3.
113
+
The second cell takes standard GPIO flags.
114
+
115
+
ldac-gpios:
116
+
description:
117
+
GPIO connected to DIG_AUX2 pin to be used as LDAC toggle to control the
118
+
transfer of data from the DAC_INPUT_A register to the DAC.
119
+
maxItems: 1
120
+
121
+
'#address-cells':
122
+
const: 1
123
+
124
+
'#size-cells':
125
+
const: 0
126
+
127
+
adi,vbias-pins:
128
+
description: Analog inputs to apply a voltage bias of (AVDD − AVSS) / 2 to.
129
+
$ref: /schemas/types.yaml#/definitions/uint32-array
130
+
minItems: 1
131
+
maxItems: 9
132
+
items:
133
+
minimum: 0
134
+
maximum: 8
135
+
136
+
allOf:
137
+
# Some devices don't have integrated DAC
138
+
- if:
139
+
properties:
140
+
compatible:
141
+
contains:
142
+
enum:
143
+
- adi,ad4190-4
144
+
- adi,ad4195-4
145
+
then:
146
+
properties:
147
+
ldac-gpios: false
148
+
149
+
# Require to specify the interrupt pin when using interrupts
150
+
- if:
151
+
required:
152
+
- interrupts
153
+
then:
154
+
required:
155
+
- interrupt-names
156
+
157
+
# If an external clock is set, the internal clock cannot go out and vice versa
158
+
- oneOf:
159
+
- required: [clocks]
160
+
properties:
161
+
'#clock-cells': false
162
+
- required: ['#clock-cells']
163
+
properties:
164
+
clocks: false
165
+
166
+
required:
167
+
- compatible
168
+
- reg
169
+
- avdd-supply
170
+
- iovdd-supply
171
+
- spi-cpol
172
+
- spi-cpha
173
+
174
+
unevaluatedProperties: false
175
+
176
+
patternProperties:
177
+
"^channel@[0-9a-f]$":
178
+
$ref: /schemas/iio/adc/adc.yaml#
179
+
unevaluatedProperties: false
180
+
description:
181
+
Represents the external channels which are connected to the ADC.
182
+
183
+
properties:
184
+
reg:
185
+
description:
186
+
The channel number.
187
+
minimum: 0
188
+
maximum: 15
189
+
190
+
diff-channels:
191
+
description: |
192
+
This property is used for defining the inputs of a differential
193
+
voltage channel. The first value is the positive input and the second
194
+
value is the negative input of the channel.
195
+
196
+
Besides the analog input pins AIN0 to AIN8, there are special inputs
197
+
that can be selected with the following values:
198
+
17: Internal temperature sensor
199
+
18: (AVDD-AVSS)/5
200
+
19: (IOVDD-DGND)/5
201
+
20: DAC output
202
+
21: ALDO
203
+
22: DLDO
204
+
23: AVSS
205
+
24: DGND
206
+
25: REFIN+
207
+
26: REFIN-
208
+
27: REFIN2+
209
+
28: REFIN2-
210
+
29: REFOUT
211
+
For the internal temperature sensor, use the input number for both
212
+
inputs (i.e. diff-channels = <17 17>).
213
+
items:
214
+
enum: [0, 1, 2, 3, 4, 5, 6, 7, 8, 17, 18, 19, 20, 21, 22, 23, 24, 25,
215
+
26, 27, 28, 29]
216
+
217
+
adi,reference-select:
218
+
description: |
219
+
Select the reference source to use when converting on the
220
+
specific channel. Valid values are:
221
+
0: REFIN+/REFIN-
222
+
1: REFIN2+/REFIN2−
223
+
2: REFOUT/AVSS (internal reference)
224
+
3: AVDD/AVSS
225
+
If not specified, REFOUT/AVSS is used.
226
+
$ref: /schemas/types.yaml#/definitions/uint32
227
+
enum: [0, 1, 2, 3]
228
+
default: 1
229
+
230
+
adi,positive-reference-buffer:
231
+
$ref: '#/$defs/reference-buffer'
232
+
233
+
adi,negative-reference-buffer:
234
+
$ref: '#/$defs/reference-buffer'
235
+
236
+
adi,sensor-type:
237
+
description:
238
+
The AD4170-4 and similar designs have features to aid interfacing with
239
+
load cell weigh scale, RTD, and thermocouple sensors. Each of those
240
+
sensor types requires either distinct wiring configuration or
241
+
external circuitry for proper sensor operation and can use different
242
+
ADC chip functionality on their setups. A key characteristic of those
243
+
external sensors is that they must be excited either by voltage supply
244
+
or by ADC chip excitation signals. The sensor can then be read through
245
+
a pair of analog inputs. This property specifies which particular
246
+
sensor type is connected to the ADC so it can be properly setup and
247
+
handled. Omit this property for conventional (not weigh scale, RTD, or
248
+
thermocouple) ADC channel setups.
249
+
$ref: /schemas/types.yaml#/definitions/string
250
+
enum: [ weighscale, rtd, thermocouple ]
251
+
252
+
adi,excitation-pin-0:
253
+
description:
254
+
Analog input to apply excitation current to while the channel
255
+
is active.
256
+
$ref: /schemas/types.yaml#/definitions/uint32
257
+
minimum: 0
258
+
maximum: 20
259
+
default: 0
260
+
261
+
adi,excitation-pin-1:
262
+
description:
263
+
Analog input to apply excitation current to while the channel
264
+
is active.
265
+
$ref: /schemas/types.yaml#/definitions/uint32
266
+
minimum: 0
267
+
maximum: 20
268
+
default: 0
269
+
270
+
adi,excitation-pin-2:
271
+
description:
272
+
Analog input to apply excitation current to while the channel
273
+
is active.
274
+
$ref: /schemas/types.yaml#/definitions/uint32
275
+
minimum: 0
276
+
maximum: 20
277
+
default: 0
278
+
279
+
adi,excitation-pin-3:
280
+
description:
281
+
Analog input to apply excitation current to while the channel
282
+
is active.
283
+
$ref: /schemas/types.yaml#/definitions/uint32
284
+
minimum: 0
285
+
maximum: 20
286
+
default: 0
287
+
288
+
adi,excitation-current-0-microamp:
289
+
description:
290
+
Excitation current in microamperes to be applied to pin specified in
291
+
adi,excitation-pin-0 while this channel is active.
292
+
enum: [0, 10, 50, 100, 250, 500, 1000, 1500]
293
+
default: 0
294
+
295
+
adi,excitation-current-1-microamp:
296
+
description:
297
+
Excitation current in microamperes to be applied to pin specified in
298
+
adi,excitation-pin-1 while this channel is active.
299
+
enum: [0, 10, 50, 100, 250, 500, 1000, 1500]
300
+
default: 0
301
+
302
+
adi,excitation-current-2-microamp:
303
+
description:
304
+
Excitation current in microamperes to be applied to pin specified in
305
+
adi,excitation-pin-2 while this channel is active.
306
+
enum: [0, 10, 50, 100, 250, 500, 1000, 1500]
307
+
default: 0
308
+
309
+
adi,excitation-current-3-microamp:
310
+
description:
311
+
Excitation current in microamperes to be applied to pin specified in
312
+
adi,excitation-pin-3 while this channel is active.
313
+
enum: [0, 10, 50, 100, 250, 500, 1000, 1500]
314
+
default: 0
315
+
316
+
adi,excitation-ac:
317
+
type: boolean
318
+
description:
319
+
Whether the external sensor has to be AC or DC excited. When omitted,
320
+
it is DC excited.
321
+
322
+
allOf:
323
+
- oneOf:
324
+
- required: [single-channel, common-mode-channel]
325
+
properties:
326
+
diff-channels: false
327
+
- required: [diff-channels]
328
+
properties:
329
+
single-channel: false
330
+
common-mode-channel: false
331
+
# Usual ADC channels don't need external circuitry excitation.
332
+
- if:
333
+
not:
334
+
required:
335
+
- adi,sensor-type
336
+
then:
337
+
properties:
338
+
adi,excitation-pin-0: false
339
+
adi,excitation-pin-1: false
340
+
adi,excitation-pin-2: false
341
+
adi,excitation-pin-3: false
342
+
adi,excitation-current-0-microamp: false
343
+
adi,excitation-current-1-microamp: false
344
+
adi,excitation-current-2-microamp: false
345
+
adi,excitation-current-3-microamp: false
346
+
adi,excitation-ac: false
347
+
# Weigh scale bridge AC excited with one pair of predefined signals.
348
+
- if:
349
+
allOf:
350
+
- properties:
351
+
adi,sensor-type:
352
+
contains:
353
+
const: weighscale
354
+
- required:
355
+
- adi,excitation-ac
356
+
- adi,excitation-pin-2
357
+
- adi,excitation-pin-3
358
+
- not:
359
+
required:
360
+
- adi,excitation-current-2-microamp
361
+
- adi,excitation-current-3-microamp
362
+
then:
363
+
properties:
364
+
adi,excitation-pin-2:
365
+
const: 19
366
+
adi,excitation-pin-3:
367
+
const: 20
368
+
# Weigh scale bridge AC excited with two pairs of predefined signals.
369
+
- if:
370
+
allOf:
371
+
- properties:
372
+
adi,sensor-type:
373
+
contains:
374
+
const: weighscale
375
+
- required:
376
+
- adi,excitation-ac
377
+
- adi,excitation-pin-0
378
+
- adi,excitation-pin-1
379
+
- adi,excitation-pin-2
380
+
- adi,excitation-pin-3
381
+
- not:
382
+
required:
383
+
- adi,excitation-current-0-microamp
384
+
- adi,excitation-current-1-microamp
385
+
- adi,excitation-current-2-microamp
386
+
- adi,excitation-current-3-microamp
387
+
then:
388
+
properties:
389
+
adi,excitation-pin-0:
390
+
const: 17
391
+
adi,excitation-pin-1:
392
+
const: 18
393
+
adi,excitation-pin-2:
394
+
const: 19
395
+
adi,excitation-pin-3:
396
+
const: 20
397
+
398
+
examples:
399
+
- |
400
+
#include <dt-bindings/interrupt-controller/irq.h>
401
+
spi {
402
+
#address-cells = <1>;
403
+
#size-cells = <0>;
404
+
405
+
adc@0 {
406
+
compatible = "adi,ad4170-4";
407
+
reg = <0>;
408
+
spi-max-frequency = <20000000>;
409
+
spi-cpol;
410
+
spi-cpha;
411
+
avdd-supply = <&avdd>;
412
+
iovdd-supply = <&iovdd>;
413
+
clocks = <&clk>;
414
+
clock-names = "xtal";
415
+
interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
416
+
interrupt-names = "dig_aux1";
417
+
adi,vbias-pins = <8>;
418
+
#address-cells = <1>;
419
+
#size-cells = <0>;
420
+
421
+
// Sample AIN0 with respect to DGND throughout AVDD/DGND input range
422
+
// Pseudo-differential unipolar
423
+
channel@0 {
424
+
reg = <0>;
425
+
single-channel = <0>;
426
+
common-mode-channel = <24>;
427
+
adi,reference-select = <3>;
428
+
};
429
+
// Weigh scale sensor
430
+
channel@1 {
431
+
reg = <1>;
432
+
bipolar;
433
+
diff-channels = <1 2>;
434
+
adi,reference-select = <0>;
435
+
adi,positive-reference-buffer = "precharge";
436
+
adi,negative-reference-buffer = "precharge";
437
+
adi,sensor-type = "weighscale";
438
+
adi,excitation-pin-2 = <19>;
439
+
adi,excitation-pin-3 = <20>;
440
+
adi,excitation-ac;
441
+
};
442
+
// RTD sensor
443
+
channel@2 {
444
+
reg = <2>;
445
+
bipolar;
446
+
diff-channels = <3 4>;
447
+
adi,reference-select = <0>;
448
+
adi,sensor-type = "rtd";
449
+
adi,excitation-pin-0 = <5>;
450
+
adi,excitation-pin-1 = <6>;
451
+
adi,excitation-current-0-microamp = <500>;
452
+
adi,excitation-current-1-microamp = <500>;
453
+
adi,excitation-ac;
454
+
};
455
+
// Thermocouple sensor
456
+
channel@3 {
457
+
reg = <3>;
458
+
bipolar;
459
+
diff-channels = <7 8>;
460
+
adi,reference-select = <0>;
461
+
adi,sensor-type = "thermocouple";
462
+
adi,excitation-pin-0 = <18>;
463
+
adi,excitation-current-0-microamp = <500>;
464
+
};
465
+
};
466
+
};
467
+
- |
468
+
#include <dt-bindings/interrupt-controller/irq.h>
469
+
spi {
470
+
#address-cells = <1>;
471
+
#size-cells = <0>;
472
+
473
+
adc@0 {
474
+
compatible = "adi,ad4170-4";
475
+
reg = <0>;
476
+
spi-max-frequency = <20000000>;
477
+
spi-cpol;
478
+
spi-cpha;
479
+
avdd-supply = <&avdd>;
480
+
iovdd-supply = <&iovdd>;
481
+
#clock-cells = <0>;
482
+
clock-output-names = "ad4170-clk16mhz";
483
+
interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
484
+
interrupt-names = "dig_aux1";
485
+
#address-cells = <1>;
486
+
#size-cells = <0>;
487
+
488
+
// Sample AIN0 with respect to AIN1 throughout AVDD/AVSS input range
489
+
// Differential bipolar. If AVSS < 0V, differential true bipolar
490
+
channel@0 {
491
+
reg = <0>;
492
+
bipolar;
493
+
diff-channels = <0 1>;
494
+
adi,reference-select = <3>;
495
+
};
496
+
// Sample AIN2 with respect to DGND throughout AVDD/DGND input range
497
+
// Pseudo-differential unipolar
498
+
channel@1 {
499
+
reg = <1>;
500
+
single-channel = <2>;
501
+
common-mode-channel = <24>;
502
+
adi,reference-select = <3>;
503
+
};
504
+
// Sample AIN3 with respect to 2.5V throughout AVDD/AVSS input range
505
+
// Pseudo-differential bipolar
506
+
channel@2 {
507
+
reg = <2>;
508
+
bipolar;
509
+
single-channel = <3>;
510
+
common-mode-channel = <29>;
511
+
adi,reference-select = <3>;
512
+
};
513
+
// Sample AIN4 with respect to DGND throughout AVDD/AVSS input range
514
+
// Pseudo-differential bipolar
515
+
channel@3 {
516
+
reg = <3>;
517
+
bipolar;
518
+
single-channel = <4>;
519
+
common-mode-channel = <24>;
520
+
adi,reference-select = <3>;
521
+
};
522
+
// Sample AIN5 with respect to 2.5V throughout AVDD/AVSS input range
523
+
// Pseudo-differential unipolar (AD4170-4 datasheet page 46 example)
524
+
channel@4 {
525
+
reg = <4>;
526
+
single-channel = <5>;
527
+
common-mode-channel = <29>;
528
+
adi,reference-select = <3>;
529
+
};
530
+
// Sample AIN6 with respect to 2.5V throughout REFIN+/REFIN- input range
531
+
// Pseudo-differential bipolar
532
+
channel@5 {
533
+
reg = <5>;
534
+
bipolar;
535
+
single-channel = <6>;
536
+
common-mode-channel = <29>;
537
+
adi,reference-select = <0>;
538
+
};
539
+
// Weigh scale sensor
540
+
channel@6 {
541
+
reg = <6>;
542
+
bipolar;
543
+
diff-channels = <7 8>;
544
+
adi,reference-select = <0>;
545
+
adi,sensor-type = "weighscale";
546
+
adi,excitation-pin-0 = <17>;
547
+
adi,excitation-pin-1 = <18>;
548
+
adi,excitation-pin-2 = <19>;
549
+
adi,excitation-pin-3 = <20>;
550
+
adi,excitation-ac;
551
+
};
552
+
};
553
+
};
554
+
...
+7
MAINTAINERS
+7
MAINTAINERS
···
1392
1392
F: Documentation/devicetree/bindings/iio/adc/adi,ad4130.yaml
1393
1393
F: drivers/iio/adc/ad4130.c
1394
1394
1395
+
ANALOG DEVICES INC AD4170-4 DRIVER
1396
+
M: Marcelo Schmitt <marcelo.schmitt@analog.com>
1397
+
L: linux-iio@vger.kernel.org
1398
+
S: Supported
1399
+
W: https://ez.analog.com/linux-software-drivers
1400
+
F: Documentation/devicetree/bindings/iio/adc/adi,ad4170-4.yaml
1401
+
1395
1402
ANALOG DEVICES INC AD4695 DRIVER
1396
1403
M: Michael Hennerich <michael.hennerich@analog.com>
1397
1404
M: Nuno Sá <nuno.sa@analog.com>