1# SPDX-License-Identifier: GPL-2.0 2%YAML 1.2 3--- 4$id: http://devicetree.org/schemas/iio/adc/adc.yaml# 5$schema: http://devicetree.org/meta-schemas/core.yaml# 6 7title: IIO Common Properties for ADC Channels 8 9maintainers: 10 - Jonathan Cameron <jic23@kernel.org> 11 12description: 13 A few properties are defined in a common way ADC channels. 14 15properties: 16 $nodename: 17 pattern: "^channel(@[0-9a-f]+)?$" 18 description: 19 A channel index should match reg. 20 21 reg: 22 maxItems: 1 23 24 label: 25 description: Unique name to identify which channel this is. 26 27 bipolar: 28 $ref: /schemas/types.yaml#/definitions/flag 29 description: If provided, the channel is to be used in bipolar mode. 30 31 diff-channels: 32 $ref: /schemas/types.yaml#/definitions/uint32-array 33 maxItems: 2 34 minItems: 2 35 description: 36 Many ADCs have dual Muxes to allow different input pins to be routed 37 to both the positive and negative inputs of a differential ADC. 38 The first value specifies the positive input pin, the second 39 specifies the negative input pin. 40 There are also some ADCs, where the differential channel has dedicated 41 positive and negative inputs which can be used to measure differential 42 voltage levels. For those setups, this property can be configured with 43 the 'reg' property for both inputs (i.e. diff-channels = <reg reg>). 44 45 single-channel: 46 $ref: /schemas/types.yaml#/definitions/uint32 47 description: 48 When devices combine single-ended and differential channels, allow the 49 channel for a single element to be specified, independent of reg (as for 50 differential channels). If this and diff-channels are not present reg 51 shall be used instead. 52 53 common-mode-channel: 54 $ref: /schemas/types.yaml#/definitions/uint32 55 description: 56 Some ADCs have differential input pins that can be used to measure 57 single-ended or pseudo-differential inputs. This property can be used 58 in addition to single-channel to signal software that this channel is 59 not differential but still specify two inputs. 60 61 The input pair is specified by setting single-channel to the positive 62 input pin and common-mode-channel to the negative pin. 63 64 settling-time-us: 65 description: 66 Time between enabling the channel and first stable readings. 67 68 oversampling-ratio: 69 $ref: /schemas/types.yaml#/definitions/uint32 70 description: 71 Oversampling is used as replacement of or addition to the low-pass filter. 72 In some cases, the desired filtering characteristics are a function the 73 device design and can interact with other characteristics such as 74 settling time. 75 76anyOf: 77 - oneOf: 78 - required: 79 - reg 80 - diff-channels 81 - required: 82 - reg 83 - single-channel 84 - required: 85 - reg 86 87additionalProperties: true 88