[PATCH v2 1/2] dt-bindings: iio: adc: add ad7944 ADCs
From: David Lechner
Date: Fri Feb 16 2024 - 14:47:48 EST
This adds a new binding for the Analog Devices, Inc. AD7944, AD7985, and
AD7986 ADCs.
Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
---
.../devicetree/bindings/iio/adc/adi,ad7944.yaml | 204 +++++++++++++++++++++
MAINTAINERS | 8 +
2 files changed, 212 insertions(+)
diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
new file mode 100644
index 000000000000..61ee81326660
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
@@ -0,0 +1,204 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7944.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices PulSAR LFCSP Analog to Digital Converters
+
+maintainers:
+ - Michael Hennerich <Michael.Hennerich@xxxxxxxxxx>
+ - Nuno Sá <nuno.sa@xxxxxxxxxx>
+
+description: |
+ A family of pin-compatible single channel differential analog to digital
+ converters with SPI support in a LFCSP package.
+
+ * https://www.analog.com/en/products/ad7944.html
+ * https://www.analog.com/en/products/ad7985.html
+ * https://www.analog.com/en/products/ad7986.html
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+ compatible:
+ enum:
+ - adi,ad7944
+ - adi,ad7985
+ - adi,ad7986
+
+ reg:
+ maxItems: 1
+
+ spi-max-frequency:
+ maximum: 111111111
+
+ spi-cpol: true
+ spi-cpha: true
+
+ adi,spi-mode:
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [ single, multi, chain ]
+ default: multi
+ description: |
+ * single: The datasheet calls this "3-wire mode". It is often used when
+ the ADC is the only device on the bus. In this mode, SDI is tied to VIO,
+ and the CNV line can be connected to the CS line of the SPI controller
+ or to a GPIO, in which case the CS line of the controller is unused.
+ * multi: The datasheet calls this "4-wire mode". This is the convential
+ SPI mode used when there are multiple devices on the same bus. In this
+ mode, the CNV line is used to initiate the conversion and the SDI line
+ is connected to CS on the SPI controller.
+ * chain: The datasheet calls this "chain mode". This mode is used to save
+ on wiring when multiple ADCs are used. In this mode, the SDI line of
+ one chip is tied to the SDO of the next chip in the chain and the SDI of
+ the last chip in the chain is tied to GND. Only the first chip in the
+ chain is connected to the SPI bus. The CNV line of all chips are tied
+ together. The CS line of the SPI controller is unused.
+
+ avdd-supply:
+ description: A 2.5V supply that powers the analog circuitry.
+
+ dvdd-supply:
+ description: A 2.5V supply that powers the digital circuitry.
+
+ vio-supply:
+ description:
+ A 1.8V to 2.7V supply for the digital inputs and outputs.
+
+ bvdd-supply:
+ description:
+ A voltage supply for the buffered power. When using an external reference
+ without an internal buffer (PDREF high, REFIN low), this should be
+ connected to the same supply as ref-supply. Otherwise, when using an
+ internal reference or an external reference with an internal buffer, this
+ is connected to a 5V supply.
+
+ ref-supply:
+ description:
+ Voltage regulator for the external reference voltage (REF). This property
+ is omitted when using an internal reference.
+
+ refin-supply:
+ description:
+ Voltage regulator for the reference buffer input (REFIN). When using an
+ external buffer with internal reference, this should be connected to a
+ 1.2V external reference voltage supply. Otherwise, this property is
+ omitted.
+
+ cnv-gpios:
+ description:
+ The Convert Input (CNV). This input has multiple functions. It initiates
+ the conversions and selects the SPI mode of the device (chain or CS). In
+ 'single' mode, this property is omitted if the CNV pin is connected to the
+ CS line of the SPI controller.
+ maxItems: 1
+
+ turbo-gpios:
+ description:
+ GPIO connected to the TURBO line. If omitted, it is assumed that the TURBO
+ line is hard-wired and the state is determined by the adi,always-turbo
+ property.
+ maxItems: 1
+
+ adi,always-turbo:
+ type: boolean
+ description:
+ When present, this property indicates that the TURBO line is hard-wired
+ and the state is always high. If neither this property nor turbo-gpios is
+ present, the TURBO line is assumed to be hard-wired and the state is
+ always low.
+
+ interrupts:
+ description:
+ The SDO pin can also function as a busy indicator. This node should be
+ connected to an interrupt that is triggered when the SDO line goes low
+ while the SDI line is high and the CNV line is low ('single' mode) or the
+ SDI line is low and the CNV line is high ('multi' mode); or when the SDO
+ line goes high while the SDI and CNV lines are high (chain mode),
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+ - avdd-supply
+ - dvdd-supply
+ - vio-supply
+ - bvdd-supply
+
+allOf:
+ # ref-supply and refin-supply are mutually exclusive (neither is also valid)
+ - if:
+ required:
+ - ref-supply
+ then:
+ properties:
+ refin-supply: false
+ - if:
+ required:
+ - refin-supply
+ then:
+ properties:
+ ref-supply: false
+ # in 'single' mode, cnv-gpios is optional, for other modes it is required
+ - if:
+ required:
+ - adi,spi-mode
+ then:
+ if:
+ properties:
+ adi,spi-mode:
+ enum: [ multi, chain ]
+ then:
+ required:
+ - cnv-gpios
+ else:
+ required:
+ - cnv-gpios
+ # chain mode has lower SCLK max rate and doesn't work when TURBO is enabled
+ - if:
+ required:
+ - adi,spi-mode
+ properties:
+ adi,spi-mode:
+ const: chain
+ then:
+ properties:
+ spi-max-frequency:
+ maximum: 90909090
+ adi,always-turbo: false
+ # turbo-gpios and adi,always-turbo are mutually exclusive
+ - if:
+ required:
+ - turbo-gpios
+ then:
+ properties:
+ adi,always-turbo: false
+ - if:
+ required:
+ - adi,always-turbo
+ then:
+ properties:
+ turbo-gpios: false
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ adc@0 {
+ compatible = "adi,ad7944";
+ reg = <0>;
+ spi-cpha;
+ spi-max-frequency = <111111111>;
+ avdd-supply = <&supply_2_5V>;
+ dvdd-supply = <&supply_2_5V>;
+ vio-supply = <&supply_1_8V>;
+ bvdd-supply = <&supply_5V>;
+ cnv-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
+ turbo-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 00d354af10f5..4f1e658e1e0d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -451,6 +451,14 @@ W: http://wiki.analog.com/AD7879
W: https://ez.analog.com/linux-software-drivers
F: drivers/input/touchscreen/ad7879.c
+AD7944 ADC DRIVER (AD7944/AD7985/AD7986)
+M: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
+M: Nuno Sá <nuno.sa@xxxxxxxxxx>
+R: David Lechner <dlechner@xxxxxxxxxxxx>
+S: Supported
+W: https://ez.analog.com/linux-software-drivers
+F: Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
+
ADAFRUIT MINI I2C GAMEPAD
M: Anshul Dalal <anshulusr@xxxxxxxxx>
L: linux-input@xxxxxxxxxxxxxxx
--
2.43.2