[PATCH v9 1/6] dt-bindings: iio: adc: Add ltc2378

Document how to describe LTC2378-20 and similar ADCs in device tree.

Reviewed-by: David Lechner <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
Signed-off-by: Marcelo Schmitt <[email protected]>
---
Change log v8 -> v9:
No changes in device tree doc.

 .../bindings/iio/adc/adi,ltc2378.yaml         | 170 ++++++++++++++++++
 MAINTAINERS                                   |   7 +
 2 files changed, 177 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ltc2378.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ltc2378.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ltc2378.yaml
new file mode 100644
index 000000000000..33de1dc4c256
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ltc2378.yaml
@@ -0,0 +1,170 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ltc2378.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices LTC2378 and similar Analog to Digital Converters
+
+maintainers:
+  - Marcelo Schmitt <[email protected]>
+
+description: |
+  Analog Devices LTC2378 series of ADCs.
+  Specifications can be found at:
+    https://www.analog.com/media/en/technical-documentation/data-sheets/233818fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236416fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236418f.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236716fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236718f.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236816f.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236818f.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/236918fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237016fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237616fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237618fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237620fb.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237716fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237718fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237720fb.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237816fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237818fa.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237820fb.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/237918fb.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/238016fb.pdf
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      # Single compatible string match.
+      - enum:
+          - adi,ltc2338-18
+          - adi,ltc2364-16
+          - adi,ltc2364-18
+          - adi,ltc2376-16
+          - adi,ltc2376-18
+          - adi,ltc2376-20
+
+      # Low sample rate fallback for 16-bit unipolar sensors.
+      - items:
+          - enum:
+              - adi,ltc2370-16 # 2 MSPS
+              - adi,ltc2368-16 # 1 MSPS
+              - adi,ltc2367-16 # 500 kSPS
+          - const: adi,ltc2364-16 # fallback (250 kSPS)
+
+      # Low sample rate fallback for 18-bit unipolar sensors.
+      - items:
+          - enum:
+              - adi,ltc2369-18 # 1.6 MSPS
+              - adi,ltc2368-18 # 1 MSPS
+              - adi,ltc2367-18 # 500 kSPS
+          - const: adi,ltc2364-18 # fallback (250 kSPS)
+
+      # Low sample rate fallback for 16-bit bipolar sensors.
+      - items:
+          - enum:
+              - adi,ltc2380-16 # 2 MSPS
+              - adi,ltc2378-16 # 1 MSPS
+              - adi,ltc2377-16 # 500 kSPS
+          - const: adi,ltc2376-16 # fallback (250 kSPS)
+
+      # Low sample rate fallback for 18-bit bipolar sensors.
+      - items:
+          - enum:
+              - adi,ltc2379-18 # 1.6 MSPS
+              - adi,ltc2378-18 # 1 MSPS
+              - adi,ltc2377-18 # 500 kSPS
+          - const: adi,ltc2376-18 # fallback (250 kSPS)
+
+      # Low sample rate fallback for 20-bit bipolar sensors.
+      - items:
+          - enum:
+              - adi,ltc2378-20 # 1 MSPS
+              - adi,ltc2377-20 # 500 kSPS
+          - const: adi,ltc2376-20 # fallback (250 kSPS)
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 100000000
+
+  vdd-supply:
+    description: A 2.5V supply that powers the chip (VDD).
+
+  ovdd-supply:
+    description:
+      A 1.71V to 5.25V supply that sets the logic level for digital interface.
+
+  ref-supply:
+    description:
+      Voltage reference input that determines the scale of ADC conversions.
+
+  refin-supply:
+    description:
+      Alternative voltage reference input.
+
+  cnv-gpios:
+    description:
+      When provided, this property indicates the GPIO that is connected to the
+      CNV pin.
+    maxItems: 1
+
+  pwms:
+    description: PWM signal connected to the CNV pin.
+    maxItems: 1
+
+  interrupts:
+    description:
+      Interrupt for signaling the completion of conversion results. The active
+      low signal provided on the BUSY pin asserts when ADC conversions finish.
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+  - ovdd-supply
+
+allOf:
+  # Except for LTC2338, all designs require a voltage reference input
+  - if:
+      properties:
+        compatible:
+          not:
+            contains:
+              enum:
+                - adi,ltc2338-18
+    then:
+      required:
+        - ref-supply
+      properties:
+        refin-supply: false
+    else:
+      properties:
+        ref-supply: false
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        adc@0 {
+            compatible = "adi,ltc2378-20", "adi,ltc2376-20";
+            reg = <0>;
+            spi-max-frequency = <71000000>;
+            vdd-supply = <&supply_2_5V>;
+            ovdd-supply = <&supply_3_3V>;
+            ref-supply = <&supply_5V>;
+            cnv-gpios = <&gpio0 88 GPIO_ACTIVE_HIGH>;
+            interrupts = <7 IRQ_TYPE_EDGE_FALLING>;
+            interrupt-parent = <&gpio>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2b1ec46c5919..f0ae26699c99 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15343,6 +15343,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/dac/lltc,ltc1660.yaml
 F:	drivers/iio/dac/ltc1660.c
 
+LTC2378 IIO ADC DRIVER
+M:	Marcelo Schmitt <[email protected]>
+L:	[email protected]
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/iio/adc/adi,ltc2378.yaml
+
 LTC2664 IIO DAC DRIVER
 M:	Michael Hennerich <[email protected]>
 M:	Kim Seer Paller <[email protected]>
-- 
2.53.0