Re: [PATCH v4 3/5] dt-bindings: iio: dac: Add adi,ltc2664.yaml

Conor Dooley
2024-06-19T17:56:42Z

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On Wed, Jun 19, 2024 at 02:49:02PM +0800, Kim Seer Paller wrote:
> Add documentation for ltc2664.
>
> Co-developed-by: Michael Hennerich <michael.hennerich@analog.com>
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
> Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
> ---
> .../bindings/iio/dac/adi,ltc2664.yaml | 167 ++++++++++++++++++
> MAINTAINERS | 8 +
> 2 files changed, 175 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
>
> diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
> new file mode 100644
> index 000000000000..be37700e3b1f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
> @@ -0,0 +1,167 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/dac/adi,ltc2664.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC2664 DAC
> +
> +maintainers:
> + - Michael Hennerich <michael.hennerich@analog.com>
> + - Kim Seer Paller <kimseer.paller@analog.com>
> +
> +description: |
> + Analog Devices LTC2664 4 channel, 12-/16-Bit, +-10V DAC
> + https://www.analog.com/media/en/technical-documentation/data-sheets/2664fa.pdf
> +
> +properties:
> + compatible:
> + enum:
> + - adi,ltc2664
> +
> + reg:
> + maxItems: 1
> +
> + spi-max-frequency:
> + maximum: 50000000
> +
> + vcc-supply:
> + description: Analog Supply Voltage Input.
> +
> + v-pos-supply:
> + description: Positive Supply Voltage Input.
> +
> + v-neg-supply:
> + description: Negative Supply Voltage Input.
> +
> + iovcc-supply:
> + description: Digital Input/Output Supply Voltage.
> +
> + ref-supply:
> + description:
> + Reference Input/Output. The voltage at the REF pin sets the full-scale
> + range of all channels. If not provided the internal reference is used and
> + also provided on the VREF pin.
> +
> + reset-gpios:
> + description:
> + Active-low Asynchronous Clear Input. A logic low at this level-triggered
> + input clears the part to the reset code and range determined by the
> + hardwired option chosen using the MSPAN pins. The control registers are
> + cleared to zero.
> + maxItems: 1
> +
> + adi,manual-span-operation-config:
> + description:
> + This property must mimic the MSPAN pin configurations. By tying the MSPAN
> + pins (MSP2, MSP1 and MSP0) to GND and/or VCC, any output range can be
> + hardware-configured with different mid-scale or zero-scale reset options.
> + The hardware configuration is latched during power on reset for proper
> + operation.
> + 0 - MPS2=GND, MPS1=GND, MSP0=GND (+-10V, reset to 0V)
> + 1 - MPS2=GND, MPS1=GND, MSP0=VCC (+-5V, reset to 0V)
> + 2 - MPS2=GND, MPS1=VCC, MSP0=GND (+-2.5V, reset to 0V)
> + 3 - MPS2=GND, MPS1=VCC, MSP0=VCC (0V to 10, reset to 0V)
> + 4 - MPS2=VCC, MPS1=GND, MSP0=GND (0V to 10V, reset to 5V)
> + 5 - MPS2=VCC, MPS1=GND, MSP0=VCC (0V to 5V, reset to 0V)
> + 6 - MPS2=VCC, MPS1=VCC, MSP0=GND (0V to 5V, reset to 2.5V)
> + 7 - MPS2=VCC, MPS1=VCC, MSP0=VCC (0V to 5V, reset to 0V, enables SoftSpan)
> + $ref: /schemas/types.yaml#/definitions/uint32
> + enum: [0, 1, 2, 3, 4, 5, 6, 7]

Can you explain why this property is required, when below there's one
that sets the ranges in microvolts? Isn't the only new information that
this provides the reset values (in a few cases that it is not 0).
What am I missing?

> + default: 7
> +
> + io-channels:
> + description:
> + ADC channel to monitor voltages and temperature at the MUXOUT pin.
> + maxItems: 1
> +
> + '#address-cells':
> + const: 1
> +
> + '#size-cells':
> + const: 0
> +
> +patternProperties:
> + "^channel@[0-3]$":
> + type: object
> + additionalProperties: false
> +
> + properties:
> + reg:
> + description: The channel number representing the DAC output channel.
> + maximum: 3
> +
> + adi,toggle-mode:
> + description:
> + Set the channel as a toggle enabled channel. Toggle operation enables
> + fast switching of a DAC output between two different DAC codes without
> + any SPI transaction.
> + type: boolean
> +
> + adi,output-range-microvolt:
> + description: Specify the channel output full scale range.
> + oneOf:
> + - items:
> + - const: 0
> + - enum: [5000000, 10000000]
> + - items:
> + - const: -5000000
> + - const: 5000000
> + - items:
> + - const: -10000000
> + - const: 10000000
> + - items:
> + - const: -2500000
> + - const: 2500000
> +
> + required:
> + - reg
> + - adi,output-range-microvolt
> +
> +required:
> + - compatible
> + - reg
> + - spi-max-frequency
> + - vcc-supply
> + - iovcc-supply
> + - v-pos-supply
> + - v-neg-supply
> +
> +allOf:
> + - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + spi {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + dac@0 {
> + compatible = "adi,ltc2664";
> + reg = <0>;
> + spi-max-frequency = <10000000>;
> +
> + vcc-supply = <&vcc>;
> + iovcc-supply = <&vcc>;
> + ref-supply = <&vref>;
> + v-pos-supply = <&vpos>;
> + v-neg-supply = <&vneg>;
> +
> + io-channels = <&adc 0>;
> +
> + #address-cells = <1>;
> + #size-cells = <0>;
> + channel@0 {
> + reg = <0>;
> + adi,toggle-mode;
> + adi,output-range-microvolt = <(-10000000) 10000000>;
> + };
> +
> + channel@1 {
> + reg = <1>;
> + adi,output-range-microvolt = <0 10000000>;
> + };
> + };
> + };
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index be590c462d91..849800d9cbf7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13074,6 +13074,14 @@ S: Maintained
> F: Documentation/devicetree/bindings/iio/dac/lltc,ltc1660.yaml
> F: drivers/iio/dac/ltc1660.c
>
> +LTC2664 IIO DAC DRIVER
> +M: Michael Hennerich <michael.hennerich@analog.com>
> +M: Kim Seer Paller <kimseer.paller@analog.com>
> +L: linux-iio@vger.kernel.org
> +S: Supported
> +W: https://ez.analog.com/linux-software-drivers
> +F: Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
> +
> LTC2688 IIO DAC DRIVER
> M: Nuno Sá <nuno.sa@analog.com>
> L: linux-iio@vger.kernel.org
> --
> 2.34.1
>

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