Re: [PATCH 2/3] dt-bindings: iio: add AD74413R

From: Jonathan Cameron
Date: Thu Oct 28 2021 - 10:44:37 EST

On Thu, 28 Oct 2021 16:48:44 +0300
Cosmin Tanislav <demonsingur@xxxxxxxxx> wrote:

> Add device tree bindings for AD74413R.
Hi Cosmin,

Welcome to IIO.

Nice to give a tiny bit of description of the device in here
to expand on what the patch title told us.

Some comments inline.

Thanks,

Jonathan
>
> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
> ---
> .../bindings/iio/addac/adi,ad74413r.yaml | 163 ++++++++++++++++++
> include/dt-bindings/iio/addac/adi,ad74413r.h | 30 ++++
> 2 files changed, 193 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/addac/adi,ad74413r.yaml
> create mode 100644 include/dt-bindings/iio/addac/adi,ad74413r.h
>
> diff --git a/Documentation/devicetree/bindings/iio/addac/adi,ad74413r.yaml b/Documentation/devicetree/bindings/iio/addac/adi,ad74413r.yaml
> new file mode 100644
> index 000000000000..ed4ee3047fbe
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/addac/adi,ad74413r.yaml
> @@ -0,0 +1,163 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/addac/adi,ad74413r.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices AD74413R/AD74412R device driver

Bindings always describe hardware, not drivers (so we don't expect to
see the word driver in them).

> +
> +maintainers:
> + - Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
> +
> +description: |
> + The AD74413R and AD74412R are quad-channel software configurable input/output
> + solutions for building and process control applications. They contain
> + functionality for analog output, analog input, digital input, resistance
> + temperature detector, and thermocouple measurements integrated
> + into a single chip solution with an SPI interface.
> + The devices feature a 16-bit ADC and four configurable 13-bit DACs to provide
> + four configurable input/output channels and a suite of diagnostic functions.
> +
> +properties:
> + compatible:
> + enum:
> + - adi,ad74413r
> + - adi,ad74412r

Alphabetical / numeric order preferred.

> +
> + reg:
> + maxItems: 1
> +
> + '#address-cells':
> + const: 1
> +
> + '#size-cells':
> + const: 0
> +
> + spi-max-frequency:
> + maximum: 1000000
> +
> + spi-cpol: true
> +
> + interrupts:
> + maxItems: 1
> +
> + refin-supply:
> + description:
> + Reference voltage regulator.
Name pretty much tells us everything in the description.

refin-supply: true

is enough here I think.

> +
> + adi,rsense-resistance-ohms:
> + $ref: /schemas/types.yaml#/definitions/uint32

I think the automatic units stuff in dt-schema should remove the need for
a ref here.

> + description:
> + RSense resistance values in Ohms.
> +
> +required:
> + - compatible
> + - reg
> + - spi-max-frequency
> + - spi-cpol
> + - refin-supply
> + - adi,rsense-resistance-ohm
> +
> +additionalProperties: false
> +
> +patternProperties:
> + "^channel@[0-3]$":
> + type: object
> + description: Represents the external channels which are connected to the device.
> +
> + properties:
> + reg:
> + description: |
> + The channel number. It can have up to 4 channels numbered from 0 to 3.
> + maxItems: 1
> + minimum: 0
> + maximum: 3
> +
> + adi,ch-func:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + Channel function.
> + HART functions are not supported on AD74412R.

Ideally enforce that with suitable conditional statements in this binding schema.

> + 0 - CH_FUNC_HIGH_IMPEDANCE
> + 1 - CH_FUNC_VOLTAGE_OUTPUT
> + 2 - CH_FUNC_CURRENT_OUTPUT
> + 3 - CH_FUNC_VOLTAGE_INPUT
> + 4 - CH_FUNC_CURRENT_INPUT_EXT_POWER
> + 5 - CH_FUNC_CURRENT_INPUT_LOOP_POWER
> + 6 - CH_FUNC_RESISTANCE_INPUT
> + 7 - CH_FUNC_DIGITAL_INPUT_LOGIC
> + 8 - CH_FUNC_DIGITAL_INPUT_LOOP_POWER
> + 9 - CH_FUNC_CURRENT_INPUT_EXT_POWER_HART
> + 10 - CH_FUNC_CURRENT_INPUT_LOOP_POWER_HART

I'm not a great fan of large enums, but it is a bit hard to
work out a scheme that would be better for this so I guess we are
stuck with this.

> + maxItems: 1
> + minimum: 0
> + maximum: 10
> +
> + adi,gpo-config:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + GPO config.

GPO is what exactly?

> + 0 - GPO_CONFIG_100K_PULL_DOWN
> + 1 - GPO_CONFIG_LOGIC

Interesting that you have defined 2 in the header...
Why not here?

> + 3 - GPO_CONFIG_DEBOUNCED_COMPARATOR
> + 4 - GPO_CONFIG_HIGH_IMPEDANCE
> + maxItems: 1
> + enum: [0, 1, 3, 4]
> +
> + required:
> + - reg

This is fine if we have a default specified for the other elements
such as what type of channel this is.

> +
> +examples:
> + - |
> + spi0 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + cs-gpios = <&gpio 17 GPIO_ACTIVE_LOW>;
> + status = "okay";
> +
> + ad74413r@0 {
> + compatible = "adi,ad74413r";
> + reg = <0>;
> + spi-max-frequency = <1000000>;
> + spi-cpol;
> +
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + interrupt-parent = <&gpio>;
> + interrupts = <26 0>;
> +
> + refin-supply = <&ad74413r_refin>;
> + adi,rsense-resistance-ohm = <100>;
> +
> + channel@0 {
> + reg = <0>;
> +
> + adi,ch-func = <CH_FUNC_VOLTAGE_OUTPUT>;
> + adi,gpo-config = <GPO_CONFIG_LOGIC>;
> + };
> +
> + channel@1 {
> + reg = <1>;
> +
> + adi,ch-func = <CH_FUNC_CURRENT_OUTPUT>;
> + adi,gpo-config = <GPO_CONFIG_LOGIC>;
> + };
> +
> + channel@2 {
> + reg = <2>;
> +
> + adi,ch-func = <CH_FUNC_VOLTAGE_INPUT>;
> + adi,gpo-config = <GPO_CONFIG_DEBOUNCED_COMPARATOR>;
> + };
> +
> + channel@3 {
> + reg = <3>;
> +
> + adi,ch-func = <CH_FUNC_CURRENT_INPUT_EXT_POWER>;
> + adi,gpo-config = <GPO_CONFIG_DEBOUNCED_COMPARATOR>;
> + };
> + };
> + };
> +...
> diff --git a/include/dt-bindings/iio/addac/adi,ad74413r.h b/include/dt-bindings/iio/addac/adi,ad74413r.h
> new file mode 100644
> index 000000000000..bde558d9731c
> --- /dev/null
> +++ b/include/dt-bindings/iio/addac/adi,ad74413r.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef _DT_BINDINGS_ADI_AD74413R_H
> +#define _DT_BINDINGS_ADI_AD74413R_H
> +
> +#define GPO_CONFIG_100K_PULL_DOWN 0x0
> +#define GPO_CONFIG_LOGIC 0x1
> +#define GPO_CONFIG_LOGIC_PARALLEL 0x2
> +#define GPO_CONFIG_DEBOUNCED_COMPARATOR 0x3
> +#define GPO_CONFIG_HIGH_IMPEDANCE 0x4
> +
> +#define GPO_CONFIG_MIN GPO_CONFIG_100K_PULL_DOWN
> +#define GPO_CONFIG_MAX GPO_CONFIG_HIGH_IMPEDANCE
> +
> +#define CH_FUNC_HIGH_IMPEDANCE 0x0
> +#define CH_FUNC_VOLTAGE_OUTPUT 0x1
> +#define CH_FUNC_CURRENT_OUTPUT 0x2
> +#define CH_FUNC_VOLTAGE_INPUT 0x3
> +#define CH_FUNC_CURRENT_INPUT_EXT_POWER 0x4
> +#define CH_FUNC_CURRENT_INPUT_LOOP_POWER 0x5
> +#define CH_FUNC_RESISTANCE_INPUT 0x6
> +#define CH_FUNC_DIGITAL_INPUT_LOGIC 0x7
> +#define CH_FUNC_DIGITAL_INPUT_LOOP_POWER 0x8
> +#define CH_FUNC_CURRENT_INPUT_EXT_POWER_HART 0x9
> +#define CH_FUNC_CURRENT_INPUT_LOOP_POWER_HART 0xA
> +
> +#define CH_FUNC_MIN CH_FUNC_HIGH_IMPEDANCE
> +#define CH_FUNC_MAX CH_FUNC_CURRENT_INPUT_LOOP_POWER_HART
> +
> +#endif /* _DT_BINDINGS_ADI_AD74413R_H */