Re: [PATCH v2 1/2] dt-bindings: hwmon: ltc2991: add bindings

From: Conor Dooley
Date: Mon Oct 02 2023 - 09:00:46 EST


Hey,

On Mon, Oct 02, 2023 at 01:18:14PM +0300, Antoniu Miclaus wrote:
> Add dt-bindings for ltc2991 octal i2c voltage, current and temperature
> monitor.
>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
> ---
> changes in v2:
> - make compatible const type
> - remove `|` where not necessary
> - switch to micro-ohms for the shunt resistor property
> - add vendor prefix for temperature-enable

Thanks for the updates...

> .../bindings/hwmon/adi,ltc2991.yaml | 114 ++++++++++++++++++
> 1 file changed, 114 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/hwmon/adi,ltc2991.yaml
>
> diff --git a/Documentation/devicetree/bindings/hwmon/adi,ltc2991.yaml b/Documentation/devicetree/bindings/hwmon/adi,ltc2991.yaml
> new file mode 100644
> index 000000000000..3811ea07a04f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/adi,ltc2991.yaml
> @@ -0,0 +1,114 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +
> +$id: http://devicetree.org/schemas/hwmon/adi,ltc2991.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC2991 Octal I2C Voltage, Current and Temperature Monitor
> +
> +maintainers:
> + - Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
> +
> +description: |
> + The LTC2991 is used to monitor system temperatures, voltages and currents.
> + Through the I2C serial interface, the eight monitors can individually measure
> + supply voltages and can be paired for differential measurements of current
> + sense resistors or temperature sensing transistors.
> +
> + Datasheet:
> + https://www.analog.com/en/products/ltc2991.html
> +
> +properties:
> + compatible:
> + const: adi,ltc2991
> +
> + reg:
> + maxItems: 1
> +
> + '#address-cells':
> + const: 1
> +
> + '#size-cells':
> + const: 0
> +
> + vcc-supply: true
> +
> +patternProperties:
> + "^channel@[0-3]$":
> + type: object
> + description:
> + Represents the differential/temperature channels.
> +
> + properties:
> + reg:
> + description:
> + The channel number. LTC2991 can monitor 4 currents/temperatures.
> + items:
> + minimum: 0
> + maximum: 3
> +
> + shunt-resistor-micro-ohms:
> + description:
> + The value of curent sense resistor in miliohms. Enables differential
> + input pair.
> +
> + adi,temperature-enable:
> + description:
> + Enables temperature readings for a input pair.
> + type: boolean

...but I did not see an answer to my question on v1:
TBH, this seems like it is used just to control software behaviour.
Why would you want to actually disable this in DT?
In other words, is there something in that hardware that precludes
measuring temperature for channels that do not contain this property?

Thanks,
Conor.

> +
> +required:
> + - compatible
> + - reg
> + - vcc-supply
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + hwmon@48 {
> + compatible = "adi,ltc2991";
> + reg = <0x48>;
> + vcc-supply = <&vcc>;
> + };
> + };
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + hwmon@48 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + compatible = "adi,ltc2991";
> + reg = <0x48>;
> + vcc-supply = <&vcc>;
> +
> + channel@0 {
> + reg = <0x0>;
> + shunt-resistor-micro-ohms = <100000>;
> + };
> +
> + channel@1 {
> + reg = <0x1>;
> + shunt-resistor-micro-ohms = <100000>;
> + };
> +
> + channel@2 {
> + reg = <0x2>;
> + temperature-enable;
> + };
> +
> + channel@3 {
> + reg = <0x3>;
> + temperature-enable;
> + };
> + };
> + };
> +...
> --
> 2.42.0
>

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