Re: [PATCH v2 2/2] hwmon: (adt7475) Added attenuator bypass support

[Guenter Roeck <linux@roeck-us.net>]

On 12/18/19 7:32 PM, Logan Shaw wrote:
> Added a new file documenting the adt7475 devicetree and added the five
> new properties to it.
> 
> Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz>
> ---
> ---
>   .../devicetree/bindings/hwmon/adt7475.txt     | 35 +++++++++++++++++++
>   1 file changed, 35 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/hwmon/adt7475.txt
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt b/Documentation/devicetree/bindings/hwmon/adt7475.txt
> new file mode 100644
> index 000000000000..388dd718a246
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt
> @@ -0,0 +1,35 @@
> +*ADT7475 hwmon sensor.
> +
> +Required properties:
> +- compatible: One of
> +	"adi,adt7473"
> +	"adi,adt7475"
> +	"adi,adt7476"
> +	"adi,adt7490"
> +
> +- reg: I2C address
> +
> +optional properties:
> +
> +- bypass-attenuator-all: Configures bypassing all voltage input attenuators.
> +	This is only supported on the ADT7476 and ADT7490, this property does
> +	nothing on other chips.

Both adt7473 and adt7475 do support configuring an attenuator on VCCP

> +		property present: Bit set to bypass all voltage input attenuators.
> +		property absent: Registers left unchanged.
> +
> +- bypass-attenuator-inx: Configures bypassing individual voltage input
> +	attenuators, where x is an integer from the set {0, 1, 3, 4}. This
> +	is only supported on the ADT7476 and ADT7490, this property does nothing
> +	on other chips.
> +		property present: Bit set to bypass specific voltage input attenuator
> +			for voltage input x.
> +		property absent: Registers left unchanged.
> +
This is interesting. It essentially means "retain configuration from ROM
Monitor", but leaves no means to _disable_ the bypass.

> +Example:
> +
> +hwmon@2e {
> +	compatible = "adi,adt7475";
> +	reg = <0x2e>;
> +	bypass-attenuator-all;
> +	bypass-attenuator-in1;

What would be the purpose of specifying both all and in1 ?

> +};
> \ No newline at end of file
>