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Sender: Guenter Roeck <groeck7@gmail.com>
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Date:   Thu, 26 Oct 2023 08:09:52 -0700
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To:     Conor Dooley <conor@kernel.org>,
        Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>
Cc:     patrick@stwcx.xyz, Jean Delvare <jdelvare@suse.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>, linux-i2c@vger.kernel.org,
        linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
References: <20231026081514.3610343-1-Delphine_CC_Chiu@Wiwynn.com>
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 <20231026-dicing-crispy-a10af575d3e5@spud>
From:   Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH v2 1/2] dt-bindings: hwmon: Add lltc ltc4286 driver
 bindings
In-Reply-To: <20231026-dicing-crispy-a10af575d3e5@spud>
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On 10/26/23 07:25, Conor Dooley wrote:
> Hey,
> 
> On Thu, Oct 26, 2023 at 04:15:11PM +0800, Delphine CC Chiu wrote:
>> Add a device tree bindings for ltc4286 driver.
> 
> Bindings are for devices, not for drivers.
> 
>>
>> Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
>>
>> Changelog:
>>    v2 - Revise vrange_select_25p6 to adi,vrange-select-25p6
>>       - Add type for adi,vrange-select-25p6
>>       - Revise rsense-micro-ohms to shunt-resistor-micro-ohms
>> ---
>>   .../bindings/hwmon/lltc,ltc4286.yaml          | 50 +++++++++++++++++++
>>   MAINTAINERS                                   | 10 ++++
>>   2 files changed, 60 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml b/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
>> new file mode 100644
>> index 000000000000..17022de657bb
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml
>> @@ -0,0 +1,50 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/hwmon/lltc,ltc4286.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: LTC4286 power monitors
>> +
>> +maintainers:
>> +  - Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - lltc,ltc4286
>> +      - lltc,ltc4287
> 
> I don't recall seeing an answer to Guenter about this ltc4287 device:
> https://lore.kernel.org/all/22f6364c-611c-ffb6-451c-9ddc20418d0a@roeck-us.net/
> 

At least the chip does officially exist now, and a datasheet is available.

https://www.analog.com/en/products/ltc4287.html

It shows that coefficients for the telemetry commands are different,
meaning that indeed both chips need to be explicitly referenced
in the properties description (and handled in the driver, which proves
my point of needing a datasheet before accepting such a driver).

>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  adi,vrange-select-25p6:
>> +    description:
>> +      This property is a bool parameter to represent the
>> +      voltage range is 25.6 or not for this chip.
> 
> 25.6 what? Volts? microvolts?
> What about Guenter's suggestion to name this so that it better matches
> the other, similar properties?
> 

I still would prefer one of the more common properties.
I still prefer adi,vrange-high-enable.

Guenter