Re: [PATCH v4 1/3] dt-bindings: hwmon: fan: Add fan binding to schema

From: Naresh Solanki <naresh.solanki@9elements.com>
To: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org, Guenter Roeck <linux@roeck-us.net>,
	Jean Delvare <jdelvare@suse.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
	Patrick Rudolph <patrick.rudolph@9elements.com>
Subject: Re: [PATCH v4 1/3] dt-bindings: hwmon: fan: Add fan binding to schema
Date: Tue, 25 Oct 2022 14:46:27 +0530	[thread overview]
Message-ID: <dcd22f70-e51c-290e-c11f-9a5ce32748c1@9elements.com> (raw)
In-Reply-To: <20221024161806.GA1855651-robh@kernel.org>

On 24-10-2022 09:48 pm, Rob Herring wrote:
> So if we unload and reload the driver module, it should go back to the
> default?
This is RPM to be set during probe if desired.
> 
> I think it is really, 'target RPM if not already configured' which could
> be keep the setting from a register (e.g. what the bootloader set) or
> perhaps you already have temperature information to use...
Yes. missed it. It should be target-rpm will correct this. in next version.
> 
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +  pwm-frequency:
>> +    description:
>> +      PWM frequency for fan in Hertz(Hz).
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +
>> +  pwm-polarity-inverse:
>> +    description:
>> +      Inverse PWM polarity for fan.
>> +    type: boolean
> As I said before, the PWM binding handles these 2 settings. Use it. Yes,
> it's a bit of an overkill when the child is the consumer of the parent.
> Until some 'clever' h/w engineer decides to use one of the PWMs for
> something else like a backlight.
I would like you to consider this as something recommended by fan 
datasheet for the given fan instance.
This info can be used by fan controller driver to configure PWM 
source/provider accordingly.

If you still feel that may not make sense then I'll remove this property.

Thanks,
Naresh