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Message-ID: <996b49ab-5e2e-76bc-efb1-38c6384871f6@linaro.org>
Date:   Tue, 4 Apr 2023 09:21:56 +0200
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Subject: Re: [PATCH v5 2/2] dt-bindings: rtc: add max313xx RTCs
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc:     Ibrahim Tilki <Ibrahim.Tilki@analog.com>, a.zummo@towertech.it,
        jdelvare@suse.com, linux@roeck-us.net, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, linux-rtc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
        devicetree@vger.kernel.org,
        Zeynep Arslanbenzer <Zeynep.Arslanbenzer@analog.com>
References: <20230403154342.3108-1-Ibrahim.Tilki@analog.com>
 <20230403154342.3108-3-Ibrahim.Tilki@analog.com>
 <dd6f0842-519f-1bc9-f7f5-459863dc3dcd@linaro.org>
 <202304040710049c9cc01a@mail.local>
Content-Language: en-US
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <202304040710049c9cc01a@mail.local>
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On 04/04/2023 09:10, Alexandre Belloni wrote:
>>
>>> +      RTC can be used as a clock source through its clock output pin when
>>> +      supplied.
>>> +    const: 0
>>> +
>>> +  clocks:
>>> +    description: |
>>
>> Do not need '|'.
>>
>>> +      RTC uses this clock for clock input when supplied. Clock has to provide
>>> +      one of these four frequencies: 1Hz, 50Hz, 60Hz or 32.768kHz.
>>> +    maxItems: 1
>>> +
>>> +  aux-voltage-chargeable:
>>> +    enum: [0, 1, 2]
>>> +    description: |
>>> +      Enables trickle charger.
>>> +      0: Charger is disabled (default)
>>> +      1: Charger is enabled
>>> +      2: Charger is enabled with a diode
>>
>> 2 is not an allowed value. I asked to drop this property. It is coming
>> from rtc.yaml. I also do not understand "with a diode". So otherwise it
>> is charging with, I don't know, FET?
> 
> No, what is not explained here (and maybe not unsterstood by the
> submitter) is that the RTC has an extra diode so, 

Value of 2 is still not allowed and if the patch was tested, it would be
clearly visible. Unfortunately patch was not tested...

> charging will always
> enable a diode, select a resistor and then have or not an extra diode.
> Figure2 of the MAX31329 datasheet is great.

So the diode is in the max313xx? Then why enabling it is a property of
DT? Either this should be inferred from compatible or is even a policy,
not a DT property. Just because device has a register for something, is
not an argument that "something" should be in DT.


Best regards,
Krzysztof