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Subject: Re: [PATCH v2 14/16] hwmon: (mr75203) parse thermal coefficients from
 device-tree
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Date:   Fri, 19 Aug 2022 10:57:58 +0300
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To:     Guenter Roeck <linux@roeck-us.net>
CC:     <jdelvare@suse.com>, <robh+dt@kernel.org>, <mark.rutland@arm.com>,
        <linux-hwmon@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <talel@amazon.com>,
        <hhhawa@amazon.com>, <jonnyc@amazon.com>, <hanochu@amazon.com>,
        <ronenk@amazon.com>, <itamark@amazon.com>, <shellykz@amazon.com>,
        <shorer@amazon.com>, <amitlavi@amazon.com>, <almogbs@amazon.com>,
        <dwmw@amazon.co.uk>, <rtanwar@maxlinear.com>,
        "Farber, Eliav" <farbere@amazon.com>
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 <20220817054321.6519-15-farbere@amazon.com>
 <20220818202839.GA3431511@roeck-us.net>
From:   "Farber, Eliav" <farbere@amazon.com>
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On 8/18/2022 11:28 PM, Guenter Roeck wrote:
> The calculation was just changed to use new defaults in a previous
> patch. This patch makes it quite clear that the coefficients
> are implementation (?) dependent. So the previous patch just changes
> the defaults to (presumably) the coefficients used in your system.
> That is inappropriate. Adding non-default corefficients is ok
> and makes sense is supported by the chip, but changing defaults
> isn't.
The calculation was changed in previous patch to match series 5 of the
Moortec Embedded Temperature Sensor (METS) datasheet.
In our SOC we use series 6 which has a slightly different equation and
different coefficients.
I did the changes in steps.
With this last change, both series 5 and 6 are supported, in addition to
calibrated vs. non-calibrated modes.
In addition the data sheet just recommends default values but they also
specifically mention that actual values might vary from product to product.

--
Regards, Eliav