linux-kernel - Re: [PATCH 0/4] rtc:abx80x: Enable distributed digital calibration

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Date:   Sun, 28 Mar 2021 23:14:03 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Kirill Kapranov <kirill.kapranov@...pulab.co.il>
Cc:     a.zummo@...ertech.it, phdm@...qel.be, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/4] rtc:abx80x: Enable distributed digital calibration

Hello,

Thank you for working on that!

On 29/03/2021 00:02:28+0300, Kirill Kapranov wrote:
> This patch series enables a Distributed Digital Calibration function for
> the RTC of the family. This feature allows to improve the RTC accuracy by
> means of compensation an XT oscillator drift. To learn more, see:
> AB08XX Series Ultra Low Power RTC IC User's Guide
> https://abracon.com/realtimeclock/AB08XX-Application-Manual.pdf
> 
> The patches 1 and 2 enable SQW output, that is necessary for subsequent
> measurement and computation. However, this feature may be enabled and used
> independently, as is.
> 

Please use the common clock framework for this part. You will need a
dummy userspace user for this to work but I know Stephen is open to that
as we discussed that use case multiple times already.

> The patches 3 and 4 enable the XT calibration feature per se. The SQW
> output must be enabled for usage of this feature.

Please use the .set_offset and .get_offset rtc_ops for this part.


-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com