Re: [PATCH V6 2/2] rtc: zynqmp: Add calibration set and get support

From: Peter Korsgaard
Date: Fri Jun 10 2022 - 06:12:24 EST


>>>>> "Neeli," == Neeli, Srinivas <srinivas.neeli@xxxxxxx> writes:

Hi,

>> >> Where do you see that? ug1085 rev2.2 still lists:
>> >>
>> >> Programming Sequences
>> >> init rtc
>> >> 1. Write the value 0019_8231h into the calibration register, CALIB_WRITE.
>> >>
>>
>> > This is a very weird value. Last time I had a look, I couldn't find an >
>> explanation for it.
>>
>> Agreed. I am not arguing that it is sensible, I just wondered where this new
>> value comes from?
>>
> This information is missing in our TRM, as per the internal RTC IP
> design specification document, the calibration value should be crystal
> clock frequency minus one.
> For a crystal oscillator of 32.768KHz(0x8000) frequency, the calibration value will be 0x7FFF.

> Will update TRM with the required information.

Ok, great!

Please put this change in a separate commit from the get/set logic.

--
Bye, Peter Korsgaard