netdev - Re: [PATCH 1/5] ptp: ocp: Add ptp_ocp_adjtime

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Date:   Fri, 17 Dec 2021 19:10:06 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Jonathan Lemon <jonathan.lemon@...il.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, kernel-team@...com
Subject: Re: [PATCH 1/5] ptp: ocp: Add ptp_ocp_adjtime_coarse for large
 adjustments

On Thu, 16 Dec 2021 12:01:00 -0800 Jonathan Lemon wrote:
> In ("ptp: ocp: Have FPGA fold in ns adjustment for adjtime."), the
> ns adjustment was written to the FPGA register, so the clock could
> accurately perform adjustments.
> 
> However, the adjtime() call passes in a s64, while the clock adjustment
> registers use a s32.  When trying to perform adjustments with a large
> value (37 sec), things fail.
> 
> Examine the incoming delta, and if larger than 1 sec, use the original
> (coarse) adjustment method.  If smaller than 1 sec, then allow the
> FPGA to fold in the changes over a 1 second window.
> 
> Fixes: 2d97ed56f671 ("ptp: ocp: Have FPGA fold in ns adjustment for adjtime.")

This SHA does not exist upstream. Please separate the fixes from the
features. Please CC Richard on the patches.