Re: [PATCH v1] rtc: mpfs: fix counter upload completion condition

[Geert Uytterhoeven]

Hi Conor,

On Wed, 13 May 2026 at 20:04, Conor Dooley <conor@xxxxxxxxxx> wrote:
> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>
> The condition that needs to be checked for upload completion is the
> UPLOAD bit in the completion register going low. The original iterations
> of this driver used a do-while and this was converted to a
> read_poll_timeout() during upstreaming without the condition being
> inverted as it should have been.
>
> I suspect that this went unnoticed until now because a) the first read
> was done when the bit was still set, immediately completing the
> read_poll_timeout() and b) because the RTC doesn't hold time when power
> is removed from the SoC reducing its utility (I for one keep it
> disabled). If my first suspicion was true when the driver was
> upstreamed, it's not true any longer though, hence the detection of the
> problem.
>
> Fixes: 0b31d703598dc ("rtc: Add driver for Microchip PolarFire SoC")
> CC: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>

Thanks, this landed as commit 9792ff8afa9017fe ("rtc: mpfs: fix counter
upload completion condition") in v7.2-rc1, and finally the endless
stream of:

    mpfs_rtc 20124000.rtc: timed out uploading time to rtc

is gone!

And no, it didn't go unnoticed, at least not for me, but you couldn't
reproduce it reliably before:
https://lore.kernel.org/bce2ca405ef96b1363fd1370887409d9e8468422.1660659437.git.geert+renesas@xxxxxxxxx/

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds