linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Jason Gunthorpe <jgg@nvidia.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: timers/core] rtc: cmos: Make rtc_cmos sync offset correct
Date: Fri, 11 Dec 2020 10:07:48 -0000	[thread overview]
Message-ID: <160768126882.3364.17475010470329427231.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20201206220541.830517160@linutronix.de>

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     b0ecd8e8c5ef376777277c4c2db7de92ac59f23f
Gitweb:        https://git.kernel.org/tip/b0ecd8e8c5ef376777277c4c2db7de92ac59f23f
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Sun, 06 Dec 2020 22:46:16 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 11 Dec 2020 10:40:52 +01:00

rtc: cmos: Make rtc_cmos sync offset correct

The offset for rtc_cmos must be -500ms to work correctly with the current
implementation of rtc_set_ntp_time() due to the following:

  tsched       twrite(t2.tv_sec - 1) 	 t2 (seconds increment)

twrite - tsched is the transport time for the write to hit the device,
which is negligible for this chip because it's accessed directly.

t2 - twrite = 500ms according to the datasheet.

But rtc_set_ntp_time() calculation of tsched is:

    tsched = t2 - 1sec - (t2 - twrite)

The default for the sync offset is 500ms which means that the write happens
at t2 - 1.5 seconds which is obviously off by a second for this device.

Make the offset -500ms so it works correct.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201206220541.830517160@linutronix.de

---
 drivers/rtc/rtc-cmos.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index c633319..7728fac 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -868,6 +868,9 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 	if (retval)
 		goto cleanup2;
 
+	/* Set the sync offset for the periodic 11min update correct */
+	cmos_rtc.rtc->set_offset_nsec = -(NSEC_PER_SEC / 2);
+
 	/* export at least the first block of NVRAM */
 	nvmem_cfg.size = address_space - NVRAM_OFFSET;
 	if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))

  parent reply	other threads:[~2020-12-11 10:09 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-06 21:46 [patch 0/8] ntp/rtc: Fixes and cleanups Thomas Gleixner
2020-12-06 21:46 ` [patch 1/8] rtc: mc146818: Prevent reading garbage Thomas Gleixner
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2021-01-25 18:40   ` [patch 1/8] rtc: mc146818: Prevent reading garbage - bug Mickaël Salaün
2021-01-26 13:26     ` Thomas Gleixner
2021-01-26 14:17       ` Mickaël Salaün
2021-01-26 15:35         ` Thomas Gleixner
2021-01-26 17:02           ` [PATCH V2] rtc: mc146818: Detect and handle broken RTCs Thomas Gleixner
2021-01-26 18:00             ` Alexandre Belloni
2021-01-27  8:41             ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
     [not found]             ` <ghft2hwevu.fsf@gouders.net>
2021-02-01 13:53               ` [PATCH V2] " Serge Belyshev
2021-02-01 19:09                 ` [PATCH] rtc: mc146818: Dont test for bit 0-5 in Register D Thomas Gleixner
2021-02-01 19:24                   ` [PATCH V2] " Thomas Gleixner
2021-02-01 19:32                     ` Linus Torvalds
2021-02-01 19:40                       ` Thomas Gleixner
2021-02-11 23:09                         ` Maciej W. Rozycki
2021-02-01 19:38                     ` Alexandre Belloni
2021-02-01 20:09                     ` Borislav Petkov
2021-02-01 20:15                     ` Dirk Gouders
2021-02-02  4:22                     ` Len Brown
2021-02-02 19:40                     ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2021-02-03 13:00                     ` [PATCH V2] " Mickaël Salaün
2020-12-06 21:46 ` [patch 2/8] rtc: mc146818: Reduce spinlock section in mc146818_set_time() Thomas Gleixner
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 3/8] rtc: cmos: Make rtc_cmos sync offset correct Thomas Gleixner
2020-12-07 20:50   ` Jason Gunthorpe
2020-12-11 10:07   ` tip-bot2 for Thomas Gleixner [this message]
2020-12-06 21:46 ` [patch 4/8] rtc: core: Make the sync offset default more realistic Thomas Gleixner
2020-12-07 20:55   ` Jason Gunthorpe
2020-12-10 23:59   ` Alexandre Belloni
2020-12-11  0:23     ` Thomas Gleixner
2020-12-11  0:28       ` Alexandre Belloni
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 5/8] ntp: Make the RTC synchronization more reliable Thomas Gleixner
2020-12-07 12:47   ` Miroslav Lichvar
2020-12-07 20:59   ` Jason Gunthorpe
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-29 19:41   ` [patch 5/8] " Geert Uytterhoeven
2021-01-11 10:12     ` Thomas Gleixner
2021-01-11 10:40       ` Geert Uytterhoeven
2020-12-06 21:46 ` [patch 6/8] ntp, rtc: Move rtc_set_ntp_time() to ntp code Thomas Gleixner
2020-12-07 20:59   ` Jason Gunthorpe
2020-12-09  3:51     ` Alexandre Belloni
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 7/8] ntp: Make the RTC sync offset less obscure Thomas Gleixner
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-06 21:46 ` [patch 8/8] ntp: Consolidate the RTC update implementation Thomas Gleixner
2020-12-07 21:05   ` Jason Gunthorpe
2020-12-11  9:23     ` Thomas Gleixner
2020-12-11 10:07   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-12-09  0:33 ` [patch 0/8] ntp/rtc: Fixes and cleanups Thomas Gleixner
2020-12-09  4:01   ` Alexandre Belloni
2020-12-09 12:39     ` Thomas Gleixner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=160768126882.3364.17475010470329427231.tip-bot2@tip-bot2 \
    --to=tip-bot2@linutronix.de \
    --cc=alexandre.belloni@bootlin.com \
    --cc=jgg@nvidia.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).