From: "Benoît Thébaudeau" <benoit@wsystem.com> To: rtc-linux@googlegroups.com Cc: linux-kernel@vger.kernel.org, "Alessandro Zummo" <a.zummo@towertech.it>, "Alexandre Belloni" <alexandre.belloni@free-electrons.com>, "Benoît Thébaudeau" <benoit@wsystem.com> Subject: [PATCH 5/6] rtc: rv8803: Stop the clock while setting the time Date: Thu, 21 Jul 2016 12:41:31 +0200 [thread overview] Message-ID: <1469097692-103146-5-git-send-email-benoit@wsystem.com> (raw) In-Reply-To: <1469097692-103146-1-git-send-email-benoit@wsystem.com> According to the application manual of the RX8900, the RESET bit must be set to 1 to prevent a timer update while setting the time. This also resets the subsecond counter. The application manual of the RV-8803 does not mention such a requirement, and it says that the 100th Seconds register is cleared when writing to the Seconds register, but using the RESET bit for the RV-8803 too should not be an issue and is probably safer. This change also ensures that the RESET bit is initialized properly in all cases. Indeed, all the registers must be initialized if the voltage has been lower than VLOW2 (triggering V2F), but not low enough to trigger a POR. Signed-off-by: Benoît Thébaudeau <benoit@wsystem.com> --- drivers/rtc/rtc-rv8803.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c index 09ab5cb..24c688e 100644 --- a/drivers/rtc/rtc-rv8803.c +++ b/drivers/rtc/rtc-rv8803.c @@ -223,11 +223,21 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm) { struct rv8803_data *rv8803 = dev_get_drvdata(dev); u8 date[7]; - int flags, ret; + int ctrl, flags, ret; if ((tm->tm_year < 100) || (tm->tm_year > 199)) return -EINVAL; + ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL); + if (ctrl < 0) + return ctrl; + + /* Stop the clock */ + ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, + ctrl | RV8803_CTRL_RESET); + if (ret) + return ret; + date[RV8803_SEC] = bin2bcd(tm->tm_sec); date[RV8803_MIN] = bin2bcd(tm->tm_min); date[RV8803_HOUR] = bin2bcd(tm->tm_hour); @@ -240,6 +250,12 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm) if (ret) return ret; + /* Restart the clock */ + ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, + ctrl & ~RV8803_CTRL_RESET); + if (ret) + return ret; + mutex_lock(&rv8803->flags_lock); flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); -- 2.5.0
WARNING: multiple messages have this Message-ID (diff)
From: "Benoît Thébaudeau" <benoit@wsystem.com> To: rtc-linux@googlegroups.com Cc: linux-kernel@vger.kernel.org, "Alessandro Zummo" <a.zummo@towertech.it>, "Alexandre Belloni" <alexandre.belloni@free-electrons.com>, "Benoît Thébaudeau" <benoit@wsystem.com> Subject: [rtc-linux] [PATCH 5/6] rtc: rv8803: Stop the clock while setting the time Date: Thu, 21 Jul 2016 12:41:31 +0200 [thread overview] Message-ID: <1469097692-103146-5-git-send-email-benoit@wsystem.com> (raw) In-Reply-To: <1469097692-103146-1-git-send-email-benoit@wsystem.com> According to the application manual of the RX8900, the RESET bit must be set to 1 to prevent a timer update while setting the time. This also resets the subsecond counter. The application manual of the RV-8803 does not mention such a requirement, and it says that the 100th Seconds register is cleared when writing to the Seconds register, but using the RESET bit for the RV-8803 too should not be an issue and is probably safer. This change also ensures that the RESET bit is initialized properly in all cases. Indeed, all the registers must be initialized if the voltage has been lower than VLOW2 (triggering V2F), but not low enough to trigger a POR. Signed-off-by: Beno=C3=AEt Th=C3=A9baudeau <benoit@wsystem.com> --- drivers/rtc/rtc-rv8803.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c index 09ab5cb..24c688e 100644 --- a/drivers/rtc/rtc-rv8803.c +++ b/drivers/rtc/rtc-rv8803.c @@ -223,11 +223,21 @@ static int rv8803_set_time(struct device *dev, struct= rtc_time *tm) { struct rv8803_data *rv8803 =3D dev_get_drvdata(dev); u8 date[7]; - int flags, ret; + int ctrl, flags, ret; =20 if ((tm->tm_year < 100) || (tm->tm_year > 199)) return -EINVAL; =20 + ctrl =3D rv8803_read_reg(rv8803->client, RV8803_CTRL); + if (ctrl < 0) + return ctrl; + + /* Stop the clock */ + ret =3D rv8803_write_reg(rv8803->client, RV8803_CTRL, + ctrl | RV8803_CTRL_RESET); + if (ret) + return ret; + date[RV8803_SEC] =3D bin2bcd(tm->tm_sec); date[RV8803_MIN] =3D bin2bcd(tm->tm_min); date[RV8803_HOUR] =3D bin2bcd(tm->tm_hour); @@ -240,6 +250,12 @@ static int rv8803_set_time(struct device *dev, struct = rtc_time *tm) if (ret) return ret; =20 + /* Restart the clock */ + ret =3D rv8803_write_reg(rv8803->client, RV8803_CTRL, + ctrl & ~RV8803_CTRL_RESET); + if (ret) + return ret; + mutex_lock(&rv8803->flags_lock); =20 flags =3D rv8803_read_reg(rv8803->client, RV8803_FLAG); --=20 2.5.0 --=20 You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. ---=20 You received this message because you are subscribed to the Google Groups "= rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to rtc-linux+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
next prev parent reply other threads:[~2016-07-21 10:47 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-07-21 10:41 [PATCH 1/6] rtc: rv8803: Kconfig: Indicate rx8900 support Benoît Thébaudeau 2016-07-21 10:41 ` [rtc-linux] " Benoît Thébaudeau 2016-07-21 10:41 ` [PATCH 2/6] rtc: rv8803: Remove the check for valid time Benoît Thébaudeau 2016-07-21 10:41 ` [rtc-linux] " Benoît Thébaudeau 2016-07-21 10:41 ` [PATCH 3/6] rtc: rv8803: Fix read day of week Benoît Thébaudeau 2016-07-21 10:41 ` [rtc-linux] " Benoît Thébaudeau 2016-07-21 10:41 ` [PATCH 4/6] rtc: rv8803: Always apply the I²C workaround Benoît Thébaudeau 2016-07-21 10:41 ` [rtc-linux] " Benoît Thébaudeau 2016-07-21 11:10 ` Alexandre Belloni 2016-07-21 11:10 ` [rtc-linux] " Alexandre Belloni 2016-07-21 12:34 ` Benoît Thébaudeau 2016-07-21 12:34 ` [rtc-linux] " Benoît Thébaudeau 2016-07-21 18:30 ` Benoît Thébaudeau 2016-07-21 18:30 ` [rtc-linux] " Benoît Thébaudeau 2016-07-21 10:41 ` Benoît Thébaudeau [this message] 2016-07-21 10:41 ` [rtc-linux] [PATCH 5/6] rtc: rv8803: Stop the clock while setting the time Benoît Thébaudeau 2016-07-21 10:41 ` [PATCH 6/6] rtc: rv8803: Clear V1F when " Benoît Thébaudeau 2016-07-21 10:41 ` [rtc-linux] " Benoît Thébaudeau 2016-07-28 8:00 ` [PATCH 1/6] rtc: rv8803: Kconfig: Indicate rx8900 support Alexandre Belloni 2016-07-28 8:00 ` [rtc-linux] " Alexandre Belloni
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