rtc: rv8803: Stop the clock while setting the time (d3700b6b) · Commits · 戴 / test

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> Signed-off-by:

Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-rv8803.c

+17 −1

Original line number	Diff line number	Diff line
		@@ -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);

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