rtc: ingenic: Reset regulator register in probe

The regulator register specifies how many input clock cycles (minus one)
are contained in one tick of the 1 Hz clock.

Since this register can contain bogus values after the system boots, it
needs to be reset in the probe register, otherwise the RTC may count way
to slow or way too fast.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20200505221336.222313-7-paul@crapouillou.netSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-jz4740.c

@@ -372,6 +372,9 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
 	rate = clk_get_rate(clk);
 	jz4740_rtc_set_wakeup_params(rtc, np, rate);
 
+	/* Each 1 Hz pulse should happen after (rate) ticks */
+	jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR, rate - 1);
+
 	ret = rtc_register_device(rtc->rtc);
 	if (ret)
 		return ret;