drivers: rtc: add max313xx series rtc driver

Adding support for Analog Devices MAX313XX series RTCs.

This is ported from the Linux driver and adapted for use in u-boot.
Notable differences are
- handling of tm_year and tm_mon differ
- clock source support is omitted
- hwmon support for the MAX31328 and MAX31343 is omitted
- rtc_ops->reset is added

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index fcfda28..2317313 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -134,6 +134,19 @@
 	  This driver supports reading and writing the RTC/calendar and detects
 	  total power failures.
 
+config RTC_MAX313XX
+	bool "Analog Devices MAX313XX RTC driver"
+	depends on DM_RTC
+	depends on DM_I2C
+	help
+	  If you say yes here you will get support for the
+	  Analog Devices MAX313XX series RTC family.
+
+	  Chip features not currently supported:
+	  - Timestamp registers as SRAM
+	  - Temperature sensor
+	  - CLKOUT generation
+
 config RTC_PCF8563
 	tristate "Philips PCF8563"
 	help