rtc: isl12026: new driver.

The ISL12026 is a combination RTC and EEPROM device with I2C
interface.  The standard RTC driver interface is provided.  The EEPROM
is accessed via the NVMEM interface.

Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/rtc/isil,isl12026.txt

@@ -0,0 +1,28 @@
+ISL12026 I2C RTC/EEPROM
+
+ISL12026 is an I2C RTC/EEPROM combination device.  The RTC and control
+registers respond at bus address 0x6f, and the EEPROM array responds
+at bus address 0x57.  The canonical "reg" value will be for the RTC portion.
+
+Required properties supported by the device:
+
+ - "compatible": must be "isil,isl12026"
+ - "reg": I2C bus address of the device (always 0x6f)
+
+Optional properties:
+
+ - "isil,pwr-bsw": If present PWR.BSW bit must be set to the specified
+                   value for proper operation.
+
+ - "isil,pwr-sbib": If present PWR.SBIB bit must be set to the specified
+                    value for proper operation.
+
+
+Example:
+
+	rtc@6f {
+		compatible = "isil,isl12026";
+		reg = <0x6f>;
+		isil,pwr-bsw = <0>;
+		isil,pwr-sbib = <1>;
+	}