dt-bindings: rtc: Update for new chip in isl1208 series

Since this documents multiple chips controlled by the isl1208 driver,
name it isil,isl1208.txt, as the convention is to use the base driver
name in the bindings document for drivers with multiple devices.

Include all chips supported by this driver in the docs.  Make it
clear which properties apply to which chips.

Expand documentation for existing isil,evienb property to explain
operation in more detail.  Existing docs just describe it in terms of
setting a bit in a register.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Mark Rutland <mark.rutland@arm.com>
CC: devicetree@vger.kernel.org
Signed-off-by: Trent Piepho <tpiepho@impinj.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/rtc/isil,isl1219.txt → Documentation/devicetree/bindings/rtc/isil,isl1208.txt

-Intersil ISL1219 I2C RTC/Alarm chip with event in
+Intersil ISL1209/19 I2C RTC/Alarm chip with event in
 
-ISL1219 has additional pins EVIN and #EVDET for tamper detection.
+ISL12X9 have additional pins EVIN and #EVDET for tamper detection, while the
+ISL1208 and ISL1218 do not.  They are all use the same driver with the bindings
+described here, with chip specific properties as noted.
 
 Required properties supported by the device:
-
- - "compatible": must be "isil,isl1219"
+ - "compatible": Should be one of the following:
+		- "isil,isl1208"
+		- "isil,isl1209"
+		- "isil,isl1218"
+		- "isil,isl1219"
  - "reg": I2C bus address of the device
 
 Optional properties:
-
  - "interrupt-names": list which may contains "irq" and "evdet"
+	evdet applies to isl1209 and isl1219 only
  - "interrupts": list of interrupts for "irq" and "evdet"
- - "isil,ev-evienb": if present EV.EVIENB bit is set to the specified
-                     value for proper operation.
-
-
-Example isl1219 node with #IRQ pin connected to SoC gpio1 pin12
- and #EVDET pin connected to SoC gpio2 pin 24:
+	evdet applies to isl1209 and isl1219 only
+ - "isil,ev-evienb": Enable or disable internal pull on EVIN pin
+	Applies to isl1209 and isl1219 only
+	Possible values are 0 and 1
+	Value 0 enables internal pull-up on evin pin, 1 disables it.
+	Default will leave the non-volatile configuration of the pullup
+	as is.
+
+Example isl1219 node with #IRQ pin connected to SoC gpio1 pin12 and #EVDET pin
+connected to SoC gpio2 pin 24 and internal pull-up enabled in EVIN pin.
 
 	isl1219: rtc@68 {
 		compatible = "isil,isl1219";