Generic device tree bindings for Real Time Clock devices ======================================================== This document describes generic bindings which can be used to describe Real Time Clock devices in a device tree. Required properties ------------------- - compatible : name of RTC device following generic names recommended practice. For other required properties e.g. to describe register sets, clocks, etc. check the binding documentation of the specific driver. Optional properties ------------------- - start-year : if provided, the default hardware range supported by the RTC is shifted so the first usable year is the specified one. The following properties may not be supported by all drivers. However, if a driver wants to support one of the below features, it should adapt the bindings below. - trickle-resistor-ohms : Selected resistor for trickle charger. Should be given if trickle charger should be enabled - trickle-diode-disable : Do not use internal trickle charger diode Should be given if internal trickle charger diode should be disabled - wakeup-source : Enables wake up of host system on alarm - quartz-load-femtofarads : The capacitive load of the quartz(x-tal), expressed in femto Farad (fF). The default value shall be listed (if optional), and likewise all valid values. Trivial RTCs ------------ This is a list of trivial RTC devices that have simple device tree bindings, consisting only of a compatible field, an address and possibly an interrupt line. Compatible Vendor / Chip ========== ============= abracon,abb5zes3 AB-RTCMC-32.768kHz-B5ZE-S3: Real Time Clock/Calendar Module with I2C Interface abracon,abeoz9 AB-RTCMC-32.768kHz-EOZ9: Real Time Clock/Calendar Module with I2C Interface dallas,ds1374 I2C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output dallas,ds1672 Dallas DS1672 Real-time Clock dallas,ds3232 Extremely Accurate I²C RTC with Integrated Crystal and SRAM epson,rx8010 I2C-BUS INTERFACE REAL TIME CLOCK MODULE epson,rx8571 I2C-BUS INTERFACE REAL TIME CLOCK MODULE with Battery Backed RAM epson,rx8581 I2C-BUS INTERFACE REAL TIME CLOCK MODULE emmicro,em3027 EM Microelectronic EM3027 Real-time Clock isil,isl1208 Intersil ISL1208 Low Power RTC with Battery Backed SRAM isil,isl1218 Intersil ISL1218 Low Power RTC with Battery Backed SRAM isil,isl12022 Intersil ISL12022 Real-time Clock microcrystal,rv3028 Real Time Clock Module with I2C-Bus microcrystal,rv3029 Real Time Clock Module with I2C-Bus microcrystal,rv8523 Real Time Clock nxp,pcf2127 Real-time clock nxp,pcf2129 Real-time clock nxp,pcf8563 Real-time clock/calendar pericom,pt7c4338 Real-time Clock Module ricoh,r2025sd I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC ricoh,r2221tl I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC ricoh,rs5c372a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC ricoh,rs5c372b I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC ricoh,rv5c386 I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC ricoh,rv5c387a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC sii,s35390a 2-wire CMOS real-time clock whwave,sd3078 I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC