• Michael Lange's avatar
    rtc: ds1307: add support for the DT property 'wakeup-source' · 8bc2a407
    Michael Lange authored
    For RTC chips with no IRQ directly connected to the SoC, the RTC chip
    can be forced as a wakeup source by stating that explicitly in
    the device's .dts file using the "wakeup-source" boolean property.
    This will guarantee the 'wakealarm' sysfs entry is available on the
    device, if supported by the RTC.
    
    With these changes to the driver rtc-ds1307 and the necessary entries
    in the .dts file, I get an working ds1337 RTC on the Witty Pi extension
    board by UUGear for the Raspberry Pi.
    
    An example for the entry in the .dts file:
    
    	rtc: ds1337@68 {
    		compatible = "dallas,ds1337";
    		reg = <0x68>;
    		wakeup-source;
    
    If the "wakeup-source" property is set, do not request an IRQ.
    Set also UIE mode to unsupported, to get a working 'hwclock' binary.
    Signed-off-by: default avatarMichael Lange <linuxstuff@milaw.biz>
    Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
    8bc2a407
rtc-ds1307.c 33 KB