Problem with PCF8563 RTC on Raspberry

[Bernd Walter]

On Mon, Feb 04, 2019 at 11:28:25AM +0100, Bernd Walter wrote:
> On Mon, Feb 04, 2019 at 10:44:34AM +0100, Emmanuel Vadot wrote:
> > On Mon, 4 Feb 2019 10:08:54 +0100
> > Bernd Walter <ticso at cicely7.cicely.de> wrote:
> > 
> > > I'm trying to get the RTC on a Waveshare ARPI600 module running on a
> > > Raspberry Pi B.
> > > This is the Overlay I'm using:
> > > /dts-v1/;
> > > /plugin/;
> > > 
> > > &i2c0 {
> > > 	 status = "okay";
> > > 	  
> > > 	  rtc: rtc at 51 {
> > > 		  compatible = "nxp,pcf8563";
> > > 		  reg = <0x51>;
> > > 	  };
> > > };
> > > 
> > > IICbus gets probed during boot:
> > > iicbus0: <OFW I2C bus> on iichb0
> > > iic0: <I2C generic I/O> on iicbus0
> > > iicbus0: <unknown card> at addr 0xa2
> > > 
> > > When I load the nxprtc moduele I get the following error:
> > > nxprtc0: <NXP PCF8563 RTC> at addr 0xa2 on iicbus0
> > > nxprtc0: cannot set up timer
> > > 
> > > I wonder if I miss something, e.g. setting GPIO.
> > > However, for spi0 no GPIO setup was required and the overlay looks
> > > quite similar.
> > 
> >  Looking at the code it means that the driver didn't managed to talked
> > to the chip via i2c, the start_timer function is the first time that
> > i2c transfer is happening.
> 
> That's my understanding of the situation as well.
> 
> >  Could be either pinmux problems or frequency (default is 100khz so it
> > should work ok). 
> >  What pin are you using to connect to the module ?
> 
> Good point.
> It is connected to Pin3/5.
> Signals scoped turn out that they stay high.
> Pinout diagram show that the Pins are named SDA1/SCL1, so probably I'm
> just using the wrong controller.
> Will give it a test on i2c1 instead.

Yes, that was exactly the problem:
nxprtc0: <NXP PCF8563 RTC> at addr 0xa2 on iicbus0
nxprtc0: WARNING: RTC battery failed; time is invalid
nxprtc0: registered as a time-of-day clock, resolution 0.015625s

And, after putting it into loader.conf to be active on kernel start:
Setting date via ntp.
 4 Feb 11:34:31 ntpdate[727]: step time server 94.130.184.193 offset -0.120565 sec
Excellent, it kept time during reboot.

But not after power loss.
Mmmm.
Have to check if the battery is good.

> >  Also it seems that the overlay i2c-rtc.dtbo from the Rpi fundation
> > list this module but I'm unsure how to use this overlay. It is
> > installed via the rpi-firmware package.

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.