Problem with PCF8563 RTC on Raspberry

[Bernd Walter]

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.

>  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.