Re: DS1307 on rpi4B

I forgot mentioning the FreeBSD version. I’m still using 14.1.

2024年12月7日土曜日 風來散人 <furaisanjin@gmail.com>:

> Hello all,
>
> I'm trying connect DS1307 on rpi4B (8M). I'm not sure how much I can rely
> on the description in https://github.com/raspberrypi/firmware/tree/
> master/boot/overlays because I don't know the difference between linux
> boot loader and FreeBSD one.
>
> I want to connect DS1307 on GPIO12/13 pin as i2c5 so I assumed i2c-rtc
> could be used so that I added one line in config.txt like below.
>
> dtoverlay=i2c-rtc,ds1307,i2c5,addr=0x68
>
> iic1 is detected at boot but it can't talk to DS1307.
>
> # dmesg | egrep iic\|ds1307
> iichb0: <BCM2708/2835 BSC controller> mem 0x7e804000-0x7e804fff irq 27 on
> simplebus0
> iichb1: <BCM2708/2835 BSC controller> mem 0x7e205a00-0x7e205bff irq 52 on
> simplebus0
> iicbus0: <OFW I2C bus> on iichb0
> iic0: <I2C generic I/O> on iicbus0
> iicbus1: <OFW I2C bus> on iichb1
> iic1: <I2C generic I/O> on iicbus1
> ds13070: <Dallas DS1307> at addr 0xd0 on iicbus1
> ds13070: is_dev_time_valid: cannot read from RTC: 35
> ds13070: WARNING: RTC clock stopped, check the battery.
> ds13070: registered as a time-of-day clock, resolution 1.000000s
> ds13070: ds1307_gettime: cannot read from RTC: 35
> ds13070: ds1307_settime: cannot write to RTC: 35
>
> The command "i2c -s -v -f /dev/iic1" can't detect anything at all. The pin
> function doesn't seem to be correct.
> # sysctl -a dev.gpio.0.pin|grep 1[23]
> dev.gpio.0.pin.13.function: input
> dev.gpio.0.pin.12.function: input
>
> If I set alt5 on these pins by sysctl and change pin configuration by
> gpioctl to enable internal pullup, iic1 works fine.
> ---
> for p in 12 13
> do
>   sysctl dev.gpio.0.pin.$p.function=alt5
>   gpioctl -c $p PU
> done
> i2c -s -v -f /dev/iic1
> /root/src/ds1307 -r -a 0x68 -f /dev/iic1
> ---
>
> I'm not familiar with dts stuff but I wrote overlay dts like this.
> /dts-v1/;
> /plugin/;
> /  {
>
>         compatible = "raspberrypi,4-model-b", "brcm,bcm2711";
>         fragment@0 {
>                         target = <&i2c5>;
>                         __overlay__ {
>                         brcm,pins = <12 13>;
>                         brcm,function = <2>;
>                         brcm,pull = <2 2>;
>                         status = "okay";
>                 };
>
>         };
> };
> However this doesn't work at all. How can I configure gpio12/13 for i2c5?
>
> Best regards,
> furaisanjin
>
>
>