1wire DS18b20 on Rock64?

[mcerveny]

Has anyone got DS18b20 to work on rock64?

Yes. Step by step:

1. Hardware setup: I suppose pin12 is unusable (works only as input). Let's make following pin connection setup - rock64 pin1 (3.3V) = DS18B20 pin3 (VDD), rock64 pin7 (GPIO1_D4) = DS18B20 pin2 (DQ), rock64 pin9 (GND) = DS18B20 pin1 (GND) and pullup resistor 4k7 ohm between DS18B20 pin3 and DS18B20 pin2.
   
2. Prepare DTOVERLAY for "w1_gpio" driver association. Let's assume GPIO1_D4 == id 60, GPIO1_D4 == GPIO1 + bit 28.
   
   Code:

   $ cat > w1_pin60.dts << 'EOF'
/dts-v1/;
/plugin/;

/ {
    compatible = "pine64,rock64", "rockchip,rk3328";
    fragment@0 {
        target-path = "/";
        __overlay__ {
            w1: onewire@0 {
                compatible = "w1-gpio";
                pinctrl-names = "default";
                pinctrl-0 = <&w1_pins>;
                gpios = <&gpio1 28 0>;
                status = "okay";
            };
        };
    };
    fragment@1 {
        target = <&gpio1>;
        __overlay__ {
            w1_pins: w1_pins@0 {
                rockchip,pins = <1 28 0 &pcfg_pull_up>;
            };
        };
    };
};
EOF
$ dtc -I dts -O dtb -@ w1_pin60.dts -o w1_pin60.dtbo
$ ### ignore warnings
3. Successful load of DTOVERLAY depends on your device tree (DTB symbols must be included). Check DTB symbols if exists skip to step 5.
   
   Code:

   $ dtc /boot/dtbs/$(uname -r)/rockchip/rk3328-rock64.dtb -o - 2>/dev/null | grep __symbols__
    __symbols__ {
$ ### ^^^^ symbols included or not included if no output
4. Symbols are NOT present in latest stable 0.7.9 based on kernel 4.4.132-1075
   So you must rebuild rk3328-rock64.dtb with symbols.
   
   Code:

   $ uname -a
Linux rock64 4.4.132-1075-rockchip-ayufan-ga83beded8524 #1 SMP Thu Jul 26 08:22:22 UTC 2018 aarch64 aarch64 aarch64 GNU/Linux
$ sudo bash
# wget https://github.com/ayufan-rock64/linux-kernel/archive/4.4.132-1075-rockchip-ayufan.tar.gz
# tar xzf 4.4.132-1075-rockchip-ayufan.tar.gz
# cd linux-kernel-4.4.132-1075-rockchip-ayufan/
# export ARCH=arm64
# make rockchip_linux_defconfig
# make DTC_FLAGS="-@" dtbs
# mv /boot/dtbs/4.4.132-1075-rockchip-ayufan-ga83beded8524/rockchip/rk3328-rock64.dtb /boot/dtbs/4.4.132-1075-rockchip-ayufan-ga83beded8524/rockchip/rk3328-rock64.dtb_orig
# cp arch/arm64/boot/dts/rockchip/rk3328-rock64.dtb /boot/dtbs/4.4.132-1075-rockchip-ayufan-ga83beded8524/rockchip/rk3328-rock64.dtb
# reboot
# ### after reboot check presented symbols
5. Load DTOVERLAY:
   
   Code:

   $ sudo bash
# ### speedup minimum CPU frequency due to polling behavior of w1-gpio
# echo 600000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq

# ### load DTOVERLAY
# mkdir -p /sys/kernel/config/device-tree/overlays/w1
# cat w1_pin60.dtbo > /sys/kernel/config/device-tree/overlays/w1/dtbo
# lsmod | grep w1
w1_gpio                16384  0
wire                   32768  1 w1_gpio

# find /sys/bus/w1/
/sys/bus/w1/
/sys/bus/w1/devices
/sys/bus/w1/devices/w1_bus_master1
/sys/bus/w1/drivers
/sys/bus/w1/drivers/w1_master_driver
/sys/bus/w1/drivers/w1_master_driver/bind
/sys/bus/w1/drivers/w1_master_driver/w1_bus_master1
/sys/bus/w1/drivers/w1_master_driver/uevent
/sys/bus/w1/drivers/w1_master_driver/unbind
/sys/bus/w1/drivers/w1_slave_driver
/sys/bus/w1/drivers/w1_slave_driver/bind
/sys/bus/w1/drivers/w1_slave_driver/uevent
/sys/bus/w1/drivers/w1_slave_driver/unbind
/sys/bus/w1/uevent
/sys/bus/w1/drivers_probe
/sys/bus/w1/drivers_autoprobe

# ### autoprobe should discover sensor after few seconds
# find /sys/bus/w1/
/sys/bus/w1/
/sys/bus/w1/devices
/sys/bus/w1/devices/w1_bus_master1
/sys/bus/w1/devices/28-000000423711
/sys/bus/w1/drivers
/sys/bus/w1/drivers/w1_master_driver
/sys/bus/w1/drivers/w1_master_driver/bind
/sys/bus/w1/drivers/w1_master_driver/w1_bus_master1
/sys/bus/w1/drivers/w1_master_driver/uevent
/sys/bus/w1/drivers/w1_master_driver/unbind
/sys/bus/w1/drivers/w1_slave_driver
/sys/bus/w1/drivers/w1_slave_driver/bind
/sys/bus/w1/drivers/w1_slave_driver/28-000000423711
/sys/bus/w1/drivers/w1_slave_driver/uevent
/sys/bus/w1/drivers/w1_slave_driver/unbind
/sys/bus/w1/uevent
/sys/bus/w1/drivers_probe
/sys/bus/w1/drivers_autoprobe

# ### check w1
# grep '' /sys/bus/w1/devices/w1_bus_master1/w1_master_slave_count /sys/bus/w1/devices/w1_bus_master1/w1_master_slaves
/sys/bus/w1/devices/w1_bus_master1/w1_master_slave_count:1
/sys/bus/w1/devices/w1_bus_master1/w1_master_slaves:28-000000423711

# ### thermal driver automatically loaded
# lsmod | grep w1
w1_therm               16384  0
w1_gpio                16384  0
wire                   32768  2 w1_gpio,w1_therm

# ### read temperature
# cat /sys/bus/w1/devices/*/w1_slave
6b 01 4b 46 7f ff 05 10 49 : crc=49 YES
6b 01 4b 46 7f ff 05 10 49 t=22687

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