Add battery and fuel guage support to device tree

[hansemro]

Reference:

• Documentation/devicetree/bindings/power/supply/bq27xxx.yaml

Kindle Fire has BQ27541 on i2c.1 at register 0x55.

arch/arm/boot/dts/omap4-kc1.dts:

&i2c1 {
    ...
    bat: battery {
        compatible = "simple-battery";
        /* Documentation/devicetree/bindings/power/supply/battery.yaml */
    };

    ti,bq27541@55 {
        compatible = "ti,bq27541";
        reg = <0x55>;
        monitored-battery = <&bat>;
        /* Documentation/devicetree/bindings/power/supply/bq27xxx.yaml */
    };
    ...
};

[hansemro]

Kernel Log:

[    3.422821] i2c i2c-0: of_i2c: invalid reg on /ocp/interconnect@48000000/segment@0/target-module@70000/i2c@0/battery
[    3.434112] i2c i2c-0: Failed to create I2C device for /ocp/interconnect@48000000/segment@0/target-module@70000/i2c@0/battery
[    3.450134] bq27xxx-battery 0-0055: data memory update not supported for chip

sysfs:

amazon-otter:~# ls /sys/class/power_supply/bq27541-0/
capacity        current_now  manufacturer  subsystem      uevent
capacity_level      cycle_count  power         technology     voltage_now
charge_full     device   power_avg     temp
charge_full_design  health   present       time_to_empty_now
charge_now      hwmon1   status        type
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/capacity
100
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/capacity_level
Full
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/charge_full
3873000
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/charge_full_design
4400000
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/health
Good
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/cycle_count
78
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/temp
270
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/current_now
200000
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/voltage_now
4162000
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/type
Battery
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/manufacturer
Texas Instruments
amazon-otter:~# cat /sys/class/power_supply/bq27541-0/power_avg
775

Device tree seems to be working despite some warnings on battery.

[hansemro]

Added to dtb_dev (commit 2d07bdfddba7b687bb3acf6c8abaa54acac43e6a)

[hansemro]

Moving battery from i2c1 to root node / fixes i2c errors from above kernel log. This makes sense since the battery is not an i2c device. Fixed in commit 38d10bd46c47e87e33abac618edb725cabeea4dd.

[hansemro]

Merged to main (relevant pull request: #14)