fix: Disable battery sensors if reporting is off

[caksoylar]

Currenly when ZMK_BATTERY_REPORTING is turned off, builds with battery sensors fail due to a kernel init priority missing (ex. 1, 2), which I think is due to SENSOR Kconfig not getting selected.

Ideally the sensors wouldn't be enabled at all if battery level reporting is disabled but having them in the DT automatically enables them. This change disables them (in a bit of a roundabout way) through disabling ZMK_BATTERY:

zmk/app/drivers/sensor/CMakeLists.txt

Line 4 in bbb27ac

add_subdirectory_ifdef(CONFIG_ZMK_BATTERY battery)

Another option to directly disable the symbols would be to add depends on ZMK_BATTERY_REPORTING on each sensor, but this seemed slightly better to me. Let me know if that makes more sense.

Alternatively, maybe there is a more direct way to fix the kernel init priority warning, in which case the sensors would get compiled but not have an effect if reporting is disabled.

[petejohanson]

One thought on the approach chosen here.

[petejohanson]

This seems reasonable, but why not also make this depends on SENSOR as an alternative?

[caksoylar]

If I understand you correctly that sounds like one of the other alternatives I mentioned:

Another option to directly disable the symbols would be to add depends on ZMK_BATTERY_REPORTING on each sensor, but this seemed slightly better to me. Let me know if that makes more sense.

But depends on SENSOR is probably better that that 😄

[caksoylar]

Although, in that case the battery sensors would still get compiled in if SENSOR is enabled through some other symbol like ZMK_KEYMAP_SENSORS.

[caksoylar]

I pushed a fixup commit that converts to that; everything builds OK but enabling sensors gets the battery sensors (but not reporting) enabled as well:

> west build -d build/kl2 -b nice_nano_v2 -- -DSHIELD=kyria_left -DCONFIG_ZMK_BATTERY_REPORTING=n -DCONFIG_EC11=y
[...]
> rg BATTERY build/kl2/zephyr/.config
87:# CONFIG_ZMK_BATTERY_REPORTING is not set
238:CONFIG_DT_HAS_ZMK_BATTERY_NRF_VDDH_ENABLED=y
481:CONFIG_ZMK_BATTERY=y
482:CONFIG_ZMK_BATTERY_NRF_VDDH=y

Not sure if that's an issue or not, I can keep or drop the commit depending on what you prefer.

[petejohanson]

I think that's expected behavior, if the nodes are enabled, and the necessary support Kconfig symbols are enabled, we auto-enable the driver. You'd either disable the node in the DTS, or disable it explicitly in the Kconfig as well.

[caksoylar]

Got it, does the current state look good in that case?

[petejohanson]

Yes, I believe this is correct now. Thanks!

[petejohanson]

Thanks!