nRF52840 Power Management Stage 1 v2.1 - Boot lockout fix

[entr0p1]

Improvements:

• Add configurable battery chemistry
• Add per-chemistry LPCOMP wake threshold and boot lockout voltage
• Add configurable enabled/disabled state for boot lockout
• Reduce Li-ion/Li-Po lockout threshold to 3.0V from 3.3V
• Initialise FS earlier in the startup process to allow reading configured settings for boot lock

Fixes:

• Add additional shutdown reason "None" for instances where the reason isn't set
• Boot lockout disabled by default

[MGJ520]

Good job

[entr0p1]

Tested on a couple of boards now without issues so far. Ready to be reviewed.

[Pacjunk]

Does setting pwrmgt.bootlock to off also prevent the low voltage shutdown? or is it only for boot?

[recrof]

I truly understand what @entr0p1 wanted to do here and I respect it, however: I feel this became tad too over-engineered and we need to regroup and make it really simple:
ability to configure shutdown voltage and make it 0V as default. adding chemistries raises complexity and resources - we need to get rid of that. make the feature opt-in and not opt-out is also important.

[entr0p1]

@recrof appreciate the respectful approach you've taken, I'm not fussed if it has to be pared right back or removed entirely. The fix is here if desired, but if you'd rather a different approach I won't be offended if you want to close it and do that.

[fschrempf]

I truly understand what @entr0p1 wanted to do here and I respect it, however: I feel this became tad too over-engineered and we need to regroup and make it really simple:
ability to configure shutdown voltage and make it 0V as default. adding chemistries raises complexity and resources - we need to get rid of that.

100% agree.

make the feature opt-in and not opt-out is also important.

This is the most crucial point. #1413 was not ready for merging and still got merged for v1.12. It broke a lot of setups and now three months and three releases later things are still broken. People need to modify their firmware manually and climb on roofs because of this.

Can we please either:

1. leave the current code as is, but add a configuration option that enables/disables the undervoltage bootlock and have this option disabled by default or
2. just disable NRF52_POWER_MANAGEMENT for all boards.

Thanks!

[ssozonoff]

When the final decision has been made and code merged and released it will be important to communicate about this in any case. I personally believe we will be seeing more and more LTO and Sodium-ion based repeaters in the future.

[fschrempf]

just disable NRF52_POWER_MANAGEMENT for all boards.

I've implemented this as a quick fix in #2377. After deciding on and implementing a proper solution this can be reenabled.

[entr0p1]

I've been thinking about this more and based on what @recrof said I remembered we already have an auto shutdown voltage in the companion firmware (I think its in others now too?). Couldn't we basically drop this entire feature out of the codebase and just build on that to make the voltage configurable via the CLI?

No chemistries, wake, or lockouts to worry about and the code basically exists and just needs a pref added.

Thoughts?

[1nerdherder]

My thoughts after being on the 2088 adventure:
In a world where people are getting busier and reading less, I agree simpler is better.
The majority of users will not be concerned with this feature because they are using standard boards, generally with the one chemistry allowed. If they do go "custom" with an external solar battery charge controller, or some other adaptation, it will be too difficult for the firmware to know all the permutations (it would be a rather large table chasing innovation). So, those of us who are using advanced configurations, should be knowledgeable enough to change the defaults.
Simplifying to one parameter (the low voltage shutdown level - using zero to disable it completely) is a good start.
The only downside I can think of is that we lose the ability to tell the iOS/Android app what battery type it is so it can calculate percentage. However I have full confidence that someone smart will figure that one out at some point.