The AXP209 is a power management chip made by X-Powers for use mainly in Allwinner ARM system-on-a-chip reference designs. It can be found in quite a few systems, so if you've got a strange need to control it from a supported Rust target, this'll get you there.
The machines I know of so far using it:
- Next Thing Co.'s C.H.I.P computer
- Retro Games Ltd's C64 Mini
- Cubietech's early Cubieboards (A10, A20, Cubietruck)
The big challenge with interfacing with this chip is that because it controls power, the kernel has exclusive access to it. That's probably a good thing if you don't know what you're doing, and if you brick your little computer, that's on you. 😜
This driver doesn't try to implement every feature yet and only supports the following:
- Reading various channels of the ADC
- Internal temperature
- Battery level (0 - 100%)
- Battery voltage, charging amperage, draining amperage
- VBUS voltage, amperage (usually tied to USB input)
- Power input voltage, amperage (additional external power)
- TS input (for external temperatures or backup battery)
- Voltage at GPIO 0 or 1
- Reading the power status
- Is external power coming in?
- Where's it coming from?
- Is there a battery attached?
- Is that battery (dis)charging?
- Using the internal 127 minute timer (see
timer_control) - Turning various output voltages on and off
Here's the output from the example program which runs on the PocketChip:
Battery level: 100%
Voltage: 4184mV
Discharge Current: 0mA
Charge Current: 0mA
ACIN Voltage: 0mV
ACIN Current: 0mA
Vbus Voltage: 0mV
Vbus Current: 0mA
Temperature: 47°C
Temp Sensor Pin: 0mV
Ipsout?!: 4583mV
ADC Control Flags: BATTERY_VOLTAGE | BATTERY_CURRENT | ACIN_VOLTAGE | ACIN_CURRENT | APS_VOLTAGE | TS | TEMPERATURE
Power Control Flags: LDO3 | DCDC2 | LDO4 | LDO2 | DCDC3 | EXTEN
Power Status Flags: VBUS_PRESENT | VBUS_USABLE | VBUS_ABOVE_HOLD | START_ON_POWER
Charge Status Flags: BATTERY_PRESENT
Timer:
Expired: false
Time (minutes): 0
If there's a feature you'd like to see implemented, either open an issue or create a pull request if you're feeling helpful. Also feel free to open an issue if you have general questions.
If you need some examples, check the examples folder. The
5FDF
y won't work until
if you have a kernel that is accessing to the chip so expect some difficulty
there. Because I was using the chip on a single board computer, I had to
re-compile my kernel with every AXP20X feature disabled.
This crate is distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.