Implement battery level interface (#24666)

Co-authored-by: Nick Brassel <nick@tzarc.org>

1 files changed, 51 insertions, 0 deletions

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+# Battery Driver
+
+This driver provides support for sampling battery level.
+
+## Usage
+
+To use this driver, add the following to your `rules.mk`:
+
+```make
+BATTERY_DRIVER_REQUIRED = yes
+```
+
+## Basic Configuration {#basic-configuration}
+
+Add the following to your `config.h`:
+
+|Define                    |Default |Description                                       |
+|--------------------------|--------|--------------------------------------------------|
+|`BATTERY_SAMPLE_INTERVAL` |`30000` |The time between battery samples in milliseconds. |
+
+## Driver Configuration {#driver-configuration}
+
+Driver selection can be configured in `rules.mk` as `BATTERY_DRIVER`. Valid values are `adc` (default), `vendor`, or `custom`. See below for information on individual drivers.
+
+### ADC Driver {#adc-driver}
+
+This is the default battery driver. The default configuration assumes the battery is connected to a ADC capable pin through a voltage divider.
+
+```make
+BATTERY_DRIVER = adc
+```
+
+The following `#define`s apply only to the `adc` driver:
+
+|Define                       |Default       |Description                                                   |
+|-----------------------------|--------------|--------------------------------------------------------------|
+|`BATTERY_PIN`                |*Not defined* |The GPIO pin connected to the voltage divider.                |
+|`BATTERY_REF_VOLTAGE_MV`     |`3300`        |The ADC reverence voltage, in millivolts.                     |
+|`BATTERY_VOLTAGE_DIVIDER_R1` |`100000`      |The voltage divider resistance, in kOhm. Set to 0 to disable. |
+|`BATTERY_VOLTAGE_DIVIDER_R1` |`100000`      |The voltage divider resistance, in kOhm. Set to 0 to disable. |
+|`BATTERY_ADC_RESOLUTION`     |`10`          |The ADC resolution configured for the ADC Driver.             |
+
+## Functions
+
+### `uint8_t battery_get_percent(void)` {#api-battery-get-percent}
+
+Sample battery level.
+
+#### Return Value {#api-battery-get-percent-return}
+
+The battery percentage, in the range 0-100.