qmk_firmware/drivers/battery/battery_adc.c
Joel Challis 6ee806f376
Implement battery level interface (#24666)
Co-authored-by: Nick Brassel <nick@tzarc.org>
2025-02-28 16:46:14 +11:00

56 lines
1.3 KiB
C

// Copyright 2025 QMK
// SPDX-License-Identifier: GPL-2.0-or-later
#include "analog.h"
#include "gpio.h"
#ifndef BATTERY_PIN
# error("BATTERY_PIN not configured!")
#endif
#ifndef BATTERY_REF_VOLTAGE_MV
# define BATTERY_REF_VOLTAGE_MV 3300
#endif
#ifndef BATTERY_VOLTAGE_DIVIDER_R1
# define BATTERY_VOLTAGE_DIVIDER_R1 100
#endif
#ifndef BATTERY_VOLTAGE_DIVIDER_R2
# define BATTERY_VOLTAGE_DIVIDER_R2 100
#endif
// TODO: infer from adc config?
#ifndef BATTERY_ADC_RESOLUTION
# define BATTERY_ADC_RESOLUTION 10
#endif
void battery_driver_init(void) {
gpio_set_pin_input(BATTERY_PIN);
}
uint16_t battery_driver_get_mv(void) {
uint32_t raw = analogReadPin(BATTERY_PIN);
uint32_t bat_mv = raw * BATTERY_REF_VOLTAGE_MV / (1 << BATTERY_ADC_RESOLUTION);
#if BATTERY_VOLTAGE_DIVIDER_R1 > 0 && BATTERY_VOLTAGE_DIVIDER_R2 > 0
bat_mv = bat_mv * (BATTERY_VOLTAGE_DIVIDER_R1 + BATTERY_VOLTAGE_DIVIDER_R2) / BATTERY_VOLTAGE_DIVIDER_R2;
#endif
return bat_mv;
}
uint8_t battery_driver_sample_percent(void) {
uint16_t bat_mv = battery_driver_get_mv();
// https://github.com/zmkfirmware/zmk/blob/3f7c9d7cc4f46617faad288421025ea2a6b0bd28/app/module/drivers/sensor/battery/battery_common.c#L33
if (bat_mv >= 4200) {
return 100;
} else if (bat_mv <= 3450) {
return 0;
}
return bat_mv * 2 / 15 - 459;
}