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