43 lines
1 KiB
C
43 lines
1 KiB
C
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/*
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* Copyright (c) 2021 The ZMK Contributors
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*
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* SPDX-License-Identifier: MIT
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*/
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#include <errno.h>
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#include <drivers/sensor.h>
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#include "battery_common.h"
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int battery_channel_get(const struct battery_value *value, enum sensor_channel chan,
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struct sensor_value *val_out) {
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switch (chan) {
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case SENSOR_CHAN_GAUGE_VOLTAGE:
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val_out->val1 = value->millivolts / 1000;
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val_out->val2 = (value->millivolts % 1000) * 1000U;
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break;
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case SENSOR_CHAN_GAUGE_STATE_OF_CHARGE:
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val_out->val1 = value->state_of_charge;
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val_out->val2 = 0;
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break;
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default:
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return -ENOTSUP;
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}
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return 0;
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}
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uint8_t lithium_ion_mv_to_pct(int16_t bat_mv) {
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// Simple linear approximation of a battery based off adafruit's discharge graph:
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// https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages
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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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