Browse Source
Added a driver which uses the nRF52's ADC channel on the VDDH pin to read the battery voltage when using high voltage mode.xmkb
Joel Spadin
4 years ago
committed by
Nick Winans
11 changed files with 236 additions and 56 deletions
@ -1,5 +1,5 @@
@@ -1,5 +1,5 @@
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# Copyright (c) 2020 The ZMK Contributors |
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# Copyright (c) 2020-2021 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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add_subdirectory_ifdef(CONFIG_ZMK_BATTERY_VOLTAGE_DIVIDER battery_voltage_divider) |
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add_subdirectory_ifdef(CONFIG_ZMK_BATTERY battery) |
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add_subdirectory_ifdef(CONFIG_EC11 ec11) |
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@@ -1,5 +1,5 @@
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# Copyright (c) 2020 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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rsource "battery_voltage_divider/Kconfig" |
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rsource "battery/Kconfig" |
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rsource "ec11/Kconfig" |
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# Copyright (c) 2020-2021 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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zephyr_include_directories(.) |
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zephyr_library() |
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zephyr_library_sources(battery_common.c) |
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zephyr_library_sources_ifdef(CONFIG_ZMK_BATTERY_NRF_VDDH battery_nrf_vddh.c) |
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zephyr_library_sources_ifdef(CONFIG_ZMK_BATTERY_VOLTAGE_DIVIDER battery_voltage_divider.c) |
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# Copyright (c) 2020-2021 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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config ZMK_BATTERY |
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bool "ZMK battery monitoring" |
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help |
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Enable battery monitoring |
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config ZMK_BATTERY_NRF_VDDH |
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bool "ZMK nRF VDDH battery monitoring" |
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select ADC |
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select ZMK_BATTERY |
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help |
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Enable ZMK nRF VDDH voltage driver for battery monitoring. |
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config ZMK_BATTERY_VOLTAGE_DIVIDER |
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bool "ZMK battery voltage divider" |
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select ADC |
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select ZMK_BATTERY |
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help |
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Enable ZMK battery voltage divider driver for battery monitoring. |
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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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/*
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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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#pragma once |
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#include <drivers/sensor.h> |
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#include <stdint.h> |
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struct battery_value { |
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uint16_t adc_raw; |
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uint16_t millivolts; |
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uint8_t state_of_charge; |
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}; |
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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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uint8_t lithium_ion_mv_to_pct(int16_t bat_mv); |
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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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* This is a simplified version of battery_voltage_divider.c which always reads |
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* the VDDHDIV5 channel of the &adc node and multiplies it by 5. |
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*/ |
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#define DT_DRV_COMPAT zmk_battery_nrf_vddh |
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#include <device.h> |
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#include <devicetree.h> |
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#include <drivers/adc.h> |
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#include <drivers/sensor.h> |
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#include <logging/log.h> |
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#include "battery_common.h" |
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LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL); |
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#define VDDHDIV (5) |
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static const struct device *adc = DEVICE_DT_GET(DT_NODELABEL(adc)); |
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struct vddh_data { |
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struct adc_channel_cfg acc; |
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struct adc_sequence as; |
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struct battery_value value; |
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}; |
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static int vddh_sample_fetch(const struct device *dev, enum sensor_channel chan) { |
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// Make sure selected channel is supported
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if (chan != SENSOR_CHAN_GAUGE_VOLTAGE && chan != SENSOR_CHAN_GAUGE_STATE_OF_CHARGE && |
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chan != SENSOR_CHAN_ALL) { |
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LOG_DBG("Selected channel is not supported: %d.", chan); |
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return -ENOTSUP; |
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} |
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struct vddh_data *drv_data = dev->data; |
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struct adc_sequence *as = &drv_data->as; |
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int rc = adc_read(adc, as); |
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as->calibrate = false; |
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if (rc != 0) { |
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LOG_ERR("Failed to read ADC: %d", rc); |
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return rc; |
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} |
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int32_t val = drv_data->value.adc_raw; |
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rc = adc_raw_to_millivolts(adc_ref_internal(adc), drv_data->acc.gain, as->resolution, &val); |
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if (rc != 0) { |
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LOG_ERR("Failed to convert raw ADC to mV: %d", rc); |
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return rc; |
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} |
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drv_data->value.millivolts = val * VDDHDIV; |
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drv_data->value.state_of_charge = lithium_ion_mv_to_pct(drv_data->value.millivolts); |
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LOG_DBG("ADC raw %d ~ %d mV => %d%%", drv_data->value.adc_raw, drv_data->value.millivolts, |
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drv_data->value.state_of_charge); |
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return rc; |
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} |
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static int vddh_channel_get(const struct device *dev, enum sensor_channel chan, |
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struct sensor_value *val) { |
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struct vddh_data const *drv_data = dev->data; |
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return battery_channel_get(&drv_data->value, chan, val); |
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} |
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static const struct sensor_driver_api vddh_api = { |
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.sample_fetch = vddh_sample_fetch, |
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.channel_get = vddh_channel_get, |
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}; |
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static int vddh_init(const struct device *dev) { |
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struct vddh_data *drv_data = dev->data; |
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if (!device_is_ready(adc)) { |
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LOG_ERR("ADC device is not ready %s", adc->name); |
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return -ENODEV; |
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} |
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drv_data->as = (struct adc_sequence){ |
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.channels = BIT(0), |
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.buffer = &drv_data->value.adc_raw, |
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.buffer_size = sizeof(drv_data->value.adc_raw), |
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.oversampling = 4, |
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.calibrate = true, |
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}; |
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#ifdef CONFIG_ADC_NRFX_SAADC |
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drv_data->acc = (struct adc_channel_cfg){ |
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.gain = ADC_GAIN_1_5, |
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.reference = ADC_REF_INTERNAL, |
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.acquisition_time = ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 40), |
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.input_positive = SAADC_CH_PSELN_PSELN_VDDHDIV5, |
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}; |
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drv_data->as.resolution = 12; |
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#else |
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#error Unsupported ADC |
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#endif |
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const int rc = adc_channel_setup(adc, &drv_data->acc); |
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LOG_DBG("VDDHDIV5 setup returned %d", rc); |
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return rc; |
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} |
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static struct vddh_data vddh_data; |
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DEVICE_DT_INST_DEFINE(0, &vddh_init, device_pm_control_nop, &vddh_data, NULL, POST_KERNEL, |
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CONFIG_SENSOR_INIT_PRIORITY, &vddh_api); |
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@@ -1,6 +0,0 @@
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# Copyright (c) 2020 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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zephyr_library() |
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zephyr_library_sources(battery_voltage_divider.c) |
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@@ -1,8 +0,0 @@
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# Copyright (c) 2020 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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config ZMK_BATTERY_VOLTAGE_DIVIDER |
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bool "ZMK battery voltage divider" |
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select ADC |
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help |
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Enable ZMK battery voltage divider driver for battery monitoring. |
@ -0,0 +1,11 @@
@@ -0,0 +1,11 @@
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# Copyright (c) 2021 The ZMK Contributors |
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# SPDX-License-Identifier: MIT |
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description: Battery SoC monitoring using nRF VDDH |
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compatible: "zmk,battery-nrf-vddh" |
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properties: |
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label: |
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required: true |
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type: string |
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