117 lines
3.2 KiB
C
117 lines
3.2 KiB
C
/*
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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, NULL, &vddh_data, NULL, POST_KERNEL,
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CONFIG_SENSOR_INIT_PRIORITY, &vddh_api);
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