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feat: Add nrf VDDH battery driver

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Added a driver which uses the nRF52's ADC channel on the VDDH pin to
read the battery voltage when using high voltage mode.
This commit is contained in:
Joel Spadin 2021-04-03 01:00:51 -05:00 committed by Nick Winans
parent 824d605c22
commit a6de43e665
11 changed files with 236 additions and 56 deletions
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4
app/drivers/sensor/CMakeLists.txt
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@ -1,5 +1,5 @@
# Copyright (c) 2020 The ZMK Contributors
# Copyright (c) 2020-2021 The ZMK Contributors
# SPDX-License-Identifier: MIT
add_subdirectory_ifdef(CONFIG_ZMK_BATTERY_VOLTAGE_DIVIDER battery_voltage_divider)
add_subdirectory_ifdef(CONFIG_ZMK_BATTERY battery)
add_subdirectory_ifdef(CONFIG_EC11 ec11)

2
app/drivers/sensor/Kconfig
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@ -1,5 +1,5 @@
# Copyright (c) 2020 The ZMK Contributors
# SPDX-License-Identifier: MIT
rsource "battery_voltage_divider/Kconfig"
rsource "battery/Kconfig"
rsource "ec11/Kconfig"

10
app/drivers/sensor/battery/CMakeLists.txt Normal file
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@ -0,0 +1,10 @@
# Copyright (c) 2020-2021 The ZMK Contributors
# SPDX-License-Identifier: MIT
zephyr_include_directories(.)
zephyr_library()
zephyr_library_sources(battery_common.c)
zephyr_library_sources_ifdef(CONFIG_ZMK_BATTERY_NRF_VDDH battery_nrf_vddh.c)
zephyr_library_sources_ifdef(CONFIG_ZMK_BATTERY_VOLTAGE_DIVIDER battery_voltage_divider.c)

21
app/drivers/sensor/battery/Kconfig Normal file
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@ -0,0 +1,21 @@
# Copyright (c) 2020-2021 The ZMK Contributors
# SPDX-License-Identifier: MIT
config ZMK_BATTERY
bool "ZMK battery monitoring"
help
Enable battery monitoring
config ZMK_BATTERY_NRF_VDDH
bool "ZMK nRF VDDH battery monitoring"
select ADC
select ZMK_BATTERY
help
Enable ZMK nRF VDDH voltage driver for battery monitoring.
config ZMK_BATTERY_VOLTAGE_DIVIDER
bool "ZMK battery voltage divider"
select ADC
select ZMK_BATTERY
help
Enable ZMK battery voltage divider driver for battery monitoring.

43
app/drivers/sensor/battery/battery_common.c Normal file
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@ -0,0 +1,43 @@
/*
* Copyright (c) 2021 The ZMK Contributors
*
* SPDX-License-Identifier: MIT
*/
#include <errno.h>
#include <drivers/sensor.h>
#include "battery_common.h"
int battery_channel_get(const struct battery_value *value, enum sensor_channel chan,
struct sensor_value *val_out) {
switch (chan) {
case SENSOR_CHAN_GAUGE_VOLTAGE:
val_out->val1 = value->millivolts / 1000;
val_out->val2 = (value->millivolts % 1000) * 1000U;
break;
case SENSOR_CHAN_GAUGE_STATE_OF_CHARGE:
val_out->val1 = value->state_of_charge;
val_out->val2 = 0;
break;
default:
return -ENOTSUP;
}
return 0;
}
uint8_t lithium_ion_mv_to_pct(int16_t bat_mv) {
// Simple linear approximation of a battery based off adafruit's discharge graph:
// https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages
if (bat_mv >= 4200) {
return 100;
} else if (bat_mv <= 3450) {
return 0;
}
return bat_mv * 2 / 15 - 459;
}

21
app/drivers/sensor/battery/battery_common.h Normal file
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@ -0,0 +1,21 @@
/*
* Copyright (c) 2021 The ZMK Contributors
*
* SPDX-License-Identifier: MIT
*/
#pragma once
#include <drivers/sensor.h>
#include <stdint.h>
struct battery_value {
uint16_t adc_raw;
uint16_t millivolts;
uint8_t state_of_charge;
};
int battery_channel_get(const struct battery_value *value, enum sensor_channel chan,
struct sensor_value *val_out);
uint8_t lithium_ion_mv_to_pct(int16_t bat_mv);

116
app/drivers/sensor/battery/battery_nrf_vddh.c Normal file
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@ -0,0 +1,116 @@
/*
* Copyright (c) 2021 The ZMK Contributors
*
* SPDX-License-Identifier: MIT
*
* This is a simplified version of battery_voltage_divider.c which always reads
* the VDDHDIV5 channel of the &adc node and multiplies it by 5.
*/
#define DT_DRV_COMPAT zmk_battery_nrf_vddh
#include <device.h>
#include <devicetree.h>
#include <drivers/adc.h>
#include <drivers/sensor.h>
#include <logging/log.h>
#include "battery_common.h"
LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
#define VDDHDIV (5)
static const struct device *adc = DEVICE_DT_GET(DT_NODELABEL(adc));
struct vddh_data {
struct adc_channel_cfg acc;
struct adc_sequence as;
struct battery_value value;
};
static int vddh_sample_fetch(const struct device *dev, enum sensor_channel chan) {
// Make sure selected channel is supported
if (chan != SENSOR_CHAN_GAUGE_VOLTAGE && chan != SENSOR_CHAN_GAUGE_STATE_OF_CHARGE &&
chan != SENSOR_CHAN_ALL) {
LOG_DBG("Selected channel is not supported: %d.", chan);
return -ENOTSUP;
}
struct vddh_data *drv_data = dev->data;
struct adc_sequence *as = &drv_data->as;
int rc = adc_read(adc, as);
as->calibrate = false;
if (rc != 0) {
LOG_ERR("Failed to read ADC: %d", rc);
return rc;
}
int32_t val = drv_data->value.adc_raw;
rc = adc_raw_to_millivolts(adc_ref_internal(adc), drv_data->acc.gain, as->resolution, &val);
if (rc != 0) {
LOG_ERR("Failed to convert raw ADC to mV: %d", rc);
return rc;
}
drv_data->value.millivolts = val * VDDHDIV;
drv_data->value.state_of_charge = lithium_ion_mv_to_pct(drv_data->value.millivolts);
LOG_DBG("ADC raw %d ~ %d mV => %d%%", drv_data->value.adc_raw, drv_data->value.millivolts,
drv_data->value.state_of_charge);
return rc;
}
static int vddh_channel_get(const struct device *dev, enum sensor_channel chan,
struct sensor_value *val) {
struct vddh_data const *drv_data = dev->data;
return battery_channel_get(&drv_data->value, chan, val);
}
static const struct sensor_driver_api vddh_api = {
.sample_fetch = vddh_sample_fetch,
.channel_get = vddh_channel_get,
};
static int vddh_init(const struct device *dev) {
struct vddh_data *drv_data = dev->data;
if (!device_is_ready(adc)) {
LOG_ERR("ADC device is not ready %s", adc->name);
return -ENODEV;
}
drv_data->as = (struct adc_sequence){
.channels = BIT(0),
.buffer = &drv_data->value.adc_raw,
.buffer_size = sizeof(drv_data->value.adc_raw),
.oversampling = 4,
.calibrate = true,
};
#ifdef CONFIG_ADC_NRFX_SAADC
drv_data->acc = (struct adc_channel_cfg){
.gain = ADC_GAIN_1_5,
.reference = ADC_REF_INTERNAL,
.acquisition_time = ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 40),
.input_positive = SAADC_CH_PSELN_PSELN_VDDHDIV5,
};
drv_data->as.resolution = 12;
#else
#error Unsupported ADC
#endif
const int rc = adc_channel_setup(adc, &drv_data->acc);
LOG_DBG("VDDHDIV5 setup returned %d", rc);
return rc;
}
static struct vddh_data vddh_data;
DEVICE_DT_INST_DEFINE(0, &vddh_init, device_pm_control_nop, &vddh_data, NULL, POST_KERNEL,
CONFIG_SENSOR_INIT_PRIORITY, &vddh_api);

50
app/drivers/sensor/battery_voltage_divider/battery_voltage_divider.c → app/drivers/sensor/battery/battery_voltage_divider.c
View file

@ -7,11 +7,14 @@
#define DT_DRV_COMPAT zmk_battery_voltage_divider
#include <device.h>
#include <devicetree.h>
#include <drivers/gpio.h>
#include <drivers/adc.h>
#include <drivers/sensor.h>
#include <logging/log.h>
#include "battery_common.h"
LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
struct io_channel_config {
@ -37,24 +40,9 @@ struct bvd_data {
const struct device *gpio;
struct adc_channel_cfg acc;
struct adc_sequence as;
uint16_t adc_raw;
uint16_t voltage;
uint8_t state_of_charge;
struct battery_value value;
};
static uint8_t lithium_ion_mv_to_pct(int16_t bat_mv) {
// Simple linear approximation of a battery based off adafruit's discharge graph:
// https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages
if (bat_mv >= 4200) {
return 100;
} else if (bat_mv <= 3450) {
return 0;
}
return bat_mv * 2 / 15 - 459;
}
static int bvd_sample_fetch(const struct device *dev, enum sensor_channel chan) {
struct bvd_data *drv_data = dev->data;
const struct bvd_config *drv_cfg = dev->config;
@ -87,18 +75,18 @@ static int bvd_sample_fetch(const struct device *dev, enum sensor_channel chan)
as->calibrate = false;
if (rc == 0) {
int32_t val = drv_data->adc_raw;
int32_t val = drv_data->value.adc_raw;
adc_raw_to_millivolts(adc_ref_internal(drv_data->adc), drv_data->acc.gain, as->resolution,
&val);
uint16_t millivolts = val * (uint64_t)drv_cfg->full_ohm / drv_cfg->output_ohm;
LOG_DBG("ADC raw %d ~ %d mV => %d mV", drv_data->adc_raw, val, millivolts);
LOG_DBG("ADC raw %d ~ %d mV => %d mV", drv_data->value.adc_raw, val, millivolts);
uint8_t percent = lithium_ion_mv_to_pct(millivolts);
LOG_DBG("Percent: %d", percent);
drv_data->voltage = millivolts;
drv_data->state_of_charge = percent;
drv_data->value.millivolts = millivolts;
drv_data->value.state_of_charge = percent;
} else {
LOG_DBG("Failed to read ADC: %d", rc);
}
@ -119,23 +107,7 @@ static int bvd_sample_fetch(const struct device *dev, enum sensor_channel chan)
static int bvd_channel_get(const struct device *dev, enum sensor_channel chan,
struct sensor_value *val) {
struct bvd_data *drv_data = dev->data;
switch (chan) {
case SENSOR_CHAN_GAUGE_VOLTAGE:
val->val1 = drv_data->voltage / 1000;
val->val2 = (drv_data->voltage % 1000) * 1000U;
break;
case SENSOR_CHAN_GAUGE_STATE_OF_CHARGE:
val->val1 = drv_data->state_of_charge;
val->val2 = 0;
break;
default:
return -ENOTSUP;
}
return 0;
return battery_channel_get(&drv_data->value, chan, val);
}
static const struct sensor_driver_api bvd_api = {
@ -173,8 +145,8 @@ static int bvd_init(const struct device *dev) {
drv_data->as = (struct adc_sequence){
.channels = BIT(0),
.buffer = &drv_data->adc_raw,
.buffer_size = sizeof(drv_data->adc_raw),
.buffer = &drv_data->value.adc_raw,
.buffer_size = sizeof(drv_data->value.adc_raw),
.oversampling = 4,
.calibrate = true,
};

6
app/drivers/sensor/battery_voltage_divider/CMakeLists.txt
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@ -1,6 +0,0 @@
# Copyright (c) 2020 The ZMK Contributors
# SPDX-License-Identifier: MIT
zephyr_library()
zephyr_library_sources(battery_voltage_divider.c)

8
app/drivers/sensor/battery_voltage_divider/Kconfig
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@ -1,8 +0,0 @@
# Copyright (c) 2020 The ZMK Contributors
# SPDX-License-Identifier: MIT
config ZMK_BATTERY_VOLTAGE_DIVIDER
bool "ZMK battery voltage divider"
select ADC
help
Enable ZMK battery voltage divider driver for battery monitoring.

11
app/drivers/zephyr/dts/bindings/sensor/zmk,battery-nrf-vddh.yaml Normal file
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@ -0,0 +1,11 @@
# Copyright (c) 2021 The ZMK Contributors
# SPDX-License-Identifier: MIT
description: Battery SoC monitoring using nRF VDDH
compatible: "zmk,battery-nrf-vddh"
properties:
label:
required: true
type: string