battery.h

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/*
 * Copyright 2024 Embeint Inc
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_DRIVERS_SENSOR_BATTERY_H_
#define ZEPHYR_INCLUDE_DRIVERS_SENSOR_BATTERY_H_
 
#include <stdint.h>
#include <errno.h>
 
#include <zephyr/devicetree.h>
#include <zephyr/math/interpolation.h>
#include <zephyr/sys/util_macro.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* Battery chemistry enumeration.
 * Value names must match those from dts/bindings/battery.yaml
 */
enum battery_chemistry {
        BATTERY_CHEMISTRY_UNKNOWN = 0,
        BATTERY_CHEMISTRY_NICKEL_CADMIUM,
        BATTERY_CHEMISTRY_NICKEL_METAL_HYDRIDE,
        BATTERY_CHEMISTRY_LITHIUM_ION,
        BATTERY_CHEMISTRY_LITHIUM_ION_POLYMER,
        BATTERY_CHEMISTRY_LITHIUM_ION_IRON_PHOSPHATE,
        BATTERY_CHEMISTRY_LITHIUM_ION_MANGANESE_OXIDE,
};
 
/* Length of open circuit voltage table */
#define BATTERY_OCV_TABLE_LEN 11
 
#define BATTERY_CHEMISTRY_DT_GET(node_id)                                                          \
        UTIL_CAT(BATTERY_CHEMISTRY_, DT_STRING_UPPER_TOKEN_OR(node_id, device_chemistry, UNKNOWN))
 
#define BATTERY_OCV_TABLE_DT_GET(node_id, table)                                                   \
        COND_CODE_1(DT_NODE_HAS_PROP(node_id, table),                                              \
                    ({DT_FOREACH_PROP_ELEM_SEP(node_id, table, DT_PROP_BY_IDX, (,))}), ({-1}))
 
static inline int32_t battery_soc_lookup(const int32_t ocv_table[BATTERY_OCV_TABLE_LEN],
                                         uint32_t voltage_uv)
{
        static const int32_t soc_axis[BATTERY_OCV_TABLE_LEN] = {
                0, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000, 100000};
 
        /* Convert voltage to SoC */
        return linear_interpolate(ocv_table, soc_axis, BATTERY_OCV_TABLE_LEN, voltage_uv);
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* ZEPHYR_INCLUDE_DRIVERS_SENSOR_BATTERY_H_ */