From adb07926b1d6760e63e19134b338f8b1ba460483 Mon Sep 17 00:00:00 2001 From: Nick Date: Sat, 24 Oct 2020 18:52:34 -0500 Subject: Remove newlib dep --- app/drivers/zephyr/battery_voltage_divider.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'app/drivers') diff --git a/app/drivers/zephyr/battery_voltage_divider.c b/app/drivers/zephyr/battery_voltage_divider.c index 6139d46..5bac544 100644 --- a/app/drivers/zephyr/battery_voltage_divider.c +++ b/app/drivers/zephyr/battery_voltage_divider.c @@ -7,12 +7,10 @@ #define DT_DRV_COMPAT zmk_battery_voltage_divider #include -#include #include #include #include #include -#include LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL); @@ -47,10 +45,16 @@ struct bvd_data { }; static uint8_t lithium_ion_mv_to_pct(int16_t bat_mv) { - // Magic function that maps mV to this discharge graph from adafruit: + // Simple linear approximation of a battery based off adafruit's discharge graph: // https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages - return round(106.818 + - (-0.032685 - 106.818) / pow(1 + pow(bat_mv / 3679.35, 58.979), 0.347386)); + + if (bat_mv >= 4200) { + return 100; + } else if (bat_mv <= 3450) { + return 0; + } + + return bat_mv * 2 / 15 - 459; } static int bvd_sample_fetch(struct device *dev, enum sensor_channel chan) { @@ -142,7 +146,7 @@ static int bvd_init(struct device *dev) { if (drv_data->adc == NULL) { LOG_ERR("ADC %s failed to retrieve", drv_cfg->io_channel.label); - return -ENOENT; + return -ENODEV; } int rc = 0; @@ -151,7 +155,7 @@ static int bvd_init(struct device *dev) { drv_data->gpio = device_get_binding(drv_cfg->power_gpios.label); if (drv_data->gpio == NULL) { LOG_ERR("Failed to get GPIO %s", drv_cfg->power_gpios.label); - return -ENOENT; + return -ENODEV; } rc = gpio_pin_configure(drv_data->gpio, drv_cfg->power_gpios.pin, GPIO_OUTPUT_INACTIVE | drv_cfg->power_gpios.flags); -- cgit v1.2.3