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sensor: current_amp: add a noise threshold

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ADC output values can have noise, even if the input is 0V. Add a noise
threshold so that raw ADC readings below the threshold can be zeroed
out. By default the threshold is disabled.

Signed-off-by: Jordan Yates <jordan@embeint.com>
This commit is contained in:
Jordan Yates 2025-02-20 13:45:47 +10:00 committed by Benjamin Cabé
parent 98f14b3ef0
commit c7bc268656
3 changed files with 18 additions and 3 deletions
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6
drivers/sensor/current_amp/current_amp.c
View File

@ -6,6 +6,8 @@
#define DT_DRV_COMPAT current_sense_amplifier
#include <stdlib.h>
#include <zephyr/drivers/adc.h>
#include <zephyr/drivers/adc/current_sense_amplifier.h>
#include <zephyr/drivers/gpio.h>
@ -53,6 +55,10 @@ static int get(const struct device *dev, enum sensor_channel chan, struct sensor
return -ENOTSUP;
}
if (abs(raw_val) < config->noise_threshold) {
return sensor_value_from_micro(val, 0);
}
ret = adc_raw_to_millivolts_dt(&config->port, &raw_val);
if (ret != 0) {
LOG_ERR("raw_to_mv: %d", ret);

7
dts/bindings/iio/afe/current-sense-amplifier.yaml
View File

@ -51,3 +51,10 @@ properties:
description: |
Enable calibration of the current sense amplifier.
This is used to calibrate the ADC prior to taking measurements.
zephyr,noise-threshold:
type: int
default: 0
description: |
Raw ADC readings below this threshold are treated as noise and
reported as 0 uA. The default value of 0 disables the threshold.

8
include/zephyr/drivers/adc/current_sense_amplifier.h
View File

@ -11,11 +11,12 @@
#include <zephyr/drivers/gpio.h>
struct current_sense_amplifier_dt_spec {
const struct adc_dt_spec port;
struct adc_dt_spec port;
struct gpio_dt_spec power_gpio;
uint32_t sense_milli_ohms;
uint16_t sense_gain_mult;
uint16_t sense_gain_div;
struct gpio_dt_spec power_gpio;
uint16_t noise_threshold;
bool enable_calibration;
};
@ -32,10 +33,11 @@ struct current_sense_amplifier_dt_spec {
#define CURRENT_SENSE_AMPLIFIER_DT_SPEC_GET(node_id) \
{ \
.port = ADC_DT_SPEC_GET(node_id), \
.power_gpio = GPIO_DT_SPEC_GET_OR(node_id, power_gpios, {0}), \
.sense_milli_ohms = DT_PROP(node_id, sense_resistor_milli_ohms), \
.sense_gain_mult = DT_PROP(node_id, sense_gain_mult), \
.sense_gain_div = DT_PROP(node_id, sense_gain_div), \
.power_gpio = GPIO_DT_SPEC_GET_OR(node_id, power_gpios, {0}), \
.noise_threshold = DT_PROP(node_id, zephyr_noise_threshold), \
.enable_calibration = DT_PROP_OR(node_id, enable_calibration, false), \
}