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drivers: sensor: ntc_thermistor: add support for generic NTC

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Add support for a generic NTC, `ntc-thermistor-generic`. In this case,
the compensation table is provided via devicetree. Note that DT property
is prefixed with `zephyr,`, because while hardware related, it is linked
to a particular software implementation.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
This commit is contained in:
Gerard Marull-Paretas 2023-05-03 13:13:39 +02:00 • committed by Carles Cufí
commit 84fd4e671f
4 changed files with 40 additions and 1 deletions
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3
drivers/sensor/ntc_thermistor/Kconfig
View file

@ -5,7 +5,8 @@
config NTC_THERMISTOR
bool "NTC Thermistor"
default y
depends on DT_HAS_EPCOS_B57861S0103A039_ENABLED
depends on DT_HAS_NTC_THERMISTOR_GENERIC_ENABLED || \
DT_HAS_EPCOS_B57861S0103A039_ENABLED
select ADC
help
Enable driver for Zephyr NTC Thermistor.

10
drivers/sensor/ntc_thermistor/ntc_thermistor.c
View file

@ -132,7 +132,17 @@ static int ntc_thermistor_init(const struct device *dev)
&ntc_thermistor_cfg_##id##inst, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY, \
&ntc_thermistor_driver_api);
/* ntc-thermistor-generic */
#define DT_DRV_COMPAT ntc_thermistor_generic
#define NTC_THERMISTOR_GENERIC_DEFINE(inst) \
static const uint32_t comp_##inst[] = DT_INST_PROP(inst, zephyr_compensation_table); \
NTC_THERMISTOR_DEFINE(inst, DT_DRV_COMPAT, comp_##inst)
DT_INST_FOREACH_STATUS_OKAY(NTC_THERMISTOR_GENERIC_DEFINE)
/* epcos,b57861s0103a039 */
#undef DT_DRV_COMPAT
#define DT_DRV_COMPAT epcos_b57861s0103a039
static __unused const struct ntc_compensation comp_epcos_b57861s0103a039[] = {

17
dts/bindings/sensor/ntc-thermistor-generic.yaml Normal file
View file

@ -0,0 +1,17 @@
# Copyright (c) 2023 Nordic Semiconductor ASA
# SPDX-License-Identifier: Apache-2.0
description: Generic NTC thermistor
compatible: "ntc-thermistor-generic"
include: ntc-thermistor.yaml
properties:
zephyr,compensation-table:
type: array
required: true
description: |
Compensation table, formatted as temperature, resistance pairs. A script
to generate a valid table is provided in
scripts/utils/ntc_thermistor_table.py.

11
tests/drivers/build_all/sensor/adc.dtsi
View file

@ -23,6 +23,17 @@ test_adc_emul: adc {
status = "okay";
};
test_ntc_thermistor_generic: ntc-thermistor-generic {
compatible = "ntc-thermistor-generic";
io-channels = <&adc0 0>;
r25-ohm = <10000>;
pullup-uv = <3300000>;
pullup-ohm = <0>;
pulldown-ohm = <10000>;
connected-positive;
zephyr,compensation-table = <0 0>, <1 1>;
};
test_epcos_b57861s0103a039: epcos-b57861s0103a039 {
compatible = "epcos,b57861s0103a039";
io-channels = <&adc0 0>;