feather-m0: add support for saul_bat_voltage

miri64 · crasbe · miri64 · commit 08b69362557f · 2025-09-05T10:27:30.000+02:00
Co-authored-by: crasbe &lt;crasbe@gmail.com&gt;
diff --git a/boards/feather-m0/Makefile.dep b/boards/feather-m0/Makefile.dep
@@ -1,5 +1,6 @@
 ifneq (,$(filter saul_default,$(USEMODULE)))
   USEMODULE += saul_gpio
+  USEMODULE += saul_bat_voltage
 endif
 
 # setup the samd21 arduino bootloader related dependencies
diff --git a/boards/feather-m0/Makefile.features b/boards/feather-m0/Makefile.features
@@ -15,5 +15,6 @@ FEATURES_PROVIDED += periph_usbdev
 # Put other features for this board (in alphabetical order)
 FEATURES_PROVIDED += arduino_analog
 FEATURES_PROVIDED += arduino_pins
+FEATURES_PROVIDED += board_bat_voltage
 FEATURES_PROVIDED += feather_shield
 FEATURES_PROVIDED += highlevel_stdio
diff --git a/boards/feather-m0/bat_voltage.c b/boards/feather-m0/bat_voltage.c
@@ -0,0 +1,32 @@
+/*
+ * SPDX-FileCopyrightText: 2024 TU Dresden
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+/**
+ * @ingroup     boards_feather-m0
+ * @ingroup     saul_bat_voltage
+ * @{
+ * @file
+ * @brief       Implementation of battery voltage convert function
+ *
+ * @author      Martine S. Lenders <martine.lenders@tu-dresden.de>
+ *
+ * @}
+ */
+
+#ifdef MODULE_SAUL_BAT_VOLTAGE
+#include "saul/bat_voltage.h"
+
+int16_t saul_bat_voltage_convert(int32_t adc_sample)
+{
+    /* See
+     * https://learn.adafruit.com/adafruit-feather-m0-basic-proto/power-management
+     *
+     * we return in millivolt so we set the reference voltage to 3300
+     * instead of 3.3
+     */
+    return (int16_t)((adc_sample * 2L * 3300L) / 1024L);
+}
+
+#endif /* MODULE_SAUL_BAT_VOLTAGE */
diff --git a/boards/feather-m0/include/bat_voltage_params.h b/boards/feather-m0/include/bat_voltage_params.h
@@ -0,0 +1,51 @@
+/*
+ * SPDX-FileCopyrightText: 2024 TU Dresden
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+#pragma once
+
+/**
+ * @ingroup     boards_feather-m0
+ * @{
+ *
+ * @file
+ * @brief       Configuration of SAUL mapped battery voltage information
+ *
+ * @author      Martine S. Lenders <martine.lenders@tu-dresden.de>
+ */
+
+#include "saul/bat_voltage.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief  Conversion function to convert ADC sample to battery voltage
+ *
+ * @param[in] adc_sample    The raw ADC sample.
+ *
+ * @return Voltage value in mV for phydat.
+ */
+int16_t saul_bat_voltage_convert(int32_t adc_sample);
+
+/**
+ * @brief   Battery voltage configuration
+ */
+static const saul_bat_voltage_params_t saul_bat_voltage_params[] =
+{
+    {
+        .name = "BAT",
+        .phydat_scale = -3,
+        .line = ADC_LINE(6),
+        .res = ADC_RES_10BIT,
+        .convert = saul_bat_voltage_convert,
+    },
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */
