PWM kinda works

code/nrf-connect/dts/bindings/pwm-fixed.yaml

@@ -0,0 +1,18 @@
+# Hello
+
+description: A fixed frequency & pulse PWM.
+
+compatible: pwm-fixed
+
+include: base.yaml
+
+properties:
+  pwms:
+    type: phandle-array
+    required: true
+    description: the PWM spec.
+
+  pulse:
+    required: true
+    type: int
+    description: The period of the PWM pulse.

code/nrf-connect/nrf52840dk_nrf52840.overlay

@@ -1,17 +1,5 @@
-// To get started, press Ctrl+Space (or Option+Esc) to bring up the completion menu and view the available nodes.
-
-// You can also use the buttons in the sidebar to perform actions on nodes.
-// Actions currently available include:
-
-// * Enabling / disabling the node
-// * Adding the bus to a bus
-// * Removing the node
-// * Connecting ADC channels
-
-// For more help, browse the DeviceTree documentation at https: //docs.zephyrproject.org/latest/guides/dts/index.html
-// You can also visit the nRF DeviceTree extension documentation at https: //nrfconnect.github.io/vscode-nrf-connect/devicetree/nrfdevicetree.html
-
 &pinctrl {
+	/* Configure pwm0 instance to use pin 5. */
 	pwm0_default: pwm0_default {
 		group1 {
 			psels = <NRF_PSEL(PWM_OUT0, 0, 5)>;
@@ -26,6 +14,7 @@
 		};
 	};
 
+	/* Configure i2c0 instance to use pins 24 (SDA) & 13 (SCL). */
 	i2c0_default: i2c0_default {
 		group1 {
 			psels = <NRF_PSEL(TWIM_SDA, 0, 24)>,
@@ -49,3 +38,11 @@
 		label = "SHTC3";
 	};
 };
+
+/ {
+	soil_pwm: soil_pwm {
+		compatible = "pwm-fixed";
+		pwms = <&pwm0 0 PWM_MSEC(100) PWM_POLARITY_INVERTED>;
+		pulse = <PWM_MSEC(50)>;
+	};
+};

code/nrf-connect/prj.conf

@@ -1,3 +1,4 @@
 CONFIG_LOG=y
+CONFIG_PWM=y
 CONFIG_CBPRINTF_FP_SUPPORT=y
 CONFIG_I2C=y

code/nrf-connect/src/main.c

@@ -1,4 +1,5 @@
 #include <drivers/i2c.h>
+#include <drivers/pwm.h>
 #include <logging/log.h>
 #include <zephyr/zephyr.h>
 
@@ -6,6 +7,16 @@
 
 LOG_MODULE_REGISTER(main, LOG_LEVEL_DBG);
 
+// PWM_DT_SPEC_GET(DT_LABEL(pwm0));
+static const struct pwm_dt_spec soil_pwm_dt =
+    PWM_DT_SPEC_GET(DT_NODELABEL(soil_pwm));
+static const uint32_t pulse = DT_PROP(DT_NODELABEL(soil_pwm), pulse);
+
 void main(void) {
-  prst_shtc3_read_t shtc3_read = prst_shtc3_read();
+  // prst_shtc3_read_t shtc3_read = prst_shtc3_read();
+  pwm_set_pulse_dt(&soil_pwm_dt, pulse);
+
+  while (true) {
+    k_msleep(500);
+  }
 }

code/nrf-connect/src/prst/adc.c

@@ -0,0 +1,3 @@
+#include "adc.h"
+
+prst_adc_photo_sensor_t prst_adc_photo_read(double battery_voltage) {}

code/nrf-connect/src/prst/adc.h

@@ -0,0 +1,34 @@
+#ifndef _PRST_ADC_H_
+#define _PRST_ADC_H_
+
+#include <stdint.h>
+
+typedef struct prst_adc_batt_val {
+  int16_t raw;
+  uint16_t millivolts;
+  double voltage;
+} prst_adc_batt_read_t;
+
+typedef struct prst_adc_soil_moisture {
+  int16_t raw;
+  // A value from 0 (completely dry) to 2^10 (completely wet).
+  uint16_t relative;
+  double percentage;
+} prst_adc_soil_moisture_t;
+
+typedef struct prst_adc_photo_sensor {
+  int16_t raw;
+  double voltage;
+  // Value in lux.
+  uint16_t brightness;
+} prst_adc_photo_sensor_t;
+
+void prst_adc_init();
+
+prst_adc_batt_read_t prst_adc_batt_read();
+
+prst_adc_soil_moisture_t prst_adc_soil_read(double battery_voltage);
+
+prst_adc_photo_sensor_t prst_adc_photo_read(double battery_voltage);
+
+#endif  // _PRST_ADC_H_