libtock: sensors: Support moisture sensor

Signed-off-by: Alistair Francis <[email protected]>

Author: alistair23

libtock-sync/sensors/moisture.c

@@ -0,0 +1,32 @@
+#include "moisture.h"
+
+typedef struct {
+  int moisture;
+  returncode_t ret;
+  bool fired;
+} moisture_result_t;
+
+static moisture_result_t result = {.fired = false};
+
+// callback for synchronous reads
+static void moisture_callback(returncode_t ret, int moisture) {
+  result.moisture = moisture;
+  result.ret      = ret;
+  result.fired    = true;
+}
+
+returncode_t libtocksync_moisture_read(int* moisture) {
+  returncode_t err;
+
+  result.fired = false;
+
+  err = libtock_moisture_read(moisture_callback);
+  if (err != RETURNCODE_SUCCESS) return err;
+
+  yield_for(&result.fired);
+  if (result.ret != RETURNCODE_SUCCESS) return result.ret;
+
+  *moisture = result.moisture;
+
+  return RETURNCODE_SUCCESS;
+}

libtock-sync/sensors/moisture.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <libtock/sensors/moisture.h>
+#include <libtock/tock.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Read the moisture sensor synchronously.
+//
+// ## Arguments
+//
+// - `moisture`: Set to the moisture in hundredths of a percent.
+//
+// ## Return Value
+//
+// A returncode indicating whether the sensor read was completed successfully.
+returncode_t libtocksync_moisture_read(int* moisture);
+
+#ifdef __cplusplus
+}
+#endif

libtock/sensors/moisture.c

@@ -0,0 +1,18 @@
+#include "moisture.h"
+
+static void moisture_upcall(int status,
+                            int moisture,
+                            __attribute__ ((unused)) int unused2, void* opaque) {
+  libtock_moisture_callback cb = (libtock_moisture_callback) opaque;
+  cb(status, moisture);
+}
+
+returncode_t libtock_moisture_read(libtock_moisture_callback cb) {
+  returncode_t err;
+
+  err = libtock_moisture_set_upcall(moisture_upcall, cb);
+  if (err != RETURNCODE_SUCCESS) return err;
+
+  err = libtock_moisture_command_read();
+  return err;
+}

libtock/sensors/moisture.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "../tock.h"
+#include "syscalls/moisture_syscalls.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Function signature for moisture data callback.
+//
+// - `arg1` (`int`): Returncode indicating status from sampling the sensor.
+// - `arg2` (`int`): moisture in hundredths of percent.
+typedef void (*libtock_moisture_callback)(returncode_t, int);
+
+// Start a moisture measurement. The reading will be provided via the callback.
+returncode_t libtock_moisture_read(libtock_moisture_callback cb);
+
+#ifdef __cplusplus
+}
+#endif

libtock/sensors/syscalls/moisture_syscalls.c

@@ -0,0 +1,15 @@
+#include "moisture_syscalls.h"
+
+bool libtock_moisture_exists(void) {
+  return driver_exists(DRIVER_NUM_MOISTURE);
+}
+
+returncode_t libtock_moisture_set_upcall(subscribe_upcall callback, void* opaque) {
+  subscribe_return_t sval = subscribe(DRIVER_NUM_MOISTURE, 0, callback, opaque);
+  return tock_subscribe_return_to_returncode(sval);
+}
+
+returncode_t libtock_moisture_command_read(void) {
+  syscall_return_t rval = command(DRIVER_NUM_MOISTURE, 1, 0, 0);
+  return tock_command_return_novalue_to_returncode(rval);
+}

libtock/sensors/syscalls/moisture_syscalls.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "../../tock.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define DRIVER_NUM_MOISTURE 0x6000A
+
+// Check if the moisture driver is installed.
+bool libtock_moisture_exists(void);
+
+// Configure the upcall for when the reading is ready.
+returncode_t libtock_moisture_set_upcall(subscribe_upcall callback, void* opaque);
+
+// Read the sensor.
+returncode_t libtock_moisture_command_read(void);
+
+#ifdef __cplusplus
+}
+#endif