Split HAL Digital Implementation files (#59)

Split to match the new headers. Uses a namespace 'hal' for internal functions and globals.
SPIAccumulator merged back into SPI header, as it was not a good split. Analog
accumulator will move back to analog input when the analog split is done.

hal/lib/athena/Relay.cpp

@@ -0,0 +1,118 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "HAL/Relay.h"
+
+#include "DigitalInternal.h"
+
+static_assert(sizeof(uint32_t) <= sizeof(void*),
+              "This file shoves uint32_ts into pointers.");
+
+using namespace hal;
+
+// Create a mutex to protect changes to the relay values
+static priority_recursive_mutex digitalRelayMutex;
+
+constexpr uint32_t kRelayPins = 8;
+
+extern "C" {
+bool checkRelayChannel(void* digital_port_pointer) {
+  DigitalPort* port = (DigitalPort*)digital_port_pointer;
+  return port->port.pin < kRelayPins;
+}
+
+/**
+ * Check a port to make sure that it is not nullptr and is a valid Relay port.
+ *
+ * Sets the status to contain the appropriate error.
+ *
+ * @return true if the port passed validation.
+ */
+static bool verifyRelayChannel(DigitalPort* port, int32_t* status) {
+  if (port == nullptr) {
+    *status = NULL_PARAMETER;
+    return false;
+  } else if (!checkRelayChannel(port)) {
+    *status = PARAMETER_OUT_OF_RANGE;
+    return false;
+  } else {
+    return true;
+  }
+}
+
+/**
+ * Set the state of a relay.
+ * Set the state of a relay output to be forward. Relays have two outputs and
+ * each is
+ * independently set to 0v or 12v.
+ */
+void setRelayForward(void* digital_port_pointer, bool on, int32_t* status) {
+  DigitalPort* port = (DigitalPort*)digital_port_pointer;
+  if (!verifyRelayChannel(port, status)) {
+    return;
+  }
+
+  {
+    std::lock_guard<priority_recursive_mutex> sync(digitalRelayMutex);
+    uint8_t forwardRelays = relaySystem->readValue_Forward(status);
+    if (on)
+      forwardRelays |= 1 << port->port.pin;
+    else
+      forwardRelays &= ~(1 << port->port.pin);
+    relaySystem->writeValue_Forward(forwardRelays, status);
+  }
+}
+
+/**
+ * Set the state of a relay.
+ * Set the state of a relay output to be reverse. Relays have two outputs and
+ * each is
+ * independently set to 0v or 12v.
+ */
+void setRelayReverse(void* digital_port_pointer, bool on, int32_t* status) {
+  DigitalPort* port = (DigitalPort*)digital_port_pointer;
+  if (!verifyRelayChannel(port, status)) {
+    return;
+  }
+
+  {
+    std::lock_guard<priority_recursive_mutex> sync(digitalRelayMutex);
+    uint8_t reverseRelays = relaySystem->readValue_Reverse(status);
+    if (on)
+      reverseRelays |= 1 << port->port.pin;
+    else
+      reverseRelays &= ~(1 << port->port.pin);
+    relaySystem->writeValue_Reverse(reverseRelays, status);
+  }
+}
+
+/**
+ * Get the current state of the forward relay channel
+ */
+bool getRelayForward(void* digital_port_pointer, int32_t* status) {
+  DigitalPort* port = (DigitalPort*)digital_port_pointer;
+  if (!verifyRelayChannel(port, status)) {
+    return false;
+  }
+
+  uint8_t forwardRelays = relaySystem->readValue_Forward(status);
+  return (forwardRelays & (1 << port->port.pin)) != 0;
+}
+
+/**
+ * Get the current state of the reverse relay channel
+ */
+bool getRelayReverse(void* digital_port_pointer, int32_t* status) {
+  DigitalPort* port = (DigitalPort*)digital_port_pointer;
+  if (!verifyRelayChannel(port, status)) {
+    return false;
+  }
+
+  uint8_t reverseRelays = relaySystem->readValue_Reverse(status);
+  return (reverseRelays & (1 << port->port.pin)) != 0;
+}
+}