presence: Add gpio presence sensor

Add a gpio presence implementation of the PresenceSensor
interface.

The gpio sensor simply maps the on off state of a gpio
directly to the xyz.openbmc_project.Inventory.Item
Present property.

Change-Id: I071dd475bebb15372edb59506352746c20542eff
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/presence/gpio.cpp b/presence/gpio.cpp
new file mode 100644
index 0000000..dfd72db
--- /dev/null
+++ b/presence/gpio.cpp
@@ -0,0 +1,98 @@
+/**
+ * Copyright © 2017 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <memory>
+#include <phosphor-logging/elog-errors.hpp>
+#include <phosphor-logging/elog.hpp>
+#include <tuple>
+#include <xyz/openbmc_project/Common/Callout/error.hpp>
+#include "gpio.hpp"
+#include "rpolicy.hpp"
+#include "sdevent.hpp"
+
+namespace phosphor
+{
+namespace fan
+{
+namespace presence
+{
+
+Gpio::Gpio(
+        const std::string& physDevice,
+        unsigned int physPin) :
+    currentState(false),
+    evdevfd(open("/dev/input/by-path/platform-gpio-keys-event",
+                 O_RDONLY | O_NONBLOCK)),
+    evdev(evdevpp::evdev::newFromFD(evdevfd())),
+    phys(physDevice),
+    pin(physPin),
+    callback(nullptr)
+{
+
+}
+
+bool Gpio::start()
+{
+    callback = std::make_unique<sdevent::event::io::IO>(
+            util::SDEvent::getEvent(),
+            evdevfd(),
+            [this](auto& s){this->ioCallback(s);});
+    currentState = present();
+    return currentState;
+}
+
+void Gpio::stop()
+{
+    callback = nullptr;
+}
+
+bool Gpio::present()
+{
+    return evdev.fetch(EV_KEY, pin) != 0;
+}
+
+void Gpio::fail()
+{
+    using namespace sdbusplus::xyz::openbmc_project::Common::Callout::Error;
+    using namespace phosphor::logging;
+    using namespace xyz::openbmc_project::Common::Callout;
+
+    report<sdbusplus::xyz::openbmc_project::Common::Callout::Error::GPIO>(
+            GPIO::CALLOUT_GPIO_NUM(pin),
+            GPIO::CALLOUT_ERRNO(0),
+            GPIO::CALLOUT_DEVICE_PATH(phys.c_str()));
+}
+
+void Gpio::ioCallback(sdevent::source::Source& source)
+{
+    unsigned int type, code, value;
+
+    std::tie(type, code, value) = evdev.next();
+    if (type != EV_KEY || code != pin)
+    {
+        return;
+    }
+
+    bool newState = value != 0;
+
+    if (currentState != newState)
+    {
+        getPolicy().stateChanged(newState);
+        currentState = newState;
+    }
+}
+} // namespace presence
+} // namespace fan
+} // namespace phosphor