uartat, le910: initial implementation.

uartat is the underlying UART driver, specifically for use with
AT-style command driven devices like modems.

The le910 support is provided in the form of examples that make use
of the uartat driver to interact with the device.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/c++/CMakeLists.txt

@@ -373,3 +373,4 @@ endif()
 add_custom_example (nmea_gps_i2c_example-cxx nmea_gps_i2c.cxx nmea_gps)
 add_custom_example (mcp2515-txrx-example-cxx mcp2515-txrx.cxx mcp2515)
 add_custom_example (ads1015-example-cxx ads1015.cxx ads1x15)
+add_custom_example (le910-example-cxx le910.cxx uartat)

examples/c++/le910.cxx

@@ -0,0 +1,175 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2017 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <iostream>
+#include <string>
+
+#include "uartat.hpp"
+#include "upm_utilities.h"
+
+using namespace std;
+
+const size_t bufferLength = 256;
+
+int main(int argc, char **argv)
+{
+//! [Interesting]
+
+    string defaultDev = string("/dev/ttyUSB0");
+    if (argc > 1)
+        defaultDev = string(argv[1]);
+
+    cout << "Using device: " << defaultDev << endl;
+
+    // Instantiate a UARTAT sensor on defaultDev at 115200 baud.
+    upm::UARTAT *sensor = new upm::UARTAT(defaultDev, 115200);
+
+    // This is a simplistic example that tries to configure the LE910,
+    // and use it's built-in socket capabilities to connect to a
+    // remote host, obtain a small piece of data, and return it.  It's
+    // mainly intended to show you how you can use the various AT
+    // commands supported by the LE910 to perform simple tasks.
+    //
+    // You must have a valid SIM card with an active data plan for
+    // this example to do anything interesting.
+    //
+    // See the LE910 AT Commands reference for full information on
+    // what is possible with this device.  The uartat driver is
+    // intended to make it a little easier to control AT-style
+    // devices, but is by no means a full-featured communication
+    // infrastructure.  A "real" application will probably need to be
+    // much more sophisticated with regard to parsing, doing retries,
+    // etc.
+    //
+    // For experimenting with various AT commands, try using an
+    // interactive terminal emulator like minicom or screen.
+
+    // make sure we are in command mode
+    if (!sensor->inCommandMode())
+    {
+        cout << "Not in command mode, switching..." << endl;
+        sensor->commandMode("+++", 1000);
+    }
+
+    // flter out CR's in responses by default
+    sensor->filterCR(true);
+
+    cout << "Configuring modem..." << endl;
+
+    // discard any waiting characters
+    sensor->drain();
+
+    // reset modem
+    sensor->command("ATZ\r");
+
+    // turn off command echo, set verbosity to 1, enable data
+    // connection mode
+    sensor->command("ATE0 V1 +FCLASS=0\r");
+    sensor->drain();
+
+    // Now issue some commands and output the results.
+
+    cout << "Modem and SIM information:" << endl;
+    std::string buffer;
+    buffer = sensor->commandWithResponse("AT+ICCID\r", bufferLength);
+    if (!buffer.empty())
+        cout << "ICCID (SIM ID): "
+             << buffer
+             << endl;
+
+    buffer = sensor->commandWithResponse("AT+CGSN=1\r", bufferLength);
+    if (!buffer.empty())
+        cout << "IMEI: "
+             << buffer
+             << endl;
+
+    // see if we are on the network....
+    buffer = sensor->commandWithResponse("AT+CREG?\r", bufferLength);
+    if (!buffer.empty())
+    {
+        cout << buffer << endl;
+
+        // look for "CGREG: 0,1" or "CGREG: 0,5"
+        if (sensor->find(buffer, "CREG: 0,1") ||
+            sensor->find(buffer, "CREG: 0,5"))
+        {
+            cout << "Connected to the cell data network." << endl;
+
+            // wait up to 5 seconds for responses now...
+            sensor->setResponseWaitTime(5000);
+
+            // setup PDP context (socket 1).  An ERROR repsonse is
+            // possible if the PDP context is already set up.
+            sensor->command("AT#SGACT=1,1\r");
+
+            // setup a TCP socket to nist.gov and read the timestamp.
+
+            cout << "Connecting to time-a.nist.gov, TCP port 13" << endl;
+
+            // Wait up to 60 seconds to find the NO CARRIER
+            // string, which will be present at the end, if the
+            // connection succeeded and the requested data was
+            // obtained.
+            buffer =
+                sensor->commandWaitFor("AT#SD=1,0,13,\"time-a.nist.gov\"\r",
+                                       bufferLength, "\nNO CARRIER\n", 60000);
+            if (!buffer.empty())
+            {
+                // print out the response
+                cout << "RESPONSE: "
+                     << endl
+                     << buffer
+                     << endl;
+            }
+            else
+            {
+                cout << "No response." << endl;
+            }
+
+            // destroy PDP context
+            sensor->setResponseWaitTime(250);
+            sensor->command("AT#SGACT=1,0\r");
+        }
+        else
+        {
+            cout << "You do not appear to be connected to the network..."
+                 << endl;
+        }
+    }
+    else
+    {
+        cout << "Error executing query\n" << endl;
+    }
+
+    // reset the modem
+    sensor->command("ATZ\r");
+
+    cout << "Exiting" << endl;
+
+    delete sensor;
+
+//! [Interesting]
+
+    return 0;
+}