Adding pin polarity and changing the constructor

To make this driver more useful, we needed to do some changes. The
wirings for the modem can differ on the board so we also need to be
flexible in our approach.
It is now mandatory to provide the power pin and pin polarity in the
constructor alongwith the file handle. Reset pin is optional.

Author: Hasnain Virk

features/cellular/framework/targets/QUECTEL/EC2X/QUECTEL_EC2X.cpp

@@ -25,6 +25,18 @@ using namespace mbed;
 using namespace rtos;
 using namespace events;
 
+#if !defined(MBED_CONF_QUECTEL_EC2X_PWR)
+#define MBED_CONF_QUECTEL_EC2X_PWR    NC
+#endif
+
+#if !defined(MBED_CONF_QUECTEL_EC2X_RST)
+#define MBED_CONF_QUECTEL_EC2X_RST    NC
+#endif
+
+#if !defined(MBED_CONF_QUECTEL_EC2X_POLARITY)
+#define MBED_CONF_QUECTEL_EC2X_POLARITY    1 // active high
+#endif
+
 static const intptr_t cellular_properties[AT_CellularBase::PROPERTY_MAX] = {
     AT_CellularNetwork::RegistrationModeLAC,    // C_EREG
     AT_CellularNetwork::RegistrationModeLAC,    // C_GREG
@@ -43,16 +55,15 @@ static const intptr_t cellular_properties[AT_CellularBase::PROPERTY_MAX] = {
     1,  // PROPERTY_AT_CGEREP
 };
 
-QUECTEL_EC2X::QUECTEL_EC2X(FileHandle *fh, PinName pwr, PinName rst)
+QUECTEL_EC2X::QUECTEL_EC2X(FileHandle *fh, PinName pwr, bool active_high, PinName rst)
     : AT_CellularDevice(fh),
-      _pwr_key(pwr, 0),
-      _rst(rst, 0)
-
+      _active_high(active_high),
+      _pwr_key(pwr, !_active_high),
+      _rst(rst, !_active_high)
 {
     AT_CellularBase::set_cellular_properties(cellular_properties);
 }
 
-#if MBED_CONF_QUECTEL_EC2X_PROVIDE_DEFAULT
 #include "UARTSerial.h"
 CellularDevice *CellularDevice::get_default_instance()
 {
@@ -62,18 +73,19 @@ CellularDevice *CellularDevice::get_default_instance()
 #if defined(MBED_CONF_QUECTEL_EC2X_RTS) && defined(MBED_CONF_QUECTEL_EC2X_CTS)
     serial.set_flow_control(SerialBase::RTSCTS, MBED_CONF_QUECTEL_EC2X_RTS, MBED_CONF_QUECTEL_EC2X_CTS);
 #endif
-    static QUECTEL_EC2X device(&serial, MBED_CONF_QUECTEL_EC2X_PWR, MBED_CONF_QUECTEL_EC2X_RST);
+    static QUECTEL_EC2X device(&serial,
+                               MBED_CONF_QUECTEL_EC2X_PWR,
+                               MBED_CONF_QUECTEL_EC2X_POLARITY,
+                               MBED_CONF_QUECTEL_EC2X_RST);
     return &device;
 }
 
 nsapi_error_t QUECTEL_EC2X::press_power_button(uint32_t timeout)
 {
-    if (_pwr_key.is_connected()) {
-        _pwr_key = 1;
-        ThisThread::sleep_for(timeout);
-        _pwr_key = 0;
-        ThisThread::sleep_for(100);
-    }
+    _pwr_key = _active_high;
+    ThisThread::sleep_for(timeout);
+    _pwr_key = !_active_high;
+    ThisThread::sleep_for(100);
 
     return NSAPI_ERROR_OK;
 }
@@ -92,24 +104,24 @@ nsapi_error_t QUECTEL_EC2X::hard_power_off()
 nsapi_error_t QUECTEL_EC2X::soft_power_on()
 {
     if (_rst.is_connected()) {
-        _rst = 1;
+        _rst = _active_high;
         ThisThread::sleep_for(460);
-        _rst = 0;
+        _rst = !_active_high;
         ThisThread::sleep_for(100);
-    }
 
-    _at->lock();
+        _at->lock();
 
-    _at->set_at_timeout(5000);
-    _at->resp_start();
-    _at->set_stop_tag("RDY");
-    bool rdy = _at->consume_to_stop_tag();
-    _at->set_stop_tag(OK);
+        _at->set_at_timeout(5000);
+        _at->resp_start();
+        _at->set_stop_tag("RDY");
+        bool rdy = _at->consume_to_stop_tag();
+        _at->set_stop_tag(OK);
 
-    _at->unlock();
+        _at->unlock();
 
-    if (!rdy) {
-        return NSAPI_ERROR_DEVICE_ERROR;
+        if (!rdy) {
+            return NSAPI_ERROR_DEVICE_ERROR;
+        }
     }
 
     return NSAPI_ERROR_OK;
@@ -119,5 +131,3 @@ nsapi_error_t QUECTEL_EC2X::soft_power_off()
 {
     return hard_power_off();
 }
-
-#endif

features/cellular/framework/targets/QUECTEL/EC2X/QUECTEL_EC2X.h

@@ -18,30 +18,29 @@
 #ifndef QUECTEL_EC2X_H
 #define QUECTEL_EC2X_H
 
-#ifdef TARGET_FF_ARDUINO
-#ifndef MBED_CONF_QUECTEL_EC2X_TX
-#define MBED_CONF_QUECTEL_EC2X_TX D1
-#endif
-#ifndef MBED_CONF_QUECTEL_EC2X_RX
-#define MBED_CONF_QUECTEL_EC2X_RX D0
-#endif
-#endif /* TARGET_FF_ARDUINO */
-
 #include "DigitalOut.h"
 #include "AT_CellularDevice.h"
 
 namespace mbed {
 
 class QUECTEL_EC2X : public AT_CellularDevice {
 public:
-    QUECTEL_EC2X(FileHandle *fh, PinName pwr = NC, PinName rst = NC);
+
+    /**
+     * Constructs the Quectel EC2X series driver. It is mandatory to provide
+     * a FileHandle object, the power pin and the polarity of the pin.
+     * Providing reset pin is optional.
+     */
+    QUECTEL_EC2X(FileHandle *fh, PinName pwr, bool active_high, PinName rst = NC);
+
     virtual nsapi_error_t hard_power_on();
     virtual nsapi_error_t hard_power_off();
     virtual nsapi_error_t soft_power_on();
     virtual nsapi_error_t soft_power_off();
 
 private:
     nsapi_error_t press_power_button(uint32_t timeout);
+    bool _active_high;
     DigitalOut _pwr_key;
     DigitalOut _rst;
 };

features/cellular/framework/targets/QUECTEL/EC2X/mbed_lib.json

@@ -25,6 +25,10 @@
             "help": "Reset control pin",
             "value": null
         },
+        "polarity": {
+            "help": "Pin polarity, 1 = Active high, 0 = Active low",
+            "value": null
+        },
         "baudrate" : {
             "help": "Serial connection baud rate",
             "value": 115200