fixup! added Preferences api spi commands

Author: andreagilardoni

src/utility/wifi_drv.cpp

@@ -1364,8 +1364,14 @@ void WiFiDrv::prefEnd() {
 
     SpiDrv::sendCmd(PREFERENCES_END, PARAM_NUMS_0);
     SpiDrv::spiSlaveDeselect();
+    //Wait the reply elaboration
+    SpiDrv::waitForSlaveReady();
+    SpiDrv::spiSlaveSelect();
 
-    // we do not need to wait for any response
+    uint8_t len = 1;
+    bool result = false;
+    SpiDrv::waitResponseCmd(PREFERENCES_END, PARAM_NUMS_1, (uint8_t*)&result, &len);
+    SpiDrv::spiSlaveDeselect();
 }
 
 bool WiFiDrv::prefClear() {
@@ -1534,30 +1540,36 @@ size_t WiFiDrv::prefGet(const char * key, PreferenceType type, uint8_t value[],
     SpiDrv::waitForSlaveReady();
     SpiDrv::spiSlaveSelect();
 
-    SpiDrv::waitResponseData16(PREFERENCES_GET, value, (uint16_t*)&len);
+    // we need to account for \0 if it is a string
+    size_t res_len = type == PT_STR? len-1 : len;
+    SpiDrv::waitResponseData16(PREFERENCES_GET, value, (uint16_t*)&res_len);
 
     SpiDrv::spiSlaveDeselect();
 
-    // if len == 0 it means that the command retuned and error
-    if(len == 0) {
+    // if res_len == 0 it means that the command retuned and error
+    if(res_len == 0) {
         return 0;
     }
 
     // fix endianness
     if(type != PT_STR && type != PT_BLOB) {
-        for(uint8_t i=0; i<len/2; i++) {
+        for(uint8_t i=0; i<res_len/2; i++) {
 
             // XOR swap algorithm:
             // a=a^b; b=a^b; a=b^a; with a != b
-            if(value[i] != value[len-i-1]) {
-                value[i]        = value[i]^value[len-i-1];
-                value[len-i-1]  = value[i]^value[len-i-1];
-                value[i]        = value[len-i-1]^value[i];
+            if(value[i] != value[res_len-i-1]) {
+                value[i]            = value[i]^value[res_len-i-1];
+                value[res_len-i-1]  = value[i]^value[res_len-i-1];
+                value[i]            = value[res_len-i-1]^value[i];
             }
         }
     }
 
-    return len;
+    if(type == PT_STR) {
+        value[res_len] = '\0';
+    }
+
+    return res_len;
 }
 
 PreferenceType WiFiDrv::prefGetType(const char * key) {