New function nfc_idle() to set the NFC device in idle mode.

nfc_disconnect() now switch NFC device into idle before disconnecting;
pn53x_data now have a operating_mode enum to know the current running mode (initiator, target or idle);
new pn53x_PowerDown wrapper for PowerDown (PN532) command;

Note: ARYGON idle mode now to be implemented and ACR122 does not support this mode.

libnfc/chips/pn53x.c

@@ -67,6 +67,9 @@ pn53x_init(nfc_device_t * pnd)
     return false;
   }
 
+  // PN53x starts in initiator mode
+  CHIP_DATA (pnd)->operating_mode = INITIATOR;
+
   // Set current target to NULL
   CHIP_DATA (pnd)->current_target = NULL;
 
@@ -660,6 +663,43 @@ pn53x_configure (nfc_device_t * pnd, const nfc_device_option_t ndo, const bool b
   return true;
 }
 
+bool
+pn53x_idle (nfc_device_t *pnd)
+{
+  switch (CHIP_DATA (pnd)->operating_mode) {
+    case TARGET:
+      return pn53x_InRelease (pnd, 0);
+    break;
+    case INITIATOR:
+      // Deselect all active communications
+      if (!pn53x_InDeselect (pnd, 0)) {
+        return false;
+      }
+      // Disable RF field to avoid heating
+      if (!nfc_configure (pnd, NDO_ACTIVATE_FIELD, false)) {
+        return false;
+      }
+      if (CHIP_DATA (pnd)->type == PN532) {
+        // Use InPowerDown to go in "Low VBat"
+        if (!pn53x_PowerDown (pnd)) {
+          return false;
+        }
+        CHIP_DATA (pnd)->power_mode = LOWVBAT;
+      } else {
+        // Use InRelease to go in "Standby mode"
+        if (!pn53x_InRelease (pnd, 0)) {
+          return false;
+        }
+      }
+    break;
+    default:
+      // Nothing to do
+    break;
+  };
+  CHIP_DATA (pnd)->operating_mode = IDLE;
+  return true;
+}
+
 bool
 pn53x_check_communication (nfc_device_t *pnd)
 {
@@ -682,6 +722,8 @@ pn53x_initiator_init (nfc_device_t * pnd)
   // Configure the PN53X to be an Initiator or Reader/Writer
   if (!pn53x_write_register (pnd, REG_CIU_CONTROL, SYMBOL_INITIATOR, 0x10))
     return false;
+
+  CHIP_DATA (pnd)->operating_mode = INITIATOR;
   return true;
 }
 
@@ -1137,7 +1179,11 @@ bool
 pn53x_target_init (nfc_device_t * pnd, nfc_target_t * pnt, byte_t * pbtRx, size_t * pszRx)
 {
   pn53x_reset_settings(pnd);
+
+  CHIP_DATA (pnd)->operating_mode = TARGET;
+
   pn53x_target_mode_t ptm = PTM_NORMAL;
+
   switch (pnt->nm.nmt) {
     case NMT_ISO14443A:
       ptm = PTM_PASSIVE_ONLY;
@@ -1600,6 +1646,13 @@ pn53x_SAMConfiguration (nfc_device_t * pnd, const uint8_t ui8Mode)
       pnd->iLastError = DENOTSUP;
       return false;
   }
+  return (pn53x_transceive (pnd, abtCmd, szCmd, NULL, NULL));
+}
+
+bool
+pn53x_PowerDown (nfc_device_t * pnd)
+{
+  byte_t  abtCmd[] = { PowerDown, 0xf0 };
   return (pn53x_transceive (pnd, abtCmd, sizeof (abtCmd), NULL, NULL));
 }
 

libnfc/chips/pn53x.h

@@ -29,6 +29,7 @@
 
 #  include <nfc/nfc-types.h>
 
+// TODO Remove double register address defines
 // Registers and symbols masks used to covers parts within a register
 #  define REG_CIU_TX_MODE           0x6302
 #  define SYMBOL_TX_CRC_ENABLE      0x80
@@ -144,15 +145,27 @@ typedef enum {
   LOWVBAT	// Only on PN532, need to be wake up to process commands with a long preamble and SAMConfiguration command
 } pn53x_power_mode;
 
+typedef enum {
+  IDLE,
+  INITIATOR,
+  TARGET,
+} pn53x_operating_mode;
+
 struct pn53x_io {
   bool (*send)(nfc_device_t * pnd, const byte_t * pbtData, const size_t szData);
   int (*receive)(nfc_device_t * pnd, byte_t * pbtData, const size_t szDataLen);
 };
 
 struct pn53x_data {
+/** Chip type (PN531, PN532 or PN533)*/
   pn53x_type type;
+/** Current power mode */
   pn53x_power_mode power_mode;
+/** Current operating mode */
+  pn53x_operating_mode operating_mode;
+/** Current emulated target */
   nfc_target_t* current_target;
+/** PN53x I/O functions stored in struct */
   const struct pn53x_io * io;
 /** Register cache for REG_CIU_BIT_FRAMING, SYMBOL_TX_LAST_BITS: The last TX bits setting, we need to reset this if it does not apply anymore */
   uint8_t ui8TxBits;
@@ -166,7 +179,6 @@ struct pn53x_data {
 
 #define CHIP_DATA(pnd) ((struct pn53x_data*)(pnd->chip_data))
 
-/* PN53x specific types */
 /**
  * @enum pn53x_modulation_t
  * @brief NFC modulation
@@ -265,6 +277,7 @@ bool    pn53x_write_register (nfc_device_t * pnd, uint16_t ui16Reg, uint8_t ui8S
 bool    pn53x_get_firmware_version (nfc_device_t * pnd, char abtFirmwareText[18]);
 bool    pn53x_configure (nfc_device_t * pnd, const nfc_device_option_t ndo, const bool bEnable);
 bool    pn53x_check_communication (nfc_device_t *pnd);
+bool    pn53x_idle (nfc_device_t * pnd);
 
 // NFC device as Initiator functions
 bool    pn53x_initiator_init (nfc_device_t * pnd);
@@ -305,6 +318,7 @@ const char *pn53x_strerror (const nfc_device_t * pnd);
 // C wrappers for PN53x commands
 bool    pn53x_SetParameters (nfc_device_t * pnd, const uint8_t ui8Value);
 bool    pn53x_SAMConfiguration (nfc_device_t * pnd, const uint8_t ui8Mode);
+bool    pn53x_PowerDown (nfc_device_t * pnd);
 bool    pn53x_InListPassiveTarget (nfc_device_t * pnd, const pn53x_modulation_t pmInitModulation,
                                    const byte_t szMaxTargets, const byte_t * pbtInitiatorData,
                                    const size_t szInitiatorDataLen, byte_t * pbtTargetsData, size_t * pszTargetsData);