From 9f38ae715de23ec2c118bd315d95e8cf0f2ae0d2 Mon Sep 17 00:00:00 2001
From: Romuald Conty <romuald@libnfc.org>
Date: Tue, 12 Jun 2012 16:51:47 +0000
Subject: [PATCH] pn53x: allow more delay for Card Presence command (tested on
 PN533 and PN532 in various contexts).

---
 libnfc/chips/pn53x.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libnfc/chips/pn53x.c b/libnfc/chips/pn53x.c
index 2178324..66b3064 100644
--- a/libnfc/chips/pn53x.c
+++ b/libnfc/chips/pn53x.c
@@ -1681,7 +1681,10 @@ pn53x_initiator_target_is_present(struct nfc_device *pnd, const nfc_target nt)
   uint8_t abtRx[1];
   int res = 0;
 
-  if ((res = pn53x_transceive(pnd, abtCmd, sizeof(abtCmd), abtRx, sizeof(abtRx), -1)) < 0)
+  // Card Presence command can take more time than default one: when a card is
+  // removed from the field, the PN53x took few hundred ms more to reply
+  // correctly. (ie. 700 ms should be enough to detect all tested cases)
+  if ((res = pn53x_transceive(pnd, abtCmd, sizeof(abtCmd), abtRx, sizeof(abtRx), 700)) < 0)
     return res;
   if (res == 1) {
     return NFC_SUCCESS;