libftdi-1: Add version of ftdi_read_data_submit with timeout

[Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

At present, ftdi_read_data_submit() waits infinite until all the requested data
is read. Appended patch add a new call with added timeout and make the old
call a special case of the new call.

This allows gracefull exit when something unexpected happens.
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
>From 21d0d0c7e22a4c89d2c750532d88c39f268d61dd Mon Sep 17 00:00:00 2001
From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 29 Mar 2011 17:00:43 +0200
Subject: Implement ftdi_read_data_submit_to and make ftdi_read_data_submit()
 a special case of the new function

---
 src/ftdi.c |   20 +++++++++++++++++++-
 src/ftdi.h |    2 ++
 2 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/src/ftdi.c b/src/ftdi.c
index 8a7b2ba..3dd1712 100644
--- a/src/ftdi.c
+++ b/src/ftdi.c
@@ -1325,6 +1325,16 @@ static void ftdi_read_data_cb(struct libusb_transfer 
*transfer)
             }
         }
     }
+    else 
+    {
+        if (tc->retries == 1)
+        {
+            tc->completed = 1;
+            return;
+        }
+        if (tc->retries > 0)
+            tc->retries --;
+    }
     ret = libusb_submit_transfer (transfer);
     if (ret < 0)
         tc->completed = 1;
@@ -1430,12 +1440,14 @@ struct ftdi_transfer_control 
*ftdi_write_data_submit(struct ftdi_context *ftdi,
     \param ftdi pointer to ftdi_context
     \param buf Buffer with the data
     \param size Size of the buffer
+    \param reties Abort when latency timer expied "reties" times with no data 
read.
+           Use '0' to wait infinite
 
     \retval NULL: Some error happens when submit transfer
     \retval !NULL: Pointer to a ftdi_transfer_control
 */
 
-struct ftdi_transfer_control *ftdi_read_data_submit(struct ftdi_context *ftdi, 
unsigned char *buf, int size)
+struct ftdi_transfer_control *ftdi_read_data_submit_to(struct ftdi_context 
*ftdi, unsigned char *buf, int size, int retries)
 {
     struct ftdi_transfer_control *tc;
     struct libusb_transfer *transfer;
@@ -1469,6 +1481,7 @@ struct ftdi_transfer_control 
*ftdi_read_data_submit(struct ftdi_context *ftdi, u
     }
 
     tc->completed = 0;
+    tc->retries = retries;
     if (ftdi->readbuffer_remaining != 0)
     {
         memcpy (buf, ftdi->readbuffer+ftdi->readbuffer_offset, 
ftdi->readbuffer_remaining);
@@ -1503,6 +1516,11 @@ struct ftdi_transfer_control 
*ftdi_read_data_submit(struct ftdi_context *ftdi, u
     return tc;
 }
 
+struct ftdi_transfer_control *ftdi_read_data_submit(struct ftdi_context *ftdi, 
unsigned char *buf, int size)
+{
+    return ftdi_read_data_submit_to(ftdi, buf, size, 0);
+}
+
 /**
     Wait for completion of the transfer.
 
diff --git a/src/ftdi.h b/src/ftdi.h
index b7c0113..ef44d58 100644
--- a/src/ftdi.h
+++ b/src/ftdi.h
@@ -161,6 +161,7 @@ enum ftdi_interface
 struct ftdi_transfer_control
 {
     int completed;
+    int retries;
     unsigned char *buf;
     int size;
     int offset;
@@ -499,6 +500,7 @@ extern "C"
     int ftdi_write_data_async(struct ftdi_context *ftdi, unsigned char *buf, 
int size);
     void ftdi_async_complete(struct ftdi_context *ftdi, int wait_for_more);
 
+    struct ftdi_transfer_control *ftdi_read_data_submit_to(struct ftdi_context 
*ftdi, unsigned char *buf, int size, int retries);
     struct ftdi_transfer_control *ftdi_read_data_submit(struct ftdi_context 
*ftdi, unsigned char *buf, int size);
     int ftdi_transfer_data_done(struct ftdi_transfer_control *tc);
 
-- 
1.7.1


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