# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1563922290 -7200
# Node ID e60d54c4797f4d91ab148f625cc0e27a9c4ad82b
# Parent  e65cdd33bc715f65c9497963bd4187fc56e7dcc9
Simplified the read threshold computation. Added some more commentary.

diff -r e65cdd33bc71 -r e60d54c4797f pkg/devices/lib/i2c/src/jz4780.cc
--- a/pkg/devices/lib/i2c/src/jz4780.cc	Mon Jul 22 00:17:30 2019 +0200
+++ b/pkg/devices/lib/i2c/src/jz4780.cc	Wed Jul 24 00:51:30 2019 +0200
@@ -472,6 +472,8 @@
   if (!can_queue)
     return;
 
+  // At most, only queue as many reads as are remaining.
+
   if (remaining < can_queue)
     can_queue = remaining;
 
@@ -487,6 +489,7 @@
   // Issue the stop condition after the final read request.
   // In practice, an extra read request works better since it does not risk a
   // transmission abort condition and would permit following transactions.
+  // However, it does risk causing an address autoincrement with some devices.
 
   if (_total == _reqpos)
     _regs[Smb_data_command] = Smb_command_read;
@@ -542,13 +545,7 @@
 
   // Read all expected.
 
-  if (queued <= Smb_fifo_limit)
-    _regs[Rx_fifo_thold] = queued - 1;
-
-  // Read to limit.
-
-  else
-    _regs[Rx_fifo_thold] = Smb_fifo_limit - 1;
+  _regs[Rx_fifo_thold] = queued - 1;
 }
 
 // Read from the target device.