V4L/DVB: IR/streamzap: functional in-kernel decoding

This patch makes in-kernel decoding with the stock Streamzap PC Remote
work out of the box. There are quite a few things going on in this
patch, all related to getting this working:

1) I had to enable reporting of a long space at the end of each signal,
   or I had weird buffering and keybounce issues.

2) The keymap has been reworked slightly to match actual decoded values,
   the first edition was missing the pre-data bits present in the lirc
   config file for this remote.

3) There's a whole new decoder included, specifically for the
   not-quite-RC5 15-bit protocol variant used by the Streamzap PC
   Remote. The decoder, while usable with other recievers (tested with
   an mceusb receiver), will only be loaded by the streamzap driver, as
   its likely not of use in almost all other situations. This can be
   revisited if/when all keytable loading (and disabling of unneeded
   protocol decoder engines) is moved to userspace, but for now, I think
   this makes the most sense.

Note that I did try to enable handling the streamzap RC5-ish protocol in
the current RC5 decoder, but there's no particularly easy way to tell if
its 14-bit RC5 or 15-bit Streamzap until we see bit 14, and even then,
in testing an attempted decoder merge, only 2/3 of the keys were
properly recognized as being the 15-bit variant and decoded correctly,
the rest were close enough to compliant with 14-bit that they were
decoded as such (but they have overlap with one another, and thus we
can't just shrug and use the 14-bit decoded values).

Also of note in this patch is the removal of the streamzap driver's
internal delay buffer. Per discussion w/Christoph, it shouldn't be
needed by lirc any longer anyway, and it doesn't seem to make any
difference to the in-kernel decoder engine. That being the case, I'm
yanking it all out, as it greatly simplifies the driver code.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/media/IR/Kconfig b/drivers/media/IR/Kconfig
index 490c57cc4cfe..152000db3526 100644
--- a/drivers/media/IR/Kconfig
+++ b/drivers/media/IR/Kconfig
@@ -79,6 +79,18 @@ config IR_SONY_DECODER
 	   Enable this option if you have an infrared remote control which
 	   uses the Sony protocol, and you need software decoding support.
 
+config IR_RC5_SZ_DECODER
+	tristate "Enable IR raw decoder for the RC-5 (streamzap) protocol"
+	depends on IR_CORE
+	select BITREVERSE
+	default y
+
+	---help---
+	   Enable this option if you have IR with RC-5 (streamzap) protocol,
+	   and if the IR is decoded in software. (The Streamzap PC Remote
+	   uses an IR protocol that is almost standard RC-5, but not quite,
+	   as it uses an additional bit).
+
 config IR_LIRC_CODEC
 	tristate "Enable IR to LIRC bridge"
 	depends on IR_CORE