164 lines
4.7 KiB
ReStructuredText
164 lines
4.7 KiB
ReStructuredText
The cx88 driver
|
|
===============
|
|
|
|
Author: Gerd Hoffmann
|
|
|
|
This is a v4l2 device driver for the cx2388x chip.
|
|
|
|
|
|
Current status
|
|
--------------
|
|
|
|
video
|
|
- Works.
|
|
- Overlay isn't supported.
|
|
|
|
audio
|
|
- Works. The TV standard detection is made by the driver, as the
|
|
hardware has bugs to auto-detect.
|
|
- audio data dma (i.e. recording without loopback cable to the
|
|
sound card) is supported via cx88-alsa.
|
|
|
|
vbi
|
|
- Works.
|
|
|
|
|
|
How to add support for new cards
|
|
--------------------------------
|
|
|
|
The driver needs some config info for the TV cards. This stuff is in
|
|
cx88-cards.c. If the driver doesn't work well you likely need a new
|
|
entry for your card in that file. Check the kernel log (using dmesg)
|
|
to see whenever the driver knows your card or not. There is a line
|
|
like this one:
|
|
|
|
.. code-block:: none
|
|
|
|
cx8800[0]: subsystem: 0070:3400, board: Hauppauge WinTV \
|
|
34xxx models [card=1,autodetected]
|
|
|
|
If your card is listed as "board: UNKNOWN/GENERIC" it is unknown to
|
|
the driver. What to do then?
|
|
|
|
1) Try upgrading to the latest snapshot, maybe it has been added
|
|
meanwhile.
|
|
2) You can try to create a new entry yourself, have a look at
|
|
cx88-cards.c. If that worked, mail me your changes as unified
|
|
diff ("diff -u").
|
|
3) Or you can mail me the config information. We need at least the
|
|
following information to add the card:
|
|
|
|
- the PCI Subsystem ID ("0070:3400" from the line above,
|
|
"lspci -v" output is fine too).
|
|
- the tuner type used by the card. You can try to find one by
|
|
trial-and-error using the tuner=<n> insmod option. If you
|
|
know which one the card has you can also have a look at the
|
|
list in CARDLIST.tuner
|
|
|
|
Documentation missing at the cx88 datasheet
|
|
-------------------------------------------
|
|
|
|
MO_OUTPUT_FORMAT (0x310164)
|
|
|
|
.. code-block:: none
|
|
|
|
Previous default from DScaler: 0x1c1f0008
|
|
Digit 8: 31-28
|
|
28: PREVREMOD = 1
|
|
|
|
Digit 7: 27-24 (0xc = 12 = b1100 )
|
|
27: COMBALT = 1
|
|
26: PAL_INV_PHASE
|
|
(DScaler apparently set this to 1, resulted in sucky picture)
|
|
|
|
Digits 6,5: 23-16
|
|
25-16: COMB_RANGE = 0x1f [default] (9 bits -> max 512)
|
|
|
|
Digit 4: 15-12
|
|
15: DISIFX = 0
|
|
14: INVCBF = 0
|
|
13: DISADAPT = 0
|
|
12: NARROWADAPT = 0
|
|
|
|
Digit 3: 11-8
|
|
11: FORCE2H
|
|
10: FORCEREMD
|
|
9: NCHROMAEN
|
|
8: NREMODEN
|
|
|
|
Digit 2: 7-4
|
|
7-6: YCORE
|
|
5-4: CCORE
|
|
|
|
Digit 1: 3-0
|
|
3: RANGE = 1
|
|
2: HACTEXT
|
|
1: HSFMT
|
|
|
|
0x47 is the sync byte for MPEG-2 transport stream packets.
|
|
Datasheet incorrectly states to use 47 decimal. 188 is the length.
|
|
All DVB compliant frontends output packets with this start code.
|
|
|
|
Hauppauge WinTV cx88 IR information
|
|
-----------------------------------
|
|
|
|
The controls for the mux are GPIO [0,1] for source, and GPIO 2 for muting.
|
|
|
|
====== ======== =================================================
|
|
GPIO0 GPIO1
|
|
====== ======== =================================================
|
|
0 0 TV Audio
|
|
1 0 FM radio
|
|
0 1 Line-In
|
|
1 1 Mono tuner bypass or CD passthru (tuner specific)
|
|
====== ======== =================================================
|
|
|
|
GPIO 16(I believe) is tied to the IR port (if present).
|
|
|
|
|
|
From the data sheet:
|
|
|
|
- Register 24'h20004 PCI Interrupt Status
|
|
|
|
- bit [18] IR_SMP_INT Set when 32 input samples have been collected over
|
|
- gpio[16] pin into GP_SAMPLE register.
|
|
|
|
What's missing from the data sheet:
|
|
|
|
- Setup 4KHz sampling rate (roughly 2x oversampled; good enough for our RC5
|
|
compat remote)
|
|
- set register 0x35C050 to 0xa80a80
|
|
- enable sampling
|
|
- set register 0x35C054 to 0x5
|
|
- enable the IRQ bit 18 in the interrupt mask register (and
|
|
provide for a handler)
|
|
|
|
GP_SAMPLE register is at 0x35C058
|
|
|
|
Bits are then right shifted into the GP_SAMPLE register at the specified
|
|
rate; you get an interrupt when a full DWORD is received.
|
|
You need to recover the actual RC5 bits out of the (oversampled) IR sensor
|
|
bits. (Hint: look for the 0/1and 1/0 crossings of the RC5 bi-phase data) An
|
|
actual raw RC5 code will span 2-3 DWORDS, depending on the actual alignment.
|
|
|
|
I'm pretty sure when no IR signal is present the receiver is always in a
|
|
marking state(1); but stray light, etc can cause intermittent noise values
|
|
as well. Remember, this is a free running sample of the IR receiver state
|
|
over time, so don't assume any sample starts at any particular place.
|
|
|
|
Additional info
|
|
~~~~~~~~~~~~~~~
|
|
|
|
This data sheet (google search) seems to have a lovely description of the
|
|
RC5 basics:
|
|
http://www.atmel.com/dyn/resources/prod_documents/doc2817.pdf
|
|
|
|
This document has more data:
|
|
http://www.nenya.be/beor/electronics/rc5.htm
|
|
|
|
This document has a how to decode a bi-phase data stream:
|
|
http://www.ee.washington.edu/circuit_archive/text/ir_decode.txt
|
|
|
|
This document has still more info:
|
|
http://www.xs4all.nl/~sbp/knowledge/ir/rc5.htm
|