Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 113 insertions, 0 deletions

diff --git a/Documentation/driver-api/media/drivers/cx88-devel.rst b/Documentation/driver-api/media/drivers/cx88-devel.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+The cx88 driver
+===============
+
+Author:  Gerd Hoffmann
+
+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