Am 11.12.2012 21:59, schrieb Antti Palosaari: > On 12/11/2012 10:51 PM, Frank Schäfer wrote: >> Am 10.12.2012 21:48, schrieb Antti Palosaari: >>> On 12/10/2012 09:24 PM, Frank Schäfer wrote: >>>> Am 10.12.2012 18:57, schrieb Antti Palosaari: >>>>> On 12/10/2012 06:13 PM, Devin Heitmueller wrote: >>>>>> On Mon, Dec 10, 2012 at 11:01 AM, Frank Schäfer >>>>>>> Adding a new property to the RC profile certainly seems to be the >>>>>>> cleanest solution. >>>>>>> Do all protocols have paritiy checking ? Otherwise we could add >>>>>>> a new >>>>>>> type RC_TYPE_NEC_NO_PARITY. >>>>>>> OTOH, introducing a new bitfield in struct rc_map might be usefull >>>>>>> for >>>>>>> other flags, too, in the future... >>>>>> >>>>>> It's probably also worth mentioning that in that mode the device >>>>>> reports four bytes, not two. I guess perhaps if parity is >>>>>> ignored it >>>>>> reports the data in some other format? You will probably have to do >>>>>> some experimentation there. >> >> ... >> >>>>> >>>>> Uh, current em28xx NEC implementation is locked to traditional 16 bit >>>>> NEC, where is hw checksum used. >>>>> >>>>> Implementation should be changed to more general to support 24 and 32 >>>>> bit NEC too. There is multiple drivers doing already that, for >>>>> example >>>>> AF9015. >>>>> >>>> >>>> Hmm... are there and documents (, links, books, ...) where I can learn >>>> more about all those RC protocols ? >>> >>> Specification comes here: >>> NEC send always 32 bit, 4 bytes. There is 3 different "sub" protocols: >>> >>> 1) 16bit NEC standard, 1 byte address code, 1 byte key code >>> full 4 byte code: AA BB CC DD >>> where: >>> AA = address code >>> BB = ~address code >>> CC = key code >>> DD = ~key code >>> >>> checksum: >>> AA + BB = 0xff >>> CC + DD = 0xff >>> >>> 2) 24bit NEC extended, 2 byte address code, 1 byte key code >>> full 4 byte code: AA BB CC DD >>> where: >>> AA = address code (MSB) >>> BB = address code (LSB) >>> CC = key code >>> DD = ~key code >>> >>> 3) 32bit NEC full, 4 byte key code >>> full 4 byte code: AA BB CC DD >>> where: >>> AA = >>> BB = >>> CC = >>> DD = >>> >>> I am not sure if there is separate parts for address and key code in >>> case of 32bit NEC. See some existing remote keytables if there is any >>> such table. It is very rare protocol. 1) and 2) are much more common. >>> >> >> Many thanks. >> So the problem is, that we have only a single RC_TYPE for all 3 protocol >> variants and need a method to distinguish between them, right ? > > Yes, that is. I have said it "million" times I would like to see that > implemented as a one single 4 byte NEC, but it is currently what it > is. What I understand David Härdeman has done some work toward that > too, but it is not ready. > See current af9015 driver as example how driver makes decision which > variant of NEC is used. You will need something similar. Read all 4 > NEC bytes from the hardware and then use driver to make decision which > variant it is. Yes, checking for inverted address and key code bytes would be a possibility... OTOH it's a kind of hack and I think this issue should be fixed in th rc core. A possible solution would be to add three new RC_TYPEs (e.g. RC_TYPE_NEC_STD, RC_TYPE_NEC_EXT, RC_TYPE_NEC_FULL). RC_TYPE_NEC can be kept for compatibility but should be marked as deprecated. Hmmm... thinking about it for some minutes... Why the hell do we bind rc maps to protocols ? A key map consists of pairs of a scan code and the corresponding key code. But that's common to all protocols, right ? So why do we restrict a keymap to a specific protocol ? Ok, rc_type is a bit field, so a key map can be bound to multiple protocols. But then we can't use it to configure the hardware driver, which is exactly out problem here... > I am quite sure em28xx hardware supports reading all 4 bytes, but if > not, you will need to do some other tricks. Yes, reading 4 bytes form the hardware seems to supported. Devin, how does it works with reg 0x50=0x01 ? Have I understood you right that it means the 32bit NEC protocol variant is used ? Can the key code be read as usual from regs 0x52-0x55 ? Any changes in reg 0x51 ? And for that matter - what's the meaning of bit 1 in reg 0x50 ? ;) Regards, Frank > > regards > Antti > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
