[linux-dvb] Re: Skystar2 i2c lockup

[Niklas Peinecke <peinecke@gdv.uni-hannover.de>]

Augusto Cardoso wrote:
> Hi!
>
> Here are the registers for the "two line serial":
>
> Reg 0x100
> WRITE
> Bits 6-0	CHIPADDRESS
> Bit 7	Reserved
> Bits 15-8 BASE ADDRESS
> Bits 23-16 DATA1
> Bit 24	Start transaction. 
> Bit 25	R/#W Read=1, Write=0
> Bit 27-26 Size of transaction. 00=1, 11=4 bytes.
> Bit 29-28 Port selection 00=Invalid, 01=Frontend, 10-EEPROM, 11=Tuner
> Bit 30	Base address presence indicator. When 1, no base address is generated.
> Bit 31	Reserved
>
> Reg 0x100
> READ
> Bit 0	R/#W - Internal states.
> Bits 7-1	CHIPADDRESS
> Bits 15-8 BASE ADDRESS
> Bits 23-16 DATA1
> Bit 24	Status. When=1, transaction underway. =0  engine is free.
> Bit 25	R/#W Read=1, Write=0
> Bit 27-26 Size of transaction. 00=1, 11=4 bytes.
> Bit 29-28 Port selection 00=Invalid, 01=Frontend, 10-EEPROM, 11=Tuner
> Bit 30	ACK error. When =1, no ACK from slave.
> Bit 31	When set, it indicate that the current transaction is done.
>
> Reg 0x104
> Bit 7-0	Data2
> Bit 15-8	Data3
> Bit 23-16 Data4
> Bit 24	Explicit STOP. When set, the transaction is done without a trailing STOP. FC3 only.
> Bit 25	When set, generates a STOP event. FC3 only.
> Bit 31-26 Reserved.
>
> Reg 0x108, 0x10c and 0x110 Have the same function, but affecting ports 1(Frontend), 2(EEPROM) and 3(Tuner), respectively.
> Bits 5-0	thi Time High for i2c timing. The reference is a pre-scale internal clock based on the main clock.
> Bits 12-8 tlo Time Low for i2c timing. The reference is a pre-scale internal clock based on the main clock.
> All other bits, reserved.
>
> I hope this is not too confusing.
> Let me know if you have any questions.
>
> 	Augusto
Ok, here I go:

> Reg 0x100
> WRITE
...
> Bits 15-8 BASE ADDRESS
...
> Bit 30	Base address presence indicator. When 1, no base address is 
generated.

Does this mean when Bit 30 is set, the base address specified in 15-8 is 
not sent via i2c but only the DATA1, DATA2, and DATA3? Suppose I only 
want to send DATA1. Should I set size of transaction to 00 or 01 then? I 
suppose 00. Thus, there is no way to send 0 byte transactions ("i2c 
pings"), right? Also there is no way to do a read only from the bus, 
without writing the base address first (or is that the purpose of Bit 30)?

I hope, I do not ask for too much.

Thanks,

Niklas



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