I don't know where else to post this, so I'm hoping someone here can
spare me a clue.

We're building a small board with two AVR Tiny MCUs chatting to each
other over an opto-isolated I2C-compatible bus, hopefully at 400kHz.

I hope to use the iicbb(4) on lpbb(4) parallel port interface to talk
with either of these MCUs for debugging, control and data acquisition.
iic(4) says:

 The iic character device driver provides generic i/o to any iicbus(4)
 instance.  In order to control I2C devices, use /dev/iic? with the fol-
 lowing ioctls:

 Ioctl         Description
 I2CSTART      send start condition to the specified device (with 7-bit
               address) on the bus
 I2CSTOP       send stop condition to the bus
 I2CRSTCARD    reset the bus

 You may also use read/write routines, then I2C start/stop handshake is
 managed by the iicbus system.

Does the latter statement suggest that ordinary reads from or writes to
/dev/iic? could be performed by redirection of say echo and read from a
script?  Or is the device only accessible by ioctl from eg a C program?

Also, iicbb(4) is a master-only interface.  I can work with that, but if
anyone knows of any iicbus slave-mode code I'm all eyes ..

Cheers, Ian  (please cc me)

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