On Wed, 16 May 2007 16:20:38 +0200, Manuel Lauss wrote: > > 2* In i2c_write and i2c_read, the stop bit is always sent together with > > the last byte, while your new code sends the stop bit on its own after > > the address byte. Is it OK? > > Well, no. However the quick probe does an i2c read IIRC so it should be > safe. I'll fix that too. >From an I2C perspective, zero-byte transactions can be both reads and writes. So if you accidentally send one more byte on the bus after the address, you are actually doing a 1-byte read or write. The variant used by the Linux kernel for probing purposes is the "write" variant. > > I am wondering if your code isn't sending > > an extra (0) byte after the address when asked to send a zero-byte > > message. That would be bad. Do you have a bus analyzer or scope to > > check what exactly is being sent on the bus in this case? > > Yes I have a scope. I'll improve the driver some more and then check > the actual data sent over the wires. OK, thanks. I have to admit I am a bit curious how (if) you can send a stop transaction on error without sending an extra byte with this chip. -- Jean Delvare
