Guenter Roeck said the following: > On Wed, Sep 29, 2010 at 03:19:28AM -0400, Jean Delvare wrote: > [ ... ] >> >> I was speaking of the PCA9540. I don't think anyone ever wrote a driver >> for the PCA9541. And in all honestly I don't think the new i2c-mux >> infrastructure is ready for this. It was written with single-master >> topologies in mind. You'll have to rethink a lot of things if you want >> to add support for "inverted" multiplexers. And I don't have the time >> to help, sorry. >> > Actually, the infrastructure works quite nicely. I use select_chan > to acquire the slave, and release_chan to initiate release. > It behaves like a one-channel multiplexer. > >> I don't quite see the point of such chips, BTW. I2C supports >> multi-master already, so two masters talking to the same slave >> sequentially is already supported. >> > Tell that to our HW team, and to them: > > http://www.lineagepower.com/oem/pdf/CPLI2C.pdf > I only took a rough look, but it seemed to me that the pca is part of the main device. >From abstraction side of view your problem seems a matter of synchronization of two independent computer systems. You will need a shared resource. The access to it could either be part of driver code or by introducing a 'one-channel multiplexer' as you did. But the sync needs to be done by your code via a shared data object. -- KR Michael -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
