On Fri, 10 Jul 2009 17:09:47 -0400, Lindsey Ings -X (ingsl - Yoh Services LLC at Cisco) wrote: > > > Resend of message in plain text form. > > > I understand the concepts involved in this project but that doesn't help me > actually make use of it.
For reference for other readers who have no clue what you're talking about: Lindsey is referring to Rodolfo's I2C multiplexing support project, described at: http://i2c.wiki.kernel.org/index.php/I2C_bus_multiplexing > Is there a sample of how to put the mux and (if feasible) I2C clients in a > DTS? Not yet. Rodolfo's code is not even in mainline. But once implementation is complete, then yes it should be possible to declare I2C multiplexers and other I2C devices in a DTS. > Also is there a user application sample of how to access the devices > downstream from the mux? This wouldn't make sense. Multiplexing is handled in the kernel and user-space does not even know it is happening. > Are the mux's created as a device so that the devices downstream are accessed > as non-mux'd devices? i.e. is dev D in segment 2 (from the diagram on the > wiki) accessed as so: > > int fd; > fd = open( "/dev/i2c-2", O_RDWR ); > > #define ADDRESS 0x38 // address of dev D > ioctl( fd, I2C_SLAVE, ADDRESS ) > > // Now r/w dev D > > // Write 0xAA to dev D > i2c_smbus_write_byte( fd, 0xAA ); > // etc. Yes, this is how the code would look like. Note that I am still waiting for Rodolfo to update his patch set so that it applies again on top of Linus' latest kernel. -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
