On Fri, May 24, 2013 at 12:41 PM, Mylene Josserand <Mylene.Josserand@xxxxxxxxxxx> wrote: > Hi all, > > > I am learning how i2c is working and I read that, to write in an i2c > register, I need to use the function "i2c_smbus_write_byte_data". Only in case your device is smbus compliant. > I wanted to know how the message are handled by using this function. If > I use this function to talk with 2 different i2d devices, how it will > handle "message collision" ? should I have to add a kind of mutex on the Message collision and detection is the job of i2c controller and if I am not wrong you are writing a chip driver. > access of the i2c bus ? > Is it possible that the message destined for one device is sent to > another one ? Or a "mix" of messages is impossible ? It is not possible as the data contains the chip address which is unique.7/10 bit mode addressing is used for addresses. > > I have read that this function "i2c_smbus_write_byte_data" uses > "i2c_smbus_xfer" which uses "i2c_lock_adapter". > In this function, there is a mutex so I thought that it will handle it > but it says "Get exclusive access to an I2C bus segment". What is > exactly an I2C segment ? Is it the device we are talking about ? Or is > it the use of the i2c bus ? Don't know what you are referring here. > > I will certainly have to create an i2c driver and I would like to know > if this "collision" handling (if it is handled) is done in old kernel > (2.6.32) or is it handled only in new kernel versions ? AFAIK collision handling and detection was not supported till now in linux kernel until recently but I think this patch is doing that. I may be wrong but I didn't see collision handling in earlier linux kernels. http://thread.gmane.org/gmane.linux.kernel/1410276 > > If you have any documentation on how the i2c messages are handled in > case of different devices uses, it will help me a lot ! I will search in > the kernel documentation but there is many files about i2c. > And if you know a good i2c driver that I can use as an example to design > mine, it will be great ! > > > Thank you in advance, > > -- > Mylène JOSSERAND > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
