Hi Guenter, On Sun, 17 Nov 2013 13:13:43 -0800, Guenter Roeck wrote: > On 11/17/2013 12:41 PM, Jean Delvare wrote: > > On Sun, 17 Nov 2013 10:56:24 -0800, Guenter Roeck wrote: > >> This retains the old mux name if the mux is not an i2c device, and adds > >> the i2c device address if it is. This solves the problem for me. > >> > >> Comments ? > > > > This "for me" worries me a bit. You basically restored the uniqueness > > for the multiple I2C-based multiplexer case. But for multiple > > GPIO-based multiplexers, for example, the name confusion still exists. > > Only if some genius connects multiple separate gpio based multiplexers > to the same bus. This is totally possible, for a variety of reasons, including physical location of the GPIO pins and bus segment ends, but also economical (using the same chips on several boards.) > In practice, though, that can be modeled as single > gpio mux with more pins, so I didn't think that is that much of a problem. I admit I had not considered this. But would it work if the different GPIO pins are on different chips (say south bridge and Super-I/O for example)? The i2c-mux-gpio driver assumes a single chip, at least when passed by name. > > If we are going to address this problem, I believe we should do so in a > > way which doesn't need revisiting in a couple months. You are changing > > adapter names people or tools may be relying on, we really don't want > > to do this too often. > > Good point. One possible solution might be to add the mux type into the name. > i2c-2-mux-i2c-76 (chan_id 0) > i2c-2-mux-gpio-77 (chan_id 0) Yes, that's pretty much what I had in mind. > We could add an additional parameter to the API, such as > const char *qualifier > to provide the "i2c-76" or "gpio-77" string. If the qualifier is NULL, > the name would revert to the old naming scheme. Would that make sense ? Yes, although your first draft gave me some hope that i2c-mux could do some magic to guess the type and identifier automatically. But maybe it's not that clean to have to touch i2c-mux for every new i2c-mux-* driver. Not that I expect too many of them... so it's mostly a matter of principle. An explicit qualifier as you suggest above might be cleaner. -- Jean Delvare -- 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
