On Tue, 17 Mar 2009, Jean Delvare wrote: > Hi Guennadi, > > On Tue, 17 Mar 2009 18:24:49 +0100 (CET), Guennadi Liakhovetski wrote: > > I have a question regarding dynimically created i2c devices. If I have a > > card with an i2c device on it. Once I load a driver for that card, it uses > > its knowledge of the hardware and registers a new i2c device using > > i2c_new_device. Then at some point a driver for that i2c device is loaded, > > it calls i2c_add_driver, then its probe() method is called with the > > dynamically created device. So far so good. Now I unload the i2c driver, > > it calls i2c_del_driver(), and then, IIUC, __detach_adapter will be called > > for all devices attached to this driver, > > Actually, __detach_adapter will be called for all *adapters* on the > system. Then in turn __detach_adapter does a number of actions on > devices present on said adapters. > > > including our device from above, > > No. Your driver is a new-style one (otherwise you couldn't use > i2c_new_device) which means that __detach_adapter returns relatively > quickly. The only part of __detach_adapter which is run is the one > which removes auto-instantiated devices. This isn't the case of your > device (you instantiated it explicitly) so __detach_adapter is a no-op > for you. Aha, so, the driver->clients list will not contain my device, and it won't get unregistered. Ic. > > then i2c_unregister_device will be called for it, a comment to which says > > > > "reverse effect of i2c_new_device()" > > > > So, our newly created device is gone, and loading the i2c driver again > > will not find it any more?... This doesn't seem to be the case, so, I > > think, the comment is wrong and has to be fixed. > > The comment is correct. What isn't is your understanding of the > (admittedly complex and often confusing) i2c-core code. But I hope to > solve it soon, by killing the legacy binding model altogether. > > In the meantime, if you have more questions, I will be pleased to > answer them. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer -- 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
