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. > 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. -- 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
