From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [Q] i2c_new_device vs i2c_del_driver Date: Fri, 20 Mar 2009 18:48:30 +0100 Message-ID: <20090320184830.2ee7a6f8@hyperion.delvare> References: <20090317183809.55320908@hyperion.delvare> <20090317191724.7ace956f@hyperion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Guennadi Liakhovetski Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hi Guennadi, On Tue, 17 Mar 2009 19:29:07 +0100 (CET), Guennadi Liakhovetski wrote: > On Tue, 17 Mar 2009, Jean Delvare wrote: > > > On Tue, 17 Mar 2009 18:50:50 +0100 (CET), Guennadi Liakhovetski wrote: > > > > > > Aha, so, the driver->clients list will not contain my device, and it won't > > > get unregistered. Ic. > > > > Correct. Maybe I should have found a better name, like > > driver->detected_clients, to make it clearer. Want me to change it > > know? It should be straightforward. > > Well, now I know the difference already, but I am not sure this would have > helped me before you've explained it:-) So, don't bother because of me. > Maybe adding a couple of words to Documentation/i2c/writing-clients > explaining the different function i2c_del_driver() performs on different > devices. Well, writing-clients is really only about writing driver code, I don't think it is the right document to describe the i2c-core internals nor the device lifetime. I have recently written a new document explaining how devices can be instantiated: ftp://ftp.kernel.org/pub/linux/kernel/people/jdelvare/linux-2.6/jdelvare-i2c/i2c-how-to-instantiate-devices.patch This document explains the conditions of destruction of the devices depending on how they were created. I hope this answers your question. If not, the document can of course be clarified. > Or a comment in the source - even better. For the piece of code which confused you, yes, I agree a short comment would help. What about: --- drivers/i2c/i2c-core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- linux-2.6.29-rc8.orig/drivers/i2c/i2c-core.c 2009-03-20 09:45:43.000000000 +0100 +++ linux-2.6.29-rc8/drivers/i2c/i2c-core.c 2009-03-20 17:21:29.000000000 +0100 @@ -581,7 +581,8 @@ static int i2c_do_del_adapter(struct dev struct i2c_client *client, *_n; int res; - /* Remove the devices we created ourselves */ + /* Remove the devices we created ourselves as the result of hardware + * probing (using a driver's detect method) */ list_for_each_entry_safe(client, _n, &driver->clients, detected) { if (client->adapter == adapter) { dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", @@ -749,6 +750,8 @@ static int __detach_adapter(struct devic struct i2c_driver *driver = data; struct i2c_client *client, *_n; + /* Remove the devices we created ourselves as the result of hardware + * probing (using a driver's detect method) */ list_for_each_entry_safe(client, _n, &driver->clients, detected) { dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", client->name, client->addr); -- Jean Delvare