From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] [RFC] i2c: Don't wait for device release in i2c_del_adapter Date: Wed, 14 Jan 2015 18:14:26 +0100 Message-ID: <20150114181426.3a39791b@endymion.delvare> References: <1421082050-10213-1-git-send-email-pantelis.antoniou@konsulko.com> <20150113152957.GL7660@katana> <20150114144938.4e3c3f52@endymion.delvare> <20150114161525.49c54acc@endymion.delvare> <20150114162442.GB18578@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150114162442.GB18578-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Guenter Roeck Cc: Pantelis Antoniou , Wolfram Sang , Matt Porter , Greg Kroah-Hartman , Grant Likely , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hi Guenter, On Wed, 14 Jan 2015 08:24:43 -0800, Guenter Roeck wrote: > On Wed, Jan 14, 2015 at 04:15:25PM +0100, Jean Delvare wrote: > > I did that. On my system the i2c-i801 driver instantiates an > > i2c-mux-gpio device. Unloading the i2c-i801 driver removes that device > > and it works fine. Note however that I am not able to unload module > > i2c-i801 immediately, I have to unload module i2c-mux-gpio first, as > > the latter holds a reference to the former. This is because > > i2c-mux-gpio calls i2c_get_adapter() on the parent I2C bus segment at > > probing time. > > > > I see that i2c-mux-pinctrl does the same, but i2c-mux-pca954x and > > i2c-mux-pca9541 do not. This might be an issue. I doubt this is related > > to your problem though, as these are module references and not device > > references. > > Should we add get/put functions to those drivers ? I'm not sure. If you unload a driver which instantiated a pca9540-like device, without unloading i2c-mux-pca954x first, does something bad happen? -- Jean Delvare SUSE L3 Support