From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934678AbdADKZ5 (ORCPT ); Wed, 4 Jan 2017 05:25:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56694 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933661AbdADKZw (ORCPT ); Wed, 4 Jan 2017 05:25:52 -0500 Date: Wed, 4 Jan 2017 11:25:44 +0100 From: Benjamin Tissoires To: Andy Shevchenko Cc: Pali =?utf-8?B?Um9ow6Fy?= , Dmitry Torokhov , =?utf-8?B?TWljaGHFgiBLxJlwaWXFhA==?= , Jean Delvare , Wolfram Sang , Steven Honeyman , Valdis Kletnieks , Jochen Eisinger , Gabriele Mazzotta , Andy Lutomirski , Mario Limonciello , Alex Hung , Takashi Iwai , linux-i2c@vger.kernel.org, "linux-kernel@vger.kernel.org" , Platform Driver Subject: Re: [PATCH] i2c: i801: Register optional lis3lv02d i2c device on Dell machines Message-ID: <20170104102544.GS5767@mail.corp.redhat.com> References: <1482843136-12838-1-git-send-email-pali.rohar@gmail.com> <201701032105.51144@pali> <20170103202418.GE16032@dtor-ws> <201701032139.13061@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 04 Jan 2017 10:25:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Jan 04 2017 or thereabouts, Andy Shevchenko wrote: > On Tue, Jan 3, 2017 at 10:39 PM, Pali Rohár wrote: > > > > With Michał we already discussed about it, see emails. Basically you can > > enable/disable kernel modules at compile time or blacklist at runtime > > (or even chose what will be compiled into vmlinux and what as external > > .ko module). Some distributions blacklist i2c-i801.ko module... > > But you understand that any of compile/not compile is not an option, right? > The case which we face will be both of them, if possible, will be > compiled as modules. > > Blacklisting means making your problem the actual user's one. Not good. > > > And > > there can be also problem with initialization of i2c-i801 driver (fix is > > in commit a7ae81952cda, but does not have to work at every time!). So > > that move on whitelisted machines can potentially cause disappearance of > > /dev/freefall and users will not have hdd protection which is currently > > working. > I am seeing the same issues with psmouse and SMBus touchpads. The PS/2 device knows about the availability of a better but unlisted device at the ACPI level. The way I solved this to not have to deal with compile/not compile and runtime errors is the same way Wolfram told you about: bus notifiers. I also use an intermediate platform driver to not add i2c dependency on psmouse. For you the solution would be: - In dell-smo8800, after checking the whitelist, add a platform driver "dell-lis3lv02d-platform", and add in the platform_data the I2C address of the chip. - create a new driver dell-lis3lv02d-platform.ko which listens for the i2c bus creation and registers the lis3lv02d I2C node when it sees a matching adapter. (see [1] for my solution) - in dell-lis3lv02d-platform.ko make sure to set the irq to -ENOENT so that lis3lv02d.ko doesn't create /dev/freefall which will still be handled by ACPI. How does that sound? Cheers, Benjamin [1] https://github.com/bentiss/linux/blob/synaptics-rmi4-v4.9-rc7+/drivers/input/rmi4/rmi_platform.c