From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936695AbdLSJ3E (ORCPT ); Tue, 19 Dec 2017 04:29:04 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:47947 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752802AbdLSJ3B (ORCPT ); Tue, 19 Dec 2017 04:29:01 -0500 Date: Tue, 19 Dec 2017 10:28:58 +0100 From: Boris Brezillon To: Greg Kroah-Hartman Cc: Wolfram Sang , linux-i2c@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Arnd Bergmann , Przemyslaw Sroka , Arkadiusz Golec , Alan Douglas , Bartosz Folta , Damian Kos , Alicja Jurasik-Urbaniak , Cyprian Wronka , Suresh Punnoose , Thomas Petazzoni , Nishanth Menon , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Vitor Soares , Geert Uytterhoeven , Linus Walleij Subject: Re: [PATCH v2 2/7] i3c: Add core I3C infrastructure Message-ID: <20171219102858.001d4bf5@bbrezillon> In-Reply-To: <20171219092119.GA32748@kroah.com> References: <20171214151610.19153-1-boris.brezillon@free-electrons.com> <20171214151610.19153-3-boris.brezillon@free-electrons.com> <20171219085250.GC15010@kroah.com> <20171219100900.35c0f66e@bbrezillon> <20171219101336.337d0afc@bbrezillon> <20171219092119.GA32748@kroah.com> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 19 Dec 2017 10:21:19 +0100 Greg Kroah-Hartman wrote: > On Tue, Dec 19, 2017 at 10:13:36AM +0100, Boris Brezillon wrote: > > On Tue, 19 Dec 2017 10:09:00 +0100 > > Boris Brezillon wrote: > > > > > On Tue, 19 Dec 2017 09:52:50 +0100 > > > Greg Kroah-Hartman wrote: > > > > > > > On Thu, Dec 14, 2017 at 04:16:05PM +0100, Boris Brezillon wrote: > > > > > +/** > > > > > + * i3c_device_match_id() - Find the I3C device ID entry matching an I3C dev > > > > > + * @i3cdev: the I3C device we're searching a match for > > > > > + * @id_table: the I3C device ID table > > > > > + * > > > > > + * Return: a pointer to the first entry matching @i3cdev, or NULL if there's > > > > > + * no match. > > > > > + */ > > > > > +const struct i3c_device_id * > > > > > +i3c_device_match_id(struct i3c_device *i3cdev, > > > > > + const struct i3c_device_id *id_table) > > > > > +{ > > > > > + const struct i3c_device_id *id; > > > > > + > > > > > + /* > > > > > + * The lower 32bits of the provisional ID is just filled with a random > > > > > + * value, try to match using DCR info. > > > > > + */ > > > > > + if (!I3C_PID_RND_LOWER_32BITS(i3cdev->info.pid)) { > > > > > + u16 manuf = I3C_PID_MANUF_ID(i3cdev->info.pid); > > > > > + u16 part = I3C_PID_PART_ID(i3cdev->info.pid); > > > > > + u16 ext_info = I3C_PID_EXTRA_INFO(i3cdev->info.pid); > > > > > + > > > > > + /* First try to match by manufacturer/part ID. */ > > > > > + for (id = id_table; id->match_flags != 0; id++) { > > > > > + if ((id->match_flags & I3C_MATCH_MANUF_AND_PART) != > > > > > + I3C_MATCH_MANUF_AND_PART) > > > > > + continue; > > > > > + > > > > > + if (manuf != id->manuf_id || part != id->part_id) > > > > > + continue; > > > > > + > > > > > + if ((id->match_flags & I3C_MATCH_EXTRA_INFO) && > > > > > + ext_info != id->extra_info) > > > > > + continue; > > > > > + > > > > > + return id; > > > > > + } > > > > > + } > > > > > + > > > > > + /* Fallback to DCR match. */ > > > > > + for (id = id_table; id->match_flags != 0; id++) { > > > > > + if ((id->match_flags & I3C_MATCH_DCR) && > > > > > + id->dcr == i3cdev->info.dcr) > > > > > + return id; > > > > > + } > > > > > + > > > > > + return NULL; > > > > > +} > > > > > +EXPORT_SYMBOL_GPL(i3c_device_match_id); > > > > > > > > I just picked one random export here, but it feels like you are > > > > exporting a bunch of symbols you don't need to. Why would something > > > > outside of the i3c "core" need to call this function? > > > > > > Because I'm not passing the i3c_device_id to the ->probe() method, and > > > if the driver is supporting different variants of the device, it may > > > want to know which one is being probed. > > > > > > I considered retrieving this information in the core just before probing > > > the driver and passing it to the ->probe() function, but it means > > > having an extra i3c_device_match_id() call for everyone even those who > > > don't care about the device_id information, so I thought exporting this > > > function was a good alternative (device drivers can use it when they > > > actually need to retrieve the device_id). > > > > > > Anyway, that's something I can change if you think passing the > > > i3c_device_id to the ->probe() method is preferable. > > > > > > > Have you looked > > > > to see if you really have callers for everything you are exporting? > > > > > > Yes, I tried to only export functions that I think will be needed by > > > I3C device drivers and I3C master drivers. Note that I didn't post the > > > dummy device driver I developed to test the framework (partly because > > > this is > > > > Sorry, I hit the send button before finishing my sentence :-). > > > > " > > Note that I didn't post the dummy device driver [1] I developed to test > > the framework (partly because the quality of the code does not meet > > mainline standards and I was ashamed of posting it publicly :-)), but > > this driver is using some of the exported functions. > > " > > We don't export functions that has no in-kernel users :) But then, I can't export device driver related functions, because there's no official device driver yet :-). So what should I do?