Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966917AbdLSJJY (ORCPT ); Tue, 19 Dec 2017 04:09:24 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:47345 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933409AbdLSJJP (ORCPT ); Tue, 19 Dec 2017 04:09:15 -0500 Date: Tue, 19 Dec 2017 10:09:00 +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: <20171219100900.35c0f66e@bbrezillon> In-Reply-To: <20171219085250.GC15010@kroah.com> References: <20171214151610.19153-1-boris.brezillon@free-electrons.com> <20171214151610.19153-3-boris.brezillon@free-electrons.com> <20171219085250.GC15010@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 Content-Length: 3087 Lines: 87 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 > > Other than that, the driver core interaction looks good now, nice job. Thanks. Boris