From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE3B5C43381 for ; Tue, 19 Jan 2021 21:38:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 788E322E01 for ; Tue, 19 Jan 2021 21:38:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727729AbhASViR (ORCPT ); Tue, 19 Jan 2021 16:38:17 -0500 Received: from mga04.intel.com ([192.55.52.120]:42889 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404220AbhASRwJ (ORCPT ); Tue, 19 Jan 2021 12:52:09 -0500 IronPort-SDR: SddFu7hFUCKoPM3ndfCYlXP3oSkzEJiXpF4y3qseLX2jBr08MvvYeDVosoDdGwmgjCD0QRjV/E n5kCfczwxnZQ== X-IronPort-AV: E=McAfee;i="6000,8403,9869"; a="176398953" X-IronPort-AV: E=Sophos;i="5.79,359,1602572400"; d="scan'208";a="176398953" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2021 09:50:17 -0800 IronPort-SDR: NRHLIESoEebePQJ7aIh64Xj3fv2mlDiXkP6Rm6JbqQMfqBaQX/fQVJEZ8JfA0fqMRjK5XKZauq tJH0M0Pc9heQ== X-IronPort-AV: E=Sophos;i="5.79,359,1602572400"; d="scan'208";a="402440188" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2021 09:50:12 -0800 Received: from andy by smile with local (Exim 4.94) (envelope-from ) id 1l1v9u-004ocq-HN; Tue, 19 Jan 2021 19:51:14 +0200 Date: Tue, 19 Jan 2021 19:51:14 +0200 From: Andy Shevchenko To: Laurent Pinchart Cc: Daniel Scally , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, platform-driver-x86@vger.kernel.org, devel@acpica.org, rjw@rjwysocki.net, lenb@kernel.org, andy@kernel.org, mika.westerberg@linux.intel.com, linus.walleij@linaro.org, bgolaszewski@baylibre.com, wsa@kernel.org, lee.jones@linaro.org, hdegoede@redhat.com, mgross@linux.intel.com, robert.moore@intel.com, erik.kaneda@intel.com, sakari.ailus@linux.intel.com, kieran.bingham@ideasonboard.com Subject: Re: [PATCH v2 6/7] platform: x86: Add intel_skl_int3472 driver Message-ID: References: <20210118003428.568892-1-djrscally@gmail.com> <20210118003428.568892-7-djrscally@gmail.com> <20210118144606.GO4077@smile.fi.intel.com> <75e99a06-4579-44ee-5f20-8f2ee3309a68@gmail.com> <20210119092448.GN4077@smile.fi.intel.com> <20210119110837.GT4077@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tue, Jan 19, 2021 at 06:48:15PM +0200, Laurent Pinchart wrote: > On Tue, Jan 19, 2021 at 01:08:37PM +0200, Andy Shevchenko wrote: > > On Tue, Jan 19, 2021 at 10:40:42AM +0000, Daniel Scally wrote: > > > On 19/01/2021 09:24, Andy Shevchenko wrote: > > > >>>>> +static struct i2c_driver int3472_tps68470 = { > > > >>>>> + .driver = { > > > >>>>> + .name = "int3472-tps68470", > > > >>>>> + .acpi_match_table = int3472_device_id, > > > >>>>> + }, > > > >>>>> + .probe_new = skl_int3472_tps68470_probe, > > > >>>>> +}; > > > >>> I'm not sure we want to have like this. If I'm not mistaken the I²C driver can > > > >>> be separated without ACPI IDs (just having I²C IDs) and you may instantiate it > > > >>> via i2c_new_client_device() or i2c_acpi_new_device() whichever suits better... > > > >> Sorry, I'm a bit confused by this. The i2c device is already > > > >> present...we just want the driver to bind to them, so what role do those > > > >> functions have there? > > > > What I meant is something like > > > > > > > > *_i2c.c > > > > real I²C driver for the TPS chip, but solely with I²C ID table, no ACPI > > > > involved (and it sounds like it should be mfd/tps one, in which you > > > > just cut out ACPI IDs and convert to pure I²C one, that what I had > > > > suggested in the first place) > > > > > > Ahh; sorry - i misunderstood what you meant there. I understand now I > > > think, but there is one complication; the ACPI subsystem already creates > > > a client for that i2c adapter and address; i2c_new_client_device() > > > includes a check to see whether that adapter / address combination has > > > an i2c device already.  So we would have to have the platform driver > > > with ACPI ID first find the existing i2c_client and unregister it before > > > registering the new one...the existing clients have a name matching the > > > ACPI device instance name (e.g i2c-INT3472:00) which we can't use as an > > > i2c_device_id of course. > > > > See how INT33FE is being handled. Hint: drivers/acpi/scan.c:~1600 > > > > static const struct acpi_device_id i2c_multi_instantiate_ids[] = { > > {"BSG1160", }, > > {"BSG2150", }, > > {"INT33FE", }, > > {"INT3515", }, > > {} > > }; > > > > So, we quirklist it here and instantiate manually from platform driver (new > > coming one). > > This is documented as used for devices that have multiple I2cSerialBus > resources. That's not the case for the INT3472 as far as I can tell. I > don't think we should abuse this mechanism. This is quite a similar case to that one. Let's avoid yak shaving, right? > Don't forget that the TPS68470 I2C driver needs to be ACPI-aware, as it > has to register an OpRegion for ACPI-based Chrome OS devices. On other > platforms (including DT platforms), it should only register regulators, > clocks and GPIOs. Given the differences between those platforms, I don't > think a TPS68470 driver that would fake being unaware of being probed > through ACPI would be a good idea. We can always refactor the code later > when we'll have a non-ACPI based platform using the TPS68470, without > such a platform there's no way we can test the I2C driver without ACPI > anyway. Are you agree that MFD approach should stay? How then we can manage to have an MFD driver cohabit with our new driver? I proposed a clean solution which will handle all possible cases via quirk driver. Having two drivers enumerated by different scenarios is a call for troubles (we have already with one of that sensors). And there is no "faking" anything, it's rather gating it depending on the platform. -- With Best Regards, Andy Shevchenko