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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 963EBC433F5 for ; Mon, 2 May 2022 14:58:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1385632AbiEBPBf (ORCPT ); Mon, 2 May 2022 11:01:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348651AbiEBPBc (ORCPT ); Mon, 2 May 2022 11:01:32 -0400 Received: from smtp2.axis.com (smtp2.axis.com [195.60.68.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6500E0B5; Mon, 2 May 2022 07:58:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1651503483; x=1683039483; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=6Jk5Cj5k7nAQkN54Q8EOZFK50a7XWFdMHwlCJE+rGok=; b=AcpTowzkJ0GT7LMhXxhIxLhoIksXkHAIxvrpd4qqp3d/0qEZXzs8n2ZB CGOkN62PW+teJtU9lQDpgehS+JHoOykJxWp8IZvbYpyPC/tPfiNNWSgeH rI72d+uwxe5hzdF4Ujv4lfuDc+ulmkXJi7HZ1VsBI2WlAY7ztBE7i/21/ WZc3HzJJU54wY1hiynbKQ/5GOez8+4/yeIsOq20sFR5a9mNKOkdbUhKYH Bo1biD2dzaqM/5MM51XhceXaPcgzyPF/0/55VrGcxeLYliYqhTHSh12oV LXU5tmeAifHAw9pbgF4L6kbpWsBttHP4ZLLJPRXa/mxDoXeHBuLNa62jQ Q==; Date: Mon, 2 May 2022 16:58:00 +0200 From: Vincent Whitchurch To: Guenter Roeck CC: Camel Guo , Jean Delvare , "linux-hwmon@vger.kernel.org" , kernel , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2] hwmon: (tmp401) Add of_match_table Message-ID: <20220502145800.GA21695@axis.com> References: <20220502091942.1083067-1-camel.guo@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 02, 2022 at 03:57:50PM +0200, Guenter Roeck wrote: > On 5/2/22 02:19, Camel Guo wrote: > > When tmp401 is built as kernel module, it won't be automatically loaded > > even through there is a device node in the devicetree. e.g: > > i2c { > > #address-cells = <1>; > > #size-cells = <0>; > > > > sensor@4c { > > compatible = "ti,tmp401"; > > reg = <0x4c>; > > }; > > }; > > In order to make sure it is loaded automatically, this commit adds > > of_match_table for tmp401. > > > > As mentioned before, historically i2c devices would instantiate based > on the i2c match table. You are claiming that this is no longer the case. Note that while the commit message in the first version of the patch did wrongly claim that probe would not work without the of_match_table, this corrected description in v2 does mention the actual problem: that the module will not be automatically loaded without the of_match_table. (If the module is loaded manually or the driver is built-in to the kernel, there is no problem.) See commit 72fc64c68decf119466 ("hwmon: (tmp103) Add OF device ID table") or commit 98b16a09861aa85d6 ("hwmon: (max31785) Add OF device ID table") for similar changes to other hwmon drivers. The potential future change mentioned in the commit messages of 72fc64c68decf119466 and 98b16a09861aa85d6 happened in commit af503716ac1444db61d80 ("i2c: core: report OF style module alias for devices registered via OF"). The commit message of af503716ac1444db61d80 has a lot of details about the change being made, and while it says that all in-tree drivers had been converted, it looks like some of them, like tmp401, were missed. > The above is no evidence; that would require a log output on an affected > system showing that the sensors are not or no longer longer instantiated. A log would simply show nothing happening so that's probably not going to be that useful, but here is what the modaliases look like. As you can see, the modalias of the device in sysfs does not match any of the alias patterns of the module without this patch: $ cat /sys/bus/i2c/devices/4-004c/modalias of:Ntemperature-sensorTCti,tmp431 modinfo without this patch: $ modinfo ./modules/lib/modules/5.18.0-rc1/kernel/drivers/hwmon/tmp401.ko filename: /storage2/femfyra/linux-2.6/.roadtest/./modules/lib/modules/5.18.0-rc1/kernel/drivers/hwmon/tmp401.ko license: GPL description: Texas Instruments TMP401 temperature sensor driver author: Hans de Goede alias: i2c:tmp435 alias: i2c:tmp432 alias: i2c:tmp431 alias: i2c:tmp411 alias: i2c:tmp401 depends: intree: Y name: tmp401 vermagic: 5.18.0-rc1 mod_unload modinfo after this patch: $ modinfo ./modules/lib/modules/5.18.0-rc1/kernel/drivers/hwmon/tmp401.ko filename: /storage2/femfyra/linux-2.6/./.roadtest/modules/lib/modules/5.18.0-rc1/kernel/drivers/hwmon/tmp401.ko license: GPL description: Texas Instruments TMP401 temperature sensor driver author: Hans de Goede alias: i2c:tmp435 alias: i2c:tmp432 alias: i2c:tmp431 alias: i2c:tmp411 alias: i2c:tmp401 alias: of:N*T*Cti,tmp435C* alias: of:N*T*Cti,tmp435 alias: of:N*T*Cti,tmp432C* alias: of:N*T*Cti,tmp432 alias: of:N*T*Cti,tmp431C* alias: of:N*T*Cti,tmp431 alias: of:N*T*Cti,tmp411C* alias: of:N*T*Cti,tmp411 alias: of:N*T*Cti,tmp401C* alias: of:N*T*Cti,tmp401 depends: intree: Y name: tmp401 vermagic: 5.18.0-rc1 mod_unload