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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 35ADFC64E7B for ; Tue, 1 Dec 2020 12:41:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA3D120857 for ; Tue, 1 Dec 2020 12:41:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="cMgFuotN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730987AbgLAMlZ (ORCPT ); Tue, 1 Dec 2020 07:41:25 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:42388 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728023AbgLAMlZ (ORCPT ); Tue, 1 Dec 2020 07:41:25 -0500 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 9CF42538; Tue, 1 Dec 2020 13:40:40 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1606826440; bh=HhiBJ8kWaly9TjVOpknv4GCCj8g3nx/JKA7v8nB8WLY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cMgFuotNmqlimzf4CKRgwwZWhUMCWn2syvrkr6O50tLRNLLG2/NbQAy9XmczZZj6l NLJ9/RxpWvuS46+fHKAxL1e5vdl+eILGDTiZ/mRDc2ePlLDYLmMv+EzpUi/+tikPmE CqjvuwOIHW6vCdlPy5NRNKEIjRs6CfnI4goX3xQQ= Date: Tue, 1 Dec 2020 14:40:32 +0200 From: Laurent Pinchart To: Sakari Ailus Cc: Dan Scally , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, linux-media@vger.kernel.org, devel@acpica.org, rjw@rjwysocki.net, lenb@kernel.org, gregkh@linuxfoundation.org, mika.westerberg@linux.intel.com, andriy.shevchenko@linux.intel.com, linus.walleij@linaro.org, bgolaszewski@baylibre.com, wsa@kernel.org, yong.zhi@intel.com, sakari.ailus@linux.intel.com, bingbu.cao@intel.com, tian.shu.qiu@intel.com, mchehab@kernel.org, robert.moore@intel.com, erik.kaneda@intel.com, pmladek@suse.com, rostedt@goodmis.org, sergey.senozhatsky@gmail.com, linux@rasmusvillemoes.dk, kieran.bingham+renesas@ideasonboard.com, jacopo+renesas@jmondi.org, laurent.pinchart+renesas@ideasonboard.com, jorhand@linux.microsoft.com, kitakar@gmail.com, heikki.krogerus@linux.intel.com Subject: Re: [PATCH 18/18] ipu3: Add driver for dummy INT3472 ACPI device Message-ID: <20201201124032.GD4569@pendragon.ideasonboard.com> References: <20201130133129.1024662-1-djrscally@gmail.com> <20201130133129.1024662-19-djrscally@gmail.com> <20201130205203.GQ4351@valkosipuli.retiisi.org.uk> <3e8494a0-a2c0-59e7-46bb-9635c3c239dd@gmail.com> <20201201064421.GR4351@valkosipuli.retiisi.org.uk> <2a548835-78c6-8fe3-cceb-1fc000707157@gmail.com> <20201201123244.GT4351@valkosipuli.retiisi.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201201123244.GT4351@valkosipuli.retiisi.org.uk> Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi Sakari, On Tue, Dec 01, 2020 at 02:32:44PM +0200, Sakari Ailus wrote: > On Tue, Dec 01, 2020 at 08:08:26AM +0000, Dan Scally wrote: > > On 01/12/2020 06:44, Sakari Ailus wrote: > > > On Mon, Nov 30, 2020 at 11:06:03PM +0000, Dan Scally wrote: > > >> On 30/11/2020 20:52, Sakari Ailus wrote: > > >>>> +static const struct acpi_device_id int3472_device_id[] = { > > >>>> + { "INT3472", 0 }, > > >>> > > >>> The INT3472 _HID is really allocated for the tps68470 PMIC chip. It may not > > >>> be used by other drivers; people will want to build kernels where both of > > >>> these ACPI table layouts are functional. > > >>> > > >>> Instead, I propose, that you add this as an option to the tps68470 driver > > >>> that figures out whether the ACPI device for the tps68470 device actually > > >>> describes something else, in a similar fashion you do with the cio2-bridge > > >>> driver. I think it may need a separate Kconfig option albeit this and > > >>> cio2-bridge cannot be used separately. > > >> > > >> It actually occurs to me that that may not work (I know I called that > > >> out as an option we considered, but that was a while ago actually). The > > >> reason I wasn't worried about the existing tps68470 driver binding to > > >> these devices is that it's an i2c driver, and these dummy devices don't > > >> have an I2cSerialBusV2, so no I2C device is created by them the kernel. > > >> > > >> Won't that mean the tps68470 driver won't ever be probed for these devices? > > > > > > Oops. I missed this indeed was not an I²C driver. So please ignore the > > > comment. > > > > > > So I guess this wouldn't be an actual problem. I'd still like to test this > > > on a system with tps68470, as the rest of the set. > > > > On my Go2, it .probes() for the actual tps68740 (that machine has both > > types of INT3472 device) but fails with EINVAL when it can't find the > > CLDB buffer that these discrete type devices have. My understanding is > > that means it's free for the actual tps68470 driver to grab the device; > > although that's not happening because I had to blacklist that driver or > > it stops the machine from booting at the moment - haven't gotten round > > to investigating yet. > > Oh, then the problem is actually there. If it probes the tps68470 driver on > the systems with Windows ACPI tables, then it should be that driver which > works with the Windows ACPI tables, too. > > Checking for random objects such as CLDB in multiple drivers and returning > an error based on them being there or not wouldn't be exactly neat. > Although I'm not sure thare are options that are obviosly pretty here. I > wouldn't two separate drivers checking for e.g. CLDB (tps68470 + this one). > > The tps68470 driver is an MFD driver that instantiates a number of platform > devices. Alternatively, if you make this one a platform device, you can, in > case the CLDB (or whatever object) is present, in the tps68470 driver > instantiate a device for this driver instead of the rest. > > So I'd think what matters is that both drivers can be selected at the same > time but the user does not need to manually select them. Both ways could > work I guess? Let's make it simpler instead of creating lots of devices. Here's what I've proposed in a different e-mail in this thread. > Given that INT3472 means Intel camera power management device (that's > more or less the wording in Windows, I can double-check), would the > following make sense ? > > A top-level module named intel-camera-pmic (or int3472, or ...) would > register two drivers, a platform driver and an I2C driver, to > accommodate for both cases ("discrete PMIC" that doesn't have an > I2cSerialBusV2, and TPS64870 or uP6641Q that are I2C devices). The probe > function would perform the following: > > - If there's no CLDB, then the device uses the Chrome OS "ACPI > bindings", and refers to a TPS64870. The code that exists in the > kernel today (registering GPIOs, and registering an OpRegion to > communicate with the power management code in the DSDT) would be > activated. > > - If there's a CLDB, then the device type would be retrieved from it: > > - If the device is a "discrete PMIC", the driver would register clocks > and regulators controlled by GPIOs, and create clock, regulator and > GPIO lookup entries for the sensor device that references the PMIC. > > - If the device is a TPS64870, the code that exists in the kernel > today to register GPIOs would be activated, and new code would need > to be written to register regulators and clocks. > > - If the device is a uP6641Q, a new driver will need to be written (I > don't know on which devices this PMIC is used, so this can probably > be deferred). > > We can split this in multiple files and/or modules. Could you reply to 20201130233232.GD25713@pendragon.ideasonboard.com to avoid splitting the conversation ? -- Regards, Laurent Pinchart