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=-5.8 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 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 CE083C433DB for ; Mon, 8 Feb 2021 13:41:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CA5864E0B for ; Mon, 8 Feb 2021 13:41:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230315AbhBHNlX (ORCPT ); Mon, 8 Feb 2021 08:41:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230174AbhBHNlT (ORCPT ); Mon, 8 Feb 2021 08:41:19 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D697DC061786; Mon, 8 Feb 2021 05:40:38 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id A4F2A3D7; Mon, 8 Feb 2021 14:40:34 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1612791634; bh=eOcGwclaPzdTGob9FYZ8pGdRuRGXncVOcLEkod11eYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hDaXCzYhsEMVAFrDWbUARWuA7f4XQvQf+JOekWsDq7oxSiFwD2OiQ2VlXTouY9t3C X2N5G6946xpTySVeMbASATyaDtG2lovHNEY0jGgcT2TCcERt4EW/LRovi7l21uVFV1 kgKopd5EbisXgYq6yEJKY9qe3EOy63VFQN3HcHIU= Date: Mon, 8 Feb 2021 15:40:10 +0200 From: Laurent Pinchart To: Mauro Carvalho Chehab Cc: Jacopo Mondi , Sakari Ailus , Linux Media Mailing List , Jacopo Mondi , Stephen Rothwell , linux-next@vger.kernel.org Subject: Re: [PATCH] media: i2c: fix max9271 build dependencies Message-ID: References: <20210208072701.GI32460@paasikivi.fi.intel.com> <20210208083616.3iulzo56mhn4ymmq@uno.localdomain> <20210208084147.GN32460@paasikivi.fi.intel.com> <20210208100822.76ca0c2e@coco.lan> <20210208092424.GP32460@paasikivi.fi.intel.com> <20210208110723.4859ddda@coco.lan> <20210208114142.skwc22xps5xiqdyo@uno.localdomain> <20210208141102.3d5999dd@coco.lan> <20210208143150.03974bca@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210208143150.03974bca@coco.lan> Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org Hi Mauro, On Mon, Feb 08, 2021 at 02:31:50PM +0100, Mauro Carvalho Chehab wrote: > Em Mon, 8 Feb 2021 14:11:02 +0100 Mauro Carvalho Chehab escreveu: > > Em Mon, 8 Feb 2021 12:41:42 +0100 Jacopo Mondi escreveu: > > > > > > > If you do, instead: > > > > > > > > > > if VIDEO_V4L2 && I2C > > > > > config VIDEO_MAX9271_SERIALIZER > > > > > tristate > > > > > > > > > > config VIDEO_RDACM20 > > > > > select VIDEO_MAX9271_SERIALIZER > > > > > ... > > > > > > > > > > config VIDEO_RDACM21 > > > > > select VIDEO_MAX9271_SERIALIZER > > > > > ... > > > > > endif > > > > > > > > > > Then you also won't need: > > > > > depends on VIDEO_MAX9271_SERIALIZER || !VIDEO_MAX9271_SERIALIZER > > > > > > > > > > As select should do the right thing in this case, ensuring that MAX9271 > > > > > will be builtin either if RDACM20 or RDACM21 is builtin. > > > > > > > > I also vote for usage of "select". > > > > > > > > > > I would prefer that too, I was concerned about possible un-met > > > dependencies, as Sakari pointed out, but the current situation is no > > > better, as the only Kconfig symbols where those can be listed are the > > > camera modules one. > > > > Works for me. I'll make a patch for it. > > Hmm... after taking a deeper look at the rcma20 drivers, and on its > Kconfig help text: > > config VIDEO_RDACM20 > tristate "IMI RDACM20 camera support" > select V4L2_FWNODE > select VIDEO_V4L2_SUBDEV_API > select MEDIA_CONTROLLER > help > This driver supports the IMI RDACM20 GMSL camera, used in > ADAS systems. > > This camera should be used in conjunction with a GMSL > deserialiser such as the MAX9286. > > I'm starting to suspect that there's something very wrong here... > > The help text mentions the MAX9286 driver, which is a complete > driver, and not MAX9271, which seems to implement a set of PHY functions > needed by those drivers, and which lacks a proper I2C binding code on it. > > The I2C binding code is, instead, inside RDACM20 and RDACM21: > > static int rdacm21_initialize(struct rdacm21_device *dev) > { > int ret; > > /* Verify communication with the MAX9271: ping to wakeup. */ > dev->serializer.client->addr = MAX9271_DEFAULT_ADDR; > i2c_smbus_read_byte(dev->serializer.client); > usleep_range(3000, 5000); > > /* Enable reverse channel and disable the serial link. */ > ret = max9271_set_serial_link(&dev->serializer, false); > if (ret) > return ret; > > /* Configure I2C bus at 105Kbps speed and configure GMSL. */ > ret = max9271_configure_i2c(&dev->serializer, > MAX9271_I2CSLVSH_469NS_234NS | > MAX9271_I2CSLVTO_1024US | > MAX9271_I2CMSTBT_105KBPS); > > /* Several other max9271-specific init code */ > > ret = ov490_initialize(dev); > if (ret) > return ret; > > And, at max9271 "driver", there's just a bunch of exported functions. > > This is all wrong. > > I'm seriously considering to move all those 3 drivers to staging, > while they're not fixed to use a proper I2C binding mechanism. They can't. The RDACM20 and RDACM21 are GMSL cameras, that are internally made of a GMSL serializer (MAX9271 in both cases) and a camera sensor (OV10625 for the RDACM20, OV10640 + OV490 ISP for the RDAMC21). The sensor and serializer are tightly couple, so much so that in the RDACM20, there's a microcontroller that configures both when power is applied. In the RDACM21, the OV490 firmware has a similar role. Due to the tight coupling and the presense of a device-specific microcontroller, the cameras need to be handled as a whole, we can't have one driver for the sensor and one driver for the serializer that would work in isolation and be controlled separately from userspace. The MAX9271, however, still needs to be configured from the host, and we've thus moved common code to a common file instead of duplicating it. -- Regards, Laurent Pinchart