From patchwork Tue Feb 2 13:56:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 374863 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 E92B5C43381 for ; Tue, 2 Feb 2021 18:56:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7D5D64E75 for ; Tue, 2 Feb 2021 18:56:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239126AbhBBSzx (ORCPT ); Tue, 2 Feb 2021 13:55:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233664AbhBBOCL (ORCPT ); Tue, 2 Feb 2021 09:02:11 -0500 Received: from hillosipuli.retiisi.eu (hillosipuli.retiisi.eu [IPv6:2a01:4f9:c010:4572::81:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26BD7C061793 for ; Tue, 2 Feb 2021 05:59:56 -0800 (PST) Received: from lanttu.localdomain (lanttu-e.localdomain [192.168.1.64]) by hillosipuli.retiisi.eu (Postfix) with ESMTP id BE724634CBF; Tue, 2 Feb 2021 15:56:09 +0200 (EET) From: Sakari Ailus To: linux-media@vger.kernel.org Cc: Hans Verkuil , kernel@collabora.com, Laurent Pinchart , Kieran Bingham , Jacopo Mondi , niklas.soderlund+renesas@ragnatech.se, Helen Koike , Dafna Hirschfeld , Hugues Fruchet , Nicolas Ferre , Yong Zhi , Sylwester Nawrocki , Maxime Ripard , Robert Foss , Philipp Zabel , Ezequiel Garcia Subject: [PATCH v5 13/13] media: Clarify v4l2-async subdevice addition API Date: Tue, 2 Feb 2021 15:56:11 +0200 Message-Id: <20210202135611.13920-14-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210202135611.13920-1-sakari.ailus@linux.intel.com> References: <20210202135611.13920-1-sakari.ailus@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Ezequiel Garcia Now that most users of v4l2_async_notifier_add_subdev have been converted, let's fix the documentation so it's more clear how the v4l2-async API should be used. Document functions that drivers should use, and their purpose. Signed-off-by: Ezequiel Garcia Reviewed-by: Laurent Pinchart Signed-off-by: Sakari Ailus Reviewed-by: Helen Koike --- .../driver-api/media/v4l2-subdev.rst | 48 +++++++++++++++---- include/media/v4l2-async.h | 15 ++++-- 2 files changed, 50 insertions(+), 13 deletions(-) diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst index 0e82c77cf3e2..8b53da2f9c74 100644 --- a/Documentation/driver-api/media/v4l2-subdev.rst +++ b/Documentation/driver-api/media/v4l2-subdev.rst @@ -197,15 +197,45 @@ unregister the notifier the driver has to call takes two arguments: a pointer to struct :c:type:`v4l2_device` and a pointer to struct :c:type:`v4l2_async_notifier`. -Before registering the notifier, bridge drivers must do two things: -first, the notifier must be initialized using the -:c:func:`v4l2_async_notifier_init`. Second, bridge drivers can then -begin to form a list of subdevice descriptors that the bridge device -needs for its operation. Subdevice descriptors are added to the notifier -using the :c:func:`v4l2_async_notifier_add_subdev` call. This function -takes two arguments: a pointer to struct :c:type:`v4l2_async_notifier`, -and a pointer to the subdevice descripter, which is of type struct -:c:type:`v4l2_async_subdev`. +Before registering the notifier, bridge drivers must do two things: first, the +notifier must be initialized using the :c:func:`v4l2_async_notifier_init`. +Second, bridge drivers can then begin to form a list of subdevice descriptors +that the bridge device needs for its operation. Several functions are available +to add subdevice descriptors to a notifier, depending on the type of device and +the needs of the driver. + +:c:func:`v4l2_async_notifier_add_fwnode_remote_subdev` and +:c:func:`v4l2_async_notifier_add_i2c_subdev` are for bridge and ISP drivers for +registering their async sub-devices with the notifier. + +:c:func:`v4l2_async_register_subdev_sensor_common` is a helper function for +sensor drivers registering their own async sub-device, but it also registers a +notifier and further registers async sub-devices for lens and flash devices +found in firmware. The notifier for the sub-device is unregistered with the +async sub-device. + +These functions allocate an async sub-device descriptor which is of type struct +:c:type:`v4l2_async_subdev` embedded in a driver-specific struct. The &struct +:c:type:`v4l2_async_subdev` shall be the first member of this struct: + +.. code-block:: c + + struct my_async_subdev { + struct v4l2_async_subdev asd; + ... + }; + + struct my_async_subdev *my_asd; + struct fwnode_handle *ep; + + ... + + my_asd = v4l2_async_notifier_add_fwnode_remote_subdev(¬ifier, ep, + struct my_async_subdev); + fwnode_handle_put(ep); + + if (IS_ERR(asd)) + return PTR_ERR(asd); The V4L2 core will then use these descriptors to match asynchronously registered subdevices to them. If a match is detected the ``.bound()`` diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h index 192a11bdc4ad..6dac6cb6290f 100644 --- a/include/media/v4l2-async.h +++ b/include/media/v4l2-async.h @@ -128,7 +128,12 @@ void v4l2_async_debug_init(struct dentry *debugfs_dir); * @notifier: pointer to &struct v4l2_async_notifier * * This function initializes the notifier @asd_list. It must be called - * before the first call to @v4l2_async_notifier_add_subdev. + * before adding a subdevice to a notifier, using one of: + * @v4l2_async_notifier_add_fwnode_remote_subdev, + * @v4l2_async_notifier_add_fwnode_subdev, + * @v4l2_async_notifier_add_i2c_subdev, + * @v4l2_async_notifier_add_subdev or + * @v4l2_async_notifier_parse_fwnode_endpoints. */ void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier); @@ -262,9 +267,11 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier); * sub-devices allocated for the purposes of the notifier but not the notifier * itself. The user is responsible for calling this function to clean up the * notifier after calling - * @v4l2_async_notifier_add_subdev, - * @v4l2_async_notifier_parse_fwnode_endpoints or - * @v4l2_fwnode_reference_parse_sensor_common. + * @v4l2_async_notifier_add_fwnode_remote_subdev, + * @v4l2_async_notifier_add_fwnode_subdev, + * @v4l2_async_notifier_add_i2c_subdev, + * @v4l2_async_notifier_add_subdev or + * @v4l2_async_notifier_parse_fwnode_endpoints. * * There is no harm from calling v4l2_async_notifier_cleanup in other * cases as long as its memory has been zeroed after it has been