From patchwork Thu Jun 22 11:39:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 695512 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 3F59FEB64DA for ; Thu, 22 Jun 2023 11:41:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230446AbjFVLlP (ORCPT ); Thu, 22 Jun 2023 07:41:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230390AbjFVLlN (ORCPT ); Thu, 22 Jun 2023 07:41:13 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 538A41BF0 for ; Thu, 22 Jun 2023 04:41:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1687434072; x=1718970072; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=SOlSwMSc5tzoSJgir+mpDSUJggMngQHIbTeg/lY9qhg=; b=kb+3sLo2PgGzqGkZYLPGoQlu503QNx+4UCPCE+7j0lMf4Agx8WU6b/vd cSW41rdV9fCejxeGFvak+xyFftrU7iQ7nwG9mR7QPN6XLVL7RZ+3GoTkZ iyk83Z8fVBsQ/3upCxgraWe22NCtKrJdfXzRIpyua2V4u2GZiE63w8z+R NJJww+QLfwKeP0Z0Lcp9IwSzsrvuK1g6GgJ5wNWHNyqhLZT38VSB7pf+5 R6tLQ6+grClysm9yrrEt93YuOccxCfteoNLw9iKZAon9H5upXuqskpW4s 4WflKS3PsUiIbbg+jmSzEF0cI6dCpuSsvoE0G7xuauev/KvorVTGrFZ/W Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10748"; a="357957581" X-IronPort-AV: E=Sophos;i="6.00,263,1681196400"; d="scan'208";a="357957581" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2023 04:41:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10748"; a="804749888" X-IronPort-AV: E=Sophos;i="6.00,263,1681196400"; d="scan'208";a="804749888" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2023 04:41:02 -0700 Received: from punajuuri.localdomain (punajuuri.localdomain [192.168.240.130]) by kekkonen.fi.intel.com (Postfix) with ESMTP id D69EE120AE2; Thu, 22 Jun 2023 14:40:50 +0300 (EEST) Received: from sailus by punajuuri.localdomain with local (Exim 4.96) (envelope-from ) id 1qCIg2-003oSQ-2Y; Thu, 22 Jun 2023 14:40:38 +0300 From: Sakari Ailus To: linux-media@vger.kernel.org Cc: laurent.pinchart@ideasonboard.com, Philipp Zabel , hverkuil@xs4all.nl, Francesco Dolcini , aishwarya.kothari@toradex.com, Robert Foss , Todor Tomov , Hyun Kwon , bingbu.cao@intel.com, niklas.soderlund@ragnatech.se, Kieran Bingham , Benjamin Mugnier , Sylvain Petinot , Eugen Hristev , Nicolas Ferre , Maxime Ripard , Rui Miguel Silva , Fabio Estevam , Bryan O'Donoghue , Sylwester Nawrocki , Dafna Hirschfeld , Hugues Fruchet , Yong Deng , Paul Kocialkowski , "Lad, Prabhakar" , Benoit Parrot , Steve Longerbeam , Thierry Reding , Jonathan Hunter , Sowjanya Komatineni , Marco Felsch Subject: [PATCH v4 07/38] media: Documentation: v4l: Add section titles for async Date: Thu, 22 Jun 2023 14:39:57 +0300 Message-Id: <20230622114028.908825-8-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230622114028.908825-1-sakari.ailus@linux.intel.com> References: <20230622114028.908825-1-sakari.ailus@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add section titles for async documentation. While the documentation is mostly fine as-is, it has grown from its original state but remains without internal structure. Add it now. Also remove an extra newline. Signed-off-by: Sakari Ailus --- .../driver-api/media/v4l2-subdev.rst | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst index c46511c9b6c87..3cc56ac8d221c 100644 --- a/Documentation/driver-api/media/v4l2-subdev.rst +++ b/Documentation/driver-api/media/v4l2-subdev.rst @@ -157,6 +157,9 @@ below. Using one or the other registration method only affects the probing process, the run-time bridge-subdevice interaction is in both cases the same. +Registering synchronous sub-devices +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + In the **synchronous** case a device (bridge) driver needs to register the :c:type:`v4l2_subdev` with the v4l2_device: @@ -175,10 +178,12 @@ You can unregister a sub-device using: :c:func:`v4l2_device_unregister_subdev ` (:c:type:`sd `). - Afterwards the subdev module can be unloaded and :c:type:`sd `->dev == ``NULL``. +Registering asynchronous sub-devices +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + In the **asynchronous** case subdevice probing can be invoked independently of the bridge driver availability. The subdevice driver then has to verify whether all the requirements for a successful probing are satisfied. This can include a @@ -190,6 +195,9 @@ performed using the :c:func:`v4l2_async_unregister_subdev` call. Subdevices registered this way are stored in a global list of subdevices, ready to be picked up by bridge drivers. +Asynchronous sub-device notifiers +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + Bridge drivers in turn have to register a notifier object. This is performed using the :c:func:`v4l2_async_nf_register` call. To unregister the notifier the driver has to call @@ -208,12 +216,18 @@ the needs of the driver. :c:func:`v4l2_async_nf_add_i2c` are for bridge and ISP drivers for registering their async sub-devices with the notifier. +Asynchronous sub-device registration helper for camera sensor drivers +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + :c:func:`v4l2_async_register_subdev_sensor` 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. +Asynchronous sub-device notifier example +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + 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: @@ -237,6 +251,9 @@ These functions allocate an async sub-device descriptor which is of type struct if (IS_ERR(my_asd)) return PTR_ERR(my_asd); +Asynchronous sub-device notifier callbacks +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + The V4L2 core will then use these descriptors to match asynchronously registered subdevices to them. If a match is detected the ``.bound()`` notifier callback is called. After all subdevices have been located the