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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED 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 7DE43C169C4 for ; Wed, 6 Feb 2019 22:01:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 36507218B0 for ; Wed, 6 Feb 2019 22:01:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549490511; bh=1rulnxBBKxbBTOSkVKAeUNzfJN6xnWwk6dEWGMhxCCI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=P8Kwc5D4eqHGkBKxeK1UXGa734J5G0A8/e73ij9WlY8uemJoAMx/b/+R21jWrIAl/ 121GsEhMbzjCGY9pIsisQoC1CfLrEDcC3RJmRF0cPpFlnXGwuqswQz/IBLKiE53x2v 1GTqLlFtXC+fq60EOo6i/8j6m5DO+IMvT1++mO8E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726624AbfBFWBt (ORCPT ); Wed, 6 Feb 2019 17:01:49 -0500 Received: from mail-ot1-f68.google.com ([209.85.210.68]:41989 "EHLO mail-ot1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726161AbfBFWBt (ORCPT ); Wed, 6 Feb 2019 17:01:49 -0500 Received: by mail-ot1-f68.google.com with SMTP id v23so14756339otk.9 for ; Wed, 06 Feb 2019 14:01:48 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ackIu6dKwLPk3LJnTbGPBgw/bawJaZTkqoaFdBswSJc=; b=ow4YRheC4QTgDu2n8ahI5aGFj6wS/j5qzjQq0DgN1+/iVgTgWO1GXP6Oz0qRm29WOX SfgjEnBdttd3S8O5tEdL0EidR/Chn0v8k5RP4098URJFmj7i87FDIU3/mdr3Q9hMMI9U 6e6R68pTSCl8+z406LpU5qM08n4S6CPct5vBTAEbky7x6UZ5CbyK05pJFKsurLp7I+S8 zHH3P/7bRJ9StrEpoC8gXdt6P9Vru6tAFQPCrYle5lF4m1+jS1CpMyr7NjJw1Jqav97g Lr4Eqc/XBYYE9olL9Fhqhe04TXjFMLOIkbvI1asr6K6HfcrKJ2JIwWpP+iSB46JfM8Zj KMOw== X-Gm-Message-State: AHQUAua2cSDooZR1YdBwUnZL7mwdus1eGXbkjpvGfgzrLFRmGv9tmi5R x0qpGvtAxf3DBrFe0XPSn/la0S3VCAZeq8qgMIg= X-Google-Smtp-Source: AHgI3IZMONrqWjzS2rqQhOF6a43Yrl7bFIganRuT94NZXT+ICPCWm6D8w4g+/6iJtFTtN3O6LIG0K3m7KYZSkVmPaa0= X-Received: by 2002:aca:fdd0:: with SMTP id b199mr796606oii.178.1549490507774; Wed, 06 Feb 2019 14:01:47 -0800 (PST) MIME-Version: 1.0 References: <20190206164551.29400-1-daniel.vetter@ffwll.ch> <20190206164702.29753-1-daniel.vetter@ffwll.ch> In-Reply-To: <20190206164702.29753-1-daniel.vetter@ffwll.ch> From: "Rafael J. Wysocki" Date: Wed, 6 Feb 2019 23:01:35 +0100 Message-ID: Subject: Re: [PATCH] component: Add documentation To: Daniel Vetter Cc: DRI Development , LKML , "C, Ramalingam" , Greg Kroah-Hartman , Russell King , "Rafael J . Wysocki" , Jaroslav Kysela , Takashi Iwai , Rodrigo Vivi , Jani Nikula , Daniel Vetter Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 6, 2019 at 5:47 PM Daniel Vetter wrote: > > While typing these I think doing an s/component_master/aggregate/ > would be useful: > - it's shorter :-) > - I think component/aggregate is much more meaningful naming than > component/puppetmaster or something like that. At least to my > English ear "aggregate" emphasizes much more the "assemble a pile of > things into something bigger" aspect, and there's not really much > of a control hierarchy between aggregate and constituing components. > > But that's way more than a quick doc typing exercise ... > > Thanks to Ram for commenting on an initial draft of these docs. > > v2: Review from Rafael: > - git add Documenation/driver-api/component.rst > - lots of polish to the wording + spelling fixes. > > v3: Review from Russell: > - s/framework/helper > - clarify the documentation for component_match_add functions. > > Cc: "C, Ramalingam" > Cc: Greg Kroah-Hartman > Cc: Russell King > Cc: Rafael J. Wysocki > Cc: Jaroslav Kysela > Cc: Takashi Iwai > Cc: Rodrigo Vivi > Cc: Jani Nikula > Signed-off-by: Daniel Vetter Reviewed-by: Rafael J. Wysocki > --- > Documentation/driver-api/component.rst | 17 ++++ > Documentation/driver-api/device_link.rst | 3 + > Documentation/driver-api/index.rst | 1 + > drivers/base/component.c | 107 ++++++++++++++++++++++- > include/linux/component.h | 71 +++++++++++++++ > 5 files changed, 196 insertions(+), 3 deletions(-) > create mode 100644 Documentation/driver-api/component.rst > > diff --git a/Documentation/driver-api/component.rst b/Documentation/driver-api/component.rst > new file mode 100644 > index 000000000000..2da4a8f20607 > --- /dev/null > +++ b/Documentation/driver-api/component.rst > @@ -0,0 +1,17 @@ > +====================================== > +Component Helper for Aggregate Drivers > +====================================== > + > +.. kernel-doc:: drivers/base/component.c > + :doc: overview > + > + > +API > +=== > + > +.. kernel-doc:: include/linux/component.h > + :internal: > + > +.. kernel-doc:: drivers/base/component.c > + :export: > + > diff --git a/Documentation/driver-api/device_link.rst b/Documentation/driver-api/device_link.rst > index d6763272e747..2d5919b2b337 100644 > --- a/Documentation/driver-api/device_link.rst > +++ b/Documentation/driver-api/device_link.rst > @@ -1,6 +1,9 @@ > .. |struct dev_pm_domain| replace:: :c:type:`struct dev_pm_domain ` > .. |struct generic_pm_domain| replace:: :c:type:`struct generic_pm_domain ` > > + > +.. _device_link: > + > ============ > Device links > ============ > diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst > index ab38ced66a44..c0b600ed9961 100644 > --- a/Documentation/driver-api/index.rst > +++ b/Documentation/driver-api/index.rst > @@ -22,6 +22,7 @@ available subsections can be seen below. > device_connection > dma-buf > device_link > + component > message-based > sound > frame-buffer > diff --git a/drivers/base/component.c b/drivers/base/component.c > index ddcea8739c12..f34d4b784709 100644 > --- a/drivers/base/component.c > +++ b/drivers/base/component.c > @@ -16,6 +16,32 @@ > #include > #include > > +/** > + * DOC: overview > + * > + * The component helper allows drivers to collect a pile of sub-devices, > + * including their bound drivers, into an aggregate driver. Various subsystems > + * already provide functions to get hold of such components, e.g. > + * of_clk_get_by_name(). The component helper can be used when such a > + * subsystem-specific way to find a device is not available: The component > + * helper fills the niche of aggregate drivers for specific hardware, where > + * further standardization into a subsystem would not be practical. The common > + * example is when a logical device (e.g. a DRM display driver) is spread around > + * the SoC on various component (scanout engines, blending blocks, transcoders > + * for various outputs and so on). > + * > + * The component helper also doesn't solve runtime dependencies, e.g. for system > + * suspend and resume operations. See also :ref:`device links`. > + * > + * Components are registered using component_add() and unregistered with > + * component_del(), usually from the driver's probe and disconnect functions. > + * > + * Aggregate drivers first assemble a component match list of what they need > + * using component_match_add(). This is then registered as an aggregate driver > + * using component_master_add_with_match(), and unregistered using > + * component_master_del(). > + */ > + > struct component; > > struct component_match_array { > @@ -301,10 +327,25 @@ static int component_match_realloc(struct device *dev, > return 0; > } > > -/* > - * Add a component to be matched, with a release function. > +/** > + * component_match_add_release - add a component match with release callback > + * @master: device with the aggregate driver > + * @matchptr: pointer to the list of component matches > + * @release: release function for @compare_data > + * @compare: compare function to match against all components > + * @compare_data: opaque pointer passed to the @compare function > + * > + * This adds a new component match to the list stored in @matchptr, which the > + * @master aggregate driver needs to function. The list of component matches > + * pointed to by @matchptr must be initialized to NULL before adding the first > + * match. > + * > + * The allocated match list in @matchptr is automatically released using devm > + * actions, where upon @release will be called to free any references held by > + * @compare_data, e.g. when @compare_data is a &device_node that must be > + * released with of_node_put(). > * > - * The match array is first created or extended if necessary. > + * See also component_match_add(). > */ > void component_match_add_release(struct device *master, > struct component_match **matchptr, > @@ -367,6 +408,18 @@ static void free_master(struct master *master) > kfree(master); > } > > +/** > + * component_master_add_with_match - register an aggregate driver > + * @dev: device with the aggregate driver > + * @ops: callbacks for the aggregate driver > + * @match: component match list for the aggregate driver > + * > + * Registers a new aggregate driver consisting of the components added to @match > + * by calling one of the component_match_add() functions. Once all components in > + * @match are available, it will be assembled by calling > + * &component_master_ops.bind from @ops. Must be unregistered by calling > + * component_master_del(). > + */ > int component_master_add_with_match(struct device *dev, > const struct component_master_ops *ops, > struct component_match *match) > @@ -403,6 +456,15 @@ int component_master_add_with_match(struct device *dev, > } > EXPORT_SYMBOL_GPL(component_master_add_with_match); > > +/** > + * component_master_del - unregister an aggregate driver > + * @dev: device with the aggregate driver > + * @ops: callbacks for the aggregate driver > + * > + * Unregisters an aggregate driver registered with > + * component_master_add_with_match(). If necessary the aggregate driver is first > + * disassembled by calling &component_master_ops.unbind from @ops. > + */ > void component_master_del(struct device *dev, > const struct component_master_ops *ops) > { > @@ -430,6 +492,15 @@ static void component_unbind(struct component *component, > devres_release_group(component->dev, component); > } > > +/** > + * component_unbind_all - unbind all component to an aggregate driver > + * @master_dev: device with the aggregate driver > + * @data: opaque pointer, passed to all components > + * > + * Unbinds all components to the aggregate @dev by passing @data to their > + * &component_ops.unbind functions. Should be called from > + * &component_master_ops.unbind. > + */ > void component_unbind_all(struct device *master_dev, void *data) > { > struct master *master; > @@ -503,6 +574,15 @@ static int component_bind(struct component *component, struct master *master, > return ret; > } > > +/** > + * component_bind_all - bind all component to an aggregate driver > + * @master_dev: device with the aggregate driver > + * @data: opaque pointer, passed to all components > + * > + * Binds all components to the aggregate @dev by passing @data to their > + * &component_ops.bind functions. Should be called from > + * &component_master_ops.bind. > + */ > int component_bind_all(struct device *master_dev, void *data) > { > struct master *master; > @@ -537,6 +617,18 @@ int component_bind_all(struct device *master_dev, void *data) > } > EXPORT_SYMBOL_GPL(component_bind_all); > > +/** > + * component_add - register a component > + * @dev: component device > + * @ops: component callbacks > + * > + * Register a new component for @dev. Functions in @ops will be called when the > + * aggregate driver is ready to bind the overall driver by calling > + * component_bind_all(). See also &struct component_ops. > + * > + * The component needs to be unregistered at driver unload/disconnect by calling > + * component_del(). > + */ > int component_add(struct device *dev, const struct component_ops *ops) > { > struct component *component; > @@ -568,6 +660,15 @@ int component_add(struct device *dev, const struct component_ops *ops) > } > EXPORT_SYMBOL_GPL(component_add); > > +/** > + * component_del - unregister a component > + * @dev: component device > + * @ops: component callbacks > + * > + * Unregister a component added with component_add(). If the component is bound > + * into an aggregate driver, this will force the entire aggregate driver, including > + * all its components, to be unbound. > + */ > void component_del(struct device *dev, const struct component_ops *ops) > { > struct component *c, *component = NULL; > diff --git a/include/linux/component.h b/include/linux/component.h > index e71fbbbc74e2..4911598b4c42 100644 > --- a/include/linux/component.h > +++ b/include/linux/component.h > @@ -4,11 +4,31 @@ > > #include > > + > struct device; > > +/** > + * struct component_ops - callbacks for component drivers > + * > + * Components are registered with component_add() and unregistered with > + * component_del(). > + */ > struct component_ops { > + /** > + * @bind: > + * > + * Called through component_bind_all() when the aggregate driver is > + * ready to bind the overall driver. > + */ > int (*bind)(struct device *comp, struct device *master, > void *master_data); > + /** > + * @unbind: > + * > + * Called through component_unbind_all() when the aggregate driver is > + * ready to bind the overall driver, or when component_bind_all() fails > + * part-ways through and needs to unbind some already bound components. > + */ > void (*unbind)(struct device *comp, struct device *master, > void *master_data); > }; > @@ -21,8 +41,42 @@ void component_unbind_all(struct device *master, void *master_data); > > struct master; > > +/** > + * struct component_master_ops - callback for the aggregate driver > + * > + * Aggregate drivers are registered with component_master_add_with_match() and > + * unregistered with component_master_del(). > + */ > struct component_master_ops { > + /** > + * @bind: > + * > + * Called when all components or the aggregate driver, as specified in > + * the match list passed to component_master_add_with_match(), are > + * ready. Usually there are 3 steps to bind an aggregate driver: > + * > + * 1. Allocate a structure for the aggregate driver. > + * > + * 2. Bind all components to the aggregate driver by calling > + * component_bind_all() with the aggregate driver structure as opaque > + * pointer data. > + * > + * 3. Register the aggregate driver with the subsystem to publish its > + * interfaces. > + * > + * Note that the lifetime of the aggregate driver does not align with > + * any of the underlying &struct device instances. Therefore devm cannot > + * be used and all resources acquired or allocated in this callback must > + * be explicitly released in the @unbind callback. > + */ > int (*bind)(struct device *master); > + /** > + * @unbind: > + * > + * Called when either the aggregate driver, using > + * component_master_del(), or one of its components, using > + * component_del(), is unregistered. > + */ > void (*unbind)(struct device *master); > }; > > @@ -38,6 +92,23 @@ void component_match_add_release(struct device *master, > void (*release)(struct device *, void *), > int (*compare)(struct device *, void *), void *compare_data); > > +/** > + * component_match_add - add a compent match > + * @master: device with the aggregate driver > + * @matchptr: pointer to the list of component matches > + * @compare: compare function to match against all components > + * @compare_data: opaque pointer passed to the @compare function > + * > + * This adds a new component match to the list stored in @matchptr, which the > + * @master aggregate driver needs to function. The list of component matches > + * pointed to by @matchptr must be initialized to NULL before adding the first > + * match. > + * > + * The allocated match list in @matchptr is automatically released using devm > + * actions. > + * > + * See also component_match_add_release(). > + */ > static inline void component_match_add(struct device *master, > struct component_match **matchptr, > int (*compare)(struct device *, void *), void *compare_data) > -- > 2.20.1 >