component: Add documentation
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. v4: Remove a few superflous "This". Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "C, Ramalingam" <ramalingam.c@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190207232759.14553-1-daniel.vetter@ffwll.ch5.1.x+fslc
Daniel Vetter
parent
8834f5600c
commit
4d69c80e0d
|
|
@ -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:
|
||||
|
||||
|
|
@ -1,6 +1,9 @@
|
|||
.. |struct dev_pm_domain| replace:: :c:type:`struct dev_pm_domain <dev_pm_domain>`
|
||||
.. |struct generic_pm_domain| replace:: :c:type:`struct generic_pm_domain <generic_pm_domain>`
|
||||
|
||||
|
||||
.. _device_link:
|
||||
|
||||
============
|
||||
Device links
|
||||
============
|
||||
|
|
|
|||
|
|
@ -22,6 +22,7 @@ available subsections can be seen below.
|
|||
device_connection
|
||||
dma-buf
|
||||
device_link
|
||||
component
|
||||
message-based
|
||||
sound
|
||||
frame-buffer
|
||||
|
|
|
|||
|
|
@ -16,6 +16,32 @@
|
|||
#include <linux/slab.h>
|
||||
#include <linux/debugfs.h>
|
||||
|
||||
/**
|
||||
* 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<device_link>`.
|
||||
*
|
||||
* 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 +327,24 @@ 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
|
||||
*
|
||||
* The match array is first created or extended if necessary.
|
||||
* 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().
|
||||
*
|
||||
* See also component_match_add().
|
||||
*/
|
||||
void component_match_add_release(struct device *master,
|
||||
struct component_match **matchptr,
|
||||
|
|
@ -367,6 +407,18 @@ 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 +455,15 @@ 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 +491,15 @@ 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 +573,15 @@ 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 +616,18 @@ 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 +659,15 @@ 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;
|
||||
|
|
|
|||
|
|
@ -4,11 +4,31 @@
|
|||
|
||||
#include <linux/stddef.h>
|
||||
|
||||
|
||||
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 +92,22 @@ 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
|
||||
*
|
||||
* 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)
|
||||
|
|
|
|||
Loading…
Reference in New Issue