#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 {
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
+ *
+ * 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,
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)
}
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)
{
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;
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;
}
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;
}
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;
#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);
};
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);
};
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)
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