diff options
Diffstat (limited to 'drivers/base/component.c')
| -rw-r--r-- | drivers/base/component.c | 206 |
1 files changed, 195 insertions, 11 deletions
diff --git a/drivers/base/component.c b/drivers/base/component.c index ddcea8739c12..532a3a5d8f63 100644 --- a/drivers/base/component.c +++ b/drivers/base/component.c @@ -16,11 +16,38 @@ #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 components (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 { void *data; int (*compare)(struct device *, void *); + int (*compare_typed)(struct device *, int, void *); void (*release)(struct device *, void *); struct component *component; bool duplicate; @@ -48,6 +75,7 @@ struct component { bool bound; const struct component_ops *ops; + int subcomponent; struct device *dev; }; @@ -132,7 +160,7 @@ static struct master *__master_find(struct device *dev, } static struct component *find_component(struct master *master, - int (*compare)(struct device *, void *), void *compare_data) + struct component_match_array *mc) { struct component *c; @@ -140,7 +168,11 @@ static struct component *find_component(struct master *master, if (c->master && c->master != master) continue; - if (compare(c->dev, compare_data)) + if (mc->compare && mc->compare(c->dev, mc->data)) + return c; + + if (mc->compare_typed && + mc->compare_typed(c->dev, c->subcomponent, mc->data)) return c; } @@ -166,7 +198,7 @@ static int find_components(struct master *master) if (match->compare[i].component) continue; - c = find_component(master, mc->compare, mc->data); + c = find_component(master, mc); if (!c) { ret = -ENXIO; break; @@ -301,15 +333,12 @@ static int component_match_realloc(struct device *dev, return 0; } -/* - * Add a component to be matched, with a release function. - * - * The match array is first created or extended if necessary. - */ -void component_match_add_release(struct device *master, +static void __component_match_add(struct device *master, struct component_match **matchptr, void (*release)(struct device *, void *), - int (*compare)(struct device *, void *), void *compare_data) + int (*compare)(struct device *, void *), + int (*compare_typed)(struct device *, int, void *), + void *compare_data) { struct component_match *match = *matchptr; @@ -341,13 +370,69 @@ void component_match_add_release(struct device *master, } match->compare[match->num].compare = compare; + match->compare[match->num].compare_typed = compare_typed; match->compare[match->num].release = release; match->compare[match->num].data = compare_data; match->compare[match->num].component = NULL; match->num++; } + +/** + * component_match_add_release - add a component match entry 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. This + * only matches against components added with component_add(). + * + * 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() and component_match_add_typed(). + */ +void component_match_add_release(struct device *master, + struct component_match **matchptr, + void (*release)(struct device *, void *), + int (*compare)(struct device *, void *), void *compare_data) +{ + __component_match_add(master, matchptr, release, compare, NULL, + compare_data); +} EXPORT_SYMBOL(component_match_add_release); +/** + * component_match_add_typed - add a component match entry for a typed component + * @master: device with the aggregate driver + * @matchptr: pointer to the list of component matches + * @compare_typed: compare function to match against all typed 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. This + * only matches against components added with component_add_typed(). + * + * The allocated match list in @matchptr is automatically released using devm + * actions. + * + * See also component_match_add_release() and component_match_add_typed(). + */ +void component_match_add_typed(struct device *master, + struct component_match **matchptr, + int (*compare_typed)(struct device *, int, void *), void *compare_data) +{ + __component_match_add(master, matchptr, NULL, NULL, compare_typed, + compare_data); +} +EXPORT_SYMBOL(component_match_add_typed); + static void free_master(struct master *master) { struct component_match *match = master->match; @@ -367,6 +452,18 @@ 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 +500,15 @@ 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 +536,15 @@ static void component_unbind(struct component *component, devres_release_group(component->dev, component); } +/** + * component_unbind_all - unbind all components of an aggregate driver + * @master_dev: device with the aggregate driver + * @data: opaque pointer, passed to all components + * + * Unbinds all components of 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 +618,15 @@ static int component_bind(struct component *component, struct master *master, return ret; } +/** + * component_bind_all - bind all components of an aggregate driver + * @master_dev: device with the aggregate driver + * @data: opaque pointer, passed to all components + * + * Binds all components of 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; @@ -537,7 +661,8 @@ int component_bind_all(struct device *master_dev, void *data) } EXPORT_SYMBOL_GPL(component_bind_all); -int component_add(struct device *dev, const struct component_ops *ops) +static int __component_add(struct device *dev, const struct component_ops *ops, + int subcomponent) { struct component *component; int ret; @@ -548,6 +673,7 @@ int component_add(struct device *dev, const struct component_ops *ops) component->ops = ops; component->dev = dev; + component->subcomponent = subcomponent; dev_dbg(dev, "adding component (ops %ps)\n", ops); @@ -566,8 +692,66 @@ int component_add(struct device *dev, const struct component_ops *ops) return ret < 0 ? ret : 0; } + +/** + * component_add_typed - register a component + * @dev: component device + * @ops: component callbacks + * @subcomponent: nonzero identifier for subcomponents + * + * Register a new component for @dev. Functions in @ops will be call when the + * aggregate driver is ready to bind the overall driver by calling + * component_bind_all(). See also &struct component_ops. + * + * @subcomponent must be nonzero and is used to differentiate between multiple + * components registerd on the same device @dev. These components are match + * using component_match_add_typed(). + * + * The component needs to be unregistered at driver unload/disconnect by + * calling component_del(). + * + * See also component_add(). + */ +int component_add_typed(struct device *dev, const struct component_ops *ops, + int subcomponent) +{ + if (WARN_ON(subcomponent == 0)) + return -EINVAL; + + return __component_add(dev, ops, subcomponent); +} +EXPORT_SYMBOL_GPL(component_add_typed); + +/** + * 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(). + * + * See also component_add_typed() for a variant that allows multipled different + * components on the same device. + */ +int component_add(struct device *dev, const struct component_ops *ops) +{ + return __component_add(dev, ops, 0); +} 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; |