component: ignore multiple additions of the same component

Permit masters to call component_master_add_child() and match the same
child multiple times.  This may happen if there's multiple connections
to a single component device from other devices.  In such scenarios,
we should not return a failure, but instead ignore the attempt.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2014-04-18 20:16:22 +01:00
parent c334940ea2
commit fcbcebce71

View File

@ -69,6 +69,11 @@ static void component_detach_master(struct master *master, struct component *c)
c->master = NULL; c->master = NULL;
} }
/*
* Add a component to a master, finding the component via the compare
* function and compare data. This is safe to call for duplicate matches
* and will not result in the same component being added multiple times.
*/
int component_master_add_child(struct master *master, int component_master_add_child(struct master *master,
int (*compare)(struct device *, void *), void *compare_data) int (*compare)(struct device *, void *), void *compare_data)
{ {
@ -76,11 +81,12 @@ int component_master_add_child(struct master *master,
int ret = -ENXIO; int ret = -ENXIO;
list_for_each_entry(c, &component_list, node) { list_for_each_entry(c, &component_list, node) {
if (c->master) if (c->master && c->master != master)
continue; continue;
if (compare(c->dev, compare_data)) { if (compare(c->dev, compare_data)) {
component_attach_master(master, c); if (!c->master)
component_attach_master(master, c);
ret = 0; ret = 0;
break; break;
} }