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Input: serio - support multiple child devices per single parent 

Some (rare) serio devices need to have multiple serio children. One of
the examples is PS/2 multiplexer present on several TQC STKxxx boards,
which connect PS/2 keyboard and mouse to single tty port.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Dmitry Eremin-Solenikov 2010-10-04 21:46:10 -07:00 committed by Dmitry Torokhov
parent a8b3c0f57b
commit 0982258264
3 changed files with 86 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/input/mouse/psmouse-base.c
View File

@ -1584,10 +1584,10 @@ static ssize_t psmouse_attr_set_protocol(struct psmouse *psmouse, void *data, co
if (!new_dev)
return -ENOMEM;
while (serio->child) {
while (!list_empty(&serio->children)) {
if (++retry > 3) {
printk(KERN_WARNING
"psmouse: failed to destroy child port, "
"psmouse: failed to destroy children ports, "
"protocol change aborted.\n");
input_free_device(new_dev);
return -EIO;

124
drivers/input/serio/serio.c
View File

@ -55,7 +55,7 @@ static struct bus_type serio_bus;
static void serio_add_port(struct serio *serio);
static int serio_reconnect_port(struct serio *serio);
static void serio_disconnect_port(struct serio *serio);
static void serio_reconnect_chain(struct serio *serio);
static void serio_reconnect_subtree(struct serio *serio);
static void serio_attach_driver(struct serio_driver *drv);
static int serio_connect_driver(struct serio *serio, struct serio_driver *drv)
@ -151,7 +151,7 @@ static void serio_find_driver(struct serio *serio)
enum serio_event_type {
SERIO_RESCAN_PORT,
SERIO_RECONNECT_PORT,
SERIO_RECONNECT_CHAIN,
SERIO_RECONNECT_SUBTREE,
SERIO_REGISTER_PORT,
SERIO_ATTACH_DRIVER,
};
@ -291,8 +291,8 @@ static void serio_handle_event(void)
serio_find_driver(event->object);
break;
case SERIO_RECONNECT_CHAIN:
serio_reconnect_chain(event->object);
case SERIO_RECONNECT_SUBTREE:
serio_reconnect_subtree(event->object);
break;
case SERIO_ATTACH_DRIVER:
@ -329,12 +329,10 @@ static void serio_remove_pending_events(void *object)
}
/*
* Destroy child serio port (if any) that has not been fully registered yet.
* Locate child serio port (if any) that has not been fully registered yet.
*
* Note that we rely on the fact that port can have only one child and therefore
* only one child registration request can be pending. Additionally, children
* are registered by driver's connect() handler so there can't be a grandchild
* pending registration together with a child.
* Children are registered by driver's connect() handler so there can't be a
* grandchild pending registration together with a child.
*/
static struct serio *serio_get_pending_child(struct serio *parent)
{
@ -448,7 +446,7 @@ static ssize_t serio_rebind_driver(struct device *dev, struct device_attribute *
if (!strncmp(buf, "none", count)) {
serio_disconnect_port(serio);
} else if (!strncmp(buf, "reconnect", count)) {
serio_reconnect_chain(serio);
serio_reconnect_subtree(serio);
} else if (!strncmp(buf, "rescan", count)) {
serio_disconnect_port(serio);
serio_find_driver(serio);
@ -515,6 +513,8 @@ static void serio_init_port(struct serio *serio)
__module_get(THIS_MODULE);
INIT_LIST_HEAD(&serio->node);
INIT_LIST_HEAD(&serio->child_node);
INIT_LIST_HEAD(&serio->children);
spin_lock_init(&serio->lock);
mutex_init(&serio->drv_mutex);
device_initialize(&serio->dev);
@ -537,12 +537,13 @@ static void serio_init_port(struct serio *serio)
*/
static void serio_add_port(struct serio *serio)
{
struct serio *parent = serio->parent;
int error;
if (serio->parent) {
serio_pause_rx(serio->parent);
serio->parent->child = serio;
serio_continue_rx(serio->parent);
if (parent) {
serio_pause_rx(parent);
list_add_tail(&serio->child_node, &parent->children);
serio_continue_rx(parent);
}
list_add_tail(&serio->node, &serio_list);
@ -558,15 +559,14 @@ static void serio_add_port(struct serio *serio)
}
/*
* serio_destroy_port() completes deregistration process and removes
* serio_destroy_port() completes unregistration process and removes
* port from the system
*/
static void serio_destroy_port(struct serio *serio)
{
struct serio *child;
child = serio_get_pending_child(serio);
if (child) {
while ((child = serio_get_pending_child(serio)) != NULL) {
serio_remove_pending_events(child);
put_device(&child->dev);
}
@ -576,7 +576,7 @@ static void serio_destroy_port(struct serio *serio)
if (serio->parent) {
serio_pause_rx(serio->parent);
serio->parent->child = NULL;
list_del_init(&serio->child_node);
serio_continue_rx(serio->parent);
serio->parent = NULL;
}
@ -608,46 +608,82 @@ static int serio_reconnect_port(struct serio *serio)
}
/*
* Reconnect serio port and all its children (re-initialize attached devices)
* Reconnect serio port and all its children (re-initialize attached
* devices).
*/
static void serio_reconnect_chain(struct serio *serio)
static void serio_reconnect_subtree(struct serio *root)
{
struct serio *s = root;
int error;
do {
if (serio_reconnect_port(serio)) {
/* Ok, old children are now gone, we are done */
break;
error = serio_reconnect_port(s);
if (!error) {
/*
* Reconnect was successful, move on to do the
* first child.
*/
if (!list_empty(&s->children)) {
s = list_first_entry(&s->children,
struct serio, child_node);
continue;
}
}
serio = serio->child;
} while (serio);
/*
* Either it was a leaf node or reconnect failed and it
* became a leaf node. Continue reconnecting starting with
* the next sibling of the parent node.
*/
while (s != root) {
struct serio *parent = s->parent;
if (!list_is_last(&s->child_node, &parent->children)) {
s = list_entry(s->child_node.next,
struct serio, child_node);
break;
}
s = parent;
}
} while (s != root);
}
/*
* serio_disconnect_port() unbinds a port from its driver. As a side effect
* all child ports are unbound and destroyed.
* all children ports are unbound and destroyed.
*/
static void serio_disconnect_port(struct serio *serio)
{
struct serio *s, *parent;
struct serio *s = serio;
/*
* Children ports should be disconnected and destroyed
* first; we travel the tree in depth-first order.
*/
while (!list_empty(&serio->children)) {
/* Locate a leaf */
while (!list_empty(&s->children))
s = list_first_entry(&s->children,
struct serio, child_node);
if (serio->child) {
/*
* Children ports should be disconnected and destroyed
* first, staring with the leaf one, since we don't want
* to do recursion
* Prune this leaf node unless it is the one we
* started with.
*/
for (s = serio; s->child; s = s->child)
/* empty */;
do {
parent = s->parent;
if (s != serio) {
struct serio *parent = s->parent;
device_release_driver(&s->dev);
serio_destroy_port(s);
} while ((s = parent) != serio);
s = parent;
}
}
/*
* Ok, no children left, now disconnect this port
* OK, no children left, now disconnect this port.
*/
device_release_driver(&serio->dev);
}
@ -660,7 +696,7 @@ EXPORT_SYMBOL(serio_rescan);
void serio_reconnect(struct serio *serio)
{
serio_queue_event(serio, NULL, SERIO_RECONNECT_CHAIN);
serio_queue_event(serio, NULL, SERIO_RECONNECT_SUBTREE);
}
EXPORT_SYMBOL(serio_reconnect);
@ -688,14 +724,16 @@ void serio_unregister_port(struct serio *serio)
EXPORT_SYMBOL(serio_unregister_port);
/*
* Safely unregisters child port if one is present.
* Safely unregisters children ports if they are present.
*/
void serio_unregister_child_port(struct serio *serio)
{
struct serio *s, *next;
mutex_lock(&serio_mutex);
if (serio->child) {
serio_disconnect_port(serio->child);
serio_destroy_port(serio->child);
list_for_each_entry_safe(s, next, &serio->children, child_node) {
serio_disconnect_port(s);
serio_destroy_port(s);
}
mutex_unlock(&serio_mutex);
}

4
include/linux/serio.h
View File

@ -41,7 +41,9 @@ struct serio {
int (*start)(struct serio *);
void (*stop)(struct serio *);
struct serio *parent, *child;
struct serio *parent;
struct list_head child_node; /* Entry in parent->children list */
struct list_head children;
unsigned int depth; /* level of nesting in serio hierarchy */
struct serio_driver *drv; /* accessed from interrupt, must be protected by serio->lock and serio->sem */