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
Dmitry Torokhov
Родитель
a8b3c0f57b
Коммит
0982258264
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@ -1584,10 +1584,10 @@ static ssize_t psmouse_attr_set_protocol(struct psmouse *psmouse, void *data, co
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if (!new_dev)
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return -ENOMEM;
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while (serio->child) {
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while (!list_empty(&serio->children)) {
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if (++retry > 3) {
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printk(KERN_WARNING
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"psmouse: failed to destroy child port, "
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"psmouse: failed to destroy children ports, "
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"protocol change aborted.\n");
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input_free_device(new_dev);
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return -EIO;
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@ -55,7 +55,7 @@ static struct bus_type serio_bus;
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static void serio_add_port(struct serio *serio);
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static int serio_reconnect_port(struct serio *serio);
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static void serio_disconnect_port(struct serio *serio);
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static void serio_reconnect_chain(struct serio *serio);
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static void serio_reconnect_subtree(struct serio *serio);
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static void serio_attach_driver(struct serio_driver *drv);
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static int serio_connect_driver(struct serio *serio, struct serio_driver *drv)
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@ -151,7 +151,7 @@ static void serio_find_driver(struct serio *serio)
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enum serio_event_type {
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SERIO_RESCAN_PORT,
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SERIO_RECONNECT_PORT,
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SERIO_RECONNECT_CHAIN,
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SERIO_RECONNECT_SUBTREE,
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SERIO_REGISTER_PORT,
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SERIO_ATTACH_DRIVER,
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};
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@ -291,8 +291,8 @@ static void serio_handle_event(void)
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serio_find_driver(event->object);
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break;
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case SERIO_RECONNECT_CHAIN:
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serio_reconnect_chain(event->object);
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case SERIO_RECONNECT_SUBTREE:
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serio_reconnect_subtree(event->object);
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break;
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case SERIO_ATTACH_DRIVER:
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@ -329,12 +329,10 @@ static void serio_remove_pending_events(void *object)
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}
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/*
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* Destroy child serio port (if any) that has not been fully registered yet.
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* Locate child serio port (if any) that has not been fully registered yet.
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*
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* Note that we rely on the fact that port can have only one child and therefore
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* only one child registration request can be pending. Additionally, children
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* are registered by driver's connect() handler so there can't be a grandchild
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* pending registration together with a child.
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* Children are registered by driver's connect() handler so there can't be a
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* grandchild pending registration together with a child.
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*/
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static struct serio *serio_get_pending_child(struct serio *parent)
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{
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@ -448,7 +446,7 @@ static ssize_t serio_rebind_driver(struct device *dev, struct device_attribute *
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if (!strncmp(buf, "none", count)) {
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serio_disconnect_port(serio);
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} else if (!strncmp(buf, "reconnect", count)) {
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serio_reconnect_chain(serio);
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serio_reconnect_subtree(serio);
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} else if (!strncmp(buf, "rescan", count)) {
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serio_disconnect_port(serio);
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serio_find_driver(serio);
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@ -515,6 +513,8 @@ static void serio_init_port(struct serio *serio)
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__module_get(THIS_MODULE);
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INIT_LIST_HEAD(&serio->node);
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INIT_LIST_HEAD(&serio->child_node);
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INIT_LIST_HEAD(&serio->children);
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spin_lock_init(&serio->lock);
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mutex_init(&serio->drv_mutex);
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device_initialize(&serio->dev);
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@ -537,12 +537,13 @@ static void serio_init_port(struct serio *serio)
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*/
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static void serio_add_port(struct serio *serio)
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{
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struct serio *parent = serio->parent;
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int error;
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if (serio->parent) {
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serio_pause_rx(serio->parent);
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serio->parent->child = serio;
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serio_continue_rx(serio->parent);
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if (parent) {
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serio_pause_rx(parent);
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list_add_tail(&serio->child_node, &parent->children);
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serio_continue_rx(parent);
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}
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list_add_tail(&serio->node, &serio_list);
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@ -558,15 +559,14 @@ static void serio_add_port(struct serio *serio)
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}
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/*
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* serio_destroy_port() completes deregistration process and removes
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* serio_destroy_port() completes unregistration process and removes
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* port from the system
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*/
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static void serio_destroy_port(struct serio *serio)
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{
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struct serio *child;
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child = serio_get_pending_child(serio);
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if (child) {
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while ((child = serio_get_pending_child(serio)) != NULL) {
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serio_remove_pending_events(child);
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put_device(&child->dev);
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}
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@ -576,7 +576,7 @@ static void serio_destroy_port(struct serio *serio)
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if (serio->parent) {
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serio_pause_rx(serio->parent);
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serio->parent->child = NULL;
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list_del_init(&serio->child_node);
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serio_continue_rx(serio->parent);
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serio->parent = NULL;
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}
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@ -608,46 +608,82 @@ static int serio_reconnect_port(struct serio *serio)
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}
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/*
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* Reconnect serio port and all its children (re-initialize attached devices)
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* Reconnect serio port and all its children (re-initialize attached
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* devices).
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*/
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static void serio_reconnect_chain(struct serio *serio)
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static void serio_reconnect_subtree(struct serio *root)
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{
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struct serio *s = root;
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int error;
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do {
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if (serio_reconnect_port(serio)) {
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/* Ok, old children are now gone, we are done */
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break;
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error = serio_reconnect_port(s);
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if (!error) {
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/*
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* Reconnect was successful, move on to do the
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* first child.
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*/
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if (!list_empty(&s->children)) {
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s = list_first_entry(&s->children,
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struct serio, child_node);
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continue;
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}
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}
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serio = serio->child;
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} while (serio);
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/*
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* Either it was a leaf node or reconnect failed and it
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* became a leaf node. Continue reconnecting starting with
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* the next sibling of the parent node.
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*/
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while (s != root) {
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struct serio *parent = s->parent;
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if (!list_is_last(&s->child_node, &parent->children)) {
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s = list_entry(s->child_node.next,
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struct serio, child_node);
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break;
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}
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s = parent;
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}
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} while (s != root);
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}
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/*
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* serio_disconnect_port() unbinds a port from its driver. As a side effect
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* all child ports are unbound and destroyed.
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* all children ports are unbound and destroyed.
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*/
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static void serio_disconnect_port(struct serio *serio)
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{
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struct serio *s, *parent;
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struct serio *s = serio;
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/*
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* Children ports should be disconnected and destroyed
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* first; we travel the tree in depth-first order.
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*/
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while (!list_empty(&serio->children)) {
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/* Locate a leaf */
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while (!list_empty(&s->children))
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s = list_first_entry(&s->children,
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struct serio, child_node);
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if (serio->child) {
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/*
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* Children ports should be disconnected and destroyed
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* first, staring with the leaf one, since we don't want
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* to do recursion
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* Prune this leaf node unless it is the one we
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* started with.
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*/
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for (s = serio; s->child; s = s->child)
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/* empty */;
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do {
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parent = s->parent;
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if (s != serio) {
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struct serio *parent = s->parent;
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device_release_driver(&s->dev);
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serio_destroy_port(s);
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} while ((s = parent) != serio);
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s = parent;
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}
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}
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/*
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* Ok, no children left, now disconnect this port
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* OK, no children left, now disconnect this port.
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*/
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device_release_driver(&serio->dev);
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}
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@ -660,7 +696,7 @@ EXPORT_SYMBOL(serio_rescan);
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void serio_reconnect(struct serio *serio)
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{
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serio_queue_event(serio, NULL, SERIO_RECONNECT_CHAIN);
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serio_queue_event(serio, NULL, SERIO_RECONNECT_SUBTREE);
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}
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EXPORT_SYMBOL(serio_reconnect);
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@ -688,14 +724,16 @@ void serio_unregister_port(struct serio *serio)
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EXPORT_SYMBOL(serio_unregister_port);
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/*
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* Safely unregisters child port if one is present.
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* Safely unregisters children ports if they are present.
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*/
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void serio_unregister_child_port(struct serio *serio)
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{
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struct serio *s, *next;
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mutex_lock(&serio_mutex);
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if (serio->child) {
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serio_disconnect_port(serio->child);
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serio_destroy_port(serio->child);
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list_for_each_entry_safe(s, next, &serio->children, child_node) {
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serio_disconnect_port(s);
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serio_destroy_port(s);
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}
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mutex_unlock(&serio_mutex);
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}
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@ -41,7 +41,9 @@ struct serio {
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int (*start)(struct serio *);
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void (*stop)(struct serio *);
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struct serio *parent, *child;
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struct serio *parent;
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struct list_head child_node; /* Entry in parent->children list */
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struct list_head children;
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unsigned int depth; /* level of nesting in serio hierarchy */
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struct serio_driver *drv; /* accessed from interrupt, must be protected by serio->lock and serio->sem */
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