Input: psmouse - introduce notion of SMBus companions

Prepare PS/2 mouse drivers to work with devices that are accessible both
via PS/2 and SMBus, which provides higher bandwidth, and thus suits better
for modern multi-touch devices.

We expect that SMBus drivers will take control over the device, so when
we detect SMBus "protocol" we forego registering input device, or enabling
PS/2 device reports (as it usually makes device unresponsive to access over
SMBus).

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index bb5d164849ea3a11acda2e2451b11e035af7e721..a84f8ed2ba5db84acebfa053d4b2b4adb0b41e45 100644 (file)
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -1424,9 +1424,8 @@ static void psmouse_cleanup(struct serio *serio)
  */
 static void psmouse_disconnect(struct serio *serio)
 {
-       struct psmouse *psmouse, *parent = NULL;
-
-       psmouse = serio_get_drvdata(serio);
+       struct psmouse *psmouse = serio_get_drvdata(serio);
+       struct psmouse *parent = NULL;
 
        sysfs_remove_group(&serio->dev.kobj, &psmouse_attribute_group);
 
@@ -1454,7 +1453,10 @@ static void psmouse_disconnect(struct serio *serio)
 
        serio_close(serio);
        serio_set_drvdata(serio, NULL);
-       input_unregister_device(psmouse->dev);
+
+       if (psmouse->dev)
+               input_unregister_device(psmouse->dev);
+
        kfree(psmouse);
 
        if (parent)
@@ -1575,12 +1577,18 @@ static int psmouse_connect(struct serio *serio, struct serio_driver *drv)
 
        psmouse_switch_protocol(psmouse, NULL);
 
-       psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
-       psmouse_initialize(psmouse);
+       if (!psmouse->protocol->smbus_companion) {
+               psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
+               psmouse_initialize(psmouse);
 
-       error = input_register_device(psmouse->dev);
-       if (error)
-               goto err_protocol_disconnect;
+               error = input_register_device(input_dev);
+               if (error)
+                       goto err_protocol_disconnect;
+       } else {
+               /* Smbus companion will be reporting events, not us. */
+               input_free_device(input_dev);
+               psmouse->dev = input_dev = NULL;
+       }
 
        if (parent && parent->pt_activate)
                parent->pt_activate(parent);
@@ -1589,7 +1597,12 @@ static int psmouse_connect(struct serio *serio, struct serio_driver *drv)
        if (error)
                goto err_pt_deactivate;
 
-       psmouse_activate(psmouse);
+       /*
+        * PS/2 devices having SMBus companions should stay disabled
+        * on PS/2 side, in order to have SMBus part operable.
+        */
+       if (!psmouse->protocol->smbus_companion)
+               psmouse_activate(psmouse);
 
  out:
        /* If this is a pass-through port the parent needs to be re-activated */
@@ -1602,8 +1615,10 @@ static int psmouse_connect(struct serio *serio, struct serio_driver *drv)
  err_pt_deactivate:
        if (parent && parent->pt_deactivate)
                parent->pt_deactivate(parent);
-       input_unregister_device(psmouse->dev);
-       input_dev = NULL; /* so we don't try to free it below */
+       if (input_dev) {
+               input_unregister_device(input_dev);
+               input_dev = NULL; /* so we don't try to free it below */
+       }
  err_protocol_disconnect:
        if (psmouse->disconnect)
                psmouse->disconnect(psmouse);
@@ -1665,14 +1680,21 @@ static int __psmouse_reconnect(struct serio *serio, bool fast_reconnect)
         * OK, the device type (and capabilities) match the old one,
         * we can continue using it, complete initialization
         */
-       psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
-
-       psmouse_initialize(psmouse);
+       if (!psmouse->protocol->smbus_companion) {
+               psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
+               psmouse_initialize(psmouse);
+       }
 
        if (parent && parent->pt_activate)
                parent->pt_activate(parent);
 
-       psmouse_activate(psmouse);
+       /*
+        * PS/2 devices having SMBus companions should stay disabled
+        * on PS/2 side, in order to have SMBus part operable.
+        */
+       if (!psmouse->protocol->smbus_companion)
+               psmouse_activate(psmouse);
+
        rc = 0;
 
 out:
@@ -1732,9 +1754,11 @@ ssize_t psmouse_attr_show_helper(struct device *dev, struct device_attribute *de
 {
        struct serio *serio = to_serio_port(dev);
        struct psmouse_attribute *attr = to_psmouse_attr(devattr);
-       struct psmouse *psmouse;
+       struct psmouse *psmouse = serio_get_drvdata(serio);
 
-       psmouse = serio_get_drvdata(serio);
+       if (psmouse->protocol->smbus_companion &&
+                       devattr != &psmouse_attr_protocol.dattr)
+               return -ENOENT;
 
        return attr->show(psmouse, attr->data, buf);
 }
@@ -1753,6 +1777,12 @@ ssize_t psmouse_attr_set_helper(struct device *dev, struct device_attribute *dev
 
        psmouse = serio_get_drvdata(serio);
 
+       if (psmouse->protocol->smbus_companion &&
+                       devattr != &psmouse_attr_protocol.dattr) {
+               retval = -ENOENT;
+               goto out_unlock;
+       }
+
        if (attr->protect) {
                if (psmouse->state == PSMOUSE_IGNORE) {
                        retval = -ENODEV;
@@ -1764,13 +1794,14 @@ ssize_t psmouse_attr_set_helper(struct device *dev, struct device_attribute *dev
                        psmouse_deactivate(parent);
                }
 
-               psmouse_deactivate(psmouse);
+               if (!psmouse->protocol->smbus_companion)
+                       psmouse_deactivate(psmouse);
        }
 
        retval = attr->set(psmouse, attr->data, buf, count);
 
        if (attr->protect) {
-               if (retval != -ENODEV)
+               if (retval != -ENODEV && !psmouse->protocol->smbus_companion)
                        psmouse_activate(psmouse);
 
                if (parent)
@@ -1879,23 +1910,29 @@ static ssize_t psmouse_attr_set_protocol(struct psmouse *psmouse, void *data, co
        psmouse_initialize(psmouse);
        psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
 
-       error = input_register_device(psmouse->dev);
-       if (error) {
-               if (psmouse->disconnect)
-                       psmouse->disconnect(psmouse);
+       if (psmouse->protocol->smbus_companion) {
+               input_free_device(psmouse->dev);
+               psmouse->dev = NULL;
+       } else {
+               error = input_register_device(psmouse->dev);
+               if (error) {
+                       if (psmouse->disconnect)
+                               psmouse->disconnect(psmouse);
 
-               psmouse_set_state(psmouse, PSMOUSE_IGNORE);
-               input_free_device(new_dev);
-               psmouse->dev = old_dev;
-               psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);
-               psmouse_switch_protocol(psmouse, old_proto);
-               psmouse_initialize(psmouse);
-               psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
+                       psmouse_set_state(psmouse, PSMOUSE_IGNORE);
+                       input_free_device(new_dev);
+                       psmouse->dev = old_dev;
+                       psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);
+                       psmouse_switch_protocol(psmouse, old_proto);
+                       psmouse_initialize(psmouse);
+                       psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);
 
-               return error;
+                       return error;
+               }
        }
 
-       input_unregister_device(old_dev);
+       if (old_dev)
+               input_unregister_device(old_dev);
 
        if (parent && parent->pt_activate)
                parent->pt_activate(parent);

diff --git a/drivers/input/mouse/psmouse.h b/drivers/input/mouse/psmouse.h
index 36bd42179456d7c388a43343dbdb699a17685563..e853dee05e79ed169dc11f5cec7b9c6f18d00504 100644 (file)
--- a/drivers/input/mouse/psmouse.h
+++ b/drivers/input/mouse/psmouse.h
@@ -76,6 +76,7 @@ struct psmouse_protocol {
        bool maxproto;
        bool ignore_parity; /* Protocol should ignore parity errors from KBC */
        bool try_passthru; /* Try protocol also on passthrough ports */
+       bool smbus_companion; /* "Protocol" is a stub, device is on SMBus */
        const char *name;
        const char *alias;
        int (*detect)(struct psmouse *, bool);