[PATCH 5/8] Input: psmouse - introduce notion of SMBus companions

Dmitry Torokhov
2017-03-09T22:18:14Z

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).

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
drivers/input/mouse/psmouse-base.c | 100 +++++++++++++++++++++++++------------
drivers/input/mouse/psmouse.h | 1 +
2 files changed, 68 insertions(+), 33 deletions(-)

diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index bb5d164849ea..40f09ce84f14 100644
--- 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 +1910,26 @@ 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) {
+ 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 36bd42179456..e853dee05e79 100644
--- 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);
--
2.12.0.246.ga2ecc84866-goog