Input: psmouse - add support for SMBus companions

This provides glue between PS/2 devices that enumerate the RMI4 devices
and Elan touchpads to the RMI4 (or Elan) SMBus driver.

The SMBus devices keep their PS/2 connection alive. If the initialization
process goes too far (psmouse_activate called), the device disconnects
from the I2C bus and stays on the PS/2 bus, that is why we explicitly
disable PS/2 device reporting (by calling psmouse_deactivate) before
trying to register SMBus companion device.

The HID over I2C devices are enumerated through the ACPI DSDT, and
their PS/2 device also exports the InterTouch bit in the extended
capability 0x0C. However, the firmware keeps its I2C connection open
even after going further in the PS/2 initialization. We don't need
to take extra precautions with those device, especially because they
block their PS/2 communication when HID over I2C is used.

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

1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index a84f8ed2ba5d..ab9bfe2af381 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -1999,16 +1999,27 @@ static int __init psmouse_init(void)
 	synaptics_module_init();
 	hgpk_module_init();
 
+	err = psmouse_smbus_module_init();
+	if (err)
+		return err;
+
 	kpsmoused_wq = alloc_ordered_workqueue("kpsmoused", 0);
 	if (!kpsmoused_wq) {
 		pr_err("failed to create kpsmoused workqueue\n");
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto err_smbus_exit;
 	}
 
 	err = serio_register_driver(&psmouse_drv);
 	if (err)
-		destroy_workqueue(kpsmoused_wq);
+		goto err_destroy_wq;
 
+	return 0;
+
+err_destroy_wq:
+	destroy_workqueue(kpsmoused_wq);
+err_smbus_exit:
+	psmouse_smbus_module_exit();
 	return err;
 }
 
@@ -2016,6 +2027,7 @@ static void __exit psmouse_exit(void)
 {
 	serio_unregister_driver(&psmouse_drv);
 	destroy_workqueue(kpsmoused_wq);
+	psmouse_smbus_module_exit();
 }
 
 module_init(psmouse_init);