ACPI: support acpi_device_ops .notify methods

This patch adds support for ACPI device driver .notify() methods.  If
such a method is present, Linux/ACPI installs a handler for device
notifications (but not for system notifications such as Bus Check,
Device Check, etc).  When a device notification occurs, Linux/ACPI
passes it on to the driver's .notify() method.

In most cases, this removes the need for drivers to install their own
handlers for device-specific notifications.

For fixed hardware devices like some power and sleep buttons, there's
no notification value because there's no control method to execute a
Notify opcode.  When a fixed hardware device generates an event, we
handle it the same as a regular device notification, except we send
a ACPI_FIXED_HARDWARE_EVENT value.  This is outside the normal 0x0-0xff
range used by Notify opcodes.

Several drivers install their own handlers for system Bus Check and
Device Check notifications so they can support hot-plug.  This patch
doesn't affect that usage.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 83 insertions, 0 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index b7308ef..20c23c0 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -359,6 +359,61 @@ static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
+static void acpi_device_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct acpi_device *device = data;
+
+	device->driver->ops.notify(device, event);
+}
+
+static acpi_status acpi_device_notify_fixed(void *data)
+{
+	struct acpi_device *device = data;
+
+	acpi_device_notify(device->handle, ACPI_FIXED_HARDWARE_EVENT, device);
+	return AE_OK;
+}
+
+static int acpi_device_install_notify_handler(struct acpi_device *device)
+{
+	acpi_status status;
+	char *hid;
+
+	hid = acpi_device_hid(device);
+	if (!strcmp(hid, ACPI_BUTTON_HID_POWERF))
+		status =
+		    acpi_install_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
+						     acpi_device_notify_fixed,
+						     device);
+	else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEPF))
+		status =
+		    acpi_install_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
+						     acpi_device_notify_fixed,
+						     device);
+	else
+		status = acpi_install_notify_handler(device->handle,
+						     ACPI_DEVICE_NOTIFY,
+						     acpi_device_notify,
+						     device);
+
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+	return 0;
+}
+
+static void acpi_device_remove_notify_handler(struct acpi_device *device)
+{
+	if (!strcmp(acpi_device_hid(device), ACPI_BUTTON_HID_POWERF))
+		acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
+						acpi_device_notify_fixed);
+	else if (!strcmp(acpi_device_hid(device), ACPI_BUTTON_HID_SLEEPF))
+		acpi_remove_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
+						acpi_device_notify_fixed);
+	else
+		acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
+					   acpi_device_notify);
+}
+
 static int acpi_bus_driver_init(struct acpi_device *, struct acpi_driver *);
 static int acpi_start_single_object(struct acpi_device *);
 static int acpi_device_probe(struct device * dev)
@@ -371,6 +426,20 @@ static int acpi_device_probe(struct device * dev)
 	if (!ret) {
 		if (acpi_dev->bus_ops.acpi_op_start)
 			acpi_start_single_object(acpi_dev);
+
+		if (acpi_drv->ops.notify) {
+			ret = acpi_device_install_notify_handler(acpi_dev);
+			if (ret) {
+				if (acpi_drv->ops.stop)
+					acpi_drv->ops.stop(acpi_dev,
+						   acpi_dev->removal_type);
+				if (acpi_drv->ops.remove)
+					acpi_drv->ops.remove(acpi_dev,
+						     acpi_dev->removal_type);
+				return ret;
+			}
+		}
+
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 			"Found driver [%s] for device [%s]\n",
 			acpi_drv->name, acpi_dev->pnp.bus_id));
@@ -385,6 +454,8 @@ static int acpi_device_remove(struct device * dev)
 	struct acpi_driver *acpi_drv = acpi_dev->driver;
 
 	if (acpi_drv) {
+		if (acpi_drv->ops.notify)
+			acpi_device_remove_notify_handler(acpi_dev);
 		if (acpi_drv->ops.stop)
 			acpi_drv->ops.stop(acpi_dev, acpi_dev->removal_type);
 		if (acpi_drv->ops.remove)
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 08ec60c..a222851 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -95,6 +95,7 @@ typedef int (*acpi_op_suspend) (struct acpi_device * device,
 typedef int (*acpi_op_resume) (struct acpi_device * device);
 typedef int (*acpi_op_bind) (struct acpi_device * device);
 typedef int (*acpi_op_unbind) (struct acpi_device * device);
+typedef void (*acpi_op_notify) (struct acpi_device * device, u32 event);
 
 struct acpi_bus_ops {
 	u32 acpi_op_add:1;
@@ -110,6 +111,7 @@ struct acpi_device_ops {
 	acpi_op_resume resume;
 	acpi_op_bind bind;
 	acpi_op_unbind unbind;
+	acpi_op_notify notify;
 };
 
 struct acpi_driver {
diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index 241d227..0352c8f 100644
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -67,6 +67,16 @@
 #define ACPI_BAY_HID			"LNXIOBAY"
 #define ACPI_DOCK_HID			"LNXDOCK"
 
+/*
+ * For fixed hardware buttons, we fabricate acpi_devices with HID
+ * ACPI_BUTTON_HID_POWERF or ACPI_BUTTON_HID_SLEEPF.  Fixed hardware
+ * signals only an event; it doesn't supply a notification value.
+ * To allow drivers to treat notifications from fixed hardware the
+ * same as those from real devices, we turn the events into this
+ * notification value.
+ */
+#define ACPI_FIXED_HARDWARE_EVENT	0x100
+
 /* --------------------------------------------------------------------------
                                        PCI
    -------------------------------------------------------------------------- */