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>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index 241d227de6c0..0352c8f0b05b 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
    -------------------------------------------------------------------------- */