ACPI / scan: Add bind/unbind callbacks to struct acpi_scan_handler

In some cases it may be necessary to perform certain setup/cleanup
operations on a device object representing a physical device after
it has been associated with an ACPI companion by acpi_bind_one() or
before disassociating it from that companion by acpi_unbind_one(),
respectively.  If there is a struct acpi_bus_type object for the
given device's bus type, the .setup()/.cleanup() callbacks from there
are executed for these purposes.  However, an analogous mechanism will
be necessary for devices whose bus types don't have corresponding
struct acpi_bus_type objects and that have specific ACPI scan handlers.

For those devices, add new .bind() and .unbind() callbacks to struct
acpi_scan_handler that will be executed by acpi_platform_notify()
right after the given device has been associated with an ACPI
comapnion and by acpi_platform_notify_remove() right before calling
acpi_unbind_one() for that device, respectively.

To make that work for scan handlers registering new devices in their
.attach() callbacks, modify acpi_scan_attach_handler() to set the
ACPI device object's handler field before calling .attach() from the
scan handler at hand.

This changeset includes a fix from Mika Westerberg.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 17 insertions, 4 deletions

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 0c789224d40d..f774c65ecb8b 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -287,6 +287,7 @@ EXPORT_SYMBOL_GPL(acpi_unbind_one);
 static int acpi_platform_notify(struct device *dev)
 {
         struct acpi_bus_type *type = acpi_get_bus_type(dev);
+        struct acpi_device *adev;
         int ret;
 
         ret = acpi_bind_one(dev, NULL);
@@ -303,9 +304,14 @@ static int acpi_platform_notify(struct device *dev)
                 if (ret)
                         goto out;
         }
+        adev = ACPI_COMPANION(dev);
+        if (!adev)
+                goto out;
 
         if (type && type->setup)
                 type->setup(dev);
+        else if (adev->handler && adev->handler->bind)
+                adev->handler->bind(dev);
 
  out:
 #if ACPI_GLUE_DEBUG
@@ -324,11 +330,17 @@ static int acpi_platform_notify(struct device *dev)
 
 static int acpi_platform_notify_remove(struct device *dev)
 {
+        struct acpi_device *adev = ACPI_COMPANION(dev);
         struct acpi_bus_type *type;
 
+        if (!adev)
+                return 0;
+
         type = acpi_get_bus_type(dev);
         if (type && type->cleanup)
                 type->cleanup(dev);
+        else if (adev->handler && adev->handler->unbind)
+                adev->handler->unbind(dev);
 
         acpi_unbind_one(dev);
         return 0;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 57b053f424d1..9c4581fd5827 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2015,13 +2015,14 @@ static int acpi_scan_attach_handler(struct acpi_device *device)
 
                 handler = acpi_scan_match_handler(hwid->id, &devid);
                 if (handler) {
+                        device->handler = handler;
                         ret = handler->attach(device, devid);
-                        if (ret > 0) {
-                                device->handler = handler;
+                        if (ret > 0)
                                 break;
-                        } else if (ret < 0) {
+
+                        device->handler = NULL;
+                        if (ret < 0)
                                 break;
-                        }
                 }
         }
         return ret;