ACPI / scan: Add a scan handler for PRP0001

If the special PRP0001 device ID is present in the given device's list
of ACPI/PNP IDs and the device has a valid "compatible" property in
the _DSD, it should be enumerated using the default mechanism,
unless some scan handlers match the IDs preceding PRP0001 in the
device's list of ACPI/PNP IDs.  In addition to that, no scan handlers
matching the IDs following PRP0001 in that list should be attached
to the device.

To make that happen, define a scan handler that will match PRP0001
and trigger the default enumeration for the matching devices if the
"compatible" property is present for them.

Since that requires the check for platform_id and device->handler
to be removed from acpi_default_enumeration(), move the fallback
invocation of acpi_default_enumeration() to acpi_bus_attach()
(after it's checked if there's a matching ACPI driver for the
device), which is a better place to call it, and do the platform_id
check in there too (device->handler is guaranteed to be unset at
the point where the function is looking for a matching ACPI driver).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>

1 files changed, 28 insertions, 5 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 8d40467d37f9..03141aa4ea95 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2392,9 +2392,6 @@ static void acpi_default_enumeration(struct acpi_device *device)
         struct list_head resource_list;
         bool is_spi_i2c_slave = false;
 
-        if (!device->pnp.type.platform_id || device->handler)
-                return;
-
         /*
          * Do not enemerate SPI/I2C slaves as they will be enuerated by their
          * respective parents.
@@ -2407,6 +2404,29 @@ static void acpi_default_enumeration(struct acpi_device *device)
                 acpi_create_platform_device(device);
 }
 
+static const struct acpi_device_id generic_device_ids[] = {
+        {"PRP0001", },
+        {"", },
+};
+
+static int acpi_generic_device_attach(struct acpi_device *adev,
+                                      const struct acpi_device_id *not_used)
+{
+        /*
+         * Since PRP0001 is the only ID handled here, the test below can be
+         * unconditional.
+         */
+        if (adev->data.of_compatible)
+                acpi_default_enumeration(adev);
+
+        return 1;
+}
+
+static struct acpi_scan_handler generic_device_handler = {
+        .ids = generic_device_ids,
+        .attach = acpi_generic_device_attach,
+};
+
 static int acpi_scan_attach_handler(struct acpi_device *device)
 {
         struct acpi_hardware_id *hwid;
@@ -2432,8 +2452,6 @@ static int acpi_scan_attach_handler(struct acpi_device *device)
                                 break;
                 }
         }
-        if (!ret)
-                acpi_default_enumeration(device);
 
         return ret;
 }
@@ -2475,6 +2493,9 @@ static void acpi_bus_attach(struct acpi_device *device)
                 ret = device_attach(&device->dev);
                 if (ret < 0)
                         return;
+
+                if (!ret && device->pnp.type.platform_id)
+                        acpi_default_enumeration(device);
         }
         device->flags.visited = true;
 
@@ -2633,6 +2654,8 @@ int __init acpi_scan_init(void)
         acpi_pnp_init();
         acpi_int340x_thermal_init();
 
+        acpi_scan_add_handler(&generic_device_handler);
+
         mutex_lock(&acpi_scan_lock);
         /*
          * Enumerate devices in the ACPI namespace.