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Subject[PATCH] ACPI / scan: Add a scan handler for PRP0001
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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 particular, 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>
---
drivers/acpi/scan.c | 34 +++++++++++++++++++++++++++++-----
1 file changed, 29 insertions(+), 5 deletions(-)

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -2390,9 +2390,6 @@ static void acpi_default_enumeration(str
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.
@@ -2405,6 +2402,30 @@ static void acpi_default_enumeration(str
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;
+ }
+ return 0;
+}
+
+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;
@@ -2430,8 +2451,6 @@ static int acpi_scan_attach_handler(stru
break;
}
}
- if (!ret)
- acpi_default_enumeration(device);

return ret;
}
@@ -2473,6 +2492,9 @@ static void acpi_bus_attach(struct acpi_
ret = device_attach(&device->dev);
if (ret < 0)
return;
+
+ if (!ret && device->pnp.type.platform_id)
+ acpi_default_enumeration(device);
}
device->flags.visited = true;

@@ -2631,6 +2653,8 @@ 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.


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