From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Add cross-links between ACPI device and "real" devices in sysfs,
exposing otherwise-hidden interrelationships between the various
device nodes which ACPI creates. As a representative example one
hardware device is exposed as two logical devices (PNP and ACPI):
.../pnp0/00:06/
.../LNXSYSTM:00/device:00/PNP0A03:00/device:15/PNP0B00:00/
The PNP device gets a "firmware_node" link pointing to the ACPI device.
The ACPI device has a "physical_node" link pointing to the PNP device.
Linux drivers currently bind only to the "physical" device nodes.
Other device trees provided by firmware tables could be exported
using the same scheme; these names aren't ACPI-specific.
(Based on a patch from Zhang Rui. This version is modified to not
depend on the patch teaching ACPI about driver model wakeup flags.)
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
---
Change from previous version: if creating the link fails, a
pr_debug level message is emitted.
drivers/acpi/glue.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
--- g26.orig/drivers/acpi/glue.c 2008-03-08 11:11:18.000000000 -0800
+++ g26/drivers/acpi/glue.c 2008-03-08 11:29:07.000000000 -0800
@@ -142,6 +142,7 @@ EXPORT_SYMBOL(acpi_get_physical_device);
static int acpi_bind_one(struct device *dev, acpi_handle handle)
{
+ struct acpi_device *acpi_dev;
acpi_status status;
if (dev->archdata.acpi_handle) {
@@ -157,6 +158,23 @@ static int acpi_bind_one(struct device *
}
dev->archdata.acpi_handle = handle;
+ status = acpi_bus_get_device(handle, &acpi_dev);
+ if (!ACPI_FAILURE(status)) {
+ int ret;
+
+ ret = sysfs_create_link(&dev->kobj, &acpi_dev->dev.kobj,
+ "firmware_node");
+ if (ret != 0)
+ pr_debug(PREFIX "Can't create %s link for %s\n",
+ "firmware_node", dev->bus_id);
+
+ ret = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
+ "physical_node");
+ if (ret != 0)
+ pr_debug(PREFIX "Can't create %s link for %s\n",
+ "physical_node", acpi_dev->dev.bus_id);
+ }
+
return 0;
}
@@ -165,8 +183,17 @@ static int acpi_unbind_one(struct device
if (!dev->archdata.acpi_handle)
return 0;
if (dev == acpi_get_physical_device(dev->archdata.acpi_handle)) {
+ struct acpi_device *acpi_dev;
+
/* acpi_get_physical_device increase refcnt by one */
put_device(dev);
+
+ if (!acpi_bus_get_device(dev->archdata.acpi_handle,
+ &acpi_dev)) {
+ sysfs_remove_link(&dev->kobj, "firmware_node");
+ sysfs_remove_link(&acpi_dev->dev.kobj, "physical_node");
+ }
+
acpi_detach_data(dev->archdata.acpi_handle,
acpi_glue_data_handler);
dev->archdata.acpi_handle = NULL;
_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/linux-pm
