In some ACPI tables we encounter, devices use the _DEP method to assert
a dependence on other ACPI devices as opposed to the OpRegions that the
specification intends. We need to be able to find those devices "from"
the dependee, so add a function to parse all ACPI Devices and check if
the include the handle of the dependee device in their _DEP buffer.
Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
---
Changes in v2:
- Used acpi_lpss_dep() as Andy suggested.
drivers/acpi/utils.c | 34 ++++++++++++++++++++++++++++++++++
include/acpi/acpi_bus.h | 2 ++
2 files changed, 36 insertions(+)
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 78b38775f18b..ec6a2406a886 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -831,6 +831,18 @@ bool acpi_lpss_dep(struct acpi_device *adev, acpi_handle handle)
return false;
}
+static int acpi_dev_match_by_dep(struct device *dev, const void *data)
+{
+ struct acpi_device *adev = to_acpi_device(dev);
+ const struct acpi_device *dependee = data;
+ acpi_handle handle = dependee->handle;
+
+ if (acpi_lpss_dep(adev, handle))
+ return 1;
+
+ return 0;
+}
+
/**
* acpi_dev_present - Detect that a given ACPI device is present
* @hid: Hardware ID of the device.
@@ -866,6 +878,28 @@ bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
}
EXPORT_SYMBOL(acpi_dev_present);
+/**
+ * acpi_dev_get_next_dep_dev - Return next ACPI device dependent on input dev
+ * @adev: Pointer to the dependee device
+ * @prev: Pointer to the previous dependent device (or NULL for first match)
+ *
+ * Return the next ACPI device which declares itself dependent on @adev in
+ * the _DEP buffer.
+ *
+ * The caller is responsible to call put_device() on the returned device.
+ */
+struct acpi_device *acpi_dev_get_next_dep_dev(struct acpi_device *adev,
+ struct acpi_device *prev)
+{
+ struct device *start = prev ? &prev->dev : NULL;
+ struct device *dev;
+
+ dev = bus_find_device(&acpi_bus_type, start, adev, acpi_dev_match_by_dep);
+
+ return dev ? to_acpi_device(dev) : NULL;
+}
+EXPORT_SYMBOL(acpi_dev_get_next_dep_dev);
+
/**
* acpi_dev_get_next_match_dev - Return the next match of ACPI device
* @adev: Pointer to the previous acpi_device matching this @hid, @uid and @hrv
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 02a716a0af5d..33deb22294f2 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -683,6 +683,8 @@ static inline bool acpi_device_can_poweroff(struct acpi_device *adev)
bool acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *uid2);
+struct acpi_device *
+acpi_dev_get_next_dep_dev(struct acpi_device *adev, struct acpi_device *prev);
struct acpi_device *
acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv);
struct acpi_device *
--
2.25.1
