From b83e2b306736cb0d108df791fd4ee39f6d52184f Mon Sep 17 00:00:00 2001 From: Daniel Scally Date: Thu, 3 Jun 2021 23:40:03 +0100 Subject: [PATCH] ACPI: scan: Add function to fetch dependent of ACPI device 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 callback and a wrapper to walk over the acpi_dep_list and return the dependent ACPI device. Reviewed-by: Andy Shevchenko Signed-off-by: Daniel Scally Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 35 +++++++++++++++++++++++++++++++++++ include/acpi/acpi_bus.h | 1 + 2 files changed, 36 insertions(+) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 2277add6da2f..708c1d84e7bf 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -2101,6 +2101,20 @@ static void acpi_bus_attach(struct acpi_device *device, bool first_pass) device->handler->hotplug.notify_online(device); } +static int acpi_dev_get_first_consumer_dev_cb(struct acpi_dep_data *dep, void *data) +{ + struct acpi_device *adev; + + adev = acpi_bus_get_acpi_device(dep->consumer); + if (!adev) + /* If we don't find an adev then we want to continue parsing */ + return 0; + + *(struct acpi_device **)data = adev; + + return 1; +} + static int acpi_scan_clear_dep(struct acpi_dep_data *dep, void *data) { struct acpi_device *adev; @@ -2164,6 +2178,27 @@ void acpi_dev_clear_dependencies(struct acpi_device *supplier) } EXPORT_SYMBOL_GPL(acpi_dev_clear_dependencies); +/** + * acpi_dev_get_first_consumer_dev - Return ACPI device dependent on @supplier + * @supplier: Pointer to the dependee device + * + * Returns the first &struct acpi_device which declares itself dependent on + * @supplier via the _DEP buffer, parsed from the acpi_dep_list. + * + * The caller is responsible for putting the reference to adev when it is no + * longer needed. + */ +struct acpi_device *acpi_dev_get_first_consumer_dev(struct acpi_device *supplier) +{ + struct acpi_device *adev = NULL; + + acpi_walk_dep_device_list(supplier->handle, + acpi_dev_get_first_consumer_dev_cb, &adev); + + return adev; +} +EXPORT_SYMBOL_GPL(acpi_dev_get_first_consumer_dev); + /** * acpi_bus_scan - Add ACPI device node objects in a given namespace scope. * @handle: Root of the namespace scope to scan. diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index 0b2c4f170f4d..4bed30e61c5b 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -692,6 +692,7 @@ 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); void acpi_dev_clear_dependencies(struct acpi_device *supplier); +struct acpi_device *acpi_dev_get_first_consumer_dev(struct acpi_device *supplier); struct acpi_device * acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv); struct acpi_device *