ACPI devices declare themselves dependent on other devices via the _DEP buffer. Fetching the dependee from dependent is a matter of parsing _DEP, but currently there's no method to fetch dependent from dependee. Add one, so we can parse sensors dependent on a PMIC from the PMIC's acpi_driver.
Signed-off-by: Daniel Scally <[email protected]> --- Changes since RFC v3: - Patch introduced drivers/acpi/utils.c | 68 +++++++++++++++++++++++++++++++++++++++++ include/acpi/acpi_bus.h | 2 ++ 2 files changed, 70 insertions(+) diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index c177165c8db2..7099529121db 100644 --- a/drivers/acpi/utils.c +++ b/drivers/acpi/utils.c @@ -807,6 +807,52 @@ static int acpi_dev_match_cb(struct device *dev, const void *data) return hrv == match->hrv; } +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; + struct acpi_handle_list dep_handles; + struct acpi_device *candidate; + acpi_handle handle; + acpi_status status; + unsigned int i; + int ret; + + handle = adev->handle; + + if (!acpi_has_method(handle, "_DEP")) + return 0; + + status = acpi_evaluate_reference(handle, "_DEP", NULL, &dep_handles); + if (ACPI_FAILURE(status)) + return 0; + + for (i = 0; i < dep_handles.count; i++) { + struct acpi_device_info *info; + + status = acpi_get_object_info(dep_handles.handles[i], &info); + if (ACPI_FAILURE(status)) + continue; + + if (info->valid & ACPI_VALID_HID) { + ret = acpi_bus_get_device(dep_handles.handles[i], &candidate); + if (ret || !candidate) { + kfree(info); + continue; + } + + if (candidate == dependee) { + acpi_dev_put(candidate); + kfree(info); + return 1; + } + + kfree(info); + } + } + return 0; +} + /** * acpi_dev_present - Detect that a given ACPI device is present * @hid: Hardware ID of the device. @@ -842,6 +888,28 @@ 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 0a028ba967d3..f5dfeb030b9c 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -688,6 +688,8 @@ 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
