[PATCH v5 13/15] ACPI / bus: Add acpi_dev_get_next_match_dev() and helper macro

Daniel Scally
2021-01-07T13:30:34Z

To ensure we handle situations in which multiple sensors of the same
model (and therefore _HID) are present in a system, we need to be able
to iterate over devices matching a known _HID but unknown _UID and _HRV
- add acpi_dev_get_next_match_dev() to accommodate that possibility and
change acpi_dev_get_first_match_dev() to simply call the new function
with a NULL starting point. Add an iterator macro for convenience.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
Changes in v5:

- Changed commit subject

drivers/acpi/utils.c | 30 ++++++++++++++++++++++++++----
include/acpi/acpi_bus.h | 7 +++++++
2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index d5411a166685..ddca1550cce6 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -843,12 +843,13 @@ bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
EXPORT_SYMBOL(acpi_dev_present);

/**
- * acpi_dev_get_first_match_dev - Return the first match of ACPI device
+ * 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
* @hid: Hardware ID of the device.
* @uid: Unique ID of the device, pass NULL to not check _UID
* @hrv: Hardware Revision of the device, pass -1 to not check _HRV
*
- * Return the first match of ACPI device if a matching device was present
+ * Return the next match of ACPI device if another matching device was present
* at the moment of invocation, or NULL otherwise.
*
* The caller is responsible to call put_device() on the returned device.
@@ -856,8 +857,9 @@ EXPORT_SYMBOL(acpi_dev_present);
* See additional information in acpi_dev_present() as well.
*/
struct acpi_device *
-acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
+acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
{
+ struct device *start = adev ? &adev->dev : NULL;
struct acpi_dev_match_info match = {};
struct device *dev;

@@ -865,9 +867,29 @@ acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
match.uid = uid;
match.hrv = hrv;

- dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
+ dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
return dev ? to_acpi_device(dev) : NULL;
}
+EXPORT_SYMBOL(acpi_dev_get_next_match_dev);
+
+/**
+ * acpi_dev_get_first_match_dev - Return the first match of ACPI device
+ * @hid: Hardware ID of the device.
+ * @uid: Unique ID of the device, pass NULL to not check _UID
+ * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
+ *
+ * Return the first match of ACPI device if a matching device was present
+ * at the moment of invocation, or NULL otherwise.
+ *
+ * The caller is responsible to call put_device() on the returned device.
+ *
+ * See additional information in acpi_dev_present() as well.
+ */
+struct acpi_device *
+acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
+{
+ return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
+}
EXPORT_SYMBOL(acpi_dev_get_first_match_dev);

/*
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 6d1879bf9440..02a716a0af5d 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -683,9 +683,16 @@ 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_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv);
struct acpi_device *
acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv);

+#define for_each_acpi_dev_match(adev, hid, uid, hrv) \
+ for (adev = acpi_dev_get_first_match_dev(hid, uid, hrv); \
+ adev; \
+ adev = acpi_dev_get_next_match_dev(adev, hid, uid, hrv))
+
static inline void acpi_dev_put(struct acpi_device *adev)
{
put_device(&adev->dev);
--
2.25.1