All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH v3 1/4] ACPI: utils: Add new acpi_dev_present helper
@ 2017-04-08 21:23 Hans de Goede
  2017-04-08 21:23 ` [PATCH v3 2/4] ACPI: battery: Fix acpi_battery_exit on acpi_battery_init_async errors Hans de Goede
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Hans de Goede @ 2017-04-08 21:23 UTC (permalink / raw)
  To: Rafael J . Wysocki, Len Brown, Sebastian Reichel
  Cc: Hans de Goede, Andy Shevchenko, Lukas Wunner, Robert Moore,
	linux-acpi, linux-pm, Mika Westerberg

acpi_dev_found just iterates over all ACPI-ids and sees if one matches.
This means that it will return true for devices which are in the dsdt
but disabled (their _STA method returns 0).

For some drivers it is useful to be able to check if a certain HID
is not only present in the namespace, but also actually present as in
acpi_device_is_present() will return true for the device. For example
because if a certain device is present then the driver will want to use
an extcon or IIO adc channel provided by that device.

This commit adds a new acpi_dev_present helper which drivers can use
to this end.

Like acpi_dev_found, acpi_dev_present take a HID as argument, but
it also has 2 extra optional arguments to only check for an ACPI
device with a specific UID and/or HRV value. This makes it more
generic and allows it to replace custom code doing similar checks
in several places.

Arguably acpi_dev_present is what acpi_dev_found should have been, but
there are too many users to just change acpi_dev_found without the risk
of breaking something.

Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v2:
-Switch to using bus_find_device() to avoid "Traversing the namespace
 over and over"
-Add optional (may be NULL / -1) uid and hrv arguments, this will
 allow this new function to replace the custom code for this in
 drivers/firmware/efi/dev-path-parser.c as well as in
 sound/soc/intel/common/sst-match-acpi.c and will allow it to be
 used to implement blacklists to avoid loading the ACPI ac / battery
 driver on systems which have a PMIC / charger acpi device with a
 native driver which offers a better (often working vs not working)
 user experience
-Dropped Mika's reviewd by as this is almost a total rewrite
Changes in v3:
-memset the entire acpi_dev_present_info struct, this fixes
 acpi_device_id.cls not getting cleared
---
 drivers/acpi/utils.c    | 72 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/acpi/acpi_bus.h |  1 +
 include/linux/acpi.h    |  5 ++++
 3 files changed, 78 insertions(+)

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 22c0995..311537a 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -736,6 +736,78 @@ bool acpi_dev_found(const char *hid)
 }
 EXPORT_SYMBOL(acpi_dev_found);
 
+struct acpi_dev_present_info {
+	struct acpi_device_id hid[2];
+	const char *uid;
+	int hrv;
+};
+
+static int acpi_dev_present_cb(struct device *dev, void *data)
+{
+	struct acpi_device *adev = to_acpi_device(dev);
+	struct acpi_dev_present_info *match = data;
+	unsigned long long hrv;
+	acpi_status status;
+
+	if (acpi_match_device_ids(adev, match->hid))
+		return 0;
+
+	if (match->uid && adev->pnp.unique_id &&
+	    strcmp(adev->pnp.unique_id, match->uid))
+		return 0;
+
+	if (match->uid && !adev->pnp.unique_id &&
+	    strcmp("0", match->uid))
+		return 0;
+
+	if (match->hrv == -1)
+		return 1;
+
+	status = acpi_evaluate_integer(adev->handle, "_HRV", NULL, &hrv);
+	if (ACPI_FAILURE(status))
+		return 0;
+
+	return hrv == match->hrv;
+}
+
+/**
+ * acpi_dev_present - Detect that a given ACPI device is present
+ * @hid: Hardware ID of the device.
+ * @uid: Unique ID of the device, pass "0" for devices without a _UID,
+ *       pass NULL to not check _UID
+ * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
+ *
+ * Return %true if a matching device was present at the moment of invocation.
+ * Note that if the device is pluggable, it may since have disappeared.
+ *
+ * Note that unlike acpi_dev_found() this function checks the status
+ * of the device so for devices which are present in the dsdt, but
+ * which are disabled (their _STA callback returns 0) this function
+ * will return false.
+ *
+ * For this function to work, acpi_bus_scan() must have been executed
+ * which happens in the subsys_initcall() subsection. Hence, do not
+ * call from a subsys_initcall() or earlier (use acpi_get_devices()
+ * instead). Calling from module_init() is fine (which is synonymous
+ * with device_initcall()).
+ */
+bool acpi_dev_present(const char *hid, const char *uid, int hrv)
+{
+	struct acpi_dev_present_info match;
+	struct device *dev;
+
+	memset(&match, 0, sizeof(match));
+	strlcpy(match.hid[0].id, hid, sizeof(match.hid[0].id));
+	match.uid = uid;
+	match.hrv = hrv;
+
+	dev = bus_find_device(&acpi_bus_type, NULL, &match,
+			      acpi_dev_present_cb);
+
+	return dev ? true : false;
+}
+EXPORT_SYMBOL(acpi_dev_present);
+
 /*
  * acpi_backlight= handling, this is done here rather then in video_detect.c
  * because __setup cannot be used in modules.
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index ef0ae8a..64498d5 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -88,6 +88,7 @@ acpi_evaluate_dsm_typed(acpi_handle handle, const u8 *uuid, u64 rev, u64 func,
 	}
 
 bool acpi_dev_found(const char *hid);
+bool acpi_dev_present(const char *hid, const char *uid, int hrv);
 
 #ifdef CONFIG_ACPI
 
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 9b05886..e5dd0f1 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -611,6 +611,11 @@ static inline bool acpi_dev_found(const char *hid)
 	return false;
 }
 
+static inline bool acpi_dev_present(const char *hid, const char *uid, int hrv)
+{
+	return false;
+}
+
 static inline bool is_acpi_node(struct fwnode_handle *fwnode)
 {
 	return false;
-- 
2.9.3


^ permalink raw reply related	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-04-08 21:40 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-04-08 21:23 [PATCH v3 1/4] ACPI: utils: Add new acpi_dev_present helper Hans de Goede
2017-04-08 21:23 ` [PATCH v3 2/4] ACPI: battery: Fix acpi_battery_exit on acpi_battery_init_async errors Hans de Goede
2017-04-08 21:23 ` [PATCH v3 3/4] ACPI: battery: Add a blacklist with PMIC ACPI HIDs with a native battery driver Hans de Goede
2017-04-08 21:23 ` [PATCH v3 4/4] ACPI: ac: Add a blacklist with PMIC ACPI HIDs with a native charger driver Hans de Goede
2017-04-08 21:40 ` [PATCH v3 1/4] ACPI: utils: Add new acpi_dev_present helper Lukas Wunner

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.