There's an idiom in use by 7 Linux drivers to detect the presence of a
particular ACPI HID by walking the namespace with acpi_get_devices().
The callback passed to acpi_get_devices() is mostly identical across
the drivers, leading to lots of duplicate code.
Add acpi_dev_present(), the ACPI equivalent to pci_dev_present(),
allowing us to deduplicate all that boilerplate in the drivers.
v2: * Instead of walking the namespace, iterate over acpi_bus_id_list
which has all HIDs cached (Hanjun Guo, Robert Moore).
* Move to utils.c (Rafael J. Wysocki). This necessitates non-static
declaration of acpi_bus_id_list.
Cc: Hanjun Guo <guohanjun@xxxxxxxxxx>
Cc: Robert Moore <robert.moore@xxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
drivers/acpi/internal.h | 8 ++++++++
drivers/acpi/scan.c | 8 +-------
drivers/acpi/utils.c | 31 +++++++++++++++++++++++++++++++
include/acpi/acpi_bus.h | 2 ++
4 files changed, 42 insertions(+), 7 deletions(-)
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 11d87bf..60bda0d 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -86,6 +86,14 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
#define ACPI_STA_DEFAULT (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED | \
ACPI_STA_DEVICE_UI | ACPI_STA_DEVICE_FUNCTIONING)
+extern struct list_head acpi_bus_id_list;
+
+struct acpi_device_bus_id{
+ char bus_id[15];
+ unsigned int instance_no;
+ struct list_head node;
+};
+
int acpi_device_add(struct acpi_device *device,
void (*release)(struct device *));
void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index a0e942b..4be2179 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -39,7 +39,7 @@ static const char *dummy_hid = "device";
static LIST_HEAD(acpi_dep_list);
static DEFINE_MUTEX(acpi_dep_list_lock);
-static LIST_HEAD(acpi_bus_id_list);
+LIST_HEAD(acpi_bus_id_list);
static DEFINE_MUTEX(acpi_scan_lock);
static LIST_HEAD(acpi_scan_handlers_list);
DEFINE_MUTEX(acpi_device_lock);
@@ -52,12 +52,6 @@ struct acpi_dep_data {
acpi_handle slave;
};
-struct acpi_device_bus_id{
- char bus_id[15];
- unsigned int instance_no;
- struct list_head node;
-};
-
void acpi_scan_lock_acquire(void)
{
mutex_lock(&acpi_scan_lock);
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 475c907..f2f9873 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -29,6 +29,7 @@
#include <linux/dynamic_debug.h>
#include "internal.h"
+#include "sleep.h"
#define _COMPONENT ACPI_BUS_COMPONENT
ACPI_MODULE_NAME("utils");
@@ -709,6 +710,36 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
}
EXPORT_SYMBOL(acpi_check_dsm);
+/**
+ * acpi_dev_present - Detect presence of a given ACPI device in the system.
+ * @hid: Hardware ID of the device.
+ *
+ * Return %true if the device was present at the moment of invocation.
+ * Note that if the device is pluggable, it may since have disappeared.
+ *
+ * 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)
+{
+ struct acpi_device_bus_id *acpi_device_bus_id;
+ bool found = false;
+
+ mutex_lock(&acpi_device_lock);
+ list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
+ if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
+ found = true;
+ break;
+ }
+ mutex_unlock(&acpi_device_lock);
+
+ return found;
+}
+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 ad0a5ff..0fe7bab 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -87,6 +87,8 @@ acpi_evaluate_dsm_typed(acpi_handle handle, const u8 *uuid, int rev, int func,
.package.elements = (eles) \
}
+bool acpi_dev_present(const char *hid);
+
#ifdef CONFIG_ACPI
#include <linux/proc_fs.h>
--
1.8.5.2 (Apple Git-48)
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