diff options
Diffstat (limited to 'drivers/acpi/utils.c')
| -rw-r--r-- | drivers/acpi/utils.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index 475c9079bf85..f2f9873bb5c3 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. |