@@ -291,6 +291,44 @@ int acpi_get_local_address(acpi_handle handle, u32 *addr)
}
EXPORT_SYMBOL(acpi_get_local_address);
+#define ACPI_MAX_SUB_BUF_SIZE 9
+
+const char *acpi_get_subsystem_id(acpi_handle handle)
+{
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ acpi_status status;
+ const char *sub;
+
+ status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);
+ if (ACPI_FAILURE(status)) {
+ acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);
+ return ERR_PTR(-ENODATA);
+ }
+
+ obj = buffer.pointer;
+ if (obj->type == ACPI_TYPE_STRING) {
+ if (strlen(obj->string.pointer) < ACPI_MAX_SUB_BUF_SIZE &&
+ strlen(obj->string.pointer) > 0) {
+ sub = kstrdup(obj->string.pointer, GFP_KERNEL);
+ if (!sub)
+ sub = ERR_PTR(-ENOMEM);
+ } else {
+ acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n",
+ strlen(obj->string.pointer));
+ sub = ERR_PTR(-EINVAL);
+ }
+ } else {
+ acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
+ sub = ERR_PTR(-EINVAL);
+ }
+
+ acpi_os_free(buffer.pointer);
+
+ return sub;
+}
+EXPORT_SYMBOL_GPL(acpi_get_subsystem_id);
+
acpi_status
acpi_evaluate_reference(acpi_handle handle,
acpi_string pathname,
@@ -762,6 +762,7 @@ static inline u64 acpi_arch_get_root_pointer(void)
#endif
int acpi_get_local_address(acpi_handle handle, u32 *addr);
+const char *acpi_get_subsystem_id(acpi_handle handle);
#else /* !CONFIG_ACPI */
@@ -1023,6 +1024,11 @@ static inline int acpi_get_local_address(acpi_handle handle, u32 *addr)
return -ENODEV;
}
+static inline const char *acpi_get_subsystem_id(acpi_handle handle)
+{
+ return ERR_PTR(-ENODEV);
+}
+
static inline int acpi_register_wakeup_handler(int wake_irq,
bool (*wakeup)(void *context), void *context)
{
Add a wrapper function to read the _SUB string from ACPI. Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com> --- drivers/acpi/utils.c | 38 ++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 6 ++++++ 2 files changed, 44 insertions(+)