acpi_get_subsystem_id
EXPORT_SYMBOL_GPL(acpi_get_subsystem_id);
subsys = acpi_get_subsystem_id(ACPI_HANDLE(dev));
const char *acpi_get_subsystem_id(acpi_handle handle);
sub = acpi_get_subsystem_id(ACPI_HANDLE(physdev));
sub = acpi_get_subsystem_id(ACPI_HANDLE(cs35l56->base.dev));
sub = acpi_get_subsystem_id(ACPI_HANDLE(physdev));
sub = acpi_get_subsystem_id(handle);