intel_th: Add ACPI glue layer

The Trace Hub devices now can be enumerated as ACPI devices, which
translates into "Host Debugger mode". There are two IDs: one for
PCH Trace Hub, and one for the uncore Trace Hub. These are expected
to stay the same across all platforms.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
diff --git a/drivers/hwtracing/intel_th/Kconfig b/drivers/hwtracing/intel_th/Kconfig
index 1b412f8..ca0527d 100644
--- a/drivers/hwtracing/intel_th/Kconfig
+++ b/drivers/hwtracing/intel_th/Kconfig
@@ -25,6 +25,18 @@
 
 	  Say Y here to enable PCI Intel TH support.
 
+config INTEL_TH_ACPI
+	tristate "Intel(R) Trace Hub ACPI controller"
+	depends on ACPI
+	help
+	  Intel(R) Trace Hub may exist as an ACPI device. This option enables
+	  support glue layer for ACPI-based Intel TH. This typically implies
+	  'host debugger' mode, that is, the trace configuration and capture
+	  is handled by an external debug host and corresponding controls will
+	  not be available on the target.
+
+	  Say Y here to enable ACPI Intel TH support.
+
 config INTEL_TH_GTH
 	tristate "Intel(R) Trace Hub Global Trace Hub"
 	help