[PATCH] dt-bindings: sound: gtm601: add the broadmobi interface

[Angus Ainslie (Purism)]

The Broadmobi BM818 uses a different sample rate and channels from the
option modem.

Signed-off-by: Angus Ainslie (Purism) <angus@xxxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20191223154712.18581-3-angus@xxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 Documentation/devicetree/bindings/sound/gtm601.txt | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/sound/gtm601.txt b/Documentation/devicetree/bindings/sound/gtm601.txt
index 5efc8c068de0..efa32a486c4a 100644
--- a/Documentation/devicetree/bindings/sound/gtm601.txt
+++ b/Documentation/devicetree/bindings/sound/gtm601.txt
@@ -1,10 +1,16 @@
 GTM601 UMTS modem audio interface CODEC
 
-This device has no configuration interface. Sample rate is fixed - 8kHz.
+This device has no configuration interface. The sample rate and channels are
+based on the compatible string
+	"option,gtm601" = 8kHz mono
+	"broadmobi,bm818" = 48KHz stereo
 
 Required properties:
 
-  - compatible : "option,gtm601"
+  - compatible : one of
+	"option,gtm601"
+	"broadmobi,bm818"
+
 
 Example:
 
-- 
2.20.1