Add the fifo-threshold property to control the DMA FIFO threshold level,
which specifies the number of words that must be loaded before the DMA
FIFO becomes ready.

This property is needed to support the da850-evm board configuration
which requires a non-default FIFO threshold value. Currently, this value
is specified through the deprecated ti,tilcdc,panel binding. Adding this
property to the tilcdc binding allows for proper configuration while
migrating away from the non-standard panel binding.

The default value is 8 words, with valid values being powers of 2 from
8 to 512.

Related commit: 55da73fa7a68c ("ARM: dts: davinci: da850-evm: Increase
fifo threshold")

Signed-off-by: Kory Maincent (TI.com) <kory.maincent@bootlin.com>
---
 Documentation/devicetree/bindings/display/tilcdc/tilcdc.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/tilcdc/tilcdc.yaml b/Documentation/devicetree/bindings/display/tilcdc/tilcdc.yaml
index 34ac1fd04d5c6..bf6d506e25e17 100644
--- a/Documentation/devicetree/bindings/display/tilcdc/tilcdc.yaml
+++ b/Documentation/devicetree/bindings/display/tilcdc/tilcdc.yaml

@@ -46,6 +46,13 @@ properties:
       The maximum pixel clock that can be supported by the lcd controller
       in KHz.
 
+  fifo-threshold:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [8, 16, 32, 64, 128, 256, 512]
+    description:
+      Number of words loaded before the DMA fifo becomes ready. The default
+      value is 8.
+
   blue-and-red-wiring:
     enum: [straight, crossed]
     description:

-- 
2.43.0