dt-bindings: soundwire: qcom: clarify data port bus parameters

Some of the parameters for data ports are not applicable or not implemented
in IP. So mark them as invalid/not applicable in DT so that controller is
aware of this.

Add comment to these bindings to provide more clarity on the values!
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210330144719.13284-2-srinivas.kandagatla@linaro.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/soundwire/qcom,sdw.txt

@@ -54,6 +54,8 @@ board specific bus parameters.
 	Value type: <prop-encoded-array>
 	Definition: should specify payload transport window offset1 of each
 		    data port. Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-offset2:
@@ -61,6 +63,8 @@ board specific bus parameters.
 	Value type: <prop-encoded-array>
 	Definition: should specify payload transport window offset2 of each
 		    data port. Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-sinterval-low:
@@ -69,12 +73,16 @@ board specific bus parameters.
 	Definition: should be sample interval low of each data port.
 		    Out ports followed by In ports. Used for Sample Interval
 		    calculation.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-word-length:
 	Usage: optional
 	Value type: <prop-encoded-array>
 	Definition: should be size of payload channel sample.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-block-pack-mode:
@@ -84,6 +92,8 @@ board specific bus parameters.
 		    0 to indicate Blocks are per Channel
 		    1 to indicate Blocks are per Port.
 		    Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-block-group-count:
@@ -92,6 +102,8 @@ board specific bus parameters.
 	Definition: should be in range 1 to 4 to indicate how many sample
 		    intervals are combined into a payload.
 		    Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-lane-control:
@@ -100,6 +112,8 @@ board specific bus parameters.
 	Definition: should be in range 0 to 7 to identify which	data lane
 		    the data port uses.
 		    Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-hstart:
@@ -109,6 +123,8 @@ board specific bus parameters.
 		    SoundWire Frame, i.e. left edge of the Transport sub-frame
 		    for each port. Values between 0 and 15 are valid.
 		    Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,ports-hstop:
@@ -118,6 +134,8 @@ board specific bus parameters.
 		    SoundWire Frame, i.e. the right edge of the Transport
 		    sub-frame for each port. Values between 0 and 15 are valid.
 		    Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 - qcom,dports-type:
@@ -128,6 +146,8 @@ board specific bus parameters.
 		    1 for simple ports
 		    2 for full port
 		    Out ports followed by In ports.
+		    Value of 0xFF indicates that this option is not implemented
+		    or applicable for the respective data port.
 		    More info in MIPI Alliance SoundWire 1.0 Specifications.
 
 Note: