dt-bindings: hwlock: qcom: Allow device on mmio bus

In modern Qualcomm platforms the mutex region of the TCSR is forked off
into its own block, all with a offset of 0 and stride of 4096, and in
some of these platforms no other registers in this region is accessed
from Linux.

Update the binding to allow the hardware block to be described directly
on the mmio bus, in addition to allowing the existing syscon based
definition for backwards compatibility.
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200622075956.171058-3-bjorn.andersson@linaro.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.yaml

@@ -19,6 +19,9 @@ properties:
       - qcom,sfpb-mutex
       - qcom,tcsr-mutex
 
+  reg:
+    maxItems: 1
+
   '#hwlock-cells':
     const: 1
 
@@ -31,7 +34,12 @@ properties:
 required:
   - compatible
   - '#hwlock-cells'
-  - syscon
+
+oneOf:
+  - required:
+    - reg
+  - required:
+    - syscon
 
 additionalProperties: false
 
@@ -46,6 +54,12 @@ examples:
                 compatible = "qcom,tcsr-mutex";
                 syscon = <&tcsr_mutex_block 0 0x80>;
 
+                #hwlock-cells = <1>;
+        };
+  - |
+        tcsr_mutex: hwlock@1f40000 {
+                compatible = "qcom,tcsr-mutex";
+                reg = <0x01f40000 0x40000>;
                 #hwlock-cells = <1>;
         };
 ...