[PATCH v4 4/5] dt-bindings: counter: microchip-tcb-capture counter

[Kamel Bouhara <kamel.bouhara@bootlin.com>]

Describe the devicetree binding for the Microchip TCB module.
Each counter blocks exposes three independent counters.

However, when configured in quadrature decoder, both channel <0> and <1>
are required for speed/position and rotation capture (yet only the
position is captured).

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
---
 .../soc/microchip/atmel,at91rm9200-tcb.yaml   | 29 +++++++++++++++++--
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml b/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
index 38403760f64d..0bd7b14a1552 100644
--- a/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
+++ b/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
@@ -52,14 +52,20 @@ properties:
 
 patternProperties:
   "^timer@[0-2]$":
-    description: The timer block channels that are used as timers.
+    description: The timer block channels that are used as timers or counters.
     type: object
     properties:
       compatible:
-        const: atmel,tcb-timer
+        items:
+          - enum:
+              - atmel,tcb-timer
+              - microchip,tcb-capture
       reg:
         description:
-          List of channels to use for this particular timer.
+          List of channels to use for this particular timer. In Microchip TCB capture
+          mode channels are registered as a counter devices, for the qdec mode TCB0's
+          channel <0> and <1> are required.
+
         minItems: 1
         maxItems: 3
 
@@ -148,3 +154,20 @@ examples:
                         reg = <1>;
                 };
         };
+examples:
+  - |
+        /* TCB Capture with qdec mode: */
+        tcb0: timer@fff7c000 {
+                compatible = "atmel,at91rm9200-tcb", "simple-mfd", "syscon";
+                #address-cells = <1>;
+                #size-cells = <0>;
+                reg = <0xfff7c000 0x100>;
+                interrupts = <18 4>;
+                clocks = <&tcb0_clk>, <&clk32k>;
+                clock-names = "t0_clk", "slow_clk";
+
+                timer@0 {
+                        compatible = "atmel,tcb-capture";
+                        reg = <0>, <1>;
+                };
+        };
-- 
2.25.0