[PATCH v3 lora-next 3/4] dt-bindings: lora: sx125x: add clock bindings

[Ben Whitten]

From: Ben Whitten <ben.whitten@xxxxxxxxx>

The SX125x consumes a clock (FXOSC) ranging from 32 to 36 MHz as its main
XTAL. It may also consume a clock for the TX synthesizer or DAC input clock
(FCLK_IN).
If the radio is coupled with an SX130x the radio is therefor operating in
master mode and it may also provide a gated version of FXOSC clock for the
concentrator. In this case the concentrator is expecting a 32 MHz input
clock.

In the example we connect fxosc to the "txco" clock source, represented by a
fixed clock. The radio also provides a clock output "fclk_out" for
consumption by the SX130x concentrator.

Signed-off-by: Ben Whitten <ben.whitten@xxxxxxxxx>
---
v2 -> v3:
* Name clock inputs and outputs
* Add FCLK_IN
v1 -> v2:
* Fixed incorrect usage of clock cells
* Fixed wording in commit and descriptions
* Dropped enforced clock names
---
 .../bindings/net/lora/semtech,sx125x.yaml     | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/lora/semtech,sx125x.yaml b/Documentation/devicetree/bindings/net/lora/semtech,sx125x.yaml
index fe2d2a23c28b..be45bcfd97be 100644
--- a/Documentation/devicetree/bindings/net/lora/semtech,sx125x.yaml
+++ b/Documentation/devicetree/bindings/net/lora/semtech,sx125x.yaml
@@ -27,12 +27,41 @@ properties:
     description: The chip select on the SPI bus or radio number in concentrator
       , with radio A = 0 and radio B = 1.
 
+  clocks:
+    maxItems: 2
+    description: Input clock (FXOSC) provider with output ranging from 32 MHz
+      to 36 MHz. TX synthesizer or DAC input clock (FCLK_IN) provider with
+      output ranging from 32 MHz to 36 MHz.
+
+  clock-names:
+    items:
+      - const: fxosc
+      - const: fclk_in
+    description: Input clock (FXOSC), TX synthesizer or DAC input clock
+      (FCLK_IN)
+
+  clock-output-names:
+    items:
+      - const: fclk_out
+    description: Output clock (FCLK_OUT) name, clock is gated version of the
+      input (FXOSC). Used in master mode operation.
+
+  '#clock-cells':
+    const: 0
+
 required:
   - compatible
   - reg
 
 examples:
   - |
+    tcxo: dummy32m {
+      compatible = "fixed-clock";
+      clock-frequency = <32000000>;
+      clock-output-names = "tcxo";
+      #clock-cells = <0>;
+    };
+
     spi {
       #address-cells = <1>;
       #size-cells = <0>;
@@ -40,5 +69,9 @@ examples:
       radio0: radio@0 {
         compatible = "semtech,sx1257";
         reg = <0>;
+        clocks = <&tcxo>;
+        clock-names = "fxosc";
+        clock-output-names = "fclk_out";
+        #clock-cells = <0>;
       };
     };
-- 
2.17.1