[PATCH v4 2/5] dt-bindings: iio: adc: ad7192: Update clock config

[Alisa-Dariana Roman <alisadariana@gmail.com>]

There are actually 4 configuration modes of clock source for AD719X
devices. Either a crystal can be attached externally between MCLK1 and
MCLK2 pins, or an external CMOS-compatible clock can drive the MCLK2
pin. The other 2 modes make use of the 4.92MHz internal clock.

Add clock name xtal alongside mclk. When an external crystal is
attached, xtal should be chosen. When an external clock is used, mclk
should be chosen.

The presence of an external clock source is optional, not required. When
absent, internal clock is used. Modify required property accordingly and
modify second example to showcase this.

Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
---
 .../devicetree/bindings/iio/adc/adi,ad7192.yaml    | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml
index a03da9489ed9..3ae2f860d24c 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7192.yaml
@@ -39,11 +39,15 @@ properties:
 
   clocks:
     maxItems: 1
-    description: phandle to the master clock (mclk)
+    description: |
+      Optionally, either a crystal can be attached externally between MCLK1 and
+      MCLK2 pins, or an external CMOS-compatible clock can drive the MCLK2
+      pin. If absent, internal 4.92MHz clock is used.
 
   clock-names:
-    items:
-      - const: mclk
+    enum:
+      - xtal
+      - mclk
 
   interrupts:
     maxItems: 1
@@ -135,8 +139,6 @@ patternProperties:
 required:
   - compatible
   - reg
-  - clocks
-  - clock-names
   - interrupts
   - dvdd-supply
   - avdd-supply
@@ -202,8 +204,6 @@ examples:
             spi-max-frequency = <1000000>;
             spi-cpol;
             spi-cpha;
-            clocks = <&ad7192_mclk>;
-            clock-names = "mclk";
             interrupts = <25 0x2>;
             interrupt-parent = <&gpio>;
             aincom-supply = <&aincom>;
-- 
2.34.1