[PATCH v4 1/2] dt-bindings: Add GPIO-locked fixed clock

Some hardware designs provide fixed-frequency clocks generated outside
software control, such as by FPGA-resident PLLs. While the clock rate is
fixed, a separate GPIO signal indicates whether the clock source is
locked and producing a valid output.

Describe a GPIO-locked fixed clock provider that exposes a fixed-rate
clock whose availability depends on one or more GPIO lock-status
signals.

Signed-off-by: Vyacheslav Yurkov <[email protected]>
Signed-off-by: Vyacheslav Yurkov <[email protected]>
---
 .../bindings/clock/gpio-locked-fixed-clock.yaml    | 59 ++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/gpio-locked-fixed-clock.yaml b/Documentation/devicetree/bindings/clock/gpio-locked-fixed-clock.yaml
new file mode 100644
index 000000000000..4d17889c51ad
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/gpio-locked-fixed-clock.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/gpio-locked-fixed-clock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: GPIO Locked Fixed Clock
+
+maintainers:
+  - Vyacheslav Yurkov <[email protected]>
+
+properties:
+  compatible:
+    const: gpio-locked-fixed-clock
+
+  "#clock-cells":
+    const: 0
+
+  clocks:
+    description: Input clocks whose validity is monitored by this provider.
+
+  clock-output-names:
+    description: Names of the clock provided by this controller.
+    maxItems: 1
+
+  locked-gpios:
+    description: |
+      GPIOs to check the lock state.
+    minItems: 1
+    maxItems: 32
+
+required:
+  - compatible
+  - "#clock-cells"
+
+anyOf:
+  - required:
+      - clocks
+  - required:
+      - locked-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    clk_gpio_locked: gpio-locked-fixed-clock {
+        compatible = "gpio-locked-fixed-clock";
+        #clock-cells = <0>;
+
+        clocks = <&clk0 0>, <&pll 0>;
+
+        locked-gpios = <&gpio0 4 GPIO_ACTIVE_HIGH>,
+                <&gpio0 5 GPIO_ACTIVE_HIGH>,
+                <&gpio1 2 GPIO_ACTIVE_LOW>;
+
+        clock-output-names = "clkout0";
+    };

-- 
2.34.1