[PATCH 1/3] dt-bindings: leds: rt8515: Support single-GPIO flash ICs with unlock gate

[Rudraksha Gupta via B4 Relay <devnull+guptarud.gmail.com@kernel.org>]

From: Rudraksha Gupta <guptarud@gmail.com>

Some flash ICs use the same one-wire pulse-count protocol as the RT8515
but have only a single GPIO line for both flash and torch modes, plus an
optional unlock gate (e.g. a PMIC MPP) that must be driven high before
the chip responds to the enable GPIO.

Make ent-gpios optional and add an unlock-gpios property to support
these variants. Add a oneOf constraint requiring exactly one of
ent-gpios or unlock-gpios. Add a binding example showing the
single-GPIO configuration.

Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
---
 .../devicetree/bindings/leds/richtek,rt8515.yaml   | 36 +++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
index 0356371a6b01..820cf8c55090 100644
--- a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
+++ b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
@@ -15,6 +15,10 @@ description: |
   current for each mode is defined in hardware using two resistors
   RFS and RTS.
 
+  This driver also supports single-GPIO flash ICs that use the same
+  one-wire pulse-count protocol on one line for both flash and torch.
+  For these, only enf-gpios is required.
+
 properties:
   compatible:
     const: richtek,rt8515
@@ -26,6 +30,14 @@ properties:
   ent-gpios:
     maxItems: 1
     description: A connection to the 'ENT' (enable torch) pin.
+      Optional for single-GPIO flash ICs where enf-gpios is used for
+      both flash and torch modes.
+
+  unlock-gpios:
+    maxItems: 1
+    description: Optional GPIO to unlock the flash LED circuit. Some
+      boards use a PMIC MPP pin that must be driven high before the
+      flash IC will respond to the enable GPIOs.
 
   richtek,rfs-ohms:
     minimum: 7680
@@ -81,10 +93,15 @@ properties:
 
 required:
   - compatible
-  - ent-gpios
   - enf-gpios
   - led
 
+oneOf:
+  - required:
+      - ent-gpios
+  - required:
+      - unlock-gpios
+
 additionalProperties: false
 
 examples:
@@ -108,4 +125,21 @@ examples:
         };
     };
 
+  - |
+    /* Single-GPIO flash IC with unlock gate */
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    led-controller {
+        compatible = "richtek,rt8515";
+        enf-gpios = <&tlmm 3 GPIO_ACTIVE_HIGH>;
+        unlock-gpios = <&pm8921_mpps 4 GPIO_ACTIVE_HIGH>;
+
+        led {
+            function = LED_FUNCTION_FLASH;
+            color = <LED_COLOR_ID_WHITE>;
+            flash-max-timeout-us = <250000>;
+        };
+    };
+
 ...

-- 
2.53.0