[PATCH 1/1] dt-bindings: mfd: add ti,lm8502 combo LED + haptic controller

[Herman van Hazendonk <github.com@herrie.org>]

Add a YAML binding for the TI LM8502, an I2C combo LED + haptic
controller used in the HP TouchPad tablet. The chip is exposed as an
MFD with two child sub-nodes:

  ti,lm8502-leds   - LED-class outputs D1..D10 (with per-LED reg
                     and led-max-microamp properties)
  ti,lm8502-haptic - EV_FF / FF_RUMBLE input device for the internal
                     H-bridge vibrator output, optional
                     ti,invert-direction property

Signed-off-by: Herman van Hazendonk <github.com@herrie.org>
---
 .../devicetree/bindings/mfd/ti,lm8502.yaml    | 160 ++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/ti,lm8502.yaml

diff --git a/Documentation/devicetree/bindings/mfd/ti,lm8502.yaml b/Documentation/devicetree/bindings/mfd/ti,lm8502.yaml
new file mode 100644
index 000000000000..10f2e32a0738
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/ti,lm8502.yaml
@@ -0,0 +1,160 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/ti,lm8502.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI LM8502 combo LED + haptic controller
+
+maintainers:
+  - Herman van Hazendonk <github.com@herrie.org>
+
+description: |
+  The TI LM8502 is an I2C combo device with ten constant-current LED
+  outputs (D1..D10) and an internal H-bridge that drives a vibrator
+  motor. Pin D10 is shared between the tenth LED channel and the
+  haptic output; the haptic driver writes D10_CURRENT_CTRL = 0 at each
+  start to mux the pin to the H-bridge path.
+
+  The chip is exposed in Linux as an MFD with two children:
+    - ti,lm8502-leds   - LED-class outputs D1..D10
+    - ti,lm8502-haptic - EV_FF / FF_RUMBLE input device
+
+  The parent node owns the I2C client, the chip-enable GPIO and the
+  vcc regulator; children share access to the parent's regmap.
+
+properties:
+  compatible:
+    const: ti,lm8502
+
+  reg:
+    maxItems: 1
+
+  vcc-supply:
+    description:
+      Power supply for the chip (V_DD). On platforms where this supply
+      is provided by an RPM-managed LDO with "regulator-allow-set-load",
+      the driver will request High Power Mode (~100 mA) so the internal
+      boost converter and ten LED outputs are not current-starved.
+
+  enable-gpios:
+    maxItems: 1
+    description:
+      GPIO connected to the chip-enable pin. Pulled high by the driver
+      at probe time and dropped low across PM suspend.
+
+  pinctrl-names: true
+  pinctrl-0: true
+
+  leds:
+    type: object
+    additionalProperties: false
+    description: LED-class child for outputs D1..D10.
+
+    properties:
+      compatible:
+        const: ti,lm8502-leds
+
+      '#address-cells':
+        const: 1
+
+      '#size-cells':
+        const: 0
+
+    patternProperties:
+      '^led@[0-9]$':
+        type: object
+        $ref: /schemas/leds/common.yaml#
+        unevaluatedProperties: false
+
+        properties:
+          reg:
+            description:
+              Zero-based D-channel index (0 = D1 .. 9 = D10).
+            minimum: 0
+            maximum: 9
+
+          led-max-microamp:
+            description: |
+              Per-channel current cap. The chip's MAX_CURRENT field
+              quantises this to one of four buckets:
+                <=3000  - 3 mA
+                <=6000  - 6 mA
+                <=9000  - 9 mA  (default)
+                 >9000  - 12.75 mA
+            default: 9000
+
+        required:
+          - reg
+
+    required:
+      - compatible
+
+  haptic:
+    type: object
+    additionalProperties: false
+    description: FF_RUMBLE child for the internal H-bridge vibrator output.
+
+    properties:
+      compatible:
+        const: ti,lm8502-haptic
+
+      ti,invert-direction:
+        type: boolean
+        description:
+          Flip the H-bridge polarity bit in HAPTIC_FEEDBACK_CTRL so the
+          motor spins in the direction the board expects.
+
+    required:
+      - compatible
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@33 {
+            compatible = "ti,lm8502";
+            reg = <0x33>;
+
+            vcc-supply = <&pm8058_l16>;
+            enable-gpios = <&tlmm 121 GPIO_ACTIVE_HIGH>;
+
+            leds {
+                compatible = "ti,lm8502-leds";
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                led@0 {
+                    reg = <0>;
+                    label = "lm8502:white:navi_left";
+                    color = <LED_COLOR_ID_WHITE>;
+                    function = LED_FUNCTION_INDICATOR;
+                    led-max-microamp = <9000>;
+                };
+
+                led@1 {
+                    reg = <1>;
+                    label = "lm8502:white:navi_right";
+                    color = <LED_COLOR_ID_WHITE>;
+                    function = LED_FUNCTION_INDICATOR;
+                    led-max-microamp = <9000>;
+                };
+            };
+
+            haptic {
+                compatible = "ti,lm8502-haptic";
+                ti,invert-direction;
+            };
+        };
+    };
-- 
2.43.0