[PATCH v3 2/4] backlight: rt4831: Adds DT binding document for Richtek RT4831 backlight

[cy_huang]

From: ChiYuan Huang <cy_huang@xxxxxxxxxxx>

Adds DT binding document for Richtek RT4831 backlight.

Signed-off-by: ChiYuan Huang <cy_huang@xxxxxxxxxxx>
---
since v3
- Move inlcude/dt-bindings/leds/rt4831-backlight.h from patch 0004 to here.
- Add dual license tag in header and backlight binding document.
- Left backlight dt-binding example only.
---
 .../leds/backlight/richtek,rt4831-backlight.yaml   | 76 ++++++++++++++++++++++
 include/dt-bindings/leds/rt4831-backlight.h        | 23 +++++++
 2 files changed, 99 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
 create mode 100644 include/dt-bindings/leds/rt4831-backlight.h

diff --git a/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
new file mode 100644
index 00000000..f24c8d1
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/backlight/richtek,rt4831-backlight.yaml
@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/backlight/richtek,rt4831-backlight.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Richtek RT4831 Backlight
+
+maintainers:
+  - ChiYuan Huang <cy_huang@xxxxxxxxxxx>
+
+description: |
+  RT4831 is a mutifunctional device that can provide power to the LCD display
+  and LCD backlight.
+
+  For the LCD backlight, it can provide four channel WLED driving capability.
+  Each channel driving current is up to 30mA
+
+  Datasheet is available at
+  https://www.richtek.com/assets/product_file/RT4831A/DS4831A-05.pdf
+
+properties:
+  compatible:
+    const: richtek,rt4831-backlight
+
+  default-brightness:
+    description: |
+      The default brightness that applied to the system on start-up.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 2048
+
+  max-brightness:
+    description: |
+      The max brightness for the H/W limit
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 2048
+
+  richtek,pwm-enable:
+    description: |
+      Specify the backlight dimming following by PWM duty or by SW control.
+    type: boolean
+
+  richtek,bled-ovp-sel:
+    description: |
+      Backlight OVP level selection, currently support 17V/21V/25V/29V.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    default: 1
+    minimum: 0
+    maximum: 3
+
+  richtek,channel-use:
+    description: |
+      Backlight LED channel to be used.
+      BIT 0/1/2/3 is used to indicate led channel 1/2/3/4 enable or disable.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    minimum: 1
+    maximum: 15
+
+required:
+  - compatible
+  - richtek,channel-use
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/rt4831-backlight.h>
+    backlight {
+      compatible = "richtek,rt4831-backlight";
+      default-brightness = <1024>;
+      max-brightness = <2048>;
+      richtek,bled-ovp-sel = /bits/ 8 <RT4831_BLOVPLVL_21V>;
+      richtek,channel-use = /bits/ 8 <RT4831_BLED_ALLCHEN>;
+    };
diff --git a/include/dt-bindings/leds/rt4831-backlight.h b/include/dt-bindings/leds/rt4831-backlight.h
new file mode 100644
index 00000000..125c635
--- /dev/null
+++ b/include/dt-bindings/leds/rt4831-backlight.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * This header provides constants for rt4831 backlight bindings.
+ *
+ * Copyright (C) 2020, Richtek Technology Corp.
+ * Author: ChiYuan Huang <cy_huang@xxxxxxxxxxx>
+ */
+
+#ifndef _DT_BINDINGS_RT4831_BACKLIGHT_H
+#define _DT_BINDINGS_RT4831_BACKLIGHT_H
+
+#define RT4831_BLOVPLVL_17V	0
+#define RT4831_BLOVPLVL_21V	1
+#define RT4831_BLOVPLVL_25V	2
+#define RT4831_BLOVPLVL_29V	3
+
+#define RT4831_BLED_CH1EN	(1 << 0)
+#define RT4831_BLED_CH2EN	(1 << 1)
+#define RT4831_BLED_CH3EN	(1 << 2)
+#define RT4831_BLED_CH4EN	(1 << 3)
+#define RT4831_BLED_ALLCHEN	((1 << 4) - 1)
+
+#endif /* _DT_BINDINGS_RT4831_BACKLIGHT_H */
-- 
2.7.4