linux-kernel - [PATCH 12/13] dt-bindings: auxdisplay: Add bindings for Hitachi HD44780

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Date:   Mon,  6 Feb 2017 15:38:14 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Miguel Ojeda Sandonis <miguel.ojeda.sandonis@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Willy Tarreau <willy@...roxy.com>,
        Ksenija Stanojevic <ksenija.stanojevic@...il.com>,
        Arnd Bergmann <arnd@...db.de>
Cc:     linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, devicetree@...r.kernel.org
Subject: [PATCH 12/13] dt-bindings: auxdisplay: Add bindings for Hitachi HD44780

Add DT bindings for an Hitachi HD44780 Character LCD Controller where
its M6800 bus interface is connected to GPIOs.

Memory-mapped configurations are not yet supported.

Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Rob Herring <robh+dt@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: devicetree@...r.kernel.org
---
 .../devicetree/bindings/auxdisplay/hit,hd44780.txt | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt

diff --git a/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt
new file mode 100644
index 0000000000000000..ee4054da458d412f
--- /dev/null
+++ b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt
@@ -0,0 +1,44 @@
+DT bindings for the Hitachi HD44780 Character LCD Controller
+
+The Hitachi HD44780 Character LCD Controller is commonly used on character LCDs
+that can display one or more lines of text. It exposes an M6800 bus interface,
+which can be used in either 4-bit or 8-bit mode.
+
+Required properties:
+  - compatible: Must contain "hit,hd44780",
+  - data-gpios: Must contain an array of either 4 or 8 GPIO specifiers,
+    referring to the GPIO pins connected to the data signal lines DB0-DB7
+    (8-bit mode) or DB4-DB7 (4-bit mode) of the LCD Controller's bus interface,
+  - enable-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+    connected to the "E" (Enable) signal line of the LCD Controller's bus
+    interface,
+  - rs-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+    connected to the "RS" (Register Select) signal line of the LCD Controller's
+    bus interface,
+  - display-height: Height of the display, in character cells,
+  - display-width: Width of the display, in character cells.
+
+Optional properties:
+  - rw-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+    connected to the "RW" (Read/Write) signal line of the LCD Controller's bus
+    interface,
+  - backlight-gpios: Must contain a GPIO specifier, referring to the GPIO pin
+    used for enabling the LCD's backlight,
+  - internal-buffer-width: Internal buffer width (default is 40 for displays
+    with 1 or 2 lines, and display-width for displays with more than 2 lines).
+
+Example:
+
+	auxdisplay {
+		compatible = "hit,hd44780";
+
+		data-gpios = <&hc595 0 GPIO_ACTIVE_HIGH>,
+			     <&hc595 1 GPIO_ACTIVE_HIGH>,
+			     <&hc595 2 GPIO_ACTIVE_HIGH>,
+			     <&hc595 3 GPIO_ACTIVE_HIGH>;
+		enable-gpios = <&hc595 4 GPIO_ACTIVE_HIGH>;
+		rs-gpios = <&hc595 5 GPIO_ACTIVE_HIGH>;
+
+		display-height = <2>;
+		display-width = <16>;
+	};
-- 
1.9.1