[PATCH] Input: keyboard - add device tree bindings for simple key matrixes

[Olof Johansson]

From: Dmitry Torokhov <dmitry.torokhov at gmail.com>

This adds a basic device tree binding for simple key matrix data.

Signed-off-by: Olof Johansson <olof at lixom.net>
---

Based on email exchange this morning, this is a first cut at a shared
definition and helper function to parse and fill in the keymap data.

Instead of doing the direct parsing into the final keymap format, I
chose to fill in the pdata-equivalent since that is how the OF pdata
fillers work right now if code is to be kept common with the legacy
platform_device probe interface.

This is a prerequisite for a revised version of the tegra-kbc device
tree support that I will repost separately once this interface is stable.


-Olof

 .../devicetree/bindings/input/matrix-keymap.txt    |   35 ++++++++++++
 include/linux/input/matrix_keypad.h                |   55 ++++++++++++++++++++
 2 files changed, 90 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/input/matrix-keymap.txt

diff --git a/Documentation/devicetree/bindings/input/matrix-keymap.txt b/Documentation/devicetree/bindings/input/matrix-keymap.txt
new file mode 100644
index 0000000..894f786
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/matrix-keymap.txt
@@ -0,0 +1,35 @@
+For matrix keyboards there are two kinds of layout bindings using
+linux key codes.
+
+Required properties:
+- compatible: "matrix-keyboard-controller"
+
+For simple keyboards with just a few buttons, you can specify each key
+as a subnode of the keyboard controller, with the following
+properties:
+
+- keypad,row: the row number to which the key is connected.
+- keypad,column: the column number to which the key is connected.
+- linux,code: the key-code to be reported when the key is pressed
+  and released.
+
+Example:
+
+	key_1 {
+		keypad,row = <0>;
+		keypad,column = <3>;
+		linux,code = <2>;
+	};
+
+
+For a more complex keyboard, such as a full laptop, a more compact
+binding can be used instead, with the following property directly in
+the keyboard controller node:
+
+- linux,keymap: an array of 3-cell entries containing the equivalent
+  of the three separate properties above: row, column and linux
+  key-code.
+
+Example:
+	linux,keymap = < 0 3 2
+			 0 4 5 >;
diff --git a/include/linux/input/matrix_keypad.h b/include/linux/input/matrix_keypad.h
index fe7c4b9..ff13cd3 100644
--- a/include/linux/input/matrix_keypad.h
+++ b/include/linux/input/matrix_keypad.h
@@ -3,6 +3,7 @@
 
 #include <linux/types.h>
 #include <linux/input.h>
+#include <linux/of.h>
 
 #define MATRIX_MAX_ROWS		32
 #define MATRIX_MAX_COLS		32
@@ -106,4 +107,58 @@ matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 	__clear_bit(KEY_RESERVED, keybit);
 }
 
+#ifdef CONFIG_OF
+static inline struct matrix_keymap_data *
+matrix_keyboard_of_fill_keymap(struct device_node *np)
+{
+	struct matrix_keymap_data *kd;
+	struct device_node *knp;
+	int proplen = 0, i;
+	u32 *keymap, row, col, key_code;
+	const __be32 *prop = of_get_property(np, "linux,keymap", &proplen);
+
+	if (!of_device_is_compatible(np, "matrix-keyboard-controller"))
+		return NULL;
+
+	kd = kmalloc(sizeof(*kd), GFP_KERNEL);
+	if (!kd)
+		return NULL;
+	kd->keymap_size = proplen / 3;
+
+	for_each_child_of_node(np, knp)
+		kd->keymap_size++;
+
+	keymap = kzalloc(kd->keymap_size * sizeof(u32), GFP_KERNEL);
+	if (!keymap) {
+		kfree(kd);
+		return NULL;
+	}
+
+	kd->keymap = keymap;
+
+	for (i = 0; i < proplen/3; i++){
+		/* property format is < row column keycode > */
+		row = be32_to_cpup(prop++);
+		col = be32_to_cpup(prop++);
+		key_code = be32_to_cpup(prop++);
+		*keymap++ = KEY(row, col, key_code);
+	}
+
+	for_each_child_of_node(np, knp) {
+               of_property_read_u32(knp, "keypad,row", &row);
+               of_property_read_u32(knp, "keypad,column", &col);
+               of_property_read_u32(knp, "linux,code", &key_code);
+               *keymap++ = KEY(row, col, key_code);
+	}
+
+	return kd;
+}
+#else
+static inline struct matrix_keymap_data *
+matrix_keyboard_of_fill_keymap(struct device_node *np)
+{
+	return NULL;
+}
+#endif
+
 #endif /* _MATRIX_KEYPAD_H */
-- 
1.7.8.GIT