Input: of_keymap - add device tree bindings for simple key matrices

This adds a simple device tree binding for simple key matrix data and
a helper to fill in the platform data.

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/of_keymap.c

@@ -0,0 +1,87 @@
+/*
+ * Helpers for open firmware matrix keyboard bindings
+ *
+ * Copyright (C) 2012 Google, Inc
+ *
+ * Author:
+ *	Olof Johansson <olof@lixom.net>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/input.h>
+#include <linux/of.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/export.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+
+struct matrix_keymap_data *
+matrix_keyboard_of_fill_keymap(struct device_node *np,
+			       const char *propname)
+{
+	struct matrix_keymap_data *kd;
+	u32 *keymap;
+	int proplen, i;
+	const __be32 *prop;
+
+	if (!np)
+		return NULL;
+
+	if (!propname)
+		propname = "linux,keymap";
+
+	prop = of_get_property(np, propname, &proplen);
+	if (!prop)
+		return NULL;
+
+	if (proplen % sizeof(u32)) {
+		pr_warn("Malformed keymap property %s in %s\n",
+			propname, np->full_name);
+		return NULL;
+	}
+
+	kd = kzalloc(sizeof(*kd), GFP_KERNEL);
+	if (!kd)
+		return NULL;
+
+	kd->keymap = keymap = kzalloc(proplen, GFP_KERNEL);
+	if (!kd->keymap) {
+		kfree(kd);
+		return NULL;
+	}
+
+	kd->keymap_size = proplen / sizeof(u32);
+
+	for (i = 0; i < kd->keymap_size; i++) {
+		u32 tmp = be32_to_cpup(prop + i);
+		int key_code, row, col;
+
+		row = (tmp >> 24) & 0xff;
+		col = (tmp >> 16) & 0xff;
+		key_code = tmp & 0xffff;
+		keymap[i] = KEY(row, col, key_code);
+	}
+
+	return kd;
+}
+EXPORT_SYMBOL_GPL(matrix_keyboard_of_fill_keymap);
+
+void matrix_keyboard_of_free_keymap(const struct matrix_keymap_data *kd)
+{
+	if (kd) {
+		kfree(kd->keymap);
+		kfree(kd);
+	}
+}
+EXPORT_SYMBOL_GPL(matrix_keyboard_of_free_keymap);