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>

6 files changed, 131 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/matrix-keymap.txt b/Documentation/devicetree/bindings/input/matrix-keymap.txt
new file mode 100644
index 000000000000..3cd8b98ccd2d
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/matrix-keymap.txt
@@ -0,0 +1,19 @@
+A simple common binding for matrix-connected key boards. Currently targeted at
+defining the keys in the scope of linux key codes since that is a stable and
+standardized interface at this time.
+
+Required properties:
+- linux,keymap: an array of packed 1-cell entries containing the equivalent
+  of row, column and linux key-code. The 32-bit big endian cell is packed
+  as:
+        row << 24 | column << 16 | key-code
+
+Optional properties:
+Some users of this binding might choose to specify secondary keymaps for
+cases where there is a modifier key such as a Fn key. Proposed names
+for said properties are "linux,fn-keymap" or with another descriptive
+word for the modifier other from "Fn".
+
+Example:
+        linux,keymap = < 0x00030012
+                         0x0102003a >;
diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
index 001b147c7f95..332597980817 100644
--- a/drivers/input/Kconfig
+++ b/drivers/input/Kconfig
@@ -25,6 +25,10 @@ config INPUT
 
 if INPUT
 
+config INPUT_OF_MATRIX_KEYMAP
+        depends on USE_OF
+        bool
+
 config INPUT_FF_MEMLESS
         tristate "Support for memoryless force-feedback devices"
         help
diff --git a/drivers/input/Makefile b/drivers/input/Makefile
index 0c789490e0b3..b173a13a73ca 100644
--- a/drivers/input/Makefile
+++ b/drivers/input/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_INPUT_TOUCHSCREEN)	+= touchscreen/
 obj-$(CONFIG_INPUT_MISC)        += misc/
 
 obj-$(CONFIG_INPUT_APMPOWER)    += apm-power.o
+obj-$(CONFIG_INPUT_OF_MATRIX_KEYMAP) += of_keymap.o
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index cdc385b2cf7d..3371954c979b 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -394,6 +394,7 @@ config KEYBOARD_NOMADIK
 config KEYBOARD_TEGRA
         tristate "NVIDIA Tegra internal matrix keyboard controller support"
         depends on ARCH_TEGRA
+        select INPUT_OF_MATRIX_KEYMAP if USE_OF
         help
           Say Y here if you want to use a matrix keyboard connected directly
           to the internal keyboard controller on Tegra SoCs.
diff --git a/drivers/input/of_keymap.c b/drivers/input/of_keymap.c
new file mode 100644
index 000000000000..061493d57682
--- /dev/null
+++ b/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);
diff --git a/include/linux/input/matrix_keypad.h b/include/linux/input/matrix_keypad.h
index fe7c4b9ae270..6c07ced0af81 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 +107,22 @@ matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
         __clear_bit(KEY_RESERVED, keybit);
 }
 
+#ifdef CONFIG_INPUT_OF_MATRIX_KEYMAP
+struct matrix_keymap_data *
+matrix_keyboard_of_fill_keymap(struct device_node *np, const char *propname);
+
+void matrix_keyboard_of_free_keymap(const struct matrix_keymap_data *kd);
+#else
+static inline struct matrix_keymap_data *
+matrix_keyboard_of_fill_keymap(struct device_node *np, const char *propname)
+{
+        return NULL;
+}
+
+static inline void
+matrix_keyboard_of_free_keymap(const struct matrix_keymap_data *kd)
+{
+}
+#endif
+
 #endif /* _MATRIX_KEYPAD_H */