1 files changed, 22 insertions, 1 deletions

diff --git a/drivers/input/matrix-keymap.c b/drivers/input/matrix-keymap.c
index d88d9be1d1b7..3ae496ea5fe6 100644
--- a/drivers/input/matrix-keymap.c
+++ b/drivers/input/matrix-keymap.c
@@ -18,6 +18,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/gfp.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/input.h>
@@ -123,6 +124,11 @@ static int matrix_keypad_parse_of_keymap(const char *propname,
  * it will attempt load the keymap from property specified by @keymap_name
  * argument (or "linux,keymap" if @keymap_name is %NULL).
  *
+ * If @keymap is %NULL the function will automatically allocate managed
+ * block of memory to store the keymap. This memory will be associated with
+ * the parent device and automatically freed when device unbinds from the
+ * driver.
+ *
  * Callers are expected to set up input_dev->dev.parent before calling this
  * function.
  */
@@ -133,12 +139,27 @@ int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
                                struct input_dev *input_dev)
 {
         unsigned int row_shift = get_count_order(cols);
+        size_t max_keys = rows << row_shift;
         int i;
         int error;
 
+        if (WARN_ON(!input_dev->dev.parent))
+                return -EINVAL;
+
+        if (!keymap) {
+                keymap = devm_kzalloc(input_dev->dev.parent,
+                                      max_keys * sizeof(*keymap),
+                                      GFP_KERNEL);
+                if (!keymap) {
+                        dev_err(input_dev->dev.parent,
+                                "Unable to allocate memory for keymap");
+                        return -ENOMEM;
+                }
+        }
+
         input_dev->keycode = keymap;
         input_dev->keycodesize = sizeof(*keymap);
-        input_dev->keycodemax = rows << row_shift;
+        input_dev->keycodemax = max_keys;
 
         __set_bit(EV_KEY, input_dev->evbit);