Input: add getkeycode and setkeycode methods

Allow drivers to implement their own get and set keycode methods. This
will allow drivers to change their keymaps without allocating huge
tables covering entire range of possible scancodes.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

2 files changed, 96 insertions, 20 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 6439f37..64b47de 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -434,32 +434,21 @@ static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 		case EVIOCGKEYCODE:
 			if (get_user(t, ip))
 				return -EFAULT;
-			if (t < 0 || t >= dev->keycodemax || !dev->keycodesize)
-				return -EINVAL;
-			if (put_user(INPUT_KEYCODE(dev, t), ip + 1))
+
+			error = dev->getkeycode(dev, t, &v);
+			if (error)
+				return error;
+
+			if (put_user(v, ip + 1))
 				return -EFAULT;
+
 			return 0;
 
 		case EVIOCSKEYCODE:
-			if (get_user(t, ip))
-				return -EFAULT;
-			if (t < 0 || t >= dev->keycodemax || !dev->keycodesize)
-				return -EINVAL;
-			if (get_user(v, ip + 1))
+			if (get_user(t, ip) || get_user(v, ip + 1))
 				return -EFAULT;
-			if (v < 0 || v > KEY_MAX)
-				return -EINVAL;
-			if (dev->keycodesize < sizeof(v) && (v >> (dev->keycodesize * 8)))
-				return -EINVAL;
-
-			u = SET_INPUT_KEYCODE(dev, t, v);
-			clear_bit(u, dev->keybit);
-			set_bit(v, dev->keybit);
-			for (i = 0; i < dev->keycodemax; i++)
-				if (INPUT_KEYCODE(dev, i) == u)
-					set_bit(u, dev->keybit);
 
-			return 0;
+			return dev->setkeycode(dev, t, v);
 
 		case EVIOCSFF:
 			if (copy_from_user(&effect, p, sizeof(effect)))
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 4486402..26393a6 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -299,6 +299,87 @@ void input_close_device(struct input_handle *handle)
 }
 EXPORT_SYMBOL(input_close_device);
 
+static int input_fetch_keycode(struct input_dev *dev, int scancode)
+{
+	switch (dev->keycodesize) {
+		case 1:
+			return ((u8 *)dev->keycode)[scancode];
+
+		case 2:
+			return ((u16 *)dev->keycode)[scancode];
+
+		default:
+			return ((u32 *)dev->keycode)[scancode];
+	}
+}
+
+static int input_default_getkeycode(struct input_dev *dev,
+				    int scancode, int *keycode)
+{
+	if (!dev->keycodesize)
+		return -EINVAL;
+
+	if (scancode < 0 || scancode >= dev->keycodemax)
+		return -EINVAL;
+
+	*keycode = input_fetch_keycode(dev, scancode);
+
+	return 0;
+}
+
+static int input_default_setkeycode(struct input_dev *dev,
+				    int scancode, int keycode)
+{
+	int old_keycode;
+	int i;
+
+	if (scancode < 0 || scancode >= dev->keycodemax)
+		return -EINVAL;
+
+	if (keycode < 0 || keycode > KEY_MAX)
+		return -EINVAL;
+
+	if (!dev->keycodesize)
+		return -EINVAL;
+
+	if (dev->keycodesize < sizeof(keycode) && (keycode >> (dev->keycodesize * 8)))
+		return -EINVAL;
+
+	switch (dev->keycodesize) {
+		case 1: {
+			u8 *k = (u8 *)dev->keycode;
+			old_keycode = k[scancode];
+			k[scancode] = keycode;
+			break;
+		}
+		case 2: {
+			u16 *k = (u16 *)dev->keycode;
+			old_keycode = k[scancode];
+			k[scancode] = keycode;
+			break;
+		}
+		default: {
+			u32 *k = (u32 *)dev->keycode;
+			old_keycode = k[scancode];
+			k[scancode] = keycode;
+			break;
+		}
+	}
+
+	clear_bit(old_keycode, dev->keybit);
+	set_bit(keycode, dev->keybit);
+
+	for (i = 0; i < dev->keycodemax; i++) {
+		if (input_fetch_keycode(dev, i) == old_keycode) {
+			set_bit(old_keycode, dev->keybit);
+			break; /* Setting the bit twice is useless, so break */
+		}
+	}
+
+	return 0;
+}
+
+
 static void input_link_handle(struct input_handle *handle)
 {
 	list_add_tail(&handle->d_node, &handle->dev->h_list);
@@ -978,6 +1059,12 @@ int input_register_device(struct input_dev *dev)
 		dev->rep[REP_PERIOD] = 33;
 	}
 
+	if (!dev->getkeycode)
+		dev->getkeycode = input_default_getkeycode;
+
+	if (!dev->setkeycode)
+		dev->setkeycode = input_default_setkeycode;
+
 	list_add_tail(&dev->node, &input_dev_list);
 
 	snprintf(dev->cdev.class_id, sizeof(dev->cdev.class_id),