Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
---
 drivers/input/keyboard/cros_ec_keyb.c | 80 ++++++++++++++++++++---------------
 1 file changed, 45 insertions(+), 35 deletions(-)

diff --git a/drivers/input/keyboard/cros_ec_keyb.c 
b/drivers/input/keyboard/cros_ec_keyb.c
index d44c5d4..03cb960 100644
--- a/drivers/input/keyboard/cros_ec_keyb.c
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -39,6 +39,7 @@
  * @keymap_data: Matrix keymap data used to convert to keyscan values
  * @ghost_filter: true to enable the matrix key-ghosting filter
  * @old_kb_state: bitmap of keys pressed last scan
+ * @kb_state: bitmap of keys currently pressed
  * @dev: Device pointer
  * @idev: Input device
  * @ec: Top level ChromeOS device to use to talk to EC
@@ -50,17 +51,17 @@ struct cros_ec_keyb {
        int row_shift;
        const struct matrix_keymap_data *keymap_data;
        bool ghost_filter;
-       u8 *old_kb_state;
-
        struct device *dev;
        struct input_dev *idev;
        struct cros_ec_device *ec;
        struct notifier_block notifier;
+
+       u8 *old_kb_state;
+       u8 kb_state[];
 };
 
 
-static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb *ckdev,
-                                         u8 *buf, int row)
+static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb *ckdev, int row)
 {
        int pressed_in_row = 0;
        int row_has_teeth = 0;
@@ -68,9 +69,9 @@ static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb 
*ckdev,
 
        mask = 1 << row;
        for (col = 0; col < ckdev->cols; col++) {
-               if (buf[col] & mask) {
+               if (ckdev->kb_state[col] & mask) {
                        pressed_in_row++;
-                       row_has_teeth |= buf[col] & ~mask;
+                       row_has_teeth |= ckdev->kb_state[col] & ~mask;
                        if (pressed_in_row > 1 && row_has_teeth) {
                                /* ghosting */
                                dev_dbg(ckdev->dev,
@@ -89,7 +90,7 @@ static bool cros_ec_keyb_row_has_ghosting(struct cros_ec_keyb 
*ckdev,
  * Returns true when there is at least one combination of pressed keys that
  * results in ghosting.
  */
-static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, u8 *buf)
+static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev)
 {
        int row;
 
@@ -120,7 +121,7 @@ static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb 
*ckdev, u8 *buf)
         * cheat because the number of rows is small.
         */
        for (row = 0; row < ckdev->rows; row++)
-               if (cros_ec_keyb_row_has_ghosting(ckdev, buf, row))
+               if (cros_ec_keyb_row_has_ghosting(ckdev, row))
                        return true;
 
        return false;
@@ -131,8 +132,7 @@ static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb 
*ckdev, u8 *buf)
  * press/release events accordingly.  The keyboard state is 13 bytes (one byte
  * per column)
  */
-static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
-                                u8 *kb_state, int len)
+static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev, int len)
 {
        struct input_dev *idev = ckdev->idev;
        int col, row;
@@ -142,7 +142,7 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
 
        num_cols = len;
 
-       if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
+       if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev)) {
                /*
                 * Simple-minded solution: ignore this state. The obvious
                 * improvement is to only ignore changes to keys involved in
@@ -157,7 +157,7 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
                        int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
                        const unsigned short *keycodes = idev->keycode;
 
-                       new_state = kb_state[col] & (1 << row);
+                       new_state = ckdev->kb_state[col] & (1 << row);
                        old_state = ckdev->old_kb_state[col] & (1 << row);
                        if (new_state != old_state) {
                                dev_dbg(ckdev->dev,
@@ -168,9 +168,12 @@ static void cros_ec_keyb_process(struct cros_ec_keyb 
*ckdev,
                                                 new_state);
                        }
                }
-               ckdev->old_kb_state[col] = kb_state[col];
        }
+
        input_sync(ckdev->idev);
+
+       memcpy(ckdev->old_kb_state, ckdev->kb_state,
+              ckdev->cols * sizeof(*ckdev->kb_state));
 }
 
 static int cros_ec_keyb_open(struct input_dev *dev)
@@ -189,10 +192,10 @@ static void cros_ec_keyb_close(struct input_dev *dev)
                                           &ckdev->notifier);
 }
 
-static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, u8 *kb_state)
+static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev)
 {
        return ckdev->ec->command_recv(ckdev->ec, EC_CMD_MKBP_STATE,
-                                         kb_state, ckdev->cols);
+                                      ckdev->kb_state, ckdev->cols);
 }
 
 static int cros_ec_keyb_work(struct notifier_block *nb,
@@ -201,11 +204,10 @@ static int cros_ec_keyb_work(struct notifier_block *nb,
        int ret;
        struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
                                                    notifier);
-       u8 kb_state[ckdev->cols];
 
-       ret = cros_ec_keyb_get_state(ckdev, kb_state);
+       ret = cros_ec_keyb_get_state(ckdev);
        if (ret >= 0)
-               cros_ec_keyb_process(ckdev, kb_state, ret);
+               cros_ec_keyb_process(ckdev, ret);
 
        return NOTIFY_DONE;
 }
@@ -217,32 +219,40 @@ static int cros_ec_keyb_probe(struct platform_device 
*pdev)
        struct cros_ec_keyb *ckdev;
        struct input_dev *idev;
        struct device_node *np;
+       unsigned int rows, cols;
+       size_t size;
        int err;
 
        np = pdev->dev.of_node;
        if (!np)
                return -ENODEV;
 
-       ckdev = devm_kzalloc(&pdev->dev, sizeof(*ckdev), GFP_KERNEL);
-       if (!ckdev)
-               return -ENOMEM;
-       err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows,
-                                           &ckdev->cols);
+       err = matrix_keypad_parse_of_params(&pdev->dev, &rows, &cols);
        if (err)
                return err;
-       ckdev->old_kb_state = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
-       if (!ckdev->old_kb_state)
-               return -ENOMEM;
 
-       idev = devm_input_allocate_device(&pdev->dev);
-       if (!idev)
+       /*
+        * Double memory for keyboard state so we have space for storing
+        * current and previous state.
+        */
+       size = sizeof(*ckdev) + 2 * cols * sizeof(*ckdev->kb_state);
+       ckdev = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+       if (!ckdev)
                return -ENOMEM;
 
+       ckdev->rows = rows;
+       ckdev->cols = cols;
+       ckdev->old_kb_state = &ckdev->kb_state[cols];
+
        ckdev->ec = ec;
-       ckdev->notifier.notifier_call = cros_ec_keyb_work;
        ckdev->dev = dev;
+       ckdev->notifier.notifier_call = cros_ec_keyb_work;
        dev_set_drvdata(&pdev->dev, ckdev);
 
+       idev = devm_input_allocate_device(&pdev->dev);
+       if (!idev)
+               return -ENOMEM;
+
        idev->name = ec->ec_name;
        idev->phys = ec->phys_name;
        __set_bit(EV_REP, idev->evbit);
@@ -282,8 +292,6 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
 /* Clear any keys in the buffer */
 static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev)
 {
-       u8 old_state[ckdev->cols];
-       u8 new_state[ckdev->cols];
        unsigned long duration;
        int i, ret;
 
@@ -294,11 +302,13 @@ static void cros_ec_keyb_clear_keyboard(struct 
cros_ec_keyb *ckdev)
         * Assume that the EC keyscan buffer is at most 32 deep.
         */
        duration = jiffies;
-       ret = cros_ec_keyb_get_state(ckdev, new_state);
+       ret = cros_ec_keyb_get_state(ckdev);
        for (i = 1; !ret && i < 32; i++) {
-               memcpy(old_state, new_state, sizeof(old_state));
-               ret = cros_ec_keyb_get_state(ckdev, new_state);
-               if (0 == memcmp(old_state, new_state, sizeof(old_state)))
+               memcpy(ckdev->old_kb_state, ckdev->kb_state,
+                      ckdev->cols * sizeof(*ckdev->kb_state));
+               ret = cros_ec_keyb_get_state(ckdev);
+               if (!memcmp(ckdev->old_kb_state, ckdev->kb_state,
+                           ckdev->cols * sizeof(*ckdev->kb_state)))
                        break;
        }
        duration = jiffies - duration;
-- 
1.8.3.1


-- 
Dmitry
--
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