diff options
Diffstat (limited to 'drivers/input')
| -rw-r--r-- | drivers/input/keyboard/tegra-kbc.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c index 99ce9032d08..5fb4b972f20 100644 --- a/drivers/input/keyboard/tegra-kbc.c +++ b/drivers/input/keyboard/tegra-kbc.c @@ -72,6 +72,7 @@ struct tegra_kbc { unsigned int repoll_dly; unsigned long cp_dly_jiffies; bool use_fn_map; + bool use_ghost_filter; const struct tegra_kbc_platform_data *pdata; unsigned short keycode[KBC_MAX_KEY * 2]; unsigned short current_keys[KBC_MAX_KPENT]; @@ -260,6 +261,8 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc) unsigned int num_down = 0; unsigned long flags; bool fn_keypress = false; + bool key_in_same_row = false; + bool key_in_same_col = false; spin_lock_irqsave(&kbc->lock, flags); for (i = 0; i < KBC_MAX_KPENT; i++) { @@ -285,6 +288,34 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc) } /* + * Matrix keyboard designs are prone to keyboard ghosting. + * Ghosting occurs if there are 3 keys such that - + * any 2 of the 3 keys share a row, and any 2 of them share a column. + * If so ignore the key presses for this iteration. + */ + if ((kbc->use_ghost_filter) && (num_down >= 3)) { + for (i = 0; i < num_down; i++) { + unsigned int j; + u8 curr_col = scancodes[i] & 0x07; + u8 curr_row = scancodes[i] >> KBC_ROW_SHIFT; + + /* + * Find 2 keys such that one key is in the same row + * and the other is in the same column as the i-th key. + */ + for (j = i + 1; j < num_down; j++) { + u8 col = scancodes[j] & 0x07; + u8 row = scancodes[j] >> KBC_ROW_SHIFT; + + if (col == curr_col) + key_in_same_col = true; + if (row == curr_row) + key_in_same_row = true; + } + } + } + + /* * If the platform uses Fn keymaps, translate keys on a Fn keypress. * Function keycodes are KBC_MAX_KEY apart from the plain keycodes. */ @@ -297,6 +328,10 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc) spin_unlock_irqrestore(&kbc->lock, flags); + /* Ignore the key presses for this iteration? */ + if (key_in_same_col && key_in_same_row) + return; + tegra_kbc_report_released_keys(kbc->idev, kbc->current_keys, kbc->num_pressed_keys, keycodes, num_down); @@ -652,6 +687,7 @@ static int __devinit tegra_kbc_probe(struct platform_device *pdev) input_dev->keycodemax *= 2; kbc->use_fn_map = pdata->use_fn_map; + kbc->use_ghost_filter = pdata->use_ghost_filter; keymap_data = pdata->keymap_data ?: &tegra_kbc_default_keymap_data; matrix_keypad_build_keymap(keymap_data, KBC_ROW_SHIFT, input_dev->keycode, input_dev->keybit); |