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Commit 34abeeb2 authored by Rakesh Iyer's avatar Rakesh Iyer Committed by Dmitry Torokhov
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Input: tegra-kbc - add ghost key filter 



Add ghost key filtering support for the Nvidia Tegra matrix keyboard.

Signed-off-by: default avatarRakesh Iyer <riyer@nvidia.com>
Reviewed-by: default avatarHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 5c9db648

arch/arm/mach-tegra/include/mach/kbc.h

+1 −0
Original line number Diff line number Diff line
@@ -58,5 +58,6 @@ struct tegra_kbc_platform_data { 


	bool wakeup;

	bool use_fn_map;

	bool use_ghost_filter;

};

#endif

drivers/input/keyboard/tegra-kbc.c

+36 −0
Original line number Diff line number Diff line
@@ -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++) {
@@ -284,6 +287,34 @@ static void tegra_kbc_report_keys(struct tegra_kbc *kbc) 
		val >>= 8;

	}



	/*

	 * 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);