From patchwork Tue Apr 19 21:20:31 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: riyer@nvidia.com X-Patchwork-Id: 720241 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p3JLKYbY019375 for ; Tue, 19 Apr 2011 21:20:55 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755534Ab1DSVUc (ORCPT ); Tue, 19 Apr 2011 17:20:32 -0400 Received: from hqemgate03.nvidia.com ([216.228.121.140]:6428 "EHLO hqemgate03.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755530Ab1DSVUc (ORCPT ); Tue, 19 Apr 2011 17:20:32 -0400 Received: from hqnvupgp06.nvidia.com (Not Verified[216.228.121.13]) by hqemgate03.nvidia.com id ; Tue, 19 Apr 2011 14:29:04 -0700 Received: from hqnvemgw01.nvidia.com ([172.17.108.22]) by hqnvupgp06.nvidia.com (PGP Universal service); Tue, 19 Apr 2011 14:20:31 -0700 X-PGP-Universal: processed; by hqnvupgp06.nvidia.com on Tue, 19 Apr 2011 14:20:31 -0700 Received: from thelma.nvidia.com (Not Verified[172.16.212.77]) by hqnvemgw01.nvidia.com with MailMarshal (v6, 7, 2, 8378) id ; Tue, 19 Apr 2011 14:20:31 -0700 Received: from localhost.localdomain (dhcp-172-17-151-19.nvidia.com [172.17.151.19]) by thelma.nvidia.com (8.13.8+Sun/8.8.8) with ESMTP id p3JLKUx3013110; Tue, 19 Apr 2011 14:20:30 -0700 (PDT) From: riyer@nvidia.com To: dmitry.torokhov@gmail.com Cc: olof@lixom.net, amartin@nvidia.com, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, Rakesh Iyer Subject: [PATCH v1] Input: tegra-kbc - add ghost key filter. Date: Tue, 19 Apr 2011 14:20:31 -0700 Message-Id: <1303248031-9633-1-git-send-email-riyer@nvidia.com> X-Mailer: git-send-email 1.7.0.4 Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Tue, 19 Apr 2011 21:21:02 +0000 (UTC) From: Rakesh Iyer Add ghost key filtering support for the Nvidia Tegra matrix keyboard. Signed-off-by: Rakesh Iyer --- v1: Do not report keypresses when matrix keyboard encounters key ghosting. arch/arm/mach-tegra/include/mach/kbc.h | 1 + drivers/input/keyboard/tegra-kbc.c | 40 ++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+), 0 deletions(-) diff --git a/arch/arm/mach-tegra/include/mach/kbc.h b/arch/arm/mach-tegra/include/mach/kbc.h index 04c7798..bd99744 100644 --- a/arch/arm/mach-tegra/include/mach/kbc.h +++ b/arch/arm/mach-tegra/include/mach/kbc.h @@ -58,5 +58,6 @@ struct tegra_kbc_platform_data { bool wakeup; bool use_fn_map; + bool use_ghost_filter; }; #endif diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c index 99ce903..bff8bfe 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]; @@ -285,6 +286,44 @@ 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 keypresses 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; + bool key_in_same_row = false; + bool key_in_same_col = false; + + /* + * 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 = 0; j < num_down; j++) { + u8 col = scancodes[j] & 0x07; + u8 row = scancodes[j] >> KBC_ROW_SHIFT; + + /* Skip checking the i-th key. */ + if (i == j) + continue; + + if (col == curr_col) + key_in_same_col = true; + if (row == curr_row) + key_in_same_row = true; + } + if (key_in_same_col && key_in_same_row) { + spin_unlock_irqrestore(&kbc->lock, flags); + return; + } + } + } + + /* * If the platform uses Fn keymaps, translate keys on a Fn keypress. * Function keycodes are KBC_MAX_KEY apart from the plain keycodes. */ @@ -652,6 +691,7 @@ 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);