From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755664Ab1HXFme (ORCPT ); Wed, 24 Aug 2011 01:42:34 -0400 Received: from emcscan.emc.com.tw ([192.72.220.5]:33543 "EHLO emcscan.emc.com.tw" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754126Ab1HXFm3 (ORCPT ); Wed, 24 Aug 2011 01:42:29 -0400 From: JJ Ding To: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Seth Forshee , Dmitry Torokhov , Aaron Huang , Tom Lin , =?UTF-8?q?=C3=89ric=20Piel?= , Daniel Kurtz , Chase Douglas , Henrik Rydberg , Alessandro Rubini , JJ Ding Subject: [PATCH v2 5/7] Input: elantech - packet checking for v2 hardware Date: Wed, 24 Aug 2011 13:44:44 +0800 Message-Id: <1314164686-866-6-git-send-email-jj_ding@emc.com.tw> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1314164686-866-1-git-send-email-jj_ding@emc.com.tw> References: <1314164686-866-1-git-send-email-jj_ding@emc.com.tw> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For v2 hardware, there is no real parity check, but we can still check some constant bits for data integrity. Also rename elantech_check_parity_v1 to elantech_packet_check_v1 to make these packet checking function names consistent. Signed-off-by: JJ Ding --- drivers/input/mouse/elantech.c | 39 ++++++++++++++++++++++++++++++++++----- 1 files changed, 34 insertions(+), 5 deletions(-) diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c index 282b8b6..008e8c2 100644 --- a/drivers/input/mouse/elantech.c +++ b/drivers/input/mouse/elantech.c @@ -350,7 +350,7 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse) input_sync(dev); } -static int elantech_check_parity_v1(struct psmouse *psmouse) +static int elantech_packet_check_v1(struct psmouse *psmouse) { struct elantech_data *etd = psmouse->private; unsigned char *packet = psmouse->packet; @@ -374,6 +374,34 @@ static int elantech_check_parity_v1(struct psmouse *psmouse) etd->parity[packet[3]] == p3; } +static int elantech_packet_check_v2(struct psmouse *psmouse) +{ + struct elantech_data *etd = psmouse->private; + unsigned char *packet = psmouse->packet; + + /* + * V2 hardware has two flavors. Older ones that do not report pressure, + * and newer ones that reports pressure and width. With newer ones, all + * packets (1, 2, 3 finger touch) have the same constant bits. With + * older ones, 1/3 finger touch packets and 2 finger touch packets + * have different constant bits. + * With all three cases, if the constant bits are not exactly what I + * expected, I consider them invalid. + */ + if (etd->reports_pressure) + return (packet[0] & 0x0c) == 0x04 && + (packet[3] & 0x0f) == 0x02; + + if ((packet[0] & 0xc0) == 0x80) + return (packet[0] & 0x0c) == 0x0c && + (packet[3] & 0x0e) == 0x08; + + return (packet[0] & 0x3c) == 0x3c && + (packet[1] & 0xf0) == 0x00 && + (packet[3] & 0x3e) == 0x38 && + (packet[4] & 0xf0) == 0x00; +} + /* * Process byte stream from mouse and handle complete packets */ @@ -389,14 +417,16 @@ static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse) switch (etd->hw_version) { case 1: - if (etd->paritycheck && !elantech_check_parity_v1(psmouse)) + if (etd->paritycheck && !elantech_packet_check_v1(psmouse)) return PSMOUSE_BAD_DATA; elantech_report_absolute_v1(psmouse); break; case 2: - /* We don't know how to check parity in protocol v2 */ + if (etd->paritycheck && !elantech_packet_check_v2(psmouse)) + return PSMOUSE_BAD_DATA; + elantech_report_absolute_v2(psmouse); break; } @@ -795,8 +825,7 @@ int elantech_init(struct psmouse *psmouse) etd->hw_version = 2; /* For now show extra debug information */ etd->debug = 1; - /* Don't know how to do parity checking for version 2 */ - etd->paritycheck = 0; + etd->paritycheck = 1; if (etd->fw_version >= 0x020800) etd->reports_pressure = true; -- 1.7.4.1