From patchwork Tue Oct 27 10:54:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 11859919 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 57ECC92C for ; Tue, 27 Oct 2020 10:55:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3880622258 for ; Tue, 27 Oct 2020 10:55:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2898734AbgJ0Kz1 (ORCPT ); Tue, 27 Oct 2020 06:55:27 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:44781 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2898733AbgJ0KzZ (ORCPT ); Tue, 27 Oct 2020 06:55:25 -0400 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kXMdM-0003lm-Ej; Tue, 27 Oct 2020 11:55:20 +0100 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1kXMdL-0006Vj-4U; Tue, 27 Oct 2020 11:55:19 +0100 From: Oleksij Rempel To: Dmitry Torokhov , Alexandru Ardelean Cc: David Jander , Oleksij Rempel , kernel@pengutronix.de, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org Subject: [PATCH v2] Input: touchscreen: ads7846.c: Fix race that causes missing releases Date: Tue, 27 Oct 2020 11:54:16 +0100 Message-Id: <20201027105416.18773-1-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-input@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org From: David Jander If touchscreen is released while busy reading HWMON device, the release can be missed. The IRQ thread is not started because no touch is active and BTN_TOUCH release event is never sent. Fixes: f5a28a7d4858f94a ("Input: ads7846 - avoid pen up/down when reading hwmon") Co-Developed-by: David Jander Signed-off-by: David Jander Signed-off-by: Oleksij Rempel --- drivers/input/touchscreen/ads7846.c | 44 +++++++++++++++++------------ 1 file changed, 26 insertions(+), 18 deletions(-) diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index f2dc2c8ab5ec..4164a9834b59 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -199,6 +199,26 @@ struct ads7846 { #define REF_ON (READ_12BIT_DFR(x, 1, 1)) #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) +static int get_pendown_state(struct ads7846 *ts) +{ + if (ts->get_pendown_state) + return ts->get_pendown_state(); + + return !gpio_get_value(ts->gpio_pendown); +} + +static void ads7846_report_pen_up(struct ads7846 *ts) +{ + struct input_dev *input = ts->input; + + input_report_key(input, BTN_TOUCH, 0); + input_report_abs(input, ABS_PRESSURE, 0); + input_sync(input); + + ts->pendown = false; + dev_vdbg(&ts->spi->dev, "UP\n"); +} + /* Must be called with ts->lock held */ static void ads7846_stop(struct ads7846 *ts) { @@ -215,6 +235,10 @@ static void ads7846_stop(struct ads7846 *ts) static void ads7846_restart(struct ads7846 *ts) { if (!ts->disabled && !ts->suspended) { + /* Check if pen was released since last stop */ + if (ts->pendown && !get_pendown_state(ts)) + ads7846_report_pen_up(ts); + /* Tell IRQ thread that it may poll the device. */ ts->stopped = false; mb(); @@ -606,14 +630,6 @@ static const struct attribute_group ads784x_attr_group = { /*--------------------------------------------------------------------------*/ -static int get_pendown_state(struct ads7846 *ts) -{ - if (ts->get_pendown_state) - return ts->get_pendown_state(); - - return !gpio_get_value(ts->gpio_pendown); -} - static void null_wait_for_sync(void) { } @@ -868,16 +884,8 @@ static irqreturn_t ads7846_irq(int irq, void *handle) msecs_to_jiffies(TS_POLL_PERIOD)); } - if (ts->pendown && !ts->stopped) { - struct input_dev *input = ts->input; - - input_report_key(input, BTN_TOUCH, 0); - input_report_abs(input, ABS_PRESSURE, 0); - input_sync(input); - - ts->pendown = false; - dev_vdbg(&ts->spi->dev, "UP\n"); - } + if (ts->pendown && !ts->stopped) + ads7846_report_pen_up(ts); return IRQ_HANDLED; }