From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E2A9C10F27 for ; Tue, 10 Mar 2020 13:21:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 444DF21D7E for ; Tue, 10 Mar 2020 13:21:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583846466; bh=uVF9Hhhe0uNmt+VdBVe8UzNmmAax9OOOWGcDcal7yGI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=H39RjeMUQJKC5qxHf1ToTQYi7w04tyeyThKD0IK6msUWeYqf4kd31nTh+SZabwm+A mwj49UCd4+nIIpDJqihmYCyUas67ITHtP9PaG7IxrruiXdmg5xGOtmc9Y0bwMy/nh0 SDaUGL3ON/jBSDscIYK1EVVY+Nvg9KQcBZhn+PkQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728574AbgCJNVE (ORCPT ); Tue, 10 Mar 2020 09:21:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:52016 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730848AbgCJNG1 (ORCPT ); Tue, 10 Mar 2020 09:06:27 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9DFA220409; Tue, 10 Mar 2020 13:06:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845586; bh=uVF9Hhhe0uNmt+VdBVe8UzNmmAax9OOOWGcDcal7yGI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=APnyGm/RiLLIddHspzqdADPZVFDmdoZxUVqW1wrFlkouApCCiBB/IFJ96zxqLvLwx vzTIV2l8odTKmi35o/Wv9lErcqDMKtqbXvu/qTXXawbQCRum308c+afr+0oALWXLmi 4aPEnWBQDx0VBEeICqI/kXzmyuEw68ZHs1BcVavg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dmitry Osipenko , "David S. Miller" Subject: [PATCH 4.14 028/126] nfc: pn544: Fix occasional HW initialization failure Date: Tue, 10 Mar 2020 13:40:49 +0100 Message-Id: <20200310124206.264467051@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200310124203.704193207@linuxfoundation.org> References: <20200310124203.704193207@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitry Osipenko [ Upstream commit c3331d2fe3fd4d5e321f2467d01f72de7edfb5d0 ] The PN544 driver checks the "enable" polarity during of driver's probe and it's doing that by turning ON and OFF NFC with different polarities until enabling succeeds. It takes some time for the hardware to power-down, and thus, to deassert the IRQ that is raised by turning ON the hardware. Since the delay after last power-down of the polarity-checking process is missed in the code, the interrupt may trigger immediately after installing the IRQ handler (right after the checking is done), which results in IRQ handler trying to touch the disabled HW and ends with marking NFC as 'DEAD' during of the driver's probe: pn544_hci_i2c 1-002a: NFC: nfc_en polarity : active high pn544_hci_i2c 1-002a: NFC: invalid len byte shdlc: llc_shdlc_recv_frame: NULL Frame -> link is dead This patch fixes the occasional NFC initialization failure on Nexus 7 device. Signed-off-by: Dmitry Osipenko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/nfc/pn544/i2c.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/nfc/pn544/i2c.c +++ b/drivers/nfc/pn544/i2c.c @@ -236,6 +236,7 @@ static void pn544_hci_i2c_platform_init( out: gpiod_set_value_cansleep(phy->gpiod_en, !phy->en_polarity); + usleep_range(10000, 15000); } static void pn544_hci_i2c_enable_mode(struct pn544_i2c_phy *phy, int run_mode)