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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7ACB0C001E0 for ; Mon, 23 Oct 2023 11:00:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229984AbjJWLA2 (ORCPT ); Mon, 23 Oct 2023 07:00:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230215AbjJWLA0 (ORCPT ); Mon, 23 Oct 2023 07:00:26 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFE1210CB for ; Mon, 23 Oct 2023 04:00:24 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 147A1C433C8; Mon, 23 Oct 2023 11:00:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698058824; bh=HTApyrNstoRf3c2TNHiBwRMxdsG4m4RErgxOWfeskQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tw5D+M209/qtwktpdxeeqlZQaZfNCAyzU4YtS0b3sruF5z1dUkXaJmQ3VtNZ4JUnL rxBW6lTsb/qD9eosY6sWZ0MlK4RwX506UyRgmoK7DNbDOcOcLVkRPhtuGwf2wTZuvu YeMJkkf8DQp3q8OEL3z0R+PMkwhTJwYrY9IuOfjU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josua Mayer , Johannes Berg Subject: [PATCH 4.14 39/66] net: rfkill: gpio: prevent value glitch during probe Date: Mon, 23 Oct 2023 12:56:29 +0200 Message-ID: <20231023104812.302082694@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231023104810.781270702@linuxfoundation.org> References: <20231023104810.781270702@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josua Mayer commit b2f750c3a80b285cd60c9346f8c96bd0a2a66cde upstream. When either reset- or shutdown-gpio have are initially deasserted, e.g. after a reboot - or when the hardware does not include pull-down, there will be a short toggle of both IOs to logical 0 and back to 1. It seems that the rfkill default is unblocked, so the driver should not glitch to output low during probe. It can lead e.g. to unexpected lte modem reconnect: [1] root@localhost:~# dmesg | grep "usb 2-1" [ 2.136124] usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd [ 21.215278] usb 2-1: USB disconnect, device number 2 [ 28.833977] usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd The glitch has been discovered on an arm64 board, now that device-tree support for the rfkill-gpio driver has finally appeared :). Change the flags for devm_gpiod_get_optional from GPIOD_OUT_LOW to GPIOD_ASIS to avoid any glitches. The rfkill driver will set the intended value during rfkill_sync_work. Fixes: 7176ba23f8b5 ("net: rfkill: add generic gpio rfkill driver") Signed-off-by: Josua Mayer Link: https://lore.kernel.org/r/20231004163928.14609-1-josua@solid-run.com Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/rfkill/rfkill-gpio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/rfkill/rfkill-gpio.c +++ b/net/rfkill/rfkill-gpio.c @@ -111,13 +111,13 @@ static int rfkill_gpio_probe(struct plat rfkill->clk = devm_clk_get(&pdev->dev, NULL); - gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW); + gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_ASIS); if (IS_ERR(gpio)) return PTR_ERR(gpio); rfkill->reset_gpio = gpio; - gpio = devm_gpiod_get_optional(&pdev->dev, "shutdown", GPIOD_OUT_LOW); + gpio = devm_gpiod_get_optional(&pdev->dev, "shutdown", GPIOD_ASIS); if (IS_ERR(gpio)) return PTR_ERR(gpio);