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=-17.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 21ED6C49361 for ; Wed, 16 Jun 2021 00:56:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0689160FE6 for ; Wed, 16 Jun 2021 00:56:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231811AbhFPA6r (ORCPT ); Tue, 15 Jun 2021 20:58:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:35946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230265AbhFPA6q (ORCPT ); Tue, 15 Jun 2021 20:58:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C966C60FE6; Wed, 16 Jun 2021 00:56:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623805001; bh=tykSCrhMj9oIg5fZltaBtQORVAoQ00lf7s/Go9WGD9g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=o8kQ/VfO6WbIfltUOrrHcjd/+jH+LBTTTLJU79jwnPsz40YyKPj1CrWWo7K/EaXzP 9JDqOsv7UgIKe46vU2Xhr2RHt0UO/EtO5HT57FhRBHWUdL8/bJxzLdUoJmttDAHJ4H ebSKEEOkepCYCVLJj/oeAQTHcjEi3FO2zwV59abQ66egiSMrNq650nm4W8xnaasRjR pxfg1prT/3FgjHQDlo3fbR4tx+i0HJLpjG/SV8Z6QVRulxeH9rUhuo4o3/IEQ2mW6P iVmb0x32LWkKPA2PYmF6u1Oc+z5Rs/TzwBt8QEJbllx53OWAZuYw43BPs/vHgigFqB 2/i28B20n+fLg== Date: Wed, 16 Jun 2021 08:56:36 +0800 From: Peter Chen To: Dmitry Osipenko Cc: Thierry Reding , Jonathan Hunter , Greg Kroah-Hartman , Felipe Balbi , Maxim Schwalm , linux-tegra@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 1/2] usb: phy: tegra: Wait for VBUS wakeup status deassertion on suspend Message-ID: <20210616005636.GA19025@nchen> References: <20210613145936.9902-1-digetx@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210613145936.9902-1-digetx@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21-06-13 17:59:35, Dmitry Osipenko wrote: > Some devices need an extra delay after losing VBUS, otherwise VBUS may > be detected as active at suspend time, preventing the PHY's suspension > by the VBUS detection sensor. This problem was found on Asus Transformer > TF700T (Tegra30) tablet device, where the USB PHY wakes up immediately > from suspend because VBUS sensor continues to detect VBUS as active after > disconnection. We need to poll the PHY's VBUS wakeup status until it's > deasserted before suspending PHY in order to fix this minor trouble. > > Fixes: 35192007d28d ("usb: phy: tegra: Support waking up from a low power mode") > Reported-by: Maxim Schwalm # Asus TF700T > Tested-by: Maxim Schwalm # Asus TF700T > Signed-off-by: Dmitry Osipenko > --- > drivers/usb/phy/phy-tegra-usb.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c > index fc5c6cab58ba..ff482c694200 100644 > --- a/drivers/usb/phy/phy-tegra-usb.c > +++ b/drivers/usb/phy/phy-tegra-usb.c > @@ -64,6 +64,7 @@ > #define A_VBUS_VLD_WAKEUP_EN BIT(30) > > #define USB_PHY_VBUS_WAKEUP_ID 0x408 > +#define VBUS_WAKEUP_STS BIT(10) > #define VBUS_WAKEUP_WAKEUP_EN BIT(30) > > #define USB1_LEGACY_CTRL 0x410 > @@ -645,6 +646,15 @@ static int utmi_phy_power_off(struct tegra_usb_phy *phy) > void __iomem *base = phy->regs; > u32 val; > > + /* > + * Give hardware time to settle down after VBUS disconnection, > + * otherwise PHY will immediately wake up from suspend. > + */ > + if (phy->wakeup_enabled && phy->mode != USB_DR_MODE_HOST) > + readl_relaxed_poll_timeout(base + USB_PHY_VBUS_WAKEUP_ID, > + val, !(val & VBUS_WAKEUP_STS), > + 5000, 100000); > + Reviewed-by: Peter Chen > utmi_phy_clk_disable(phy); > > /* PHY won't resume if reset is asserted */ > -- > 2.30.2 > -- Thanks, Peter Chen