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 9D542C433EF for ; Wed, 12 Jan 2022 16:00:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354887AbiALQAk (ORCPT ); Wed, 12 Jan 2022 11:00:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243611AbiALQAi (ORCPT ); Wed, 12 Jan 2022 11:00:38 -0500 Received: from mail-ot1-x331.google.com (mail-ot1-x331.google.com [IPv6:2607:f8b0:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0485C06173F for ; Wed, 12 Jan 2022 08:00:37 -0800 (PST) Received: by mail-ot1-x331.google.com with SMTP id h20-20020a9d6f94000000b0059100e01744so3028130otq.4 for ; Wed, 12 Jan 2022 08:00:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=+VpQUriFLzw4q5uRjYZngK/VxtrTJXV1FXPcVYxOgBI=; b=hSzytLqkxJ/8K8M9SiQ4AF7K6bo5gswaZuHTWkt3Vg3fa8Hn4IEWYiCMc+HPHvjUGS dntTL38EUFQsP9Oy2po4v8tFGXAhPJNRayaKM90+dadYJnPPYKpviEXJhPyAbrxksSDI SP5W17PeEYXrtgpLdy0y0N9NsNdoEwrxlaKdK94ISBnwjftbNF5HTi1/hNY885whzYCk oaUqvinYgZp44MzvH7CZ+mdwvzHyQW2TZHVOOkkzUUTm6nR734SkXHUGPXka3h950XO8 eJ76XX3Z0oMzgTDKUgRTEv3bguqZLk80m+8NEfjzNM8O2SoSqJhGX8s1LTENEWOGxqUu 59/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=+VpQUriFLzw4q5uRjYZngK/VxtrTJXV1FXPcVYxOgBI=; b=nIFmBIq9Sm80tr8Cvtp19K5yfJ49IL5LPBw7Rhe1Stuski0EGPWUhSoaPHTaxcbCie jobUSQw8BaiEZG4Odg9tKJ7Yi8ubLvlZmMoRXTaqFv0LQB0wiPGjqiGxlVSDwHkKtYUn U6qKSGQENOTOOBCU/UV6MFGZEIwlEE6PQp5Q1VIsYUuF791560/E9M8P9a+tydzWnGlR X5EG83hOiRPXbVbJzIgrfUVBH6kAVegdUx/iUa8irRix9ZnUE6hO8f7UBPxxeEjgKWPL gzGx4q516rFUGJN00E/rTgjnuBeuSbms5R2dICCnzTQpwODqs2hK8cVnrk7Tj95SBB9w cKKw== X-Gm-Message-State: AOAM530I2KlxYEZDZWOiiRshjeLXg7z+mJqgdi0p4WY4HWYOJxDJm5PS 9L9S6q2MmfBzA0jS98GlTKveDTF6p9c= X-Google-Smtp-Source: ABdhPJzySMtXHnFWXYwY9JVcWLUj3/ZL2u87+CnyXy50SOtNSafrqattnTbpMsgLIiYaudvgCpbaqA== X-Received: by 2002:a05:6830:2b0f:: with SMTP id l15mr344356otv.42.1642003237204; Wed, 12 Jan 2022 08:00:37 -0800 (PST) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id n8sm41906oos.44.2022.01.12.08.00.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jan 2022 08:00:36 -0800 (PST) Sender: Guenter Roeck Date: Wed, 12 Jan 2022 08:00:35 -0800 From: Guenter Roeck To: Xu Yang Cc: heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, jun.li@nxp.com, linux-imx@nxp.com Subject: Re: [PATCH v2] usb: typec: tcpci: don't touch CC line if it's Vconn source Message-ID: <20220112160035.GB386615@roeck-us.net> References: <20220112094116.616272-1-xu.yang_2@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220112094116.616272-1-xu.yang_2@nxp.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Jan 12, 2022 at 05:41:16PM +0800, Xu Yang wrote: > With the AMS and Collision Avoidance, tcpm often needs to change the CC's > termination. When one CC line is souring Vconn, if we still change its s/souring/sourcing/ > termination, the voltage of the another CC line is likely to be fluctuant > and unstable. > > Therefore, we should verify whether a CC line is soucing Vconn before s/soucing/sourcing/ > changing its termination. And only changing the termination that is > not a Vconn line. This can be done by reading the VCONN Present bit of ... and only change ... maybe to make it a full sentence. > POWER_ STATUS register. To determinate the polarity, we can read the determine > Plug Orientation bit of TCPC_CONTROL register. Since only if Plug > Orientation is set, Vconn can be sourced. Maybe something like Vconn can only be be sourced if Plug Orientation is set. > > Fixes: 0908c5aca31e ("usb: typec: tcpm: AMS and Collision Avoidance") > cc: > Signed-off-by: Xu Yang > > --- > v2: changed subject line > --- > drivers/usb/typec/tcpm/tcpci.c | 27 +++++++++++++++++++++++++++ > drivers/usb/typec/tcpm/tcpci.h | 1 + > 2 files changed, 28 insertions(+) > > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c > index 35a1307349a2..0bf4cbfaa21c 100644 > --- a/drivers/usb/typec/tcpm/tcpci.c > +++ b/drivers/usb/typec/tcpm/tcpci.c > @@ -75,9 +75,26 @@ static int tcpci_write16(struct tcpci *tcpci, unsigned int reg, u16 val) > static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc) > { > struct tcpci *tcpci = tcpc_to_tcpci(tcpc); > + bool vconn_pres = false; > + enum typec_cc_polarity polarity = TYPEC_POLARITY_CC1; > unsigned int reg; > int ret; > > + ret = regmap_read(tcpci->regmap, TCPC_POWER_STATUS, ®); > + if (ret < 0) > + return ret; > + > + if (reg & TCPC_POWER_STATUS_VCONN_PRES) { > + vconn_pres = true; How about vconn_pres = !!(reg & TCPC_POWER_STATUS_VCONN_PRES); if (vconn_pres) { ... > + > + ret = regmap_read(tcpci->regmap, TCPC_TCPC_CTRL, ®); > + if (ret < 0) > + return ret; > + > + if (reg & TCPC_TCPC_CTRL_ORIENTATION) > + polarity = TYPEC_POLARITY_CC2; > + } > + > switch (cc) { > case TYPEC_CC_RA: > reg = (TCPC_ROLE_CTRL_CC_RA << TCPC_ROLE_CTRL_CC1_SHIFT) | > @@ -112,6 +129,16 @@ static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc) > break; > } > > + if (vconn_pres) { > + if (polarity == TYPEC_POLARITY_CC2) { > + reg &= ~(TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT); > + reg |= (TCPC_ROLE_CTRL_CC_OPEN << TCPC_ROLE_CTRL_CC1_SHIFT); > + } else { > + reg &= ~(TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT); > + reg |= (TCPC_ROLE_CTRL_CC_OPEN << TCPC_ROLE_CTRL_CC2_SHIFT); > + } > + } > + > ret = regmap_write(tcpci->regmap, TCPC_ROLE_CTRL, reg); > if (ret < 0) > return ret; > diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h > index 2be7a77d400e..b2edd45f13c6 100644 > --- a/drivers/usb/typec/tcpm/tcpci.h > +++ b/drivers/usb/typec/tcpm/tcpci.h > @@ -98,6 +98,7 @@ > #define TCPC_POWER_STATUS_SOURCING_VBUS BIT(4) > #define TCPC_POWER_STATUS_VBUS_DET BIT(3) > #define TCPC_POWER_STATUS_VBUS_PRES BIT(2) > +#define TCPC_POWER_STATUS_VCONN_PRES BIT(1) > #define TCPC_POWER_STATUS_SINKING_VBUS BIT(0) > > #define TCPC_FAULT_STATUS 0x1f > -- > 2.25.1 >