Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751430AbdHFOwc (ORCPT ); Sun, 6 Aug 2017 10:52:32 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:53744 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751336AbdHFOwa (ORCPT ); Sun, 6 Aug 2017 10:52:30 -0400 Subject: Re: [PATCH 01/18] staging: typec: tcpm: Add get_usb2_current_limit tcpc_dev callback To: Hans de Goede , Darren Hart , Andy Shevchenko , Wolfram Sang , Sebastian Reichel , Greg Kroah-Hartman , Heikki Krogerus Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, Liam Breck , Tony Lindgren , linux-pm@vger.kernel.org, devel@driverdev.osuosl.org References: <20170806123555.5124-1-hdegoede@redhat.com> <20170806123555.5124-2-hdegoede@redhat.com> <24f52936-c07e-8e57-6c30-259dd3f36e61@roeck-us.net> <5c9f12b9-f121-d33d-33eb-922e9ddbd43c@redhat.com> From: Guenter Roeck Message-ID: Date: Sun, 6 Aug 2017 07:52:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <5c9f12b9-f121-d33d-33eb-922e9ddbd43c@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2922 Lines: 78 On 08/06/2017 07:29 AM, Hans de Goede wrote: > Hi, > > On 06-08-17 16:18, Guenter Roeck wrote: >> On 08/06/2017 05:35 AM, Hans de Goede wrote: >>> A Rp signalling the default current limit indicates that we're possibly >>> connected to an USB2 power-source. In some cases the type-c >>> port-controller may provide the capability to detect the current-limit >>> for USB2 power-sources (through e.g. BC1.2 detection). >>> >>> This commit adds an optional get_usb2_current_limit tcpc_dev callback >>> which allows the port-controller to return the detected current-limit >>> if the CC pin is pulled up with Rp. >>> >>> Signed-off-by: Hans de Goede >>> --- >>> drivers/staging/typec/tcpm.c | 5 ++++- >>> drivers/staging/typec/tcpm.h | 1 + >>> 2 files changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c >>> index 20eb4ebcf8c3..9f5adace4309 100644 >>> --- a/drivers/staging/typec/tcpm.c >>> +++ b/drivers/staging/typec/tcpm.c >>> @@ -660,7 +660,10 @@ static u32 tcpm_get_current_limit(struct tcpm_port *port) >>> break; >>> case TYPEC_CC_RP_DEF: >>> default: >>> - limit = 0; >>> + if (port->tcpc->get_usb2_current_limit) >> >> I think this callback should just be get_current_limit. > > This is only used in the Rp-def case, which usually indicates being connected > with an A->C cable to a USB-2 device and the intend is for the callback to > implement some USB-2 specific method to detect the supported current-limit, > hence the name. If you prefer to name it just get_current_limit I can > change it for v2, but IMHO the usb2 part of the name is important as this > will not get called when USB-PD negotiation is used, nor when Rp has the Rp15 > or Rp30 values. > As you say, it gets called in the Rp-def case, which can be set anytime. I'd rather have a generic name and explain in tcpm.h as part of the API description when it is used/called. Note that it is also called in SNK_DISCOVERY if cc=Rp-def to calculate and set the initial current limit, even with pd. Thanks, Guenter > Regards, > > Hans > > > >> >>> + limit = port->tcpc->get_usb2_current_limit(port->tcpc); >>> + else >>> + limit = 0; >>> break; >>> } >>> diff --git a/drivers/staging/typec/tcpm.h b/drivers/staging/typec/tcpm.h >>> index 19c307d31a5a..01b7d89379a3 100644 >>> --- a/drivers/staging/typec/tcpm.h >>> +++ b/drivers/staging/typec/tcpm.h >>> @@ -108,6 +108,7 @@ struct tcpc_dev { >>> int (*init)(struct tcpc_dev *dev); >>> int (*get_vbus)(struct tcpc_dev *dev); >>> + int (*get_usb2_current_limit)(struct tcpc_dev *dev); /* Optional */ >>> int (*set_cc)(struct tcpc_dev *dev, enum typec_cc_status cc); >>> int (*get_cc)(struct tcpc_dev *dev, enum typec_cc_status *cc1, >>> enum typec_cc_status *cc2); >>> >> >