From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chanwoo Choi Subject: Re: [PATCH v3 2/4] extcon: usb-gpio: add support for VBUS detection Date: Thu, 16 Apr 2015 17:26:50 +0900 Message-ID: <552F724A.1050500@samsung.com> References: <552CEC97.1050205@samsung.com> <552CEE42.1050907@ti.com> <552CFA1E.5070400@samsung.com> <20150415032734.GA29095@shlinux2> <552E1862.6090709@ti.com> <552E2EBF.5090906@samsung.com> <20150416015922.GB22269@shlinux2> <552F5E17.5020902@samsung.com> <1429168424.26621.1.camel@mm-sol.com> <552F6BE3.5080604@samsung.com> <20150416080107.GC1709@shlinux2> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20150416080107.GC1709@shlinux2> Sender: linux-kernel-owner@vger.kernel.org To: Peter Chen Cc: "Ivan T. Ivanov" , "Balbi, Felipe" , "ABRAHAM, KISHON VIJAY" , Roger Quadros , Robert Baldyga , myungjoo.ham@samsung.com, linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, m.szyprowski@samsung.com List-Id: devicetree@vger.kernel.org On 04/16/2015 05:01 PM, Peter Chen wrote: > On Thu, Apr 16, 2015 at 04:59:31PM +0900, Chanwoo Choi wrote: >> On 04/16/2015 04:13 PM, Ivan T. Ivanov wrote: >>> Hi, >>> >>> On Thu, 2015-04-16 at 16:00 +0900, Chanwoo Choi wrote: >>>> Hi Peter, >>>> >>>> On 04/16/2015 10:59 AM, Peter Chen wrote: >>>>> >>> >>>>> Ok, from USB point, external id/vbus value can't decide >>>>> which role the controller will be, the controller driver >>>>> will decide role according to many things, eg, user configurations, >>>>> id/vbus value, OTG HNP, etc. >>>>> >>>>> So, from USB controller/phy driver, it doesn't care which cable is >>>>> inserted, it cares about id/vbus value. Eg, it can get id/vbus value >>>>> and it will be notified when the id/vbus value has changed. >>>> >>>> OK, I change the notifier name and add notifier events as following: >>>> >>>> - extcon_{register|unregister}_usb_notifier(struct extcon_dev *edev, struct notifier_block *nb); >>>> - list of notifier events >>>> #define EXTCON_USB_ID_L_VBUS_L0 /* ID low and VBUS low */ >>>> #define EXTCON_USB_ID_L_VBUS_H1 /* ID low and VBUS high */ >>>> #define EXTCON_USB_ID_H_VBUS_L2 /* ID high and VBUS low */ >>>> #define EXTCON_USB_ID_H_VBUS_H3 /* ID high and VBUS high */ >>> >>> I am still confused, why we mix ID and VBUS events into one? >>> Those are two lines and they are not necessarily handled by >>> the same extcon_dev. >> >> IMO, if some usb driver check both id and vbus pin at the same time, >> the usb driver can know the both id and vbus pin state through only one notifier event. >> >> Also, >> If some usb driver want to know the state of id pin except of vbus state, >> when receiving following events, id pin is low. >> #define EXTCON_USB_ID_L_VBUS_L0 >> #define EXTCON_USB_ID_L_VBUS_H1 >> when receiving following events, id pin is high. >> #define EXTCON_USB_ID_H_VBUS_L2 >> #define EXTCON_USB_ID_H_VBUS_H3 >> Also, some usb driver would catch the vbus pin state with same method. >> >> But, it is just my opinion. We may use following notifier events for each pin. >> We need to discuss it. >> #define EXTCON_USB_ID_LOW >> #define EXTCON_USB_ID_HIGH >> #define EXTCON_USB_VBUS_LOW >> #define EXTCON_USB_VBUS_HIGH >> > > I agree with above definition. > OK. I understand.