Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754878AbbDICMm (ORCPT ); Wed, 8 Apr 2015 22:12:42 -0400 Received: from mailout3.samsung.com ([203.254.224.33]:20161 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753200AbbDICMj (ORCPT ); Wed, 8 Apr 2015 22:12:39 -0400 X-AuditID: cbfee690-f796f6d000005054-06-5525e0129ecd Message-id: <5525E012.5050207@samsung.com> Date: Thu, 09 Apr 2015 11:12:34 +0900 From: Chanwoo Choi User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-version: 1.0 To: Robert Baldyga Cc: myungjoo.ham@samsung.com, rogerq@ti.com, linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, m.szyprowski@samsung.com Subject: Re: [PATCH v3 2/4] extcon: usb-gpio: add support for VBUS detection References: <1427980385-21285-1-git-send-email-r.baldyga@samsung.com> <1427980385-21285-3-git-send-email-r.baldyga@samsung.com> In-reply-to: <1427980385-21285-3-git-send-email-r.baldyga@samsung.com> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprFIsWRmVeSWpSXmKPExsWyRsSkRFfogWqowfI7uhbzj5xjtbi8aw6b xaJlrcwWa4/cZbe43biCzeLB4Z3sFj2PtBzYPfq2rGL0OH5jO5PH501yAcxRXDYpqTmZZalF +nYJXBkd+/6zFbxTrti85xprA+NuyS5GTg4JAROJybtbWSBsMYkL99azdTFycQgJLGWUuPmi jwmm6Pys4+wQiemMEle+HmOCcB4wSvyY288IUsUroCXxYf5CZhCbRUBV4vS63awgNhtQfP+L G2wgtqhAmMTK6VdYIOoFJX5MvgdmiwDV3Pk4H2wDs8A8RonFc98DORwcwgI+EgtvsEIsa2SU OHR1CVgDp4CbxLl9K8BsZgEdif2t09ggbHmJzWveMoM0SAjsY5c4c76XHeIiAYlvkw+xgAyV EJCV2HSAGeI1SYmDK26wTGAUm4XkpllIxs5CMnYBI/MqRtHUguSC4qT0IhO94sTc4tK8dL3k /NxNjMAoO/3v2YQdjPcOWB9iFOBgVOLhFVisEirEmlhWXJl7iNEU6IqJzFKiyfnAWM4riTc0 NjOyMDUxNTYytzRTEud9LfUzWEggPbEkNTs1tSC1KL6oNCe1+BAjEwenVANj7B69rq1tO04Z v7HLzFmqcf3DtzlTww03C9yzyJ/02zN/F3umftnm0HJFPq311ZwcXAfmquntZr2qfv3l8i1z p4kqam90XXomLWryzbn2a3fdDlTivTVZ9EhVUg7nT744SWX+vJ0HFnU3vzs/h3tF3W62ty9b IvI8N2gly6oxbnv3NMWcW1dciaU4I9FQi7moOBEAArWnXK0CAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrCIsWRmVeSWpSXmKPExsVy+t9jQV2hB6qhBgvXqVrMP3KO1eLyrjls FouWtTJbrD1yl93iduMKNosHh3eyW/Q80nJg9+jbsorR4/iN7UwenzfJBTBHNTDaZKQmpqQW KaTmJeenZOal2yp5B8c7x5uaGRjqGlpamCsp5CXmptoqufgE6Lpl5gAtV1IoS8wpBQoFJBYX K+nbYZoQGuKmawHTGKHrGxIE12NkgAYS1jBmdOz7z1bwTrli855rrA2MuyW7GDk5JARMJM7P Os4OYYtJXLi3nq2LkYtDSGA6o8SVr8eYIJwHjBI/5vYzglTxCmhJfJi/kBnEZhFQlTi9bjcr iM0GFN//4gYbiC0qECaxcvoVFoh6QYkfk++B2SJANXc+zmcHGcosMI9RYvHc90AOB4ewgI/E whusEMsaGSUOXV0C1sAp4CZxbt8KMJtZQEdif+s0NghbXmLzmrfMExgFZiHZMQtJ2SwkZQsY mVcxiqYWJBcUJ6XnGukVJ+YWl+al6yXn525iBMfwM+kdjKsaLA4xCnAwKvHwCixWCRViTSwr rsw9xCjBwawkwmu1WTVUiDclsbIqtSg/vqg0J7X4EKMpMAgmMkuJJucD00teSbyhsYmZkaWR uaGFkbG5kjjvHF25UCGB9MSS1OzU1ILUIpg+Jg5OqQbGhjOOdbeOn7jr9O3dCe76Nqnb9dZM XN2XK6yWuy3ME/CaUGu/eUtPxfZ7pz88XrHo4qoPsyILqm5Gc6UfPrKkbJ/t8v3heqJrBevm pC9kcyyeXiMU+XpV4f7DH6YmNW3tXqbV+VZcOeqO8DQRfY/Hn/8yTk37fK9my6K/YWu0Pr7o MnpvNPUwrxJLcUaioRZzUXEiAASoWsH3AgAA DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4698 Lines: 142 Hi Robert, On 04/02/2015 10:13 PM, Robert Baldyga wrote: > This patch adds VBUS pin detection support to extcon-usb-gpio driver. > It allows to use this driver with boards which have both VBUS and ID > pins, or only one of them. > > Following table of states presents relationship between this signals > and detected cable type: > > State | ID | VBUS > ---------------------------------------- > [1] USB | H | H > [2] none | H | L > [3] USB & USB-HOST | L | H > [4] USB-HOST | L | L > > In case we have only one of these signals: > - VBUS only - we want to distinguish between [1] and [2], so ID is always 1. > - ID only - we want to distinguish between [1] and [4], so VBUS = ID. > > Signed-off-by: Robert Baldyga > --- > drivers/extcon/extcon-usb-gpio.c | 169 +++++++++++++++++++++++++++------------ > 1 file changed, 119 insertions(+), 50 deletions(-) > > diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c > index f6aa99d..baf7add 100644 > --- a/drivers/extcon/extcon-usb-gpio.c > +++ b/drivers/extcon/extcon-usb-gpio.c > @@ -32,7 +32,9 @@ struct usb_extcon_info { > struct extcon_dev *edev; > > struct gpio_desc *id_gpiod; > + struct gpio_desc *vbus_gpiod; > int id_irq; > + int vbus_irq; > > unsigned long debounce_jiffies; > struct delayed_work wq_detcable; > @@ -52,40 +54,51 @@ static const char *usb_extcon_cable[] = { > NULL, > }; > > +/* > + * "USB" = VBUS and "USB-HOST" = !ID, so we have: > + * > + * State | ID | VBUS > + * ---------------------------------------- > + * [1] USB | H | H > + * [2] none | H | L > + * [3] USB & USB-HOST | L | H > + * [4] USB-HOST | L | L > + * > + * In case we have only one of these signals: > + * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1. > + * - ID only - we want to distinguish between [1] and [4], so VBUS = ID. > + */ > + > static void usb_extcon_detect_cable(struct work_struct *work) > { > int id; > + int vbus; > struct usb_extcon_info *info = container_of(to_delayed_work(work), > struct usb_extcon_info, > wq_detcable); > > - /* check ID and update cable state */ > - id = gpiod_get_value_cansleep(info->id_gpiod); > - if (id) { > - /* > - * ID = 1 means USB HOST cable detached. > - * As we don't have event for USB peripheral cable attached, > - * we simulate USB peripheral attach here. > - */ > + /* check ID and VBUS and update cable state */ > + > + id = info->id_gpiod ? > + gpiod_get_value_cansleep(info->id_gpiod) : 1; > + > + vbus = info->vbus_gpiod ? > + gpiod_get_value_cansleep(info->vbus_gpiod) : id; > + > + /* at first we clean states which are no longer active */ > + if (id) > extcon_set_cable_state(info->edev, > - usb_extcon_cable[EXTCON_CABLE_USB_HOST], > - false); > + usb_extcon_cable[EXTCON_CABLE_USB_HOST], false); > + if (!vbus) > extcon_set_cable_state(info->edev, > - usb_extcon_cable[EXTCON_CABLE_USB], > - true); > - } else { > - /* > - * ID = 0 means USB HOST cable attached. > - * As we don't have event for USB peripheral cable detached, > - * we simulate USB peripheral detach here. > - */ > + usb_extcon_cable[EXTCON_CABLE_USB], false); > + > + if (!id) > extcon_set_cable_state(info->edev, > - usb_extcon_cable[EXTCON_CABLE_USB], > - false); > + usb_extcon_cable[EXTCON_CABLE_USB_HOST], true); > + if (vbus) > extcon_set_cable_state(info->edev, > - usb_extcon_cable[EXTCON_CABLE_USB_HOST], > - true); > - } > + usb_extcon_cable[EXTCON_CABLE_USB], true); > } Looks good to me of this patch. But, I have one question about case[3] If id is low and vbus is high, this patch will update the state of both USB and USB-HOST cable as attached state. Is it possible that two different cables (both USB and USB-HOST) are connected to one port simultaneously? > + * "USB" = VBUS and "USB-HOST" = !ID, so we have: > + * > + * State | ID | VBUS > + * ---------------------------------------- > + * [1] USB | H | H > + * [2] none | H | L > + * [3] USB & USB-HOST | L | H > + * [4] USB-HOST | L | L > + * [snip] Thanks, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/