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Mon, 4 Jan 2021 19:03:39 +0000 (UTC) Received: from [10.110.33.65] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: wcheng) by smtp.codeaurora.org (Postfix) with ESMTPSA id A6CCBC433C6; Mon, 4 Jan 2021 19:03:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A6CCBC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=wcheng@codeaurora.org Subject: Re: [PATCH 3/3] usb: gadget: configfs: Add a specific configFS reset callback To: Greg KH Cc: peter.chen@nxp.com, balbi@kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org References: <1609283011-21997-1-git-send-email-wcheng@codeaurora.org> <1609283011-21997-4-git-send-email-wcheng@codeaurora.org> From: Wesley Cheng Message-ID: <81ae4b83-2dd8-e605-4f7b-e7b63f959d8d@codeaurora.org> Date: Mon, 4 Jan 2021 11:03:38 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 1/4/2021 7:45 AM, Greg KH wrote: > On Tue, Dec 29, 2020 at 03:03:31PM -0800, Wesley Cheng wrote: >> In order for configFS based USB gadgets to set the proper charge current >> for bus reset scenarios, expose a separate reset callback to set the >> current to 100mA based on the USB battery charging specification. >> >> Reviewed-by: Peter Chen >> Signed-off-by: Wesley Cheng >> --- >> drivers/usb/gadget/configfs.c | 24 +++++++++++++++++++++++- >> 1 file changed, 23 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c >> index 56051bb97349..80ca7ff2fb97 100644 >> --- a/drivers/usb/gadget/configfs.c >> +++ b/drivers/usb/gadget/configfs.c >> @@ -1481,6 +1481,28 @@ static void configfs_composite_disconnect(struct usb_gadget *gadget) >> spin_unlock_irqrestore(&gi->spinlock, flags); >> } >> >> +static void configfs_composite_reset(struct usb_gadget *gadget) >> +{ >> + struct usb_composite_dev *cdev; >> + struct gadget_info *gi; >> + unsigned long flags; >> + >> + cdev = get_gadget_data(gadget); >> + if (!cdev) >> + return; >> + >> + gi = container_of(cdev, struct gadget_info, cdev); >> + spin_lock_irqsave(&gi->spinlock, flags); >> + cdev = get_gadget_data(gadget); >> + if (!cdev || gi->unbind) { >> + spin_unlock_irqrestore(&gi->spinlock, flags); >> + return; >> + } >> + >> + composite_reset(gadget); >> + spin_unlock_irqrestore(&gi->spinlock, flags); >> +} >> + >> static void configfs_composite_suspend(struct usb_gadget *gadget) >> { >> struct usb_composite_dev *cdev; >> @@ -1530,7 +1552,7 @@ static const struct usb_gadget_driver configfs_driver_template = { >> .unbind = configfs_composite_unbind, >> >> .setup = configfs_composite_setup, >> - .reset = configfs_composite_disconnect, >> + .reset = configfs_composite_reset, >> .disconnect = configfs_composite_disconnect, >> >> .suspend = configfs_composite_suspend, >> -- >> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, >> a Linux Foundation Collaborative Project >> > > So this changes the existing userspace functionality? What will break > because of this now unexpected change? > > thanks, > > greg k-h > Hi Greg, Happy new years! This wouldn't affect the userspace interaction with configFS, as this is modifying the reset callback for the UDC core. The reset callback is only executed during usb_gadget_udc_reset(), which is specifically run when vendor UDC drivers (i.e. DWC3 gadget) receive a USB bus reset interrupt. This is similar to the composite.c patch, because for configFS based gadgets, they do not directly register the USB composite ops and have their own routines. Thanks Wesley Cheng -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project