linux-kernel - [PATCH v4 2/2] usb: gadget: composite: Draw 100mA current if not configured

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Date:   Fri, 24 Feb 2023 11:16:59 +0530
From:   Prashanth K <quic_prashk@...cinc.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        Jakob Koschel <jakobkoschel@...il.com>,
        Jó Ágila Bitsch <jgilab@...il.com>,
        Alan Stern <stern@...land.harvard.edu>
CC:     Pratham Pratap <quic_ppratap@...cinc.com>,
        Jack Pham <quic_jackp@...cinc.com>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Prashanth K <quic_prashk@...cinc.com>
Subject: [PATCH v4 2/2] usb: gadget: composite: Draw 100mA current if not configured

Currently we don't change the current value if device isn't in
configured state. But in battery charging specification (section
1.2 and 1.4.13), it is mentioned that the device can draw up to
100mA of current if it's in unconfigured state. Hence add vbus
draw work in composite_resume to draw 100mA if the device isn't
configured.

Signed-off-by: Prashanth K <quic_prashk@...cinc.com>
---
 drivers/usb/gadget/composite.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 403563c..386140f 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -2449,6 +2449,10 @@ void composite_resume(struct usb_gadget *gadget)
 			usb_gadget_clear_selfpowered(gadget);
 
 		usb_gadget_vbus_draw(gadget, maxpower);
+	} else {
+		maxpower = CONFIG_USB_GADGET_VBUS_DRAW;
+		maxpower = min(maxpower, 100U);
+		usb_gadget_vbus_draw(gadget, maxpower);
 	}
 
 	cdev->suspended = 0;
-- 
2.7.4