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From:   William Sung <william.sung@advantech.com.tw>
To:     Johan Hovold <johan@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        William Sung <william.sung@advantech.com.tw>,
        Campion Kang <campion.kang@advantech.com.tw>
Subject: [PATCH 1/2] usb: serial: option: Fix the lackage for Quectel EG95 LTE modem support
Date:   Tue, 1 Sep 2020 13:00:21 +0800
Message-ID: <20200901050022.3319-1-william.sung@advantech.com.tw>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

* Add reset-resume callback for resetting USB devices after MCU exits
from suspend/sleep mode.

* Because Quectel EG95 uses USB interface 4 as a USB network device, so
return from option_startup() to prevent being used as a USB serial
device.

Fixes: da6902e5b6db ("USB: serial: option: add Quectel EG95 LTE modem"

Signed-off-by: William Sung <william.sung@advantech.com.tw>
---
 drivers/usb/serial/option.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 89b3192af326..9de8aec47e5e 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -2069,6 +2069,7 @@ static struct usb_serial_driver option_1port_device = {
 #ifdef CONFIG_PM
 	.suspend           = usb_wwan_suspend,
 	.resume            = usb_wwan_resume,
+	.reset_resume      = usb_wwan_resume,
 #endif
 };
 
@@ -2104,6 +2105,11 @@ static int option_probe(struct usb_serial *serial,
 	if (device_flags & NUMEP2 && iface_desc->bNumEndpoints != 2)
 		return -ENODEV;
 
+	/* Quectel EC25 & EC21 & EG91 & EG95 ... interface 4 can be used as USB network device */
+	if (serial->dev->descriptor.idVendor == cpu_to_le16(0x2c7c) &&
+		serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4)
+		return -ENODEV;
+
 	/* Store the device flags so we can use them during attach. */
 	usb_set_serial_data(serial, (void *)device_flags);
 
-- 
2.17.1