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Date:   Fri, 18 Sep 2020 09:52:00 +0200
From:   Johan Hovold <johan@kernel.org>
To:     William Sung <william.sung@advantech.com.tw>
Cc:     Johan Hovold <johan@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Campion Kang <campion.kang@advantech.com.tw>
Subject: Re: [PATCH 1/2] usb: serial: option: Fix the lackage for Quectel
 EG95 LTE modem support
Message-ID: <20200918075200.GO24441@localhost>
References: <20200901050022.3319-1-william.sung@advantech.com.tw>
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In-Reply-To: <20200901050022.3319-1-william.sung@advantech.com.tw>
Precedence: bulk

On Tue, Sep 01, 2020 at 01:00:21PM +0800, William Sung wrote:
> * Add reset-resume callback for resetting USB devices after MCU exits
> from suspend/sleep mode.

Please split this in it's own patch and argue for why it's needed.

> * 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;

And please use the normal mechanisms for blacklisting interfaces (e.g.
the RSVD() macro).

> +
>  	/* Store the device flags so we can use them during attach. */
>  	usb_set_serial_data(serial, (void *)device_flags);

Also make sure your patches have distinct and descriptive summaries
(Subject lines).

Johan