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Date:   Fri, 15 Jul 2022 08:45:34 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     sdlyyxy <sdlyyxy@bupt.edu.cn>
Cc:     johan@kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: serial: option: adding support for OPPO R11 diag
 port
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On Fri, Jul 15, 2022 at 02:39:06PM +0800, sdlyyxy wrote:
> Hi Greg,
> Thanks for your comments!
> 
> > On Jul 14, 2022, at 18:56, Greg KH <gregkh@linuxfoundation.org> wrote:
> > 
> > On Thu, Jul 14, 2022 at 06:20:37PM +0800, sdlyyxy wrote:
> >> From: Yan Xinyu <sdlyyxy@bupt.edu.cn>
> >> 
> >> This patch adds support for OPPO R11 USB diag serial port to option
> >> driver. This phone uses Qualcomm Snapdragon 660 SoC.
> >> 
> >> usb-devices output:
> >> T: Bus=03 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#= 10 Spd=480 MxCh= 0
> >> D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
> >> P: Vendor=22d9 ProdID=276c Rev=04.04
> >> S: Manufacturer=OPPO
> >> S: Product=SDM660-MTP _SN:09C6BCA7
> >> S: SerialNumber=beb2c403
> >> C: #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=500mA
> >> I: If#=0x0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=30 Driver=option
> > 
> > I do not think this has an option usb-serial chip in the device, this is
> > a phone with a debug port instead.
> > 
> Yeah, this phone uses a Qualcomm chip, not an option usb-serial chip.
> It has the functionality to enter into a special mode, which provides 
> a QCDM-capable diag port as the same behaviour of USB modems. For
> Qualcomm devices, there are several drivers: qcserial, qcaux, and 
> option. According to qcserial.c, qcaux.c source code and mailing list
> conversations [1], this device with diag+adb layout should be driven
> by option.

No, this is not an option chip, and does not follow the option device
protocols at all.  So this is not the driver to use here.

We should probably switch those other devices as well, they aren't
really option devices either.

> >> I: If#=0x1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=42 Prot=01 Driver=usbfs
> > 
> > What userspace program is bound to this endpoint?
> > 
> I think it is used by adb via libusb.
> >> 
> >> Signed-off-by: Yan Xinyu <sdlyyxy@bupt.edu.cn>
> >> ---
> >> drivers/usb/serial/option.c | 5 +++++
> >> 1 file changed, 5 insertions(+)
> >> 
> >> diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
> >> index de59fa919540..cf65cb84c3ca 100644
> >> --- a/drivers/usb/serial/option.c
> >> +++ b/drivers/usb/serial/option.c
> >> @@ -573,6 +573,10 @@ static void option_instat_callback(struct urb *urb);
> >> #define WETELECOM_PRODUCT_6802			0x6802
> >> #define WETELECOM_PRODUCT_WMD300		0x6803
> >> 
> >> +/* OPPO products */
> >> +#define OPPO_VENDOR_ID				0x22d9
> >> +#define OPPO_PRODUCT_R11			0x276c
> >> +
> >> 
> >> /* Device flags */
> >> 
> >> @@ -2155,6 +2159,7 @@ static const struct usb_device_id option_ids[] = {
> >> 	{ USB_DEVICE_INTERFACE_CLASS(0x305a, 0x1404, 0xff) },			/* GosunCn GM500 RNDIS */
> >> 	{ USB_DEVICE_INTERFACE_CLASS(0x305a, 0x1405, 0xff) },			/* GosunCn GM500 MBIM */
> >> 	{ USB_DEVICE_INTERFACE_CLASS(0x305a, 0x1406, 0xff) },			/* GosunCn GM500 ECM/NCM */
> >> +	{ USB_DEVICE_AND_INTERFACE_INFO(OPPO_VENDOR_ID, OPPO_PRODUCT_R11, 0xff, 0xff, 0x30) },
> > 
> > This does not look correct, sorry. Try using the usbserial generic
> > driver instead to transmit and recieve?
> > 
> Yes I have tried using usbserial generic driver. As for the interface
> #0x0 diag port, it seems working. However, in the same time the 
> generic driver will also be attached to interface #0x1, which causes
> nonfunction of adb. Using this patch, diag and adb can run 
> simultaneously. So it's better than the generic driver?

Ah, we should just bind the simple usb-serial driver to this interface
and not bind the generic usb-serial driver to this interface.

Let me make up a simple patch for this for you to test...

thanks,

greg k-h