usb: serial: qcserial: add support for the Dell DW5821e module

["Bjørn Mork" <bjorn@mork.no>]

Aleksander Morgado <aleksander@aleksander.es> writes:

> On Tue, Jun 26, 2018 at 8:09 AM, Johan Hovold <johan@kernel.org> wrote:
>> On Sat, Jun 23, 2018 at 11:24:08PM +0200, Aleksander Morgado wrote:
>>> This module exposes two USB configurations: a QMI+AT capable setup on
>>> USB config #1 and a MBIM capable setup on USB config #2.
>>>
>>> By default the kernel will choose the MBIM capable configuration as
>>> long as the cdc_mbim driver is available. This patch adds support for
>>> the serial ports in the secondary configuration.
>>
>> Could you please post the usb-devices output for this device?
>>
>> Depending on another driver to select a specific configuration seems
>> fragile (and that behaviour is even configurable).
>>
>
> This would be when running on configuration #1:
>
> T:  Bus=04 Lev=03 Prnt=04 Port=02 Cnt=01 Dev#=  7 Spd=5000 MxCh= 0
> D:  Ver= 3.10 Cls=ef(misc ) Sub=02 Prot=01 MxPS= 9 #Cfgs=  2
> P:  Vendor=413c ProdID=81d7 Rev=03.18
> S:  Manufacturer=DELL
> S:  Product=DW5821e Snapdragon X20 LTE
> S:  SerialNumber=0123456789ABCDEF
> C:  #Ifs= 5 Cfg#= 1 Atr=a0 MxPwr=896mA
> I:  If#=0x0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=qcserial
> I:  If#=0x1 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=qmi_wwan
> I:  If#=0x2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=qcserial
> I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=qcserial
> I:  If#=0x4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
>
> This would be when running on configuration #2:
>
> T:  Bus=04 Lev=03 Prnt=04 Port=02 Cnt=01 Dev#=  6 Spd=5000 MxCh= 0
> D:  Ver= 3.10 Cls=ef(misc ) Sub=02 Prot=01 MxPS= 9 #Cfgs=  2
> P:  Vendor=413c ProdID=81d7 Rev=03.18
> S:  Manufacturer=DELL
> S:  Product=DW5821e Snapdragon X20 LTE
> S:  SerialNumber=0123456789ABCDEF
> C:  #Ifs= 3 Cfg#= 2 Atr=a0 MxPwr=896mA
> I:  If#=0x0 Alt= 0 #EPs= 1 Cls=02(commc) Sub=0e Prot=00 Driver=cdc_mbim
> I:  If#=0x1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=02 Driver=cdc_mbim
> I:  If#=0x2 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=ff Prot=ff Driver=qcserial


Thanks.  This illustrates the arbitrary default configuration choice
very well: Imagine switching the order of the qcserial and mbim
functions, making qcserial use the first interface. Linux would then
select cfg #1 as default, even if the set of functions in both
configuratoons were the same as before.


Bjørn
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