[U-Boot] [PATCH v1 0/2] usb: dfu: am335x: allow dfu in fullspeed mode only

[Bin Liu]

Lukasz,

On 09/09/2014 08:43 AM, Lukasz Majewski wrote:
> Hi Heiko,
>
>> This patchserie adds the new config option CONFIG_DFU_FULLSPEED.
>
> Is there any special reason to support Full Speed (12 Mbit/sec - USB
> 1.1) and not rely solely on the High Speed (USB 2.0) as we do now?
>

The drivers must support full-speed anyway based on the USB2.0 Specs.

I have seen many cases in which only full-speed is suitable due to 
either board design or specific USB use case.

One example is that to better fit to the production firmware flashing 
automation, a board does not use standard USB receptacle or plug, but a 
four touch pads on the PCB, so that the robot can grab the board and 
touch the pads to download the firmware. In this case signal integrity 
is a concern, but not download speed.

Regards,
-Bin.

>> If this is enabled DFU uses fullspeed only. This is used on the
>> siemens boards.
>
> Is there any DFU problem with the mentioned Siemens board, that we must
> use USB 1.1?
>
> I'd also appreciate more verbose rationale for this patch series - why
> this change is needed? What is the expected improvement?
>
> Thanks in advance.
>
>>
>> Cc: Tom Rini <trini at ti.com>
>> Cc: Lukasz Majewski <l.majewski at samsung.com>
>> Cc: Marek Vasut <marex at denx.de>
>> Cc: Liu Bin <b-liu at ti.com>
>> Cc: Lukas Stockmann <lukas.stockmann at siemens.com>
>>
>> Heiko Schocher (2):
>>    usb: dfu: add config option to use in dfu mode fullspeed only
>>    arm: am335x: siemens board use in DFU mode fullspeed only
>>
>>   README                                 | 3 +++
>>   drivers/usb/gadget/f_dfu.c             | 3 +++
>>   drivers/usb/gadget/g_dnl.c             | 3 +++
>>   include/configs/siemens-am33x-common.h | 3 ++-
>>   4 files changed, 11 insertions(+), 1 deletion(-)
>>
>
>
>