From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bin Liu Date: Tue, 9 Sep 2014 09:05:23 -0500 Subject: [U-Boot] [PATCH v1 0/2] usb: dfu: am335x: allow dfu in fullspeed mode only In-Reply-To: <20140909154309.6609949a@amdc2363> References: <1410266224-4051-1-git-send-email-hs@denx.de> <20140909154309.6609949a@amdc2363> Message-ID: <540F0923.7060406@ti.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 >> Cc: Lukasz Majewski >> Cc: Marek Vasut >> Cc: Liu Bin >> Cc: Lukas Stockmann >> >> 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(-) >> > > >