From: "Steven J. Ackerman" <steve@acscontrol.com>
To: 'Greg KH' <gregkh@linuxfoundation.org>
Cc: "'Bjørn Mork'" <bjorn@mork.no>,
linux-usb@vger.kernel.org, linux-serial@vger.kernel.org
Subject: RE: Linux USB Serial
Date: Mon, 17 Sep 2012 18:27:40 -0400 [thread overview]
Message-ID: <00c501cd9523$a68524f0$f38f6ed0$@acscontrol.com> (raw)
In-Reply-To: <20120917220813.GA7780@kroah.com>
> That's fine, the cdc-acm interface will work for that.
>
> But is your device really a CDC ACM device? Or is it something else?
The device is a 3.5" color LCD display with touchscreen that can act as a
serial
terminal. It just needs to be able to send and receive characters over an
USB
serial port.
> You wouldn't, if you use the ftdi serial chip in your device. Which
> begs me to ask, what type of usb to serial chip is in your device? What
> protocol does it use to talk to the host?
The device is based upon a Renesas RX62N processor which has a USB interface
in it. The protocol is supposedly based upon the CDC - a control endpoint
and
two bulk endpoints. The software was derived from a demo supplied by the
manufacturer - and it does work under Windows. The device enumerates as
a COM port and you can interact with the display using a program or a
terminal
emulator. Unfortunately the chip vendor doesn't have any support for Linux.
> They shouldn't have to do that, once we get it working, they get the
> update automatically from their distro. But if you can't test any
> changes we make to try to get this to work, there's not much we can do
> here, right?
>
I guess that I'm operating under the assumption that there is something
wrong on my end - an incorrectly configured descriptor for example. It
appears
the other USB serial devices work OK under Linux - even without custom
drivers. I'm hoping that I can find an error message somewhere that will
tell me what I'm doing wrong - or that somebody who has been down that
path before can't point to something obvious - like Bjrn did.
> Oh, and fix that descriptor up in your firmware, that might solve
> everything :)
Going through the USB CDC documentation between e-mails. Other than
the incorrect bInterfaceSubClass value - which I have corrected - nothing
else seems wrong.
>
> Hope this helps,
>
> greg k-h
Always appreciate your assistance - thank you!
Steven J. Ackerman, Consultant
ACS, Sarasota, FL
http://www.acscontrol.com
mailto:steve@acscontrol.com
next prev parent reply other threads:[~2012-09-17 22:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-17 19:28 Linux USB Serial Steven J. Ackerman
2012-09-17 20:07 ` Bjørn Mork
2012-09-17 21:07 ` Steven J. Ackerman
2012-09-17 21:41 ` Greg KH
2012-09-17 21:56 ` Steven J. Ackerman
2012-09-17 22:08 ` 'Greg KH'
2012-09-17 22:27 ` Steven J. Ackerman [this message]
2012-09-18 6:46 ` Oliver Neukum
[not found] ` <5789366.GGq3fAeCyr-ugxBuEnWX9yG/4A2pS7c2Q@public.gmane.org>
2012-09-18 14:00 ` Steven J. Ackerman
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