[Pkg-raspi-maintainers] Serial on Raspi 3

[Thomas Wuensche]

Hello, thank you for your reply. To me it does not seem
like an upstream problem, but as a raspi specific mess
with the serial port hardware setup, concretely the question,
which of the two uarts is mapped to the port pins.

In my case the miniuart seems to be mapped to the port
pins (and can't be changed to 115200 8n1, which is what
I would like to use). If I output to ttyS1 (which I assume
to be the miniuart) I can see signals on the port pins.

The full uart (pl011) seems not to be mapped to the pins.
I can change parameters with stty, but do not see any
signals on the pins when writing to that port (ttyAMA0).

As a side note I have the impression that changes to
config.txt are without effect (for example "enable_uart").
I understand that should be read and processed by the
binary module to set up hardware, right? Whom can I contact
regarding behaviour of the binary module?

Raspbian seems to deal with such things with device tree
overlays to configure the hardware on boot, but I can't
see an equivalent on debian.

Any more hints? Thank you!

Best regards,

Thomas Wuensche

Am 18.02.2018 um 22:08 schrieb Michael Stapelberg:
> [+cc pkg-raspi-maintainers, in case someone else has run into this issue
> before]
> 
> I have only verified the serial port works with 115200 8n1.
> 
> Please report an upstream Linux kernel bug, as there are no
> Debian-specific changes in this area of the kernel.
> 
> Sorry I can’t be of more help,
> 
> On Sun, Feb 18, 2018 at 11:59 AM, Thomas Wuensche
> <wuensche at ems-wuensche.com <mailto:wuensche at ems-wuensche.com>> wrote:
> 
>     Hello,
> 
>     after having troubles with the unclear kernel upgrade structures
>     on raspbian I switched to your debian image. However I have troubles
>     with the serial port - hope you can help.
> 
>     My project needs serial data from a sensor module. If I go with
>     serial-over-usb it works, however not with direct connection.
> 
>     After a number of fruitless tries I have the following constellation:
> 
>     If I output serial data to /dev/ttyS1 I can see the data on the port
>     lines with the oscilloscope and read back the data from that port.
>     However when trying to switch line parameters, stty does not come
>     back. So I can not adjust the required terminal parameters.
> 
>     If I try the same with /dev/ttyAMA0 I do not see anything on the
>     port and can't read back data. However changing port parameters
>     works. In message log I have a line:
> 
>     uart-pl011 3f201000.serial: no DMA platform data
> 
>     I have tried both with and without "enable_uart=1" in
>     /boot/firmware/config.txt
> 
>     As I'm playing for weeks now with that issue and no result I would
>     be glad if you could help me!
> 
>     Best regards,
> 
>     Thomas Wuensche
>     --
>     EMS Dr. Thomas Wuensche e.K.
>     Sonnenhang 3
>     85304 Ilmmuenster
>     HR Ingolstadt, HRA 170106
> 
>     Phone: +49-8441-490260 <tel:%2B49-8441-490260>
>     Fax  : +49-8441-81860 <tel:%2B49-8441-81860>
>     http://www.ems-wuensche.com
> 
> 
> 
> 
> -- 
> Best regards,
> Michael
-- 
EMS Dr. Thomas Wuensche e.K.
Sonnenhang 3
85304 Ilmmuenster
HR Ingolstadt, HRA 170106

Phone: +49-8441-490260
Fax  : +49-8441-81860
http://www.ems-wuensche.com