Hi Paul,
You just need to be a member of the right group and/or set permissions
right in udev rules afaik.
HTH,
Eli
For instance:
~$ cat /etc/udev/rules.d/99-ftdi-usb.rules
SUBSYSTEM=="usb",ACTION=="add",ATTRS{idVendor}=="0e50",MODE="0666"
Op vr 13 sep. 2019 om 00:49 schreef Paul E Ourada <[email protected]
>:
> Some of you may recognize me from earlier posts.
>
> I am working on an RPi3 B+ system running the most recent Raspbian Buster
> which has been updated. Results of uname -a:
>
> Linux tse09b 4.19.66-v7+ #1253 SMP Thu Aug 15 11:49:46 BST 2019 armv7l
> GNU/Linux
>
>
> The target FTDI devices are on a custom board on which there are four
> FT4232H/Q devices. Two are used for normal serial I/O such as rs232, 422,
> 485, and the others are used mostly for GPIO. The FTDI devices are
> hardwired to a Microchip USB hub, which is then connected to the RPi3 via
> cable. We keep track of which FTDI does what function by programming a
> FLASH eeprom. The /dev/ttyUSB* devices are all set up using udev rules,
> and everything seems to be playing nicely there wrt to group and
> permissions. All 16 interfaces get assigned to a /dev/ttyUSBx device via
> the kernel and the ftdi_sio driver, mode 664 and group plugdev. When I
> run minicom on /dev/ttyUSB[0-9]*, it runs fine. All of this part of the
> system seems to be copacetic.
>
> The issue is that I cannot open the FTDI devices used for GPIO via the
> methods that use a device handle or a description (ftdi_usb_open*() )
> unless I elevate permissions to sudo/root.
>
> To troubleshoot, I pulled the latest libftdi1 sources down, and built
> directly on the RPi3. Since I'm using the FT4232, I modified the product
> code to 0x6011. Then I used the example programs to see how they compared
> to my custom programs. They fared no better. I attempted to use the
> bitbang example, and I get an error like this:
>
> $./bitbang
>
> unable to open ftdi device: -4 (usb_open() failed)
>
>
> But when I run bitbang with sudo, it runs just fine. Other example
> programs have the same issue.
>
> $sudo ./bitbang
> ftdi open succeeded: 0
> enabling bitbang mode
> turning everything on
> turning everything off
> fe fd fb f7 ef df bf 7f
> fe fd fb f7 ef df bf 7f
> fe fd fb f7 ef df bf 7f
> fe fd fb f7 ef df bf 7f
> disabling bitbang mode
>
> Previously, I had been running on an RPi2 B+ system with Raspbian Jessie.
> I had no issues needing root access on this system. I used libftdi1-1.4 on
> both systems.
>
> Was there some change in udev or the kernel that messes w/the usb device
> permissions? I looked through the git log and saw that there is a new
> AUTO_DETACH_REATACH_SIO_MODULE enum and this gets initialized in the
> ftdi_init() function, just like the old AUTO_DETACH_SIO_MODULE.
>
> Thanks in Advance,
>
> Paul E Ourada
>
> Principal/Owner
>
> BluSkai Systems, LLC
>
> [email protected]
>
> (m) 303-396-2872
>
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