[lcd4linux] LCD4linux on NSLU2

[Vincent P. <vp...@fr...>]

Hi all,
 
I'am trying to play with lcd4linux and my LCD HD44780 20x4 on my
OpenSlug 2.7 Linksys NSLU2 (http://www.nslu2-linux.org/).
I'am not using the same circuit as described here :
http://chezphil.org/slugterm/
I'am using a cheap USB to // converter with USS720 Lucent chip.
This chip is supported by Linux and the driver is available in the
kernel source tree (drivers/usb/misc/uss720.c).
 
As I didn't find much info on the net about uss720 and LCD (only here :
http://www.g-cipher.net/~reboots/projects/lcd/index.html) , I'll first
sum up my successful experience using this chip on my Gentoo PC, and
then ask my question about the NSLU2 port right after :-)
 
Hardware :
PIII/600 PC running Gentoo
 
I bought a cheap USB to // converted using a USS720 Lucent chip (USS720E
is marked on the chip). The converter model is Infowave USP-1284
(Infowave Wireless Messaging Inc. P/N 901-0030) But other model use this
chip (see here :
http://www.g-cipher.net/~reboots/projects/lcd/index.html).
I've connected my HD44780 generic LCD (16 pins) to the centronic plug
following the winamp wiring.
 
Software :
 
First, you must activate support for USS720 and PPDEV in you kernel. I
selected them as Modules.
 
Rem : Parallel port should be already activated on your PC.
 
In Kernel configuration menu select :
 
<*> Parallel port support 
[*] IEEE 1284 transfer modes (don't know if it's mandatory or not)
 
<M> Support for user-space parallel port device drivers
 
<M> USS720 parport driver
 
Recompile, install new kernel (if necessary) and modules, reboot.
 
Plug the adaptor to USB
 
If you use module as me, you need to :
modprobe ppdev
modprobe uss720
 
You should have with dmesg :
[.]
ppdev: user-space parallel port driver
lp1: using parport1 (polling).
usbcore: registered new driver uss720
drivers/usb/misc/uss720.c: v0.6:USB Parport Cable driver for Cables
using the Lucent Technologies USS720 Chip
drivers/usb/misc/uss720.c: NOTE: this is a special purpose driver to
allow nonstandard
drivers/usb/misc/uss720.c: protocols (eg. bitbang) over USS720 usb to
parallel cables
drivers/usb/misc/uss720.c: If you just want to connect to a printer, use
usblp insteadDisplay 
 
LCD4linux conf :
 
I use the following configuration :
 
HD44780-20x4 {
    Driver 'HD44780'
    Model 'Generic'
    Port '/dev/parport1'
    Bits '8'
    Size '20x4'
    Wire {
        RW        'AUTOFD'
        RS        'INIT'
        ENABLE    'STROBE'
        ENABLE2   'GND'
        BACKLIGHT 'GND'
        GPO       'GND'
    }
}
 
then : lcd4linux -Fvv
 
So, in my case, everything fine, the welcome message is displayed and
the test messages are shown.
 
Ok. Now I want do to the same on my NSLU2.
 
I configure the kernel to support parallel port. Compiled uss720.ko,
parport.ko and
ppdev.ko
After registered the uss720 and parport modules and plugged the
converter I get :
 
usb 3-1.3: new full speed USB device using ohci_hcd and address 7
uss720: probe: vendor id 0x47e, device id 0x1001
uss720: set inteface result 0
uss720: (C) 1999 by Thomas Sailer, <sa...@if...>
uss720: reg: 78 0c 23 00 00 00 01
uss720: epaddr 131 interval 1
 
root@SLUG:~# more /proc/sys/dev/parport/parport0/modes
PCSPP,TRISTATE,COMPAT,EPP,ECP
 
And I get a /dev/parport0 device.
 
I'v tried to compile LCD4linux but get an error about rep_nop in
udelay.c.
As this fct is only for x86 and my slug run an Intel Xscale, I've
commented out the line. 
Even if lcd4linux compiled fine then it's not running ok . 
 
With same configuration as above I get :
 
root@SLUG:~/lcd4linux-0.10.0-RC1# ./lcd4linux -Fvv
Version 0.10.0-RC1 starting
plugin_cfg.c: Variable minute = '60000' (60000.000000)
plugin_cfg.c: Variable tack = '100' (100.000000)
plugin_cfg.c: Variable tick = '500' (500.000000)
i2c_sensors: unable to autodetect i2c sensors!
[POP3] No 'Plugin:POP3.server2' entry from /etc/lcd4linux.conf,
disabling POP3 account #2
[POP3] No 'Plugin:POP3.server3' entry from /etc/lcd4linux.conf,
disabling POP3 account #3
[POP3] 1 POP3 accounts have been succesfully defined
lcd4linux.c: initializing driver HD44780
HD44780: using model 'generic'
HD44780: using parallel port
HD44780: using 1 controller(s)
HD44780: using 8 bit mode
udelay: The file 'include/asm/msr.h' was missing at compile time.
udelay: Even if your CPU supports TSC, it will not be used!
udelay: You *really* should install msr.h and recompile LCD4linux!
udelay: using gettimeofday() delay loop
HD44780: using ppdev /dev/parport0
HD44780: wiring: [DISPLAY:RS]<==>[PARPORT:INIT]
HD44780: wiring: [DISPLAY:RW]<==>[PARPORT:AUTOFD]
HD44780: wiring: [DISPLAY:ENABLE]<==>[PARPORT:STROBE]
HD44780: wiring: [DISPLAY:ENABLE2]<==>[PARPORT:GND]
HD44780: wiring: [DISPLAY:GPO]<==>[PARPORT:GND]
HD44780: not using busy-flag checking
HD44780: reserving 1 of 8 user-defined characters for icons
initializing layout 'Default'
lcd4linux.c: starting main loop
 
But nothing on the LCD :-( .....
 
Here is my questions :
Does some one compile lcd4linux on armeb platform ?
Is rep_nop mandatory ? I've seen that some people provide a patch for
other arch but can't find for armed.
Is lcd4linux big-endian/little-endian dependent ? As the NSLU2 is big
endian I was wondering .
I've also seen that uss720.c is v6 on my PC and v5 on my NSLU2, does
some one have experience with this 
driver (I know it's not the good mailing list for this question) ?
 
Thanks for your help,
Best regards,
Vincent.
PS: Sorry for my broken english