serial port discovery on a motion computing tablet

serial port discovery on a motion computing tablet

[Bret Hughes]

I am evaluating a motion computing LE1600 tablet for possible use with 
linux using Centos 4.4 since that is what we use for several servers and 
had the installation media handy.  This device uses a TouchKO serial 
touchscreen that has been used by linux in the past but the issue I am 
facing is that the bios does not expose the serial ports.  I spoke with 
an engineer at TouchKO familiar with the LE1600 project an he told me I 
would have to access the serial port via acpi.  Hmm says I, I guess I 
have some reading to do.  DO after a day or so of trying to get up to 
speed, I feel I can ask a fairly decent question or two. 

I found a lot of wacom references but as this touchscreen has ELO and 
Microtouch emulations I am hard pressed to figure out where to separate 
the detection of the port from the driver of the device.

What I need to do is get a connection to the serial port send a couple 
of commands to it to set the baud rate and emulation mode and then start 
X where the MuTouch Driver should work.

So.  Is this where I need to be asking acpi serial port questions?  I 
found a tc1100 prog somewhere but could not get it to compile 
correctly,  pacpidump compiled ok and I have the output of of acpidump 
if that helps.

Is this a doable deal?  I dled the current (2.6.9-42xxx I think) kernel 
tree from Centos as the last thing I did before leaving work today and 
will look at both how Centos (and the upstream provider) configure the 
kernel and if there are options that look like it might work. 

Googling today turned up several references to a 8250_acpi module and 
then I found a patch somewhere that indicated that it was no longer 
needed.  I wish I had looked at the kernel tree before leaving today but 
I thought i would ask for some tips to get me going and possibly add 
some known good hardware to the list before I am done.

Am I correct in thinking that I should be able to get a reference to the 
serial port through acpi on this box?  Any tips ?  Any testing that you 
guys would like done while I have this hardware?

TIA

Bret

Re: serial port discovery on a motion computing tablet

[Matthew Garrett]

On Tue, Mar 13, 2007 at 10:14:19PM -0500, Bret Hughes wrote:
> I am evaluating a motion computing LE1600 tablet for possible use with 
> linux using Centos 4.4 since that is what we use for several servers and 
> had the installation media handy.  This device uses a TouchKO serial 
> touchscreen that has been used by linux in the past but the issue I am 
> facing is that the bios does not expose the serial ports.  I spoke with 
> an engineer at TouchKO familiar with the LE1600 project an he told me I 
> would have to access the serial port via acpi.  Hmm says I, I guess I 
> have some reading to do.  DO after a day or so of trying to get up to 
> speed, I feel I can ask a fairly decent question or two. 

It sounds like it ought to be exposed via ACPIPNP. If you do cat 
/sys/bus/pnp/devices/*/id, do any of them look plausibly linked to the 
tablet device? If so, add the id to drivers/serial/8250_pnp.c, build it, 
see if that binds and gives you a serial port and if so send a patch.

-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: serial port discovery on a motion computing tablet

[Bret Hughes]

Matthew Garrett wrote:
> On Tue, Mar 13, 2007 at 10:14:19PM -0500, Bret Hughes wrote:
>   
>> I am evaluating a motion computing LE1600 tablet for possible use with 
>> linux using Centos 4.4 since that is what we use for several servers and 
>> had the installation media handy.  This device uses a TouchKO serial 
>> touchscreen that has been used by linux in the past but the issue I am 
>> facing is that the bios does not expose the serial ports.  I spoke with 
>> an engineer at TouchKO familiar with the LE1600 project an he told me I 
>> would have to access the serial port via acpi.  Hmm says I, I guess I 
>> have some reading to do.  DO after a day or so of trying to get up to 
>> speed, I feel I can ask a fairly decent question or two. 
>>     
>
> It sounds like it ought to be exposed via ACPIPNP. If you do cat 
> /sys/bus/pnp/devices/*/id, do any of them look plausibly linked to the 
> tablet device? If so, add the id to drivers/serial/8250_pnp.c, build it, 
> see if that binds and gives you a serial port and if so send a patch.
>   
Thanks for the help.

nothing there:
[root@localhost serial]# ls -a /sys/bus/pnp/devices/
.  ..

nothing loaded in drivers either:
[root@localhost serial]# ls -Ra /sys/bus/pnp/drivers/
/sys/bus/pnp/drivers/:
.  ..  ide  parport_pc  serial  system

/sys/bus/pnp/drivers/ide:
.  ..

/sys/bus/pnp/drivers/parport_pc:
.  ..

/sys/bus/pnp/drivers/serial:
.  ..

/sys/bus/pnp/drivers/system:
.  ..


Is there a module I should load before this works? perhaps a kernel 
recompile with some additional modules are needed?

Now that I am back at the office and looking at the kernel .config via 
make xconfig I see that 8250/16550 device discovery via ACPI namespace 
(SERIAL_8250_ACPI) is not enabled.  Is is safe to assume that it should 
be (go ahead and groan, I probably would) anything else that should be 
included? 

I am going to enable it and start a compile.  I guess we will see what 
kind of horsepower this little dude has.

Thanks again,

Bret

Re: serial port discovery on a motion computing tablet

[Matthew Garrett]

On Wed, Mar 14, 2007 at 09:29:05AM -0500, Bret Hughes wrote:
> nothing there:
> [root@localhost serial]# ls -a /sys/bus/pnp/devices/
> .  ..

That's, uh, surprising - is CONFIG_PNPACPI set?

> Now that I am back at the office and looking at the kernel .config via 
> make xconfig I see that 8250/16550 device discovery via ACPI namespace 
> (SERIAL_8250_ACPI) is not enabled.  Is is safe to assume that it should 
> be (go ahead and groan, I probably would) anything else that should be 
> included? 

Hm. How old is this kernel? SERIAL_8250_ACPI was merged into 
SERIAL_8250_PNP a while back.

-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: serial port discovery on a motion computing tablet

[Bret Hughes]

Matthew Garrett wrote:
> On Wed, Mar 14, 2007 at 09:29:05AM -0500, Bret Hughes wrote:
>   
>> nothing there:
>> [root@localhost serial]# ls -a /sys/bus/pnp/devices/
>> .  ..
>>     
>
> That's, uh, surprising - is CONFIG_PNPACPI set?
>
>   

not there:

[root@localhost linux-2.6.9]# grep PNPACPI .config
[root@localhost linux-2.6.9]#


>> Now that I am back at the office and looking at the kernel .config via 
>> make xconfig I see that 8250/16550 device discovery via ACPI namespace 
>> (SERIAL_8250_ACPI) is not enabled.  Is is safe to assume that it should 
>> be (go ahead and groan, I probably would) anything else that should be 
>> included? 
>>     
>
> Hm. How old is this kernel? SERIAL_8250_ACPI was merged into 
> SERIAL_8250_PNP a while back.
>
>   
2.6.9-42 Latest Centos kernel.  Too old?

Bret

Re: serial port discovery on a motion computing tablet

[Matthew Garrett]

On Wed, Mar 14, 2007 at 10:03:06AM -0500, Bret Hughes wrote:
> >That's, uh, surprising - is CONFIG_PNPACPI set?
> >
> >  
> 
> not there:
> 
> [root@localhost linux-2.6.9]# grep PNPACPI .config
> [root@localhost linux-2.6.9]#

Ok. You'll certainly need that.

> 2.6.9-42 Latest Centos kernel.  Too old?

Ouch. Life will probably be easier if you can use anything newer - I 
don't have any trees anywhere near that old now.

-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: serial port discovery on a motion computing tablet

[Bret Hughes]

Bret Hughes wrote:
>
>
> Matthew Garrett wrote:
>> On Wed, Mar 14, 2007 at 10:03:06AM -0500, Bret Hughes wrote:
>>    
>>> 2.6.9-42 Latest Centos kernel.  Too old?
>>>     
>>
>> Ouch. Life will probably be easier if you can use anything newer - I 
>> don't have any trees anywhere near that old now.
>>
>>   
> OK DL'ing latest stable from kernel.org now 2.6.20.3 .  I wonder what 
> will break on Centos without all the RH patches.  Mya have to punt and 
> go with one of the ever changing and never supported (for long) 
> fedoras.  Hmm.
>
> I'll let you know.
>

Woo hoo! I see my device it's id is TKO0001 just like the engr told me 
it would be.  At the time I had little to no idea what he was talking about.

On to look at the code and see how that works.

Bret

Re: serial port discovery on a motion computing tablet

[Matthew Garrett]

On Wed, Mar 14, 2007 at 01:37:55PM -0500, Bret Hughes wrote:

> Woo hoo! I see my device it's id is TKO0001 just like the engr told me 
> it would be.  At the time I had little to no idea what he was talking about.
> 
> On to look at the code and see how that works.

Something like the following should work, if you haven't already got it 
figured:

diff --git a/drivers/serial/8250_pnp.c b/drivers/serial/8250_pnp.c
index d3d6b82..c7b019b 100644
--- a/drivers/serial/8250_pnp.c
+++ b/drivers/serial/8250_pnp.c
@@ -340,6 +340,8 @@ static const struct pnp_device_id pnp_dev_table[] = {
 	{       "FUJ02B8",              0 },
 	{       "FUJ02B9",              0 },
 	{       "FUJ02BC",              0 },
+	/* TouchKO touchscreen */
+	{       "TKO0001",              0 },
 	/* Rockwell's (PORALiNK) 33600 INT PNP */
 	{	"WCI0003",		0	},
 	/* Unkown PnP modems */

and then just make sure that you have CONFIG_8250_PNP enabled. After 
that, it should just appear as a touchscreen. You may still need to 
perform some handshaking in the protocol interaction to get it working, 
but ideally that would be done in the X driver.
-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: serial port discovery on a motion computing tablet

[Bret Hughes]

Matthew Garrett wrote:
> On Wed, Mar 14, 2007 at 01:37:55PM -0500, Bret Hughes wrote:
>
>   
>> Woo hoo! I see my device it's id is TKO0001 just like the engr told me 
>> it would be.  At the time I had little to no idea what he was talking about.
>>
>> On to look at the code and see how that works.
>>     
>
> Something like the following should work, if you haven't already got it 
> figured:
>
> diff --git a/drivers/serial/8250_pnp.c b/drivers/serial/8250_pnp.c
> index d3d6b82..c7b019b 100644
> --- a/drivers/serial/8250_pnp.c
> +++ b/drivers/serial/8250_pnp.c
> @@ -340,6 +340,8 @@ static const struct pnp_device_id pnp_dev_table[] = {
>  	{       "FUJ02B8",              0 },
>  	{       "FUJ02B9",              0 },
>  	{       "FUJ02BC",              0 },
> +	/* TouchKO touchscreen */
> +	{       "TKO0001",              0 },
>  	/* Rockwell's (PORALiNK) 33600 INT PNP */
>  	{	"WCI0003",		0	},
>  	/* Unkown PnP modems */
>
> and then just make sure that you have CONFIG_8250_PNP enabled. After 
> that, it should just appear as a touchscreen. You may still need to 
> perform some handshaking in the protocol interaction to get it working, 
> but ideally that would be done in the X driver.
>   
[root@localhost serial]# diff 8250_pnp.c.orig 8250_pnp.c                        326,327c326,329

<       /* Wacom tablets */

<       {       "WACF004",              0       },

---

>       /* TouchKO tablets */

>       {       "TKO0001",              0       },

>       /* wacom tablets */

>       {       "wacf004",              0       },



As you can see, that is almost exactly what I did.  Once I recompiled, 
the device came up attached to ttyS0 irq5 just like the windows side 
does.  I am struggling a bit to get to where I can send the command to 
place the controller into Microtouch mode.  There is a little perl prog 
I got from the TouchKo site to do that and I thought I could make it 
work but it is kicking my butt.  The controller comes up at 38400 and if 
my notes are correct, going into MT mode should drop it to 9600  and a 
reconfig of the port needs to occur to continue talking to it.  Right 
now I cannot get any response back in perl at all.

I CAN use minicom to ping the controller and I get the expected response 
'Pass' but can't figure out how to send 0x0D  0x01 FMT 0x0D.   IIRC this 
only has to happen once and the controller will remember what mode its 
in.  Once  get it working in linux I bet it will be broken in Windows 
until it gets reset.   Hmm have to think about that. I have a feeling I 
am going to have to write something to toggle this dude so we can switch 
back and forth.

I'll dig in tomorrow and get the engineer back on the horn to see if he 
can help.  Is this something that this driver could/should do?  Is there 
some other place that the kernel or a module can set this up so the user 
does not have to worry about it or is that beyond the scope of what is 
done in kernel space?

Once I get it working I'll post again with final details just so those 
that come behind me will have a chance of not reinventing the wheel but 
I think as far as the acpi side goes you got me going.

Thanks again.

Bret

Re: serial port discovery on a motion computing tablet

[Matthew Garrett]

It would be possible to do it in the kernel, but I think that would 
effectively require a new serial driver. It's probably easier to do it 
in userspace, either in an X driver or gpm or whatever's being used to 
accept input. Beyond that, I'm afraid I'm not sure what the problem is 
right now!

-- 
Matthew Garrett | mjg59@srcf.ucam.org