I2C with bus muxes

I2C with bus muxes

[Ben Warren]

Hello,

Has anyone implemented devices like the Philips PCA954x I2C bus muxes
under the /sysfs device model?  I have some optical transponders on my
board that through the wisdom of some committee all have the same fixed
I2C address.  To get around this, we put them behind muxes, creating
'virtual' I2C busses.  I imagine this could be modeled something like
the USB hub model, but that's just a first stab.

regards,
Ben

Re: I2C with bus muxes

[Travis B. Sawyer]

Ben Warren wrote:
> Hello,
>
> Has anyone implemented devices like the Philips PCA954x I2C bus muxes
> under the /sysfs device model?  I have some optical transponders on my
> board that through the wisdom of some committee all have the same fixed
> I2C address.  To get around this, we put them behind muxes, creating
> 'virtual' I2C busses.  I imagine this could be modeled something like
> the USB hub model, but that's just a first stab.
>
>   
Ben:

I have a driver for 2.4.x that works with our SFP/XFPs.  We also have a 
bunch of other 'stuff'
hanging off of muxes.  I haven't given it a go on 2.6, but I have it 
compiled and it doesn't complain on
startup.

Not sure if I should send it here, as it won't be in patch form...

Lemme know if you want a look-see,

Travis

Re: I2C with bus muxes

[Ben Warren]

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Thanks Travis,

 On Thu, 2006-07-20 at 11:22 -0400, Travis B. Sawyer wrote:


> I have a driver for 2.4.x that works with our SFP/XFPs.  We also have a 
> bunch of other 'stuff'
> hanging off of muxes.  I haven't given it a go on 2.6, but I have it 
> compiled and it doesn't complain on
> startup.
> 

I'm happy to see anything.  Due to time constraints, I may end up doing
most of my devices stuff 2.4-style anyway, at least for now, since I
have a much firmer grasp on the concepts...  


> Not sure if I should send it here, as it won't be in patch form...
> 

Please pass your code along whenever it's convenient.  Your call whether
to the list or just to me.

Cheers,
Ben

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Re: I2C with bus muxes

[Kumar Gala]

On Jul 20, 2006, at 10:16 AM, Ben Warren wrote:

> Hello,
>
> Has anyone implemented devices like the Philips PCA954x I2C bus muxes
> under the /sysfs device model?  I have some optical transponders on my
> board that through the wisdom of some committee all have the same  
> fixed
> I2C address.  To get around this, we put them behind muxes, creating
> 'virtual' I2C busses.  I imagine this could be modeled something like
> the USB hub model, but that's just a first stab.

I'm pretty sure I submitted a set of patches for this upstream.   
However there was some desire to hold off until some other changes.

http://marc.theaimsgroup.com/?l=linux-kernel&m=114376108231285&w=2
http://marc.theaimsgroup.com/?t=114316214100001&r=1&w=2

- kumar

Re: I2C with bus muxes

[Ben Warren]

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Way cool!  Thanks a lot.  I'll try it out when my hardware comes in...

regards,
Ben

 On Thu, 2006-07-20 at 13:51 -0500, Kumar Gala wrote:

> On Jul 20, 2006, at 10:16 AM, Ben Warren wrote:
> 
> > Hello,
> >
> > Has anyone implemented devices like the Philips PCA954x I2C bus muxes
> > under the /sysfs device model?  I have some optical transponders on my
> > board that through the wisdom of some committee all have the same  
> > fixed
> > I2C address.  To get around this, we put them behind muxes, creating
> > 'virtual' I2C busses.  I imagine this could be modeled something like
> > the USB hub model, but that's just a first stab.
> 
> I'm pretty sure I submitted a set of patches for this upstream.   
> However there was some desire to hold off until some other changes.
> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=114376108231285&w=2
> http://marc.theaimsgroup.com/?t=114316214100001&r=1&w=2
> 
> - kumar
> 
> 

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Re: I2C with bus muxes

[Kumar Gala]

On Jul 20, 2006, at 2:01 PM, Ben Warren wrote:

> Way cool!  Thanks a lot.  I'll try it out when my hardware comes in...

Cool, I no longer have access the the system that used the mux, so  
when I rework the driver can I get you to test it?

- k