platform, pnp and mmc bus

[David Zeuthen]

On Sat, 2005-01-29 at 02:00 +0100, Pierre Ossman wrote:
> I'm trying to make the necessary additions to HAL to allow it to detect 
> mmc cards. This has proven to be a bit more work than I first thought.
> 

I'm not sure exactly what you mean by mmc cards? Can you clarify a bit
more?

> Step 1:
> 
> The MMC cards reside on their own bus, so I need to add a new bus type. 
> Using the other bus handlers in hal this wasn't too difficult.
> 

Right.

> Step 2:
> 
> Devices too deep in the sysfs structure are expected to have a parent 
> already in the hal tree. This was not true for my mmc controller since 
> it is a lpc device. So it seemed I had to fix that into the tree first.
> Studying the platform bus handler I found that it is hardcoded to only 
> accept floppy drives. A couple of if:s around critical sections and I 
> got it accepting all platform devices.
> 
> This got it fairly up and running. I got the controller in the tree and 
> mmc cards, including their block devices, were correctly detected.
> Then I ran into some more problems. The driver can also be used in PNP 
> mode, which means it shows up in the pnp bus. So I guess there'll be a:
> 
> Step 3:
> 
> Create a pnp bus handler.
> 

This already exists on HEAD.

> Now for the actual questions. So far I've just been playing around to 
> get my stuff working and it's a bit of a mess. Has anyone looked at 
> these problems and perhaps already has a plan for handling them? 
> Otherwise I could continue working on it and get a more clean version.
> 
> The pnp is also a problem. It doesn't really correspond to a physical 
> bus (platform doesn't really either, but it's closer at least). But pnp 
> devices are in every case I can think of, devices that belong on the 
> platform bus. So should the pnp bus be a seperate bus in hal or should 
> we try to group it with the platform bus?
> 

Not sure until I understand the problem domain yet. Can you possibly
post
the output of 'tree /sys' and describe how it works today?

Thanks,
David


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